Post on 03-Jan-2016
Discerning the Helpful From the Hedge: Imaging Tips for
Abdominal Emergencies Emergencies
Angela M. Mills, MDMarch 5, 2012
Department of Emergency Department of Emergency
MedicineMedicineUniversity of Pennsylvania Health SystemUniversity of Pennsylvania Health System
DisclosuresDisclosures
None related to this talkNone related to this talk Allere, Inc. Allere, Inc.
– Research FundingResearch Funding Siemens Health Care DiagnosticsSiemens Health Care Diagnostics
– Research FundingResearch Funding EM Clinics of North America EM Clinics of North America
– HonorariumHonorarium
Hedge (hHedge (hĕĕj)j)
n.n.
4. 4. An intentionally noncommittal or An intentionally noncommittal or ambiguous statement.ambiguous statement.
v.intr.v.intr.
3. 3. To avoid making a clear, direct To avoid making a clear, direct response or statement.response or statement.
The American Heritage® Dictionary of the English Language
OverviewOverview
EpidemiologyEpidemiology Right upper quadrant painRight upper quadrant pain Pelvic painPelvic pain Right lower quadrant pain in Right lower quadrant pain in
pregnancypregnancy Contrast for suspected appendicitisContrast for suspected appendicitis
Kocher et al. Ann Emerg Med. 2011.
Almost 10x higher likelihood of CT in 2007 than 1996Almost 10x higher likelihood of CT in 2007 than 1996
UltrasoundUltrasound
““……Recommend HIDA scan if there is Recommend HIDA scan if there is concern for acute cholecystitisconcern for acute cholecystitis””
Acute CholecystitisAcute Cholecystitis
EMBU comparable to RadEMBU comparable to Rad– Sensitivity 87% vs. 83%Sensitivity 87% vs. 83%– Specificity 82% vs. 86%Specificity 82% vs. 86%– Prior studies sensitivity 84-98%Prior studies sensitivity 84-98%
CT sensitivity 75%CT sensitivity 75%– Perforation, emphysematous chole, Perforation, emphysematous chole,
alternative diagnosesalternative diagnoses
Summers et al. Ann Emerg Med. 2010.Privette et al. EMCNA. 2011.
HIDAHIDA
Privette et al. EMCNA. 2011. Blaivas et al. J Emerg Med. 2007.
Nonfilling of GB Nonfilling of GB suggestive of ACsuggestive of AC– GB normally visualized GB normally visualized
within 30 minswithin 30 mins Sensitivity 90-100%Sensitivity 90-100% Specificity 85-90%Specificity 85-90%
99 pts, ED US and HIDA99 pts, ED US and HIDA Agreement 77% Agreement 77% 80% (12/15) +HIDA but –US, 80% (12/15) +HIDA but –US,
path agreed with USpath agreed with US 5 pts with normal HIDA but +US, 5 pts with normal HIDA but +US,
path agreed with USpath agreed with US
Blaivas et al. J Emerg Med. 2007.
Other HIDA IndicationsOther HIDA Indications
Symptoms of biliary dyskinesia Symptoms of biliary dyskinesia (chronic acalculous cholecystitis)(chronic acalculous cholecystitis)
Biliary tree anomaliesBiliary tree anomalies Evaluation of bile leak post choleEvaluation of bile leak post chole Sick ICU patient Sick ICU patient
– GN sepsis and unreliable examGN sepsis and unreliable exam– Unexplained leukocytosis on TPNUnexplained leukocytosis on TPN
Lambie et al. Clin Rad. 2011.
HIDA LimitationsHIDA Limitations
Does not image other structures Does not image other structures High bilirubin (>4.4 mg/dL) can High bilirubin (>4.4 mg/dL) can ↓↓ sensitivity sensitivity Recent eating or fasting for 24 hrs Recent eating or fasting for 24 hrs False negatives (filling in 30 min) in 0.5%False negatives (filling in 30 min) in 0.5%
– Filling between 30-60 mins associated with false-Filling between 30-60 mins associated with false-negative rates of 15-20% negative rates of 15-20%
False-positive results (10-20%) False-positive results (10-20%)
Blaivas et al. J Emerg Med. 2007.
Computed TomographyComputed Tomography
““……Recommend US if there is concern Recommend US if there is concern for ovarian torsionfor ovarian torsion””
Chiou et al. J US Med. 2007.
100% OT had abnormal ovary on CT100% OT had abnormal ovary on CT
Moore et al. Emerg Rad. 2009.
CT with normal ovaries rules out torsionCT with normal ovaries rules out torsion
US for Ovarian TorsionUS for Ovarian Torsion
Abnormal flow Abnormal flow – Sensitivity 44%, Specificity 92%Sensitivity 44%, Specificity 92%– PPV 78%, NPV 71%PPV 78%, NPV 71%
Accuracy 71%Accuracy 71%
Bar-On et al. Fertil Steril. 2010.Chiou et al. J US Med. 2007.
US for TOAUS for TOA
Sensitivity 56-93%Sensitivity 56-93% Specificity 86-98%Specificity 86-98% Only prospective study showed Only prospective study showed
Sensitivity 56%, Specificity 86%Sensitivity 56%, Specificity 86%
Lee et al. J Emerg Med. 2011.Tukeva et al. Rad. 1999.
CT for TOACT for TOA
No studies to evaluate Sens/SpecNo studies to evaluate Sens/Spec Ovarian masses, dilated tubes, free Ovarian masses, dilated tubes, free
fluid equally seen CT and USfluid equally seen CT and US Fat stranding better seen on CTFat stranding better seen on CT May be more difficult to May be more difficult to
differentiate pyosalpinx from T-O differentiate pyosalpinx from T-O complex or abscess by CTcomplex or abscess by CT
Horrow et al. US Quart. 2004.
US for AppendicitisUS for Appendicitis
““……Recommend MRI if there is concern Recommend MRI if there is concern for acute appendicitisfor acute appendicitis””
US for AppendicitisUS for Appendicitis
Systematic review 14 studies (adults)Systematic review 14 studies (adults)– Sensitivity 81%, Specificity 80%Sensitivity 81%, Specificity 80%
Appendix not seen 25-35% of timeAppendix not seen 25-35% of time– Positive when diameter >6-7mmPositive when diameter >6-7mm
False negatives with perforation, False negatives with perforation, retrocecal or tip inflammation onlyretrocecal or tip inflammation only
Eresawa et al. Ann Int Med. 2004.Horn et al. EMCNA. 2011.
Kessler et al. Rad. 2004.
Systematic review Systematic review Imaging after normal or inconclusive Imaging after normal or inconclusive
US in pregnancyUS in pregnancy– CT: Sensitivity 86%, Specificity 97%CT: Sensitivity 86%, Specificity 97%– MRI: Sensitivity 80%, Specificity 99%MRI: Sensitivity 80%, Specificity 99%
Basaran et al. Ob Gyn Surv. 2009.
MRI vs. CT in PregnancyMRI vs. CT in Pregnancy
MRI has NPV 98% for acute abd painMRI has NPV 98% for acute abd pain Both show alternative diagnosesBoth show alternative diagnoses Retrospective study 1998-2005 greater Retrospective study 1998-2005 greater
increase in abd CT in pregnancyincrease in abd CT in pregnancy– 22%/yr/1,000 deliveries vs. 13%/yr22%/yr/1,000 deliveries vs. 13%/yr– Suspected appy most common indicationSuspected appy most common indication
Oto et al. Abd Imaging. 2009. Goldberg-Stein et al. Am J Roentgenol. 2011.
No consensus for imaging algorithm No consensus for imaging algorithm for abd pain in pregnancyfor abd pain in pregnancy
Radiology surveyRadiology survey– 96% respondents perform CT when 96% respondents perform CT when
benefit/risk ratio is highbenefit/risk ratio is high– MRI preferred 1MRI preferred 1stst trimester trimester– CT preferred 2CT preferred 2ndnd / 3 / 3rdrd trimesters trimesters
Jaffe et al. Am J Roentgenol. 2007.
Contrast
Oral– Limits resp misregistration, motion artifacts
• Development of fast multidetector CT
– Protocols: 60-90 mins to opacify bowel IV
– Highlights differences btwn soft tissues– Risk of CIN, allergic reaction
Holmes et al. Ann EM. 2004.Stuhlfaut et al. Rad. 2004.
Retrospective, 183 pts– 81 oral contrast, 102 no oral contrast– Stat sig increased ED LOS
• 358 vs. 599 min, p<0.001
– Difference of 241 min >> 90 min
Huynh et al. Emerg Rad. 2004.
Systematic review of 23 studies– 19/23 prospective, total 3474 patients
• 1510 patients no oral contrast
– Final dx by path or clinical follow up
Anderson et al. Am J Surg. 2005.
7-study systematic review– 1060 patients– Final dx at surgery or min 2 week f/u – Noncontrast = no oral or IV
Sensitivity 93%, Specificity 96%– Comparable to prior published reviews
Hlibczuk et al. Ann Emerg Med. 2010.