NEWSLETTER OF THE SECTION FOR MAGNETIC RESONANCE TECHNOLOGISTS … · 2010-10-20 · 12 Low- and...

Number 42

2002 Issue 3

IN THIS ISSUE2 Editor’s Letter2 SMRT Educational Seminars Update3 SMRT 12th Annual Meeting

Announcement4 SMRT External Liaison Report5 Your Vote Counts!5 News for ARRT Registered Members

Annual Meeting Highlights6 2002 2nd Place Proffered Paper–

Clinical Oral PresentationThe Effect of Peripheral ArterialOcclusive Disease on Venous Filling inGadolinium-Enhanced MRA of theDistal Aorta and Lower Extremities

7 2002 2nd Place Proffered Paper–Research Oral PresentationCoronary Magnetic ResonanceAngiography: New Non-ContrastTechnique

8 2002 2nd Place Proffered Paper–Clinical PosterMRI Breast Needle Localization

9 2002 2nd Place Proffered Paper–Research PosterDiagnostic MRI of Zoo Animals

Regional News10 Report on the SMRT Northeast

Regional Seminar11 Upcoming Regional Seminars:

Northeast Regional EducationalSeminarSoutheast Regional EducationalSeminarEastern Canada Regional EducationalSeminar

Information for You12 Low- and Mid-field MRI13 MRI Safety17 Gradient Echo Imaging Contrast

Phenomenology20 SMRT/ISMRM Calendar20 Awards Committee Update20 Highlight Your Site!

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NEWSLETTER OF THE SECTION FOR MAGNETIC RESONANCE TECHNOLOGISTS

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President’s LetterJohn A. Koveleski, R.T. (R)(MR)

ith this year’s Annual Meeting

behind us, its back to thereal world of dailyscanning. The ExecutiveCommittee and PolicyBoard have already beento work on SMRT activitiessince the meeting in May.

The Executive Committee had it’sfirst telephone conference in July andnew issues were discussed.

Maureen Hood, our ExternalRelations Committee Chair, is busy asusual. She will be attending the HealthProfessions Network meeting in Madison,Wisconsin, in September representingSMRT. We’ve also created a subcommit-tee in the External Relations Committee.Muriel Cockburn, Policy Board member,from Glasgow, Scotland, will head thenew Global Development Subcommitteeand will interact with other MRItechnologist groups throughout theworld. Muriel will also try to generateinterest in parts of the world where theSMRT has little involvement. This is anopportunity for the SMRT to provide thequality education that we’re all familiarwith to other technologists.

Laurian Rohoman, from MontrealGeneral Hospital, is the Program Chairfor next year’s Annual Meeting inToronto, Ontario, Canada. Laurian andthe 2003 Program Committee arealready hard at work organizing theagenda for next year’s meeting. It maysound a bit premature but a lot of workgoes into organizing a meeting of thismagnitude. We’re strongly encouragingelectronic abstract submission for theToronto meeting. Laurie reports that shehopes to have a completed programready by this fall.

Julia Lowe, from Indianapolis,Indiana, is the Education Chair for thisyear. The Education Committee is a verybusy committee within the SMRT. Juliareports that the Joint Review Committeefor Education in Radiologic Technology(JRCERT) has finalized their standardsfor MRI course curriculum and they will

take effect on 1 January 2003. TheSMRT offered input and assisted theJRCERT in developing a more standard-ized curriculum for MR technologyprograms. Julia’s committee will be busyin the near future once the abstracts forToronto have been submitted.

Heidi Berns, SMRT Past President,from Iowa and the Chair of the Nomi-nations Committee and the AwardsCommittee. Heidi is currently gather-ing names of candidates for the SMRTPolicy Board election, which will beheld in the fall. She’s also solicitingcandidates for the Crues-KresselAward. If you would like to nominatea colleague, please e-mail or call Heidiimmediately.

Cindy Comeau, from New York City,is our Regional Seminars CommitteeChair for this year. Cindy reported thatMark Spooner hosted a very successfulNortheast Regional in Utica, New York,in June. Future Regional Seminars willbe in Atlanta and Montreal in Septem-ber. It’s a lot of work but very rewardingto host a Regional.

The local Chairperson of theseminar will work with Cindy inorganizing the seminar and will alsoreceive a free one-year membership tothe SMRT. It was nice to have aRegional in central New York and welook forward to Laurian Rohomanhosting our first Eastern CanadaRegional. The SMRT Local Chapterorganizers in Atlanta always do aspectacular job in hosting theirRegional as well. I look forward toseeing many of you in Atlanta andMontreal.

Bobbie Burrow, from Atlanta,Georgia, is the Local Chapter CommitteeChair. There are currently eight localchapters. They are Atlanta (Georgia),Iowa City (Iowa), Springfield (Illinois),Kansas City (Missouri), Wichita (Kan-sas), Central Pennsylvania, RhodeIsland, and Australia/New Zealand.Drop Bobbie a line if you’re interested instarting your own local chapter.

NUMBER 42 2002 ISSUE 3 S i g n a l s 2

hank you for all your wonderful comments about the Neuroanatomy

home study. We hope that you enjoy theMRI of the Ankle and Foot issue just aswell. Because of your suggestions, thePublications Committee will strive toprovide one anatomy issue per year!A change you will notice, starting with theissue, MRI of the Foot and Ankle, is that

the quiz answer sheet has been separated from the booklet.This is a cost effective method to facilitate any changesthat may need to be made to question sets when theseissues are reprinted in the future. You now have in yourhands, MR Imaging of the Breast, which is lengthy, but ispacked full of much needed information. After completingit, you will have grasped the very latest MR imagingtechniques used for the breast. The remaining issue of theyear will be Diffusion Weighted Imaging of the Brain. Thisissue is a short and sweet synopsis of a very useful tech-nique. Please feel free to contact the SMRT office or me at:[email protected] if you would like to participate inproducing a home study by reviewing material, authoringquestions, or proofing the text. As always your suggestionsand comments are welcomed. �

G

Editor’s LetterJulie Strandt-Peay, B.S.M., R.T. (R)(MR)

reetings, This issue of Signals

is packed with topicalinformation for you!SMRT President, JohnKoveleski, brings us upto date on activitiessince the Annual

Meeting. Check out what your electedPolicy Board members are doing asthey serve to chair their standingcommittees. Publication Chair, KellyBaron, announces the newest homestudy and a change in the question andanswer format. Laurian Rohoman,2003 Program Chair, has alreadyinitiated the planning course for nextyear’s meeting.

News from the imaging world isbrought to you by Maureen Hood,SMRT External Liaison. See what isoccurring that may affect you or yourwork place. Also, for those of you whoare ARRT Registered, be sure to keepup to date with the latest developments.

You are responsible for theprogress and direction of the SMRT byyour informed vote. Don’t miss out onthis opportunity to select the leaders

T

Update on

SMRT Educational SeminarsKelly D. Baron B.S., R.T. (R)(MR), Chair, SMRT Publications Committee

Are you a new SMRT member?Did you miss an earlier issue?All of the previously publishedSMRT Educational Seminarshome studies are now availablefor purchase by SMRT Membersin good standing for onlyUS$20 per issue.For more SMRT membershipinformation or an order form,please e-mail: [email protected] visit the SMRT Website:http://www.ismrm.org/smrt

Scott Kurdilla, from Pittsburgh, isthe Chair of the By-Laws Committee.Scott was busy in Honolulu rounding upsome new faces to serve on his committee.

Ray Cruz, from the state ofWashington, is returning for his secondyear as Membership Committee Chair.Ray reports that the SMRT has 1181members and also that the renewalrate dropped by 5% from last year. Hiscommittee has formulated a question-naire that will be mailed to those whohave dropped their membership in aneffort to ascertain their reasons for notcontinuing their membership. ForUS$75 each year, the SMRT has so muchto offer. Examples include reducedregistration fees for Regional and AnnualSMRT educational meetings, the Signalsnewsletter, and the ever-popular SMRTEducational Seminars (AKA HomeStudies). The home studies offerAmerican technologists all the creditsthey need to satisfy their certificationthough the ARRT plus you may learnsomething by reading these as well!

Kelly Baron, from Indiana, chairsthe Publications Committee and JulieStrandt-Peay is the Signals Editor.Kudos goes out to both Kelly and Juliefor their efforts in two of the mostdemanding roles in the SMRT. By now,you should have received your MRI of theAnkle and Foot home study. Make sureyou complete the quiz and return it tothe SMRT. It’s worth three credits.

Maureen Ainslie, President-Elect,from the Duke Image Analysis Lab, is inthe process of creating a new feature onthe SMRT Website. “Highlight Your Site”which will give SMRT members theopportunity to tell the SMRT communityabout their site. Look for this in the nearfuture. Drop an e-mail to Maureen(maureen.ainslie@ duke.edu) if you’dlike your site featured.

As you can see, it’s been a busy fewmonths for the SMRT Board since ourmeeting in Honolulu in May. As volun-teers, we have to find the time in ourbusy schedules to do our SMRT responsi-bilities. We welcome comments andcontributions to our organization. Whynot get involved yourself? It’s a greatway to contribute to the MR world andalso a good way to make new friends.

As always, please feel free to contactme at: [email protected] if you have anyquestions or concerns. �

President’s Letter continued

The SMRT gratefully acknowledges

MRI Devices CorporationWaukesha, Wisconsin, USA

for their generous support of the2002 SMRT Educational

Seminars home study series. Thisdonation demonstrates the

consideration of MRI DevicesCorporation for quality MR

technologist education.Contact information can be found

at: www.mridevices.com

The Student Scope submissions previously fea-tured in Signals will be moving to the SMRTWebsite http://www.ismrm.org/smrt. The Edu-cation Committee is spearheading this projectand revising the guidelines to aide students withtheir submission. Look for this popular featureon the SMRT Website in early 2003! �

and potential award recipients of yourorganization.

We continue to share with you theinformation from the Annual Meet-ing. In this issue of Signals you willfind the abstracts of those presenterswho were awarded second place in thevarious categories. Our educationalperspective continues with an articleby Bill Faulkner addressing low-fieldscanners. A generous contributor to theSMRT, Frank Shellock, shares hisresearch on devices used forinterventional studies. MR technolo-gist, Jim Hamilton, shares his viewson Gradient Echo Imaging.

Regional Seminar news is broughtto us by Mark Spooner. Be sure tocheck for upcoming Regional Seminarsnear you on the SMRT Website. Thewebsite is in the process of beingexpanded to include an electronic copyof Signals, an area to boast about yoursite, and opportunities for students toshare their work. And last of all, notethe upcoming meetings and activitiesthat are of interest to you....you don’twant to miss any of these greatofferings. �


Announcing the SMRT 12th Annual MeetingLaurian Rohoman, R.T. (R)(MR), 2003 Program Committee Chair

The SMRT would liketo invite technologists

from around the world toattend the TwelfthAnnual Meeting of theSection for MagneticResonance Technologists.This meeting will be held9 to 11 May 2003 in

conjunction with the Eleventh ScientificMeeting and Exhibition of the Interna-tional Society for Magnetic Resonancein Medicine at the Metro TorontoConvention Centre in Toronto, Ontario,Canada.

The goal of the SMRT is to providequality educational opportunities for theMR technologist and to establish andmaintain a high level of professionalismin the field. MR technologists are facedwith many challenges: keeping abreastof advancing technology, the everexpanding field of MR, coping with theday-to-day problems of technologistshortages, and a continuously increasingworkload. We must strive to maintain ahigh standard of performance inaddition to continuing to provideoptimal patient care.

The agenda of the Annual Meetingwill be geared toward bringing tech-nologists the latest information ondevelopments in MR technology thatwill be of value whether one is from aclinical or research site. The topicschosen and speakers invited will bebased on the comments and feedbackreceived from the attendees of previousannual meetings.

The Meeting will commence witha Poster Exhibit and Walking TourReception at 18:30, on Friday evening9 May 2003. This will be a great wayto learn about new and innovativeclinical and research studies that arebeing performed by our colleaguesworldwide. It also provides a greatopportunity to interact with the posterauthors and to meet and share ideaswith fellow technologists from aroundthe world.

An important aspect of the meetingremains the submission of abstractsfor oral and poster presentations bytechnologists. Proffered papers will beinterlaced throughout the sessions. Westrongly encourage all technologists to

participate in the meeting by submittingan oral or poster abstract. The deadlinefor SMRT abstract submissions will be17 January 2003. Again this year, theSMRT will continue with the onlineprocess for abstract submissions. TheSMRT experienced a 100% electronicsubmission rate for the 2002 meetingabstracts. Online abstract submissionwill be available on the SMRT Website:http//www.ismrm.org/smrt. Theproffered papers and posters have beenone of the highlights of past SMRTmeetings.

The SMRT Annual BusinessMeeting will be held on Saturday,10 May, giving members a chance toactively participate in the professionalMR organization.

As Chair of the 2003 ProgramCommittee, it is my pleasure to inviteyou to attend this meeting and to jointhe SMRT in bringing to technologists,an exciting, quality educationalweekend in the wonderful city ofToronto. �


SMRT External Liaison ReportMaureen Hood, B.S.N., R.N., R.T. (R)(MR) External Liaison Chair

T he SMRT is a member of the

Associated SciencesConsortium of theRadiological Society ofNorth America (RSNA)that works hard eachyear to present a varietyof courses geared to the

disciplines that work within the radiol-ogy or diagnostic imaging fields. TheRSNA Annual Meeting in Chicago iscoming up December 1-6, 2002. Themini-symposia and refresher coursesput on by the Associated SciencesConsortium have been a huge successsince switching to the Sunday throughFriday format. The RSNA board wasvery pleased with the quality of thepresentations last year. This year’s mini-symposia are going to be covering thenew combined PET/CT scanners withstrategies on how to manage them. TheAssociated Sciences Consortium has abooth at the RSNA staffed by volunteersfrom the SMRT as much as possible.If you are attending the RSNA, pleasesupport the Associated Sciences presen-tations and stop by the booth to say hi.

The SMRT continues to be an activemember of the Health ProfessionsNetwork (HPN), an association of alliedhealth societies dedicated to communi-cation, consensus, and advocacy onbehalf of allied health professionals.Radiology technologists (including MRtechnologists) were highlighted as the

“Allied Health Profession of the Month”for June 2002. To view the article, go tohttp://www.healthpronet.org/ahp_month/06_02.html. Also included on the HPNwebsite is a listing of activities and linksof interest including conferences,scholarship opportunities, and otherallied health links.

Among its many activities, the HPNhas been bringing people together towork on the allied health workforceshortage. The American Society forHealthcare Human Resource Adminis-tration (ASHHRA) has been studyingthe American workforce as well as theBureau of Health Professions. Theyfound that one in every ten Americansin the workforce is employed inhealthcare, with forty percent of thehealthcare workforce employed inhospitals. The demand for healthcareworkers is expected to continue to growthrough the year 2010. Currently, thereis a shortage of all healthcare workerswith the greatest shortages found withpharmacists, radiological technologists,billing/coding clerks, laboratory tech-nologists, registered nurses, housekeep-ing and maintenance personnel. Unfor-tunately no one has a simple solution tothe workforce challenge although theAmerican Hospital Association hasidentified that the shortage of health-care professionals is at crisis levels.Current recommendations by ASHHRAinclude increasing recognition of peopleas a key strategic resource, investing inretention of employees, recruitment anddevelopment of care givers, increasinginterest in healthcare career and educa-tional programs, and making healthcaresystems the employers of choice. TheAmerican Hospital Association has anew report titled “In Our Hands: HowHospital Leaders Can Build a ThrivingWorkforce,” which can be found at:http://www.hospitalconnect. com/ahakey_issues/ workforce index.html. Thisis an excellent source of strategies forhospitals battling the workforceshortage.

Another resource our involvementwith the HPN allows us to enjoy is thesharing of information for educationprograms in allied health. The WorldHealth Organization’s “Healthy People

2010” initiative has a big push towardincreasing culturally competent care.Educational programs need to incorpo-rate cultural competencies into theircurricula. The Center for HealthProfessions, University of Californiaat San Francisco, provides access toeducators its new curriculum “TowardCulturally Competent Care: A Toolboxfor Teaching Communication Strategies.”The curriculum is designed to teachskills for practical communicationbetween health care providers andpatients. The curriculum includes bothdidactic and lab exercises. This curricu-lum is available through request byvisiting the UCSF website at: http://www.futurehealth.ucsf.edu.

The Joint Review Committee onEducation in Radiologic Technology(JRCERT) has announced its Standardsfor Accredited Educational Program inMagnetic Resonance, effective January1, 2003. The JRCERT is the onlyorganization recognized by the U.S.Department of Education for theaccreditation of education programs forradiographers and radiation therapistsin the United States. The JRCERTpromotes excellence in education andenhances quality and safety of patientcare through the accreditation ofeducational programs. You can view theMR standards by going to the down-loads page at: http://www.jrcert.org/.The JRCERT encourages all existingMR educational programs to apply foraccreditation.

This past year, the SMRT has beeninvolved in consulting with the JRCERTin helping formulate the subcommitteethat will be charged with reviewingeducational programs in magneticresonance. Any MR technologist, MReducator, or MR physicist interested inpossibly serving on this subcommitteecan contact Maureen Hood at:[email protected] to have your nameincluded on an interest list. This is aninterest list only! At this time, thesubcommittee is not finalized. Furtherinformation will be released after theJRCERT finalizes the subcommitteestructure. The actual selection of thesubcommittee will be conducted by theJRCERT. �

December 1-6, 2002Chicago, Illinois, USA

Radiological Societyof North AmericaFounded in 1915(630) 571-2670

www.rsna.org


Your Vote Counts!Heidi Berns, M.S., R.T. (R)(MR), SMRT Past-President, Nominating Committee Chair

I

Editor’s Note: Following is an excerpt from the August 1, 2002 press release of The American Registry of Radiologic Technologists (ARRT)

News for ARRT Registered MembersThe Continuing Education Require- ments for Renewal of Registrationare revised to specify what is and is notapproved for CE, and new “should”language is introduced regarding choiceof CE topics by Registered Technolo-gists. See below for more detail.

CE ChangesARRT’s Board of Trustees changed

the CE requirements to reflect theirtrue intent regarding CE topic selectionby R.T.s. ARRT has always expected thattechnologists rely on their professionaljudgment to select continuing educationtopics that update their knowledge andskills in their specific area of practice.To re-affirm that position, the require-ments document now states: “All tech-nologists should select CE topics thatare related to their area of practice andthat will address the needs of the patientand of the Registered Technologist.”

The CE document updates alsoreflect the following changes:• ARRT’s recent decision to award CE

credits for NMTCB’s new examination innuclear cardiology.

• Recognition of the CE evaluation mecha-nism administered by the Texas Society ofRadiologic Technologists on behalf of theTexas Department of Health. (Thischange adds Texas to the states of Florida,Illinois, Iowa, Kentucky, Massachusetts,New Mexico, and Oregon that also haveARRT recognition.)

• Acceptance of CPR certification proceduresof the American Safety and Health Institute.

• No longer accepting for ARRT Category Acredit any courses approved through theAmerican Medical Association or theAmerican Nurses Credentialing Center –unless they are also approved by aRCEEM (Recognized Continuing Educa-tion Evaluation Mechanism) or a recog-nized state licensing agency. AMA/ANCCcourses may still be used for Category B,and up to half of a biennium’s 24 creditsmay be Category B.

If you have questions about ARRT’srequirements for R.T. continuing educa-tion, check the www.arrt.org website formore information, or contact the CEdepartment at (651) 687-0048, ext. 540.

The updated governing documentsappear on ARRT’s web site and will bepublished in next year’s certificationhandbooks and Annual Report toRegistered Technologists.

ARRT, the American Registry ofRadiologic Technologists, recognizesindividuals qualified in the use ofionizing and non-ionizing radiation topromote high standards of patient carein diagnostic medical imaging,interventional procedures and therapeu-tic treatment. Headquartered in St.Paul, Minnesota, USA, it tests, certifiesand annually registers more than226,000 radiologic technologists acrossthe United States. �

t is that time of year when you have the

opportunity to partici-pate in the future of theSMRT. As a votingmember you not onlyhave the privilege but theresponsibility to vote forthe individuals who will

become the President-Elect and the newPolicy Board Members. As your ballotarrives please take some time to reviewthe qualities and experience of thecandidates and select those individualswhom you think will serve you and theSMRT well. This is your chance todetermine the future leadership of theSMRT. You will also have the occasion toselect the recipient of the Crues-KresselAward.

The President-Elect position is athree-year commitment, beginning asPresident-Elect followed by Presidentand then Past President. As a memberof the Executive Committee, the Presi-dent-Elect is mentored for one year andthen becomes the President. During theyear as President, this leader representsthe SMRT to the parent society, ISMRM,and presides over all of the business ofthe SMRT. This includes contact with alleleven standing committees, as well as

any other pertinent issues that arise.As Past President this person serves onthe Executive Committee to ease thetransition from one year to the next andis Chair of the Nominating and AwardsCommittees.

Policy Board members are electedfor a three-year term, and are expectedduring that time to chair at least one ofthe eleven standing committees andserve on others as needed. Those electedto the Policy Board are expected to behighly motivated, concerned individualswho will complete those tasks necessaryfor the SMRT to have ongoing success.Face to face meetings are rare, becausemembers of any given committeemay be from a variety of countries.Communication among Policy Boardand committee members is generallyconducted through electronic mail,which is both efficient and economical.It is a tribute to those many volunteerswho have already completed terms onthe Policy Board as well as those beingconsidered for election, that the SMRTcontinues to evolve into a recognizedprofessional organization for MRtechnologists around the world. Bycarefully selecting your choices, you willensure the SMRT will thrive for years tocome.

You will also be asked to select arecipient of the Crues-Kressel Award.This award was established in honor ofDrs. John Crues and Herb Kressel fortheir support in establishment of theSMRT. The person nominated to receivethis award is someone who is recognized“for outstanding contributions to theeducation of magnetic resonancetechnologists.” For a listing of those whohave received this award in previousyears please check the SMRT Website.

Included with the ballot are briefbiographical histories for all the candi-dates. Please review them and markyour choices. As a reminder, only thosevoting members in good standing, withannual dues paid, are eligible to vote.Follow the directions carefully to signand mail your ballot or it may not becounted. Ballots will be mailed 15October 2002. The postmark deadline is1 December 2002 and the ballots mustbe received no later than 9 December2002. The ballots will be counted andthe results announced in a future issueof Signals. If you have any questionsabout the election procedure or youreligibility to vote, please contact me at:[email protected], or the SMRToffice at: +1 510 841 1899. �


2002 2nd Place Proffered Paper–Clinical Oral Presentation

The Effect of Peripheral Arterial Occlusive Diseaseon Venous Filling in Gadolinium-Enhanced MRAof the Distal Aorta and Lower ExtremitiesFrank Londy R.T. (R), William J. Weadock M.D., Hero K. Hussain M.D., Joseph J. Gemmete M.D.,and Stefan S. Schoenberg M.D.*Department of Radiology, University of Michigan, Ann Arbor, Michigan*Department of Radiology, Ludwig-Maximilians-Universitaet, Munich, Germany

PurposeGadolinium-enhanced multi

station MRA (MSMRA) examination ofthe aorta and lower extremities isbecoming more common. The advan-tages of this noninvasive, iodine free,high-resolution examination aremaking this procedure a necessarycomponent of today’s MR department.The goal of an MSMRA study is todefine the arterial bed from the aortato at least the level of the ankle, free ofvenous overlay however the timing ofcontrast arrival in the calves may bealtered by different disease states. Thepurpose of this work is to explore therelationship between the amount ofvenous overlay of the MSMRA, thedegree of peripheral arterial occlusivedisease (PAOD), and the length of scantime.

MethodAfter receiving Internal Review

Board approval, MSMRA images of57 consecutive patients were retro-spectively reviewed and the venouscontamination (VC) of the distal (calf)station was scored on a 3-point scale.(1 = arterial study without or withvery little venous contamination,2 = diagnostic arterial study with mildto moderate venous contamination,3 = failed exam, non-diagnostic arterialstudy secondary to extensive venouscontamination). Three board certifiedradiologists, experienced in interpret-ing MSMRA exams, performed thescoring. All 57 patients’ medicalrecords were reviewed and assigneda PAOD value of 0 through 4:(1 = asymptomatic with diagnosismade coincidentally during otherdiagnostic procedures, 2 = intermittentclaudication, 3 = constant pain even atrest, 4 = necrosis or ulcers with orwithout rest pain). The additionalscore of 0 was added to the normalgrading criteria to indicate thosepatients that underwent MSMRA butwere asymptomatic and without

suspicion of PAOD. All readers wereblinded to the PAOD scores of thepatients. Only the leg with the highestPAOD score was included in this study.In those cases when both legs receivedthe same PAOD score, the leg with theworst scan result was recorded. Thescan times of the abdominal (1st) andthigh (2nd) stations were recorded aswell as any history of diabetes. All 57patients received a biphasic contrastinjection of 40cc gadolinium consistingof a contrast bolus followed by salineflush. All injections were completedduring the scanning of the 2nd station.Contrast arrival detection software andautomatic table movement were used.Table movement added approximately8 seconds per move between stations1-2 and 2-3. A 12-element phasedarray coil was used for all patients.Elliptic centric K-space filling was usedon all calf stations.

ResultsPAOD score vs. Venous Contamination:There was a strong correlation betweenPAOD score and venous contamination.All 17 cases with VC significant enoughto make the case non-diagnostic had aPAOD score of 2 or above. The percent-age of failed cases increased along withincreasing PAOD score. (Table #1)

Diabetes: Of the 57 patients, 14patients had diabetes mellitus. Ofthese, 8 had a VC score of 1 (arterialstudy without or with very littlevenous contamination,, while 6 had aVC score of 3 (non-diagnostic arterialstudy secondary to extensive venouscontamination).

Age: The average VC score of the age20 to 49 year old group (N=13) was 1.7,the age 50 to 69 year old group (N=21)was 2.1 and the 70 year old and overgroup (N=23) was 1.7. None of thesedifferences were statistically significant.

Scan Time vs. Result: The averagescan times (1st & 2nd stations) of theVC group 1 (with no or little VC) was35.8 seconds, VC group 2 (some VC)was 37.6 and the VC group 3 (failedexam) was 33.5. None of these differ-ences were statistically significant.

Scan Time vs. PAOD Score: Theaverage scan time (1st & 2nd stations)of the PAOD score 0 and 1 group(patients without claudication) was36.7 seconds and the average scan timeof PAOD groups 2, 3 and 4 (patientswith claudication or ulcers) was 37.8seconds. None of these differenceswere statistically significant.

ConclusionsDue to the likelihood of venous

contamination, patients with a PAODscore of 2 or above should not receivethe traditional 3-station MSMRAexam. Rather, these patients maybenefit from a separate injection forthe calf station prior to the abdominaland thigh stations. Within the limits ofour study, total scan time, diabetes, andpatient age were not statisticallysignificant predictors of venouscontamination. �

Table 1.

VC Score

1 2 3 % Failed

0 14 4 0 0

1 2 1 0 0

2 8 6 6 30

3 2 1 4 57

4 1 1 7 77

PA

OD

Sco

re


2002 2nd Place Proffered Paper–Research Oral Presentation

Coronary Magnetic Resonance Angiography:New Non-Contrast TechniqueC. Callahan,* R. Niemczura, J.P. Finn, V. Deshpande, S. Shea, D. Li, R. McCarthy, and J. CarrAdvanced MRI Consulting, Inc. Evergreen Park, Illinois, USA, Northwestern University, Chicago, Illinois, USA

Purpose

Coronary artery disease (CAD) isresponsible for an estimated onemillion deaths a year.1 This compellingstatistic is the driving force behindimproving Coronary Magnetic Reso-nance Angiography (CMRA) fordetection of disease. In order tocharacterize coronary anatomy, CMRArequires high performance gradientcapabilities and advanced software tohandle the intrinsic physiological andartifact challenges. These technicalrequirements and diagnostic obstaclescombined with current contrastenhanced (CE) techniques render MRIa very difficult and under-utilizedmodality for clinical coronary imag-ing.1-3 The purpose of this study was toexplore a new non-contrast CMRAtechnique and assess its diagnosticcontributions to coronary arteryexamination.

Methods

Informed consent was obtained on12 adult subjects with suspected CAD.Procedures were performed on aMagnetom Sonata, 1.5 Tesla MRSystem, Siemens Medical Solutions(Iselin, New Jersey, USA). ECGelectrodes were placed for cardiactriggering and patients given specificbreath-hold (BH) instructions for

consistency of anatomical localization.The protocol consisted of a series of3-5 localization sequences. The non-contrast CMRA technique was asfollows: 3D magnetization-preparedTrue FISP, TE: 1.6-2.0 ms, TR: 3-4 ms,(126-143) x 512 matrix, 12 partitions,18-24 mm slab thickness, (166-190) x380 mm2 FOV, fat saturation, 20dummy scans and preparation pulsesfor artifact minimization were imple-mented prior to acquisition andadjusted for diastolic cycle. 3D TrueFISP data was acquired in axialoblique orientation to include left main(LM) and left anterior descending(LAD) arteries and acquired in sagittaloblique orientation to include rightcoronary artery (RCA) (Figure 1a & 1b).Volume data was evaluated usingstandard MPR and MIP software forvessel delineation, artifacts, signal/noise ratios (SNR) and contrast/noiseratios (CNR). All data was compared toprior 3D Flash CE CMRA images.

Results

The data resulted in the optimalcombination of improved vascularconspicuity and artifact reduction. TheTrue FISP data demonstrated a highSNR and CNR, in both axial andsagittal oblique volumes. Patientpreparation techniques allowed forsuccessful localization of coronary

anatomy. When compared to 3D FlashCE images, True FISP showed amarked improvement in anatomicalvisualization of coronary arteries andsignificant artifact reduction inrespiratory motion, cardiac pulsationand gradient susceptibility. SNR forTrue FISP measured 17.7 (59%increase compared to Flash at 11.1).The CNR for True FISP measured 6.8(172% increase compared to Flash at2.5) (Figure 2.a & 2.b).

Conclusions

Based on these results there areconsiderable advantages to the 3DTrue FISP technique. Compared to theCE Flash sequence, this non-contrasttechnique offers a substantial improve-ment in SNR, CNR, and artifactreduction. This technique demon-strates a promising non-invasivealternative for evaluating coronaryarteries. With ongoing advancementsin technology, CMRA will continue togain recognition as a diagnostic tool indetection of CAD. �

References1. Li, D. Topics Magn. Reson. Imag. 2001;

12: 337-348.2. Li, D. Radiology. 2001; 219: 270-277.3. Deshpande, V. Magn. Reson. Med. 2001;

46: 494-502.

Figure 1a. True FISP LM, LAD. Figure 1b. True FISP RCA. Figure 2b. True FLASH LCA.Figure 2a. True FISP LCA.


2002 2nd Place Proffered Paper–Clinical Poster

MRI Breast Needle LocalizationR. Walcarius, C.A. Piron, D.B. Plewes, R. Shumak, and P. CauserDepartment of Imaging and Bioengineering Research and Medical Imaging,Sunnybrook and Women’s College Health Science Center, Toronto, Ontario, Canada

Purpose

A high risk breast imaging studyutilizing mammography, ultrasound,and MRI is currently being run at oursite.1 This has created a need for tissuesampling of suspicious lesions detectedonly on MRI. The method used for thisis a pre-operative needle-wire localiza-tion using MRI guidance. The purposeof this study is to describe the MRIstereotactic system we use whichenables medial and lateral approachesto the breast, provides access to lesionsnear the chest wall, and utilizes aphased array coil configuration duringthe entire procedure.

Method

All scans are performed on a closed1.5 Tesla GE signa CVMR system. Aretrofit frame and tabletop is placed onthe GE patient bed (see Figure 1b).The patient is placed in a proneposition with the breast to be localizedcompressed between medial and lateralplates (see Figure 1a). The otherbreast rests on a flexible bridgecompressing it against the chest wall.This bridge allows for medial approachto the breast being localized if neces-sary. Phased array coils are attachedto the compression plates, one medialand the other lateral. Fiducial mark-ers are embedded into the compressionplates both horizontally and verticallyto help calculate needle position anddepth.

Axial and coronal localizing scansare used to not only localize the breastbut to determine the positions of thefiducial markers. The lesion is thenidentified using a dynamic contrastenhanced sagittal 2D SPGR sequencewith fat suppression (TR = 150,TE = 4.2, flip = 40 degrees,slice thickness = 5.0 mm, FOV = 18 cc,matrix = 256 X 128, 13 slices, and aninjection of 0.2 cc/kg gadolinium). Thedesired approach (lateral or medial),plus the lesion and fiducial markercoordinates are entered into a computer

program to calculate needle positionand depth. With the patient removedfrom the bore of the magnet, theRadiologist inserts an MRI compatible,titanium localizing needle hook-wireinto the breast, according to the3-dimensional coordinates. The needleis guided through a fenestrated plugwith 2 mm spaced boreholes. Theneedle position is then verified in thesuperior-inferior, anterior-posterior andmedial-lateral directions using sagittaland axial 2D SPGR (SPoiled GRadientecho) sequences without contrast.Once needle placement has beenverified, the patient is again removedfrom the magnet bore. The wire isdeployed and the needle is removed.A final ax 2D SPGR is performed toverify wire position.

Results

Ten MRI guided breast needlelocalizations have been performed atour site. Six lateral and four medial

approaches. The average size of thelesions was 8.0 mm. The procedure,including set up takes about 1 hour.The time from localizing the lesionwith contrast to verfication of needleplacement was on average 4 minutes.All needle placements were within thebounds of the lesion.

Conclusions

This stereotactic breast needlelocalization device has allowed forefficient localization of breast lesions inboth medial and lateral approachesusing a closed 1.5 tesla magnet. Thisallows for breast lesions seen only onMRI to be sampled for pathologies. �

References1. Warner, E., Plewes, D., et al, J. Clin. Oncol.,

19, 3524-3531, 2001

Figure 1a. Schematic of the localization system. The designpermits access to the breast from medial, or lateral approach.Figure 1b. System with retrofit frame on standard GE bed.Figure 1c. Lateral view of system, with coil detached.


2002 2nd Place Proffered Paper–Research Poster

Diagnostic MRI of Zoo AnimalsJulia B. Lowe, B.S.R.T. (R)(MR), Mark J. Lowe, Ph.D., Micheal D. Phillips, M.D., Jan C. Ramer, D.V.M.,and Jeffry S. Proudfoot, D.V.M.Indiana University School of Medicine, Radiology and the Indianapolis Zoo, Indianapolis, Indiana, USA

Purpose

Over the past four years, veteri-narians from the Indianapolis Zoo andresearchers from the Indiana Univer-sity School of Medicine (IUSOM) havecollaborated in multiple attempts toobtain diagnostic imaging informationon certain animals whose diagnosiswas not possible with the standardimaging equipment available even to alarge urban zoo hospital such as theIndianapolis Zoo. As with humans,MRI technology can provide imageswith good soft tissue contrast thatcan be advantageous in diagnosingillnesses in animals that other imagingequipment cannot. We report here theresults of four such studies that weredone on animals with symptomsindicating neurologic illness. Our goalis to illustrate that MRI can be used toprovide diagnostic information thatmay lead to improved treatmentoptions for valuable zoologic animals.

Methods

The lions were transported fromthe zoo under gas anesthesia and uponarrival at the MRI suite were switchedto an MRI-compatible anesthesia unit.Other animals were transported awakeand were anesthetized on site. Allimaging was performed on a 1.5 TeslaGE Echospeed scanner (GE MedicalSystems, Waukesha, Wisconsin, USA).

Case 1: An African Lion cub presentedwith blindness and disorientation.Blood and spinal fluid analysis indi-cated a possibility of canine distemper,which in a zoologic setting is typicallymanaged through euthanasia. Athorough neurologic examination ledthe veterinarians to believe that thecentral nervous system was involved.They were anxious to rule out stroke orother neurologic disorder beforedeciding on a course of action.Imaging: The lions were imaged usingthe standard GE head coil. FLAIR,FSE T2, FSE T1, MPGR, and DWIsequences were obtained in the axialplane as well as a high resolutionFSE T2 in the sagittal plane. The

asymptomatic sibling of the lion cubwas scanned as a comparison fornormal anatomy.

Case 2: An adult African Lion presentedwith neurologic symptoms includingblindness, disorientation, and ataxia.Blood and spinal fluid analyses werenegative. Veterinarians asked for anMRI to rule out stroke or anotherneurologic event.Imaging: The lion was imaged usingthe body RF coil, since its head was toolarge to fit in the standard head coil.FLAIR, FSE T2, and T1 sequenceswere obtained axially as well as a highresolution FSE T2 in the sagittal plane.The lion was intravenously injectedwith Magnevist (Berlex LaboratoriesInc., New Jersey, USA), a paramagneticcontrast agent, and a T1 scan wasobtained.

Case 3: A Rock Hopper Penguinpresented with recurring seizures.X-ray screening and blood workrevealed no abnormalities. Veterinar-ians requested an MRI to rule outpathology so that the penguin could betreated with anti-seizure medication.Imaging: The penguin was imagedusing a Medrad (Indianola, PA) phasedarray knee coil to attempt to match thevolume of the scan region to a coil ofappropriate dimension. T2, FLAIR, and3D SPGR T1-weighted images wereobtained.

Case 4: An Emerald Tree Boa presentedwith sensory coordination problems.Due to the animal’s inability to strikehis prey, the veterinarians speculatedthat the problem was with the animal’svision and thermal sensing ability tolocate nearby prey.Imaging: A 3-inch diameter surfacecoil was used for imaging the brain ofthe snake. T2-weighted, FLAIR, 3DSPGR T1-weighted, and Spin EchoT1-weighted images were obtained.

Results

Case 1: The African Lion cub wasscanned on two different occasions.She was scanned soon after the sudden

onset of her symptoms. The first brainMRI scan was negative. A follow-upscan was done weeks later revealingfocal areas of white matter T2 abnor-mality which suggested a demyelinat-ing or ischemic process. The lab resultsfrom blood draws suggested caninedistemper because of a four-foldincrease in the titer. Because hersymptoms never improved she waseuthanized. Canine distemper wassuggested by autopsy.

Case 2: The adult lion’s MRI wasnegative. After returning to the zoo sherecovered from the anesthesia and wasalert but still suffered from severemotor impairment (unable to stand)and therefore was euthanized. Duringthe autopsy retinal lesions werevisualized explaining her blindness.Her lab results were unremarkableand her motor illness remains amystery.

Case 3: The MRI scan for the penguinwas negative, which helped theveterinarians make a presumeddiagnosis of idiopathic epilepsy. Theanimal is now treated daily by placinganti-seizure medication inside of fishthat is fed to the penguin. Thepenguin’s seizures are now undercontrol and he is able to live normallyin the zoo habitat.

Case 4: The MRI scan of the EmeraldTree Boa’s brain was negative.Although there was no evidence ofpathology the brain measured only8 x 9 mm and was difficult to image.Eventually the snake regained hisneuro-sensory skills and is now ableto successfully strike his prey.

Conclusion

With slight modifications, it ispossible to use a whole-body clinicalMRI scanner to obtain useful diagnos-tic information on a variety of zoologicanimals. This information was used bythe IUSOM and the Indianapolis Zoo tomanage the illness of several animalswhose diagnosis was incompletewithout the usage of MRI. �


Report on the SMRT Northeast Regional SeminarMark Spooner, B.P.S., R.T. (R)(MR)(CT), Regional Seminar Coordinator, Utica, New York, USA

T

SMRT Regional News

he SMRT Northeast Regional Seminar was held in Utica, New York, USA,on 22 June 2002. Over 50 technologistsfrom New York, Pennsylvania, Connecticut,New Hampshire, New Jersey, and Ontario,Canada gathered at the St. Luke’s Homefor a variety of MRI lectures. The seminarprovided the attendees with eight ECEcredits.

After welcoming our guests, the meeting started with a lecture by Carolyn Kaut Roth, R.T. (R)(MR)(CT)(M)(CV),from the University of Pennsylvania Medical Center.Candi covered both Abdominal and Pelvic MRI. She didan excellent job of providing the attendees with usefuland practical information.

After a break, Nikolaus M. Szeverenyi, Ph.D., coveredFunctional MRI. He started with a basic introduction tofunctional imaging, and described the different types ofresearch being performed at SUNY Upstate MedicalUniversity, in Syracuse, New York.

John Ferriter, R.T. (R)(MR)(CT), a Medrad ApplicationsSpecialist, gave a lecture describing Concepts and Applica-tions for Contrast Enhanced Angiography. John providedsome tips for everyone to take back to their sites.

After lunch, Cindy Comeau, B.S. R.T. (N)(MR), pre-sented an informative lecture on the Essentials of VascularMRA for Technologists. Her lecture complimented John’sand provided additional information from a workingtechnologists’ perspective.

Jason Miller, R.T. (R), from Hitachi Medical SystemsAmerica, Inc., described the latest Advances in Open MRI.

The last two lectures of the day were given by JamesJ. Stuppino, B.S., R.T. (R)(MR). James’ lectures entitledObesity and Other Difficult Imaging Challenges: Tips andAdvice and ACR MRI Accreditation: The Technologistsand Administrators Role.

I would like to thank the St. Luke’s Home for provid-ing the lecture hall for the seminar. I would also like tothank my employer, Cooperative Magnetic Imaging, inUtica, New York, for providing the refreshments andlunch. I would especially like to thank Berlex Imaging,Medrad, Inc., and Hitachi Medical Systems America, Inc.,for their support. �

Cindy Comeau helpingJames Stuppino set upprior to his presentation.

Nikolaus Szeverenyi and Carolyn Kaut Roth giving theirpresentations at the podium.

John Ferriter, Medrad Applications Specialist, answering afew of the attendees questions following his presentation.


Southeast RegionalEducational SeminarSaturday, 21 September 2002Saint Joseph’s HospitalAtlanta, Georgia, USA

Donna O’Brien, R.T. (R)(MR)(CT), Co-ChairCarolyn Brown, R.T. (R)(MR), Co-ChairBobbie Burrow, R.T. (R)(CT)(MR), Co-Chair

Upcoming SMRT Regional Seminars–

PROGRAM 07:55 – 16:4507:00 Registration and Continental Breakfast

07:55 Welcome and Announcements

08:00-08:50 Contrast Enhanced MRACarolyn Kaut Roth, R.T. (R)(MR)(CT)(M)(CV)University of Pennsylvania Medical Center,Philadelphia, Pennsylvania, USA

08:55-09:45 Cardiac ImagingStephen Frohwein, M.D.St. Joseph’s Hospital, Atlanta, Georgia, USA

09:45-10:00 Break

10:00-10:50 Fetal ImagingRita Clemons, R.T. (R)MR)Baylor University, Dallas, Texas, USA

10:55-11:45 Spectroscopy 101Robin Greene-Avison, C.N.M.T., R.T. (N)(MR)The University of Kentucky, Lexington, Kentucky, USA

11:45-12:45 Lunch

12:45-13:40 Abdominal ImagingCarolyn Kaut Roth, R.T. (R)(MR)(CT)(M)(CV)University of Pennsylvania Medical Center,Philadelphia, Pennsylvania, USA

13:45-14:40 Open MRI: Physics and ProtocolsJames J. Stuppino, B.S., R.T. (R)(MR)Valley Advanced Imaging & MRI,Bethlehem, Pennsylvania, USA

14:45-15:00 Break and Dessert

15:00-15:50 Surface Coil TechnologyKevin Bolen, IGC/Medical Advances, Milwaukee, Wisconsin, USARick Cloud, MRI Devices, Waukesha, Wisconsin, USA

15:55-16:45 ACR Accreditation UpdateJames J. Stuppino, B.S., R.T. (R)(MR)Valley Advanced Imaging & MRIBethlehem, Pennsylvania, USA

16:45 Adjournment

Eastern Canada RegionalEducational SeminarSaturday, 28 September 2002Jeanne Timmins Amphitheatre,Montreal Neurological HospitalMontreal, Quebec, Canada

Laurian Rohoman, A.C.R., R.T. (R)(MR), Local CoordinatorLouise Gaudreau, R.T. (R), R.D.M.S., Co-ChairMarian Stern, R.T. (R), B.F.A., Co-Chair

PROGRAM 07:55 – 17:3007:00 Registration and Continental Breakfast

07:55 Welcome and Announcements

08:00 Advances in MR Imaging of Multiple SclerosisPierre Bourgouin, M.D.Centre Hospitalier de l’Université de MontréalMontreal, Canada

09:00 Advantages of MRI over CT in Head Traumaand Meningeal CarcinomatosisRaquel del Carpio-O’Donovan, M.D.McGill University Health CentreMontreal General Hospital, Montreal, Canada

10:00 Break

10:15 Functional Imaging of the BrainPierre Bourgouin, M.D.Centre Hospitalier de l’Université de MontréalMontreal, Canada

11:15 Cardiovascular Imaging and TechniquesNaeem Merchant, M.D.Mount Sinai and University Health Centre,Toronto, Ontario, Canada

12:15 Lunch

13:15 MRI-Guided Focused Ultrasound Surgery ofBreast CancerDavid Gianfelice, M.D.Centre Hospitalier de l’Université de MontréalHôpital St. Luc, Montreal, Canada

14:15 Essentials of Vascular MRA for TechnologistsCindy Comeau, B.S., R.T. (N)(MR)Manager Cardiovascular MRI,New York, New York, USA

15:15 Break

15:30 MR Imaging of the Biliary Tree and PancreasCaroline Reinhold, M.D.McGill University Health CentreMontreal General Hospital, Montreal, Canada

16:30 Common Pathologies in the MusculoskeletalSystemAdel Assaf, M.D.McGill University Health CentreMontreal General Hospital, Montreal, Canada

17:30 Closing Remarks


A

PRECESSING IN A VERTICAL FIELD“We’re go’na get an OPEN MRI”William Faulkner, B.S., R.T. (R)(MR)(CT)

This article represents the views of its author only and does not reflect those of the International Society forMagnetic Resonance in Medicine and are not made with its authority or approval.

ny time I hear someone say that

I cringe. It makes mewonder why they aredoing it. Is it becausethey want a secondsystem and they arelooking at operatingcosts? Is it because they

are afraid they are losing referrals toan OPEN MR system across town ordown the street? Is it because theywant to serve the more generous sizedpatients? Is it because the hospitaladministrator decided to buy one andnow meets with the radiologists to“bring them on board with our plan?”

Whatever the reason, I’m reallyliking the term “OPEN MRI” less andless. I’m afraid it causes people to buythem and/or want to be scanned onthem for the wrong reasons. I have afriend who, upon installing theirvertical-field (better terminology)scanner, framed a very nice posterprovided for them by the vendor. Theposter showed a small child sitting onthe end of the table holding a teddybear and smiling. They hung this in

Figure 2. Same patient scanned at 1.5 T.

LOW- AND MID-FIELD MRI

Figure 1. Images acquired at 0.2 T.

their main waiting room but soon hadto take it down. It seemed patientsexpected to be scanned while sitting onthe end of the table (the teddy bearwas not necessarily a requirement).

Many of the vertical-field systemsare lower field (a classification thatnow seems up for debate). By lowerfield, I mean less than 0.5 T. Lowerfield systems have several advantagesover higher field systems. As fieldstrength increases, the followingincreases: magnetic susceptibilityartifact, flow artifact, chemical shiftartifact, and T1-relaxation times, justto name the top ones that come tomind. Unfortunately, SNR decreaseswith field strength. But, as the greatphilosopher Huey Lewis once said,“There ain’t no living in a perfectworld.” We can, however overcomesome of the SNR losses by well-designed surface/local coils and the uselower receiver bandwidths. At lowerfields, we have the luxury of using alower receiver bandwidth due to themuch lower chemical shift artifact.I’m not going to go further with thattopic since Linda Varnis did an excellent


job with it in a previous issue (thanksagain Linda).

I’d like to show you a neat exampleof one of the benefits of scanning at alower field compliments of Dr. LarryTannenbaum (yes – Dr. High-Fieldhimself). The images on the left wereacquired at 0.2T. The T1 is a conven-tional SE while the PD and T2 are FastSpin Echoes (FSE). The PD and T2were acquired as two separate acquisi-tions. You will notice the metal artifactfrom the surgical screws or rods is lesson the T2 than on the PD or T1. Thatis primarily because the T2 utilizes ahigher Echo Train Length (ETL) thanthe PD and certainly the T1. You willremember that the purpose of the180-degree refocusing pulse is tore-focus spins that have dephased dueto inhomogeneities and chemical shift.The greater the number of 180-degreepulses utilized in a given pulsesequence, the greater the “clean-up”so-to-speak. That is why we like to useFSE (whether at low- or high-field)in the presence of metal to reduce theartifact.



T

Medical Devices and AccessoriesDeveloped for Use in the MREnvironment and Interventional MRIProceduresFrank G. Shellock, Ph.D., Adjunct Clinical Professor of Radiology, University of SouthernCalifornia, Founder, Institute for Magnetic Resonance Safety, Education, and Research,Los Angeles, California, USA www.MRIsafety.com www.IMRSER.org

This article represents the views of its author only and does not reflect those of the International Society forMagnetic Resonance in Medicine and are not made with its authority or approval.

MRI SAFETY

Figure 1. Non-magneticoxygen tanks of varioussizes (Magmedix, Gardner,Massachusetts, USA).

he increasing capabilities of

magnetic resonance(MR) studies to impactmedical diagnosis andprognosis has dramati-cally increased thenumber of MR proce-dures performed world-

wide. Many more patients, especiallythose in high-risk or special populationgroups, are undergoing MR examina-tions for an ever-widening spectrum ofmedical indications.

Additionally, as Jolesz, et al., havestated, continuous progress has beenmade to expand the use of MRI beyonddiagnosis into intervention. This hasresulted in the development andperformance of innovative proceduresthat include percutaneous biopsy(e.g., breast, bone, brain, abdominal),endoscopic surgery of the abdomen,spine, and sinuses, open brain surgery,and MR-guided monitoring of thermaltherapies (i.e., laser-induced, RF-induced, and cryomediated procedures).

Various vendors and manufacturers,prompted by recommendations andrequests from MR healthcare profes-sionals, have recognized the need fordeveloping specialized medical devices,equipment, accessories, and instrumentsnecessary for use in the MR environ-ment and for interventional MRIprocedures. Accordingly, there are nownumerous patient support devices andaccessories that have been developedand which have undergone thoroughevaluation to assess and verify appropri-ate use in the MR environment orduring interventional MRI procedures.

In consideration of the manydevices and accessories that are com-

mercially-available for safe use duringMRI procedures, it is surprising thatincidents and accidents related toferromagnetic projectiles, excessiveheating of devices, and other problemscontinue to occur. These have resulted inat least one fatality, several injuries,substantial damage to MR systems, anddown-time (i.e., loss of revenue) for MRIcenters.

Therefore, the intent of this articleis to review the various devices andaccessories that are specifically designedfor use in the MR environment or forinterventional MRI procedures, with thehope that this information will helpprompt MR healthcare professionals torecognize the many products that existwhich are essential to ensure patientsafety. In addition, these devices andaccessories may help to create a moreefficient or more profitable MR center.

Non-Magnetic Oxygen & GasCylinders. According to Chaljub, et al.,accidents related to ferromagneticoxygen tanks and other gas cylindersthat become projectiles may be increas-ing. Therefore, MR facilities shoulddevise an appropriate policy for deliveryof oxygen or other gases to patientsundergoing MR procedures. The use of

What’s interesting in this case isthe image on the right. It is the samepatient scanned at 1.5 T. As you cansee, regardless of the pulse sequence,the inhomogeneities caused by thepresence of the metal, result in atotally non-diagnostic study. This isnot the case for the study performedat 0.2 T.

The reason I like this example isthat it shows there are reasons to scansomeone on a low-field system otherthan they are “claustrophobic” or “toobig to fit in the big magnet.” I’ve spokenwith a number of technologists that saytheir radiologists tell them to use theOPEN scanner only on those patientswho can’t fit into the high field. Themain problem with this is that nowevery image that comes off theirvertical-field will be in all likelihoodbe sub-optimal in image quality.

The physics of a vertical magnetrequire the receiving coils to be sole-noid in design, meaning they have toencompass the patient. If the patientis rather large, then unfortunately thecoil is equally as large. The largest coilon our 0.2 T system is 72 inches whenunfurled. Using a large coil, while verynecessary, will result in low SNR.I usually use the following analogy.Imagine doing a thoracic spine on your1.5 T whole-body system using thebody coil. You wouldn’t expect the SNRto be very good especially consideringthe spatial resolution parameters youselected. Now if you don’t expect thatscenario to produce a high quality,“picture-perfect” study, why would youexpect it at 0.2 T?

I’m not saying we shouldn’t useour vertical-field MR systems for thelarger patients; they are certainly theonly hope some of these patients haveof getting an MR study. I’m just sayinglet’s have a little reality check here.There are things we have to leaveoutside of the MR environment; ourbrains aren’t one of them. �

Low- and Mid-Field MRI continued

This website was created and is maintained byFrank G. Shellock, Ph.D.

For more information on safetyrelated issues, please visit:


healthcare worker regarding pain,respiratory problem, cardiac distress, orother difficulty that might arise duringthe examination. In addition, a patientshould be monitored if there is a greaterpotential for a change in physiologicstatus during the MR procedure.

In 1992, the Safety Committee ofthe Society for Magnetic ResonanceImaging published guidelines andrecommendations concerning the

MRI Safety continued


Table 1. Examples of companies that provide devices and accessories for use in theMR environment or for interventional MRI procedures (for a comprehensive listing ofcompanies, please refer to Shellock FG. Reference Manual for Magnetic Resonance Safety:2002 Edition. Amirsys, Inc., Salt Lake City, Utah, 2002 USA).

Company Products

AESCULAP, INC. MRI Surgical instruments3773 Executive Center ParkwayCenter Valley, Pennsylvania 18034 USA+1 800 282 9000www.aesculap.com

DRAEGER MEDICAL , INC. Anesthesia equipment 3135 Quarry Road VentilatorTelford, Pennsylvania 18969 USA+1 800 437 2437www.draeger.com

E-Z-EM, INC. Biopsy needles717 Main Street Biopsy gunsWestbury, New York 11590 USA Biopsy site markers+1 800 544 4624www.ezem.com

IN-VIVO RESEARCH Monitoring equipment12601 Research ParkwayOrlando, Florida 32826 USA+1 800 331 3220www.invivoresearch.com

MAGMEDIX Nonmagnetic accessories158R Main Street Respiratory equipmentGardner, Massachusetts 01440 USA MR facility start up kits+1 866 646 3349, +1 978 630 5580 Monitoring equipmentwww.Magmedix.com Patient comfort/positioning devices

MRI tools and instrumentsPatient transport equipmentCryogen accessoriesMRI carts and maintenance devicesSigns and site control devices

MALLINCKRODT, INC. OptiStar MR Contrast Delivery System675 McDonnell BoulevardSt. Louis, Missouri 63134 USA+1 314 654 3981, +1 314 654 2000www.mallinckrodt.com

MEDRAD Monitoring equipmentOne Medrad Drive Music systemIndianola, Pennsylvania 15051 USA Spectris MR Injection System+1 800 633 7231, +1 412 767 2400www.Medrad.com

MRI DEVICES CORPORATION Biopsy needles1515 Paramount Drive Biopsy positioning devicesWaukesha, Wisconsin 53186 USA Biopsy localition systems+1 800 524 1476www.mridevices.com

RESONANCE TECHNOLOGY, INC. MRI audio/video systems18121 Parthenia Street fMRI productsNorthridge, California 91325 USA Custom built devices+1 818 882 1997www.fmri.com, www.mrivideo.com

non-magnetic (usually aluminum)oxygen and other gas cylinders is onemeans of maintaining a risk free MRenvironment with regard to this equip-ment (Figure 1). It should be noted thatnonmagnetic tanks must be prominentlylabeled to avoid confusion with magneticcylinders. Furthermore, all healthcareworkers that work in and around theMR environment must be informedregarding the fact that only nonmag-netic oxygen and other gas cylinders areallowed into the MR system room.

Nonmagnetic oxygen regulators,flow meters, cylinder carts, cylinderstands, cylinder holders for wheelchairs,and suction devices are also commer-cially available to provide safe respira-tory support of patients in the MRenvironment.

Patient Comfort Devices.Certain patients who undergo MRIprocedures experience emotionaldistress that can range from mildanxiety to a full-blown panic attack.Patient distress contributes to adverseoutcomes for the MRI procedure thatincludes unintentional exacerbation ofpatient anxiety, a compromise in thequality and, thus, the diagnostic powerof the imaging study, and decreasedefficiency of the imaging facility due todelayed, cancelled or prematurelyterminated studies.

Fortunately, there are a variety oftechniques that can help minimize theseproblems for patients. For example,special systems can be used during MRIprocedures to manage the anxiouspatient such as MR-compatible head-phones to provide music to the patient(which also reduce gradient magneticfield-induced noise) and MR-compatiblevideo systems that provide a visualdistraction to the patient (Table 1).There is even a virtual reality environ-ment system that provides audio andvisual distraction to the patient (Figure 2).A similar device is designed for use infMRI procedures.

Monitoring Equipment. Ingeneral, monitoring during an MRIexamination is indicated whenever apatient requires observations of vitalphysiologic parameters due to anunderlying health problem or whenevera patient is unable to respond or alertthe MRI technologist or other

monitoring of patients during MRprocedures. This information indicatesthat all patients undergoing MRprocedures should, at the very least, bevisually and/or verbally (e.g., intercomsystem) monitored, and that patientswho are sedated, anesthetized, or areunable to communicate should bephysiologically monitored and supportedby the appropriate means. Of note isthat guidelines issued by the JointCommission on Accreditation of




Figure 3. The Omni-Vent Series DVentilator used for respiratory support ofpatients in the MR environment (Magmedix,Garner, Massachusetts, USA).

Figure 2. Specialized equipment used toprovide virtual reality environment and forfMRI studies (Resonance Technology, Inc.,Northridge, California, USA).

Healthcare Organizations (JCAHO)indicate that patients that receivesedatives or anesthetics require moni-toring during the administration andrecovery from these medications.

Additionally, there must be policiesand procedures implemented to con-tinue appropriate physiologic monitor-ing of the patient by trained personnelafter the MRI procedure is performed.This is especially needed for a patientrecovering from the effects of a sedativeor general anesthesia.

Conventional monitoring equip-ment and accessories were not designedto operate in the harsh magneticresonance (MR) environment wherestatic, gradient, and radiofrequency (RF)electromagnetic fields can adverselyeffect or alter the operation of thesedevices. However, various physiologicmonitors and other patient supportdevices have been developed or spe-cially-modified to perform properlyduring MRI procedures (Table 1).Besides patient monitoring, varioussupport devices and accessories may beneeded for use in the high-risk patientto ensure safety. Many of these likewisehave been modified or designed to besafe to use in the MR environment orduring interventional MRI procedures(Table 1).

Emergency-Related Equipment.Emergencies can and do happen in theMR environment. Therefore, the devel-opment and regular practice of anemergency plan that addresses anddefines the activities, use of equipment,

and other pertinent issues pertaining toa medical or other emergency areimportant for patient safety in the MRsetting.

For example, a specific plan needsto be developed for handling a patient ifthere is the need to perform cardiopul-monary resuscitation in the event of acardiac or respiratory arrest. Thisincludes having a means to immediatelyremove the patient from the MR systemto a place outside the MR environmentto properly conduct CPR, allowing theuse of necessary equipment such as acardiac defibrillator. For this reason, itmay be necessary to have a stand-bynonmagnetic stretcher or gurneyavailable that can be used to quicklytransfer the patient (especially for MRsystems that do not have tables thatseparate from the MR system or thatquickly disengage).

Notably, the healthcare profession-als that are members of the Code Blueteam, (i.e., responsible for establishingand maintaining the patient’s airway,administering drugs, recording events,and conducting other emergency-relatedduties) must be identified, trained inMR safety, and continuously practiced inthe performance of these critical activitiesrelative to the MR environment.

For instances when it may not bepossible to remove the patient from theMR system room during an emergency,especially if the patient is experiencinga respiratory or cardiac arrest, it isadvisable to have various nonmagneticdevices and accessories readily availableincluding an oxygen cylinder, laryngo-scope, suction system, stethoscope, bloodpressure manometer, and other similaremergency equipment that is appropri-ate for the MR environment (Table 1).

MR Contrast Agent InjectionSystems. The controlled, powerinjection of MR contrast agents isgaining in popularity for a variety ofclinical applications including examina-tions of abdominal organs, vascularanatomy, and dynamic MRI studies ofthe breast. Power injectors must be ableto operate in the MR environmentwithout affecting magnet homogeneity,degrading signal-to-noise, or causingartifacts. To date, two devices areavailable for power delivery of MRcontrast agents: the Optistar MR

Contrast Delivery System (Mallinckrodt,St. Louis, Missouri, USA) and theSpectris MR Injection System (Medrad,Inc., Indianola, Pennsylvania, USA)(Table 1).

MRI Compatible Ventilators.Devices used for ventilation of patientstypically contain mechanical switches,microprocessors, and ferromagneticcomponents that may be adverselyaffected by the electromagnetic fieldsused by MR systems. Ventilators thatare activated by high-pressure oxygenand controlled by use of fluidics (i.e., norequirements for electricity) may stillhave ferromagnetic parts that canmalfunction as a result of interferencefrom MR systems.

MR-compatible ventilators havebeen modified or specially designed foruse during MRI procedures that areperformed in adult as well as neonatalpatients. These devices tend to beconstructed from non-ferromagneticmaterials and have undergone pre-clinical evaluations to ensure that theyoperate properly in the MR environment,without producing artifacts on MRimages. There are at least two sources ofrespirators for patients that requirerespiratory support in the MR environ-ment (Table 1). These devices have beentested in association with MR systemsoperating at 1.5-Tesla or less (Figure 3).

Basic Patient ManagementAccessories and Equipment. All newand existing MR facilities should beprepared to handle patients and every-day situations (e.g., maintenance) in the



Figure 4. Examples of nonmagnetic devices andaccessories developed or modified for use in the MRenvironment.

Figure 5. Non-magneticcustodial cart (thewheels, casters, andbucket handle are allnonmagnetic). Anonmagnetic mophandle and mopheadclamp should be usedwith this equipment.

Figure 6. MR-compatiblesurgical instruments(Aesculap, Center Valley,Pennsylvania, USA).

References1. Chaljub G, et al. Projectile cylinder accidents

resulting from the presence of ferromagneticnitrous oxide or oxygen tanks in the MR suite.American Journal of Roentgenology2001;177:27-30.

2. Food and Drug Administration, Guidance forthe Submission Of Premarket Notifications forMagnetic Resonance Diagnostic Devices,Document issued on: November 14, 1998.http://www.fda.gov/cdrh/ode/95.html

3. http://www.MRIsafety.com4. Holshouser B, Hinshaw DB, Shellock FG.

Sedation, anesthesia, and physiologicmonitoring during MRI. Journal of MagneticResonance Imaging, 3: 553-558, 1993.

5. Jolesz FA, et al. Compatible instrumentationfor intraoperative MRI: expanding resources.Journal of Magnetic Resonance Imaging,1998;8:8-11.

6. Kanal E, Shellock FG. Policies, guidelines, andrecommendations for MR imaging safety andpatient management. Patient monitoringduring MR examinations. Journal of MagneticResonance Imaging, 1992;2: 247-248.

7. Keeler EK, et al. Accessory equipmentconsiderations with respect to MRI compatibil-ity. Journal of Magnetic Resonance Imaging,1998;8:12-18.

8. Shellock FG. Magnetic Resonance Procedures:Health Effects and Safety. CRC Press, BocaRaton, FL, 2001.

9. Shellock FG. Guide to MR Procedures andMetallic Objects: Update 2001. SeventhEdition, Lippincott Williams & WilkinsHealthcare, Philadelphia, 2001.

10. Shellock FG. Reference Manual for MagneticResonance Safety: 2002 Edition. Amirsys, Inc.,Salt Lake City, Utah, 2002.

11. Shellock FG. Surgical instruments forinterventional MRI procedures: assessment ofMR safety. Journal of Magnetic ResonanceImaging, 2001;13:152-157.

12. Shellock FG, Crues JV. Commentary: MRsafety and the American College of RadiologyWhite Paper. American Journal of Roentgenol-ogy, 2002;178:1349-1352.

13. Shellock FG, Shellock VJ. Metallic markingclips used after stereotactic breast biopsy:ex vivo testing of ferromagnetism, heating, andartifacts associated with MRI. AmericanJournal of Roentgenology, 1999,72:1417-1419.

MR environment by obtaining a selec-tion of nonmagnetic or other suitableaccessories or equipment. For example,useful items for an out-patient facilityinclude nonmagnetic equipment such asa wheelchair (one or more), stretcher orgurney, step stool, IV pole, laundry cart,stethoscope, blood pressure manometer,storage or utility care, fire extinguisher,and custodial cart (Figures 4 and 5).

MR facilities that handle both out-patients and in-patients should addi-tionally consider obtaining a nonmag-netic patient slider board, physiologicmonitoring equipment (e.g., fiber-opticpulse oximeter), nonmagnetic oxygentank (including nonmagnetic regulator,cart or stand), portable suction, Mayostand, and other devices and accessories(Table 1).

Of note is that MR centers shouldhave a sufficient number of nonmag-netic oxygen tanks and fire extinguish-ers in the immediate and general areato prevent responding emergency staffmembers from introducing ferromag-netic objects into the MR environment.In fact, some hospital-based MR centershave nonmagnetic oxygen tanks and fireextinguishers used throughout theirbuildings to prevent projectile accidents.

Biopsy Needles, Biopsy Guns,and Tissue Markers. InterventionalMRI has been used to guide tissuebiopsy and apply markers with encour-

aging results. Obviously, the perfor-mance of these specialized proceduresrequires tools that are compatible withMR systems. Many conventional biopsyneedles, biopsy guns, and tissue mark-ers have been evaluated with respect tocompatibility with MR procedures, notonly to determine ferromagnetic qualities but also to characterize imaging artifacts.The results have indicated that most of

these are not useful for MRI-guided biopsy procedures dueto the presence of excessiveferromagnetism and associ-ated imaging artifacts thatlimit or obscure the area ofinterest. Fortunately, severalbiopsy needles and biopsyguns have been constructedout of nonferromagneticmaterials specifically for usein interventional MRIprocedures. These are nowcommercially available fromvarious vendors (Table 1).

The placement of a marking clip orwire enables the accurate localization ofthe surgical excision site and is a usefulsurrogate target, even if the entirelesion is removed and there is a subse-quent need for wire localization prior tosurgery. Marking clips and wires havebeen specially designed for use ininterventional MRI procedures (Table 1).

Surgical Instruments. Inter-ventional MRI procedures have evolvedinto clinically viable techniques for avariety of minimally invasive surgicaland therapeutic applications. Besidesthe typical MRI safety concerns, thereare possible hazards in the interven-tional MRI environment related to theinstrumentation and accessory equip-ment that must be addressed to ensurethe safety of MR healthcare practitio-ners and patients. Surgical instrumentsare an obvious necessity for interven-tional MRI procedures. However, manyof these instruments are made frommetallic materials that can createsubstantial problems in association withinterventional MRI procedures.

The interventional MRI safetyissues that exist for a surgical instru-ment include unwanted movementcaused by magnetic field interactions(e.g., the missile effect, translationalattraction, torque), heating generated byRF power deposition, and artifacts

associated with the use of the instru-ment, if it is in the imaging area ofinterest during its intended use. Toaddress these various problems, surgicalinstruments have been developed thatdo not present a hazard or additionalrisk to the MR healthcare practitioneror patient in the interventional MRIenvironment (Table 1, Figure 6). �


Editor’s Note: SMRT member, Jim Hamilton, shares his understanding of a technical area of Magnetic Resonance Imaging based onhis experience with a GE Signa1.5T scanning system.

Gradient Echo Imaging ContrastPhenomenologyJames B. Hamilton, R.T. (R)(MR)(ARRT), Diagnostic Imaging – MRI, Kaiser Hospital, Woodland Hills, California, USA

I t can be argued that within the huge

arsenal of MR pulsesequences available onscanners today, gradientrefocused echoes (GRE)are the least used orunderstood. Part of theproblem lies within how

to manipulate the contrast of a GREsequence and understand why thecontrast is different from radiofrequency (RF) refocused spin echoes.This article attempts to shed light onboth answers since gradient echoes arestaging a strong comeback in the formof echo planar imaging (EPI).

GRE imaging became clinicallyavailable in the mid 1980s and contin-ues to evolve to this day. Initially,sequential 2D, 3D, and multi planaracquired GRE appeared soon followedby more heavily T1- and T2-weightedofferings. The reasons for these newpulse sequences were:1. Speed: effectiveness of the examination

per unit time.2. Patient comfort.3. Breath holding capabilities for liver and

renal studies.4. Shorter TEs that increase the number of

slices per TR and reduce susceptibilityeffects.

5. Reduced SAR that again increased thenumber of slices per TR due to the removalof the180° refocusing pulse.

6. Dynamic imaging: cine cardiac andvascular studies.

7. RF flip angle manipulation to changeimage contrast.

RF echo formation is familiar andmost of us can give fair detail to the howand why of it. What information maynot be so widespread is that any twoslice selective RF pulses will causerephasing. How can this be? RF pulsesare a function of their amplitude andwaveform over time and contain ele-ments from 0° to 180°. A 10° RF pulsewill move spins from an equilibriumstate to the desired transverse magneti-zation of 10°. Some spins excited by this10° RF pulse may move as much as180°. Not many, but some. This isbecause an RF pulse is optimally tunedto move the majority of spins to thedesired flip angle. Even conventional

spin echo sequences are hampered bythese phenomena and use crusher/spoiler gradients to remove any un-wanted nutations. Is a perfectly tunedRF pulse possible, thereby having onlythe desired elements? Not yet but, it isunderstood a 90°/180° combinationresults in optimal spin re-phasing.

RF refocused echo formation is veryefficient in compensating for extrinsicdephasing caused by T2/ (T2 prime)effects. As a general classification theseeffects are called magnetic field inhomo-geneities. This is dephasing (signal lossover time) caused by:1. Main magnetic field inhomogeneities,2. Magnetic susceptibility effects, and3. Chemical shift of the second kind (hydrogen

frequency differences within the same voxel).

I’ll expand on T2/ a little further on.However, keep in mind there are no RFcombinations that corrects for true T2tissue decay.

Now a word about flow effects andRF echo formation. RF echo formationis primarily a slice selective imagingscheme. So when moving blood or CSFfeel a 90° RF excitation pulse, it tends tomove out of the selected/excited slicebefore it is phase encoded and refocusedby the 180° RF pulse. Meanwhile, bloodthat was not in the slice is phaseencoded, enters the slice during readoutand displays miss-mapped signal asflow artifact. You can see signal void,pulsatile flow artifact or bright signaldependent upon the velocity of themoving spins and the timing of thesequence. All of these issues changewhen we enter the world of gradientrecalled echoes.

In GRE formation, refocused signalis dependent on reversed polaritygradients alone (as compared to the180° RF seen in RF echo formation).Since the 180° RF pulse has beeneliminated, several factors affecting thescan will become apparent. First, GREechoes are not as efficient in refocusingT2/ effects as conventional spin echo(CSE); they only correct for de-phasingcaused by other gradients. Second, theapplied refocusing gradient affects theacquired slice and all tissues outside theslice as well. Moving spins that enter

this slice will generally develop phasecorrection and display bright signal.This is referred to as non-selectiverefocusing. Third, it is understood RFecho formation is dependent on:• Tau; the time between the 90° excitation

and 180° refocusing pulses whereTau = one half TE

• RF pulse duration• Gradient rise time and• Killer/crusher gradients which take time

to play out.

Once the 180° RF pulse is removedwe see that gradient echo formation isdependent on gradient reversal and risetime. Removing the 180° RF pulse fromour MR experiment looks to benefitscanning until you see how important itis to contrast phenomenology andsomething we call T2* (T2 star). De-pending on TE, TR and flip angle, GREimages display varying degrees of T2*influenced contrast. T2* is the com-bined signal loss in an image caused byintrinsic tissue T2 decay (irreversible)and extrinsic T2/ effects (which arereversible). T2, T2/ and T2* are allforms of spin phase dispersion; loss ofsignal in the transverse plane and areaffected by the chosen TE value. T2/

effects may not be as familiar as tissueT2 de-phasing. Simply put, T2/ isadditional signal loss not seen underCSE conditions. Gradient echo se-quences are just not as efficient as CSEin removing T2/ effects. So, let’s detailwhat is signal loss caused by T2/ effects.

T2/ Effects are Caused by:Main magnetic field (BO) inhomoge-neities (manufacturer dependent).This is a function of how well yourparticular magnet has been made(linear homogeneity) measured in partsper million (PPM) and the value of theshim it exhibits at any given time. Thelower the value of PPM the less mag-netic inhomogeneities will adverselyaffect your images. Problem is, whenyou place a person in the magnet,human tissues change the homogeneityof BO. However, in terms of superiorimage quality no matter what oneplaces in the magnet, it is better to startoff with a great shim value than a poorone. Inhomogeneities express them-



selves as shading, usually seen on imageedges. Shorter TE values will de-emphasize this effect since shading is adephasing phenomenon. Any signal lossseen around metal in a spin echosequence will “bloom” much larger in aGRE sequence.

Chemical shift of the second kind.This is where the known precessionaldifferences between hydrogen in watermolecules and hydrogen in fat moleculesexist within the same voxel. Thisprecessional difference is a 3.5 PPMconstant occurring out of phase everyother 2.1 milliseconds at 1.5 Tesla.Assuming 1.5 Tesla, hydrogen existingin water precess 223 Hz faster thanhydrogen existing in fat. How can thisbe? According to the Larmor equation,where we have created transversemagnetization from an RF pulse, thespins at each location in the sampledvolume will precess at a rate deter-mined by the local magnetic fieldstrength. This holds true as long as allspins experience the same magneticfield. The problem is, human tissues arevaried in their composition. Our tissues/molecules differ greatly. We agree thathydrogen is found in nearly 99.999% ofall human tissues. This is not to say weare 100% free water molecules, insteadwe are made of both simple and morecomplex macromolecules and everythingin between. Fat triglicerides are said tobe a complex carbon chain moleculewhere hydrogen, oxygen and carbon linkup structurally different from ourfamiliar water molecule H2O. Addition-ally, hydrogen in the fat molecule formscovalent bonds with atoms of oxygenand carbon and experiences “electronshielding” from it’s neighboring atomsand therefore will not feel the same localmagnetic field strength as hydrogen inwater. It is understood when an RFexcitation pulse is applied hydrogenmolecules experience phase coherence.Once that pulse is turned off, preces-sional differences develop between fatand water molecules (very much like thehands of a clock) until their magneticvectors oppose each other. This opposi-tion occurs at every other 2.1 millisec-onds (@1.5T) after excitation causingcancellation of signal within the voxel.This is commonly seen at the tissueboundaries of many internal organs anddisplays as a “magic marker outlining”of the organ. This effect will not occurunless fat and water molecules existwithin the same voxel. On the otherhand, phase coherence will occur everyother 4.2 milliseconds; the vectors of fatand water will combine to add signal tovoxels bordering different tissues.

Magnetic susceptibility effects(patient tissue induced differences).This is a form of transverse signal loss(dephasing) characterized by theamount that different human tissuesmagnetize when exposed to a magneticfield. Human tissues are diamagneticand will reduce the strength of theapplied external magnetic field that thespins “feel.” Therefore the magneticfield within a patient is said to be“effective,” attributable to whether thesubstance magnetized is diamagnetic,paramagnetic or ferromagnetic. Tissuesmagnetize differently by factors of partsper million (PPM) and give rise tointrinsic susceptibility field gradientsthat form in areas where PPM differ-ences occur such as air tissue interfaces.Gradient echoes do not correct for thisas efficiently as 180 degree RF refocusedspin echoes.

Steady State EffectsA clear understanding of steady

state effects is necessary to controlcontrast in a gradient echo sequence.Therefore, factors affecting both longitu-dinal and transverse steady state arelisted. Additionally, the words “steadystate” should be expanded on so let’s getstarted:

Steady state is a term used inphysics describing phenomenology ofthe very large (cosmology) and the verysmall (quantum mechanics) and howthings are kept in check even thoughchange is occurring. What I prefer is ananalogy as applied to nature; the ratio ofpredators over prey in a given region.Even though rain plays against howmuch grass and trees exist that feedherbivores that feed carnivores, neitherside seems to expand or contract beyonda given range of values at any time.They are said to be in a “steady state” ofexistence. For that matter, equilibriumis a steady state condition whererandom spins are held in either a highor low energy state by B0. So, what doesthis have to do with gradient echocontrast? A steady state is achieved inGRE where TR values are shorter thanT1 and T2 times in tissues. In MRI,steady state has coexistence in bothlongitudinal and transverse magnetiza-tion.

Longitudinal Steady StateIn gradient echo imaging four factors

affect longitudinal magnetization (Mz):1. TR.2. Pulse flip angle (FA).3. Relative Proton Density (RPD) / Tissue T1.

4. Flow.

TR. Longitudinal steady state existswhere TR is less than a tissues’ T1 time.Each tissue has it’s own T1 value butwill lengthen as the main magnetic fieldstrength increases. As a general rule,once TR is less than 100ms, Mz does notrecover. So, there will be residual Mxy(transverse steady state) and is convertedto Mz at the next alpha pulse. Under-stand that under GRE conditions,residual Mxy is a function of TR and T2*(which was described earlier). In brief, ifyou increase TR, you will decreasesaturation and decrease longitudinalsteady state. Why? Because more spinsare allowed to return to equilibrium andare available for excitation to the desiredflip angle, be it 90° or any other angle.

Alpha Pulse Flip Angle (FA):Different manufactures use differentterminology describing the initialexcitation RF pulse of their pulsesequences. If Mz is converted to Mxy, theamount converted can be controlled viathe FA (see Figure 1). For low FAs, lessRF amplitude or duration time is usedto accomplish this and therefore less Mzis converted to Mxy. This in turndecreases the amount of time needed forMz to recover (equilibrium) as comparedwith higher FAs. Obviously, higher FAsincrease both Mxy and Mz.

Relative Proton Density (RPD)/Tissue T1: We agree these factors areout of our control since there are only somany protons in a sample of tissue andtheir T1 value is linked to their environ-ment.

Flow: Flow signal appears bright undergradient echo conditions as describedearlier in this article.

Figure 1. Notice how the flip angledetermines both Transverse magnetizationMxy and Longitudinal magnetization Mz.We agree that maximum signal is achievedwhen we have magnetization perpendicularto equilibrium. This implies an inverserelationship between Mz and Mxy:increases in flip angle up to 90° willincrease transverse magnetization whiledecreasing longitudinal magnetization(which maximizes at equilibrium or 180°inversion).

Gradients continued



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Signals is produced quarterly forthe benefit of the SMRT membership.

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Transverse Steady StateIt is said that when a pulse

sequence’s TR is less than four timeslonger than tissue T2, a transversesteady state or residual transversemagnetization is present. In otherwords, under CSE T2 conditions, the TRis normally set equal to or greater than2000ms. Most every tissue is completelyde-phased by 300ms and four times thatis just 1200ms. Even T1-weightedsequences are immune since we typi-cally use minimum TE values reducingT2 influences as well as using killergradients after readout.

Non-hybrid GRE sequences use TRsin the range of less than 100ms to about800ms. This means whatever tissue hasa T2 value of 25-200ms will haveresidual (left over) transverse magneti-zation at the next TR. This transversesteady state is determined by:1. How much time between RF excitation (TR).2. Flip angle.3. How much T2 decay occurred (TE/T2*).4. How many protons to begin with (RPD).

5. Use of a rewind or spoiler gradient.

TR: If you decrease TR, you will allowless time for T2/ T2* to decay, therebyincreasing transverse steady state.Remember: It is said that when a pulsesequence’s TR is less than four timeslonger than tissue T2, a transversesteady state or residual transversemagnetization is present. Increasing TRhas the opposite effect.

Flip Angle: If you increase flip angle,you will increase transverse steadystate because more Mz is converted toMxy. Decreasing the flip angle has theopposite effect.

TE: Just like a conventional spin echo,increasing TE will allow more T2/ T2* todecay, therefore decreasing transversesteady state (Of course it does! We justallowed the spins to diphase. Oncesignal is de-phased you have to wait forTR to hit it with another RF excitationpulse to re-phase it. Refer again to TRabove).

T2/ T2*: Obviously, Tissue T2 is not inour control but understand that if tissueT2 is longer, T2 decay will decrease andthe transverse steady state will increase.

RPD: The RPD is dependent on the tis-sue being imaged. The greater the RPD,the greater the transverse steady state.

Re-winder gradient: This type ofgradient usage simply applies the lawthat says, “Whatever you do with agradient, you have to eventually un-do.”

This means that where a gradient isturned on, some de-phasing will takeplace depending on the strength of thegradient and how long it was turned on.This is the foundation of GRE imagingwhere we use a gradient to refocus ourecho instead of a 180° RF pulse. Herewe are using a gradient to “wrap-up”spins that have de-phased, makingthem available as residual transversemagnetization for the next alpha(excitation) pulse.

Spoiler gradient: Here, whateverspins are still in phase, a large “killercrusher spoiler” gradient is engaged tocompletely de-phase any residualtransverse magnetization before thenext TR.

Sequence Names and AcronymsRemember my experience has been

with a GE Signa scanner. Following aresome of the acronyms used for GREsequences and a brief description foreach.

GRASS (Gradient Recalled Acquisi-tion in a Steady State) is a non-spoiledsequence where slices are acquiredsequentially due in part to the relativeshort TR (<100ms). Grass tends to beT2*/ mixed-weighted in that PD compo-nents will always be present.

MPGR (Multi Planar GRASS) is asequence where all slices are acquiredwithin a single TR (100 - 800ms), mixed-weighted with no transverse steadystate spoiling.

SPGR (Spoiled GRASS) is a gradi-ent recalled multi-planar sequence thatspoils the transverse component afterreadout each TR. Very little transversesteady state effects are seen in theimage making it less mixed, and moreT1-weighted.

SSFP (Steady State Free Preces-sion) is a unique pulse sequence thathas seen less usage than other GREsequences due to it’s sensitivity to flowand relative low signal to noise ratio.SSFP is very T2/ T2* weighted but lostfavor with the advent of fast spin echo.

What I am driving at is this: befamiliar with the sequences on yoursystem. Then extract from your radiolo-gist the contrast he wishes the tissues toexhibit and pick the sequence thatdelivers this best. �

AcknowledgmentsI would like to thank Bill Faulkner and

the following: truly gifted MRI educators:Tom Schrack, Jack O’Blein, Irv Stutzman,Anne Sawyer-Glover, and Dick Prorock ofGeneral Electric Medical Systems, for theirefforts in helping me understand MRI.

Gradients continued

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ISMRM/SMRT CALENDAR

ISMRM Workshop on ChildhoodWhite Matter Diseases11-13 September 2002Rotterdam, The Netherlands

ISMRM Workshop on In Vivo FunctionalMolecular Assessment of Cancer19-21 October 2002Chaminade at Santa Cruz,Santa Cruz, California, USA

ISMRM Workshop onCurrent Issues in MR Safety23-24 February 2003ArabellaSheraton Grand,München, Germany

SMRT Southeast Regional21 September 2002St. Joseph’s HospitalAtlanta, Georgia, USA

SMRT Eastern Canada Regional28 September 2002Montreal Neurological HospitalMontreal, Quebec, Canada

ISMRM Eleventh ScientificMeeting & Exhibition10-16 May 2003Metro Toronto Convention CentreToronto, Ontario, Canada

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For more registration information, please contact:ISMRM/SMRTPhone: +1 510 841 1899Fax: +1 510 841 2340E-mail: [email protected] site: http://www.ismrm.org/smrt

Highlight Your SiteMaureen Ainslie, M.S., R.T. (R),(MR), SMRT President-Elect

F ellow SMRT members!

We are announcing a new feature available on our websitethis fall at http://www.ismrm.org/smrt. A column will bededicated to you our members and where you work!This is an opportunity to see your site highlighted on the Web!Its time for your fifteen minutes of fame.

• Are you proud of your imaging facility?

• Do you have great co-workers or dynamic staff?

• Do you have a specialty that makes your site unique?

• Is your site a great place to work with exceptional people?

• Are you looking to expand your staff?

Send in pictures of your facility, co-workers and staff alongwith description of your facility and we will enable you tohighlight your site and personnel.

This feature will be available to SMRT members only. If youwould be interested in participating please contact me at:[email protected], or the ISMRM staff at:[email protected]. The process is simple. The exposure isunique! We’re looking forward to seeing you on the Web! �

Awards Committee UpdateHeidi Berns, M.S., R.T. (R)(MR), SMRT Past-President, AwardsCommittee Chair

Suggestions for the following awards are welcomed by the Awards Committee:

Honorary Membership:SMRT membership is not required. It is awarded in recogni-tion of extraordinary achievement and an exceptional level ofservice and support for the section and the mission of theSMRT. This is a “lifetime” award.

Distinguished Service Award:This award is given to a current member in good standing.This award is for outstanding contributions and level of effortand service to the operation, effectiveness, and good reputationof the Section.

Fellow of the Section:This award is given to a current SMRT voting member in goodstanding. This award is given for significant and substantialcontributions to the mission of the SMRT over the courseof at least five years including participation in the AnnualMeetings, Regional Meetings and Publications, and forcontributions to the development of the Section. This is a“lifetime” award for the recipient who remains in goodstanding with the Section.

Please feel free to e-mail me at [email protected] any suggestions. �

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