Emergencies Discerning the Helpful From the Hedge: Imaging Tips for Abdominal Emergencies Angela M. Mills, MD March 5, 2012 Department of Emergency Medicine University of Pennsylvania Health System

Disclosures None related to this talk n Allere, Inc. –Research Funding n Siemens Health Care Diagnostics –Research Funding n EM Clinics of North America –Honorarium

Hedge (hĕj) n. 4. An intentionally noncommittal or ambiguous statement. v.intr. 3. To avoid making a clear, direct response or statement. The American Heritage® Dictionary of the English Language

The Hedge

Overview n Epidemiology n Right upper quadrant pain n Pelvic pain n Right lower quadrant pain in pregnancy n Contrast for suspected appendicitis

Over 8 million visits for abdominal pain in 2006

Kocher et al. Ann Emerg Med % all ED pts

Kocher et al. Ann Emerg Med Almost 10x higher likelihood of CT in 2007 than 1996

Cat Scan

RUQ Pain: Is It Acute Cholecystitis?

Ultrasound “…Recommend HIDA scan if there is concern for acute cholecystitis”

Acute Cholecystitis n EMBU comparable to Rad –Sensitivity 87% vs. 83% –Specificity 82% vs. 86% –Prior studies sensitivity 84-98% n CT sensitivity 75% –Perforation, emphysematous chole, alternative diagnoses Summers et al. Ann Emerg Med Privette et al. EMCNA

HIDA Blaivas et al. J Emerg Med n Nonfilling of GB suggestive of AC –GB normally visualized within 30 mins n Sensitivity % n Specificity 85-90%

n 99 pts, ED US and HIDA n Agreement 77% n 80% (12/15) +HIDA but –US, path agreed with US n 5 pts with normal HIDA but +US, path agreed with US Blaivas et al. J Emerg Med

Other HIDA Indications n Symptoms of biliary dyskinesia (chronic acalculous cholecystitis) n Biliary tree anomalies n Evaluation of bile leak post chole n Sick ICU patient –GN sepsis and unreliable exam –Unexplained leukocytosis on TPN Lambie et al. Clin Rad

HIDA Limitations n Does not image other structures n High bilirubin (>4.4 mg/dL) can ↓ sensitivity n Recent eating or fasting for 24 hrs n False negatives (filling in 30 min) in 0.5% –Filling between mins associated with false- negative rates of 15-20% n False-positive results (10-20%) Blaivas et al. J Emerg Med

Gallstones

Pelvic Pain: Is It Ovarian Torsion?

Computed Tomography “…Recommend US if there is concern for ovarian torsion” Chiou et al. J US Med

n 100% OT had abnormal ovary on CT Moore et al. Emerg Rad CT with normal ovaries rules out torsion

Moore et al. Emerg Rad

US for Ovarian Torsion n Abnormal flow –Sensitivity 44%, Specificity 92% –PPV 78%, NPV 71% n Accuracy 71% Bar-On et al. Fertil Steril Chiou et al. J US Med

US for TOA n Sensitivity 56-93% n Specificity 86-98% n Only prospective study showed Sensitivity 56%, Specificity 86% Lee et al. J Emerg Med Tukeva et al. Rad

CT for TOA n No studies to evaluate Sens/Spec n Ovarian masses, dilated tubes, free fluid equally seen CT and US n Fat stranding better seen on CT n May be more difficult to differentiate pyosalpinx from T-O complex or abscess by CT Horrow et al. US Quart

CT for TOA Hiller et al. JRM

Cat Scan

RLQ Pain in Pregnancy: Is It Appendicitis?

US for Appendicitis “…Recommend MRI if there is concern for acute appendicitis”

US for Appendicitis n Systematic review 14 studies (adults) –Sensitivity 81%, Specificity 80% n Appendix not seen 25-35% of time –Positive when diameter >6-7mm n False negatives with perforation, retrocecal or tip inflammation only Eresawa et al. Ann Int Med Horn et al. EMCNA Kessler et al. Rad

US for Appendicitis

n Systematic review n Imaging after normal or inconclusive US in pregnancy –CT: Sensitivity 86%, Specificity 97% –MRI: Sensitivity 80%, Specificity 99% Basaran et al. Ob Gyn Surv

MRI Appendicitis in Pregnancy

MRI vs. CT in Pregnancy n MRI has NPV 98% for acute abd pain n Both show alternative diagnoses n Retrospective study greater increase in abd CT in pregnancy –22%/yr/1,000 deliveries vs. 13%/yr –Suspected appy most common indication Oto et al. Abd Imaging Goldberg-Stein et al. Am J Roentgenol

n No consensus for imaging algorithm for abd pain in pregnancy n Radiology survey –96% respondents perform CT when benefit/risk ratio is high –MRI preferred 1 st trimester –CT preferred 2 nd / 3 rd trimesters Jaffe et al. Am J Roentgenol

Suspected Appendicitis: Is Contrast Needed?

Contrast n n Oral – –Limits resp misregistration, motion artifacts Development of fast multidetector CT – –Protocols: mins to opacify bowel n n IV – –Highlights differences btwn soft tissues – –Risk of CIN, allergic reaction Holmes et al. Ann EM Stuhlfaut et al. Rad

n n 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

n n 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

n n 7-study systematic review – –1060 patients – –Final dx at surgery or min 2 week f/u – –Noncontrast = no oral or IV n n Sensitivity 93%, Specificity 96% – –Comparable to prior published reviews Hlibczuk et al. Ann Emerg Med

Questions