Post on 15-Jan-2017
EMERGENCY CT – IS IT BEING OVERUSED?!!!
PROF.C.AMARNATH, MD, FRCR, PHD,
PROF & HEAD , DEPT OF RADIODIAGNOSIS,STANLEY MEDICAL COLLEGE, CHENNAI – 1
CONSULTANT RADIOLOGIST,SCANS WORLD, CHENNAI
Is CT scan overused?
Overuse has been defined as any procedure or test which is undergone to a patient for an inappropriate indication.
Definitely, the answer is “yes”.
Virtually anyone who presents in the emergency room with abdomen pain or a headache or syncope or minor head injury will automatically get a CT scan.
The rate of CT use grew 11 times faster than the rate of ED visits during the last 10 year period.
Just 3.2 percent of emergency patients received CT scans in 1996, while 13.9 percent of emergency patients seen in 2007 received them.
This means that by 2007, 1 in 7 ED patients got a CT scan. It also means that about 25 percent of all the CT scans done in the United States are performed in the ED.
Less than 7.1 percent of patients presenting to the emergency department with dizziness and 6.4 percent complaining of syncope or near-syncope benefited from head CT
Why overused?
Several factors contribute to the increased use of CT scans: The greater availability of the equipment; Doctors’ fear of being sued for malpractice; A perception that patients want the test;
and Financial pressure to make use of the
machine
CT is “user-friendly” for the clinician, the patient and the radiologist.
It is readily available, very fast, produces high-quality images, and is capable of detecting a wide array of illnesses
CT scanners are commonly housed in or near the ED itself, and there is no barriers to get the CT done.
At the same time, the relatively high-radiation doses associated with CT have also raised health concerns
EMERGENCY CT
Trauma headache vertigo, dizziness or light-headedness abdominal pain convulsions impairments of nerve, spinal cord or brain
function flank pain general weakness
PAN SCAN (WHOLE BODY CTSCAN)
Pan scan should be used only on certain prescribed indications.
But nowadays it is used even in minor injuries as well as in stable patients.
Whole-body computed tomography in polytrauma: techniques and management. Linsenmaier U et al Eur Radiol. 2002 Jul; 12 (7): 1728-40. Epub 2001 Dec 13
HOW TO REDUCE OVERUSAGE?
Many of these recommendations are being promoted through the “Choosing Wisely initiative”, a campaign developed by the ABIM Foundation that has collected and communicated guidelines from across the medical community.
to help physicians and patients engage in informed conversations about unnecessary tests, treatments and procedures.
Choosing Wisely Campaign guidelines
Three specific guidelines (initial). American College of Emergency Physicians (ACEP),
states that doctors should “avoid CT scans of the head in emergency department patients with minor head injury who are at low risk based on validated decision rules.”
For syncope: “Avoid CT of the head in asymptomatic adult patients in the emergency department with syncope, insignificant trauma and a normal neurological evaluation
The another guideline on headache: patients who come to the emergency room with a headache but no other complications or risk factors should not get CT scans.
Some other recent recommendations Don’t do imaging for low back pain
within the first six weeks, unless red flags are present. ( severe or progressive neurological deficits or when serious underlying conditions such as osteomyelitis are suspected).
Don’t start with CT for children suspected of appendicitis. (USG –PRIMARY)
Neuroimaging (CT, MRI) is not necessary in a child with simple febrile seizure.
Avoid Unnecessary CT
The Canadian CT Head Rule (CCHR), a clinical
decision rule designed to safely reduce imaging in minor head injury by
differentiating mild
traumatic brain injury
from clinically important
brain injuryOne in every three CT scans performed on patients with minor head injury is unnecessary
Indications for CT C-spine in ER
The Canadian C-spine Rules and NEXUS rules -an x-ray or CT as the their first line imaging modality.
Clearly CT is much more accurate than x-ray at detecting significant injuries( a moderate-high suspicion for a fracture or dislocation).
3 factors… The patient’s “protoplasm” – Do they have a history of
osteoporosis? Are they very elderly? Do they have a history of ankylosing spondylitis?
The likelihood of obtaining a high quality x-ray image – Is the patient bull-necked? Do they have severe osteoarthritis?
The mechanism of injury and physical exam – Was it a high risk mechanism of injury such as ejection from a car? Are they altered making the physical exam unreliable? Are there any focal neurological signs?
Avoid Unnecessary CT
Facet dislocation
Cervical spine fracture dislocation
Burst fracture
Involvement of middle and posterior columns Presence of retropulsed bone fragments Integrity of above and below vertebrae
TRAUMATIC PSEUDOANEURYSM
Post traumatic vascular occlusion
Diagnostic work
up
Acute Abdomen
Ultrasound Abdominal plain film
CT MRI
Which is the best choice?
Diagnostic work
up
Acute Abdomen
US
US CT CT
CT CT
Acute Abdomen
MRI
Pregnancy Young
patientswhen US inconclusive
Cholecystitis
Gallstone Wall thickening Intraluminal sludge Sonographic
Murphy’s sign +++
Gynecologic emergency
Salpingitis
Ovary cyst
Ovary torsion
Case RUQ
What does the US examination show?
1) Acute cholecystitis
2) Free fluid in the Morrison pouch
3) Increased echogenicity of the intraperitoneal fat in RUQ
CaseRUQ
Which is the main CT
finding?
1) Ascending colon
diverticulitis
2) Omental inhomogeneity
3) Mesentery inhomogeneity
CT as the first line examination
CT is used as a first line modality in a number of emergency cases where we can’t rely on other modalities, or if there is a danger of missing diagnosis or if there is a fear of getting delayed for treatment.
When ? When the sensitivity of other modalities in acute abdomen is too low to diagnose conditions…
Why ? How ? What side effects ?
CT versus APF : APF is an insensitive modality
Sensitivity of APF Ahn Radiology 2002 871 patients
Bowel obstruction : 49 % Urolithiasis : 9 % Appendicitis, pyelonephritis, pancreatitis,
diverticulitis : 0 % Intraabdominal foreign body : 90 %
Sensitivity of APF Mackersy Radiology 2005 91 patients
30 % for APF versus 96 % for CT
APF for the diagnosis of pneumoperitoneum
Sen : 50 - 70 % Accuracy decreases
APF less and less analyzed (even if performed) Compromise Sen/Spe
170 p with suspicion of bowel perforation APF upright including diaphragmatic domes Sen = 78 % with Spe = 50 % Chen SC J Emerg Med 2002
ACUTE ABDOMEN Consider abdominal
ultrasound as the initial diagnostic test in suspected uncomplicated appendicitis, nephrolithiasis, or diverticulitis, gynecologic conditions and biliary conditions.
Acute appendicitis Diameter ≥ 6 mmPPV, NPV ≥ 95 %Kessler Radiology 2004
Acute appendicitis
Identification of the normal appendix - A weakness of US
A normal appendix would be identified in only 5 % of patients (NEJM jan 2003)!!!appendix is identified in 64 % of cases (Kessler Radiology 2003)
- A strength of CTCT identifies normal appendix in 80 % of cases (Benjaminof Radiology 2003)
CT or US in appendicitis
US CT first line
- thin patients - fat patients- young women - peritoneal
findings- recent clinical findings - diffuse pain- children - failure with
US
Colic pain
CT advantages : Sen Spe Alternatives
Dgs Easier Faster
37
High velocity accident Middle-aged female Hemodynamically unstable Glasgow Coma Score 3/15
Case 2
• Suggested method of examination
1. X-ray2. US3. CT4. DSA
38
CT revealed subarachnoidal bleeding, cervical spine fracture, normal chest
Abdominal CT was also performed
Case 2
39
Case No. 2.
• Any further remarkable findings?
– complex pelvic fracture
– right psoas muscle hematoma
– liver parenchymal tear
Case 2
40
Types of shock: hypovolemic cardiogenic distributive
Patient developed a hypovolemic shock due to a large hemorrhage
“Hypoperfusion complex” consists of diffuse dilatation of intestines with fluid intense enhancement of bowel wall increased enhancement of the adrenal glands diminished caliber of the abdominal vessels
(„flat cava” sign) decreased splenic enhancement
Case 2
41
Case No. 2. – A similar case
42
Abdominal injury – diagnostic algorithm
• (history, physical examination, lab tests)
• Plain X-ray– abdomen
• erect or decubitus• supine
– chest– bones
• lower ribs• spine• pelvis
• Ultrasound
• Computed tomography
MDCT
43
4 good reasons to perform CT:
plain abdominal X-ray / abdominal US may not be executable
plain abdominal X-ray / abdominal US may not be diagnostic
relevant information may be expected from CT only:(complete overview of the parenchymal organs, bowels, mesentery, omentum, peritoneum, retroperitoneum, vessels, bones, etc.)
time requirement of CT is much shorter
Abdominal injury – diagnostic algorithm
62 year-old female, acute onset of abdominal pain
What is your diagnosis?1) Acute mesenteric ischemia2) Crohn disease3) Infectious enteritis4) Portal vein thrombosis
Case
Acute mesenteric ischemia
Arterial contrast phase:Embolus in SMA
•Enhancement of prox. Jejunum
• No enhancement of remaining small bowel
• Clot or reduced lumen in SMA
• Segmental wall thickening
• Lack of mucosal enhancement
• No stranding
• Pneumatosis intestinalis
Bowel perforation : choice of surgical procedure
Ulcer perforation coelioscopy
Bowel perforation : choice of surgical procedure
Jejunal diverticulitis with perforation → laparotomy
Bowel perforation : choice of surgical procedure
Colic perforation with stercoral peritonitis → colostomy
Bowel obstruction : choice of surgical procedure
• When a surgical procedure is scheduled, CT has an impact +++
How ?
Multidetector CT : axial 1 mm thick slice for acquisition, 3mm for reading
2 questions Added value of reformatting
SBO Appendicitis Bowel perforation
Added value of iv contrast
Value of reformatting in BO
Same Sen and Spe
the diagnostic confidency
Paulson Radiology 2005
Value of reformatting in appendicitis
Same Sen and Spe
the diagnostic confidency
Paulson Radiology 2005
Subtle finding : the whirl finding
Patients with suspicion of BO in an oncologic population : 1213 patients
Small bowel volvulus at surgery : 11 patients (1%)
Sensitivity Specialized GI radiologist : 64 % Senior resident : 27 %
Gollub JCAT 2006
Midgut Volvulus
Midgut Volvulus
Whirl sign
Soft-tissue mass with an internal architecture of swirling strands of soft tisssue and fat attenuation
Best shown in the plane perpendicular to the axis of rotation
Non specialized physician will ask CT
Prevalence of disease decreases Suspicion of appendicitis
Surgeon : 70 % Emergency department physician : 40 %
Suspicion of colic pain urologist : 80 % Emergency department physician : 60 %
Predictive positive value decreases
OMGE(6 097 cases)
ARC(3 772 cases)
MODALITY
Appendicitis 24,1 % 26 % CT / USCholecystitis 8,9 % 10 % USGynecologic disease
6 % 7 % US
Obstruction 4 % 9 % CT SAP in FU
Colic pain 3,4 % 4 % CT or nothing
GI perforation 2,8 % 4 % CTPancreatitis 2,3 % 4 % CTDiverticulitis 2,1 % 2 % CTMesenteric ischemia
1 % 1 % CT
NSAP 43 % 22 % CT or nothing
Is the abdominal x-ray dead?There still remains several indications for the use of abdominal x-rays in emergency radiology.
1. Radio-opaque foreign body – metal, leaded glass or large objects such as packets found in drug mules
2. To look for free air in suspected perforated viscous in patient who is not stable enough to leave the ED for a CT
3. Known chronic diagnosis with multiple frequent recurrent acute exacerbations such as recurrent small bowel obstruction, especially in patients who have had multiple CT scans in the past
RADIATION HAZARD
There is no safe dose of radiation. Edward P Radford, MD
Scholar of the Risks from Radiation
Diagnostic Imaging Risk Procedures Effective Dose (mSv)
Risks
CXR (PA), extremity XR <0.1 Negligible
Abdomen XR, LS spine XR
0.5- 1 Extremely low “death from flying 7200 km”
Brain CT, single-phase abdomen CT, single-phase chest CT
1-10 Very low “death from driving 3200 km)
Multiphase CT 10-100 Low
Interventions, repeated CT
>100 Moderate
Comparative dose
DoseEquivalent
background radiation
Estimated deaths
Chest X-ray PA 0.1 mSv 3 d 1/1 million examinations
Abdomen X-ray 3 views 1.5 mSv 8 months 1/12,500
examinations
Standard-dose MDCT
10-15 mSv 100-150 times 7.2 y 1/1,250
examinations
Fo radults
Children who undergo CT scans in early childhood tend to be at greater risk for developing leukemia , primary brain tumors , and other malignancies later in life
Justification
Main goal: reducing radiation dose (ALARA).
Only when properly indicated: is this examination of importance
(essential) for diagnosis and therapy in this patient?
Consider alternatives: Ultrasound: abdomen, neck, soft tissues,
chest MRI: small bowel, liver, brain
Conclusion CT ideally should be used as a diagnostic test rather
than a screening one because of its expense and unnecessary radiation exposure to the patient
CT scan overused –brain, Pulmonary angio
There are recommendations about when it is appropriate for physicians to order CT scans.- guidelines
CT may be considered as the first line imaging test in acute abdomen EXcept for suspicion of gynecologic conditions, biliary conditions, appendicitis in some cases, and except in children
Select the Right Imaging Exam-Radiation (ALARA ) Alternative diagnostic imaging
Thank youGood luck &
all the best !!!
Thank you for your
attention