Discerning the Helpful From the Hedge: Imaging Tips for Abdominal Emergencies

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

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

3. 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

4. The Hedge

5. Overview • Epidemiology • Right upper quadrant pain • Pelvic pain • Right lower quadrant pain in pregnancy • Contrast for suspected appendicitis

6. Over 8 million visits for abdominal pain in 2006

7. 13.9% all ED pts Kocher et al. Ann Emerg Med. 2011.

8. Almost 10x higher likelihood of CT in 2007 than 1996 Kocher et al. Ann Emerg Med. 2011.

9. Cat Scan

10. RUQ Pain: Is It Acute Cholecystitis?

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

12. Acute Cholecystitis • EMBU comparable to Rad • Sensitivity 87% vs. 83% • Specificity 82% vs. 86% • Prior studies sensitivity 84-98% • CT sensitivity 75% • Perforation, emphysematous chole, alternative diagnoses Summers et al. Ann Emerg Med. 2010. Privette et al. EMCNA. 2011.

13. HIDA • Nonfilling of GB suggestive of AC • GB normally visualized within 30 mins • Sensitivity 90-100% • Specificity 85-90% Privette et al. EMCNA. 2011. Blaivas et al. J Emerg Med. 2007.

14. 99 pts, ED US and HIDA • Agreement 77% • 80% (12/15) +HIDA but –US, path agreed with US • 5 pts with normal HIDA but +US, path agreed with US Blaivas et al. J Emerg Med. 2007.

15. Other HIDA Indications • Symptoms of biliary dyskinesia (chronic acalculous cholecystitis) • Biliary tree anomalies • Evaluation of bile leak post chole • Sick ICU patient • GN sepsis and unreliable exam • Unexplained leukocytosis on TPN Lambie et al. Clin Rad. 2011.

16. HIDA Limitations • Does not image other structures • High bilirubin (>4.4 mg/dL) can ↓ sensitivity • Recent eating or fasting for 24 hrs • False negatives (filling in 30 min) in 0.5% • Filling between 30-60 mins associated with false-negative rates of 15-20% • False-positive results (10-20%) Blaivas et al. J Emerg Med. 2007.

17. Gallstones www.cartoonstock.com

18. Pelvic Pain: Is It Ovarian Torsion?

19. Computed Tomography “…Recommend US if there is concern for ovarian torsion” Chiou et al. J US Med. 2007.

20. 100% OT had abnormal ovary on CT CT with normal ovaries rules out torsion Moore et al. Emerg Rad. 2009.

21. Moore et al. Emerg Rad. 2009.

22. US for Ovarian Torsion • Abnormal flow • Sensitivity 44%, Specificity 92% • PPV 78%, NPV 71% • Accuracy 71% Bar-On et al. Fertil Steril. 2010. Chiou et al. J US Med. 2007.

23. US for TOA • Sensitivity 56-93% • Specificity 86-98% • Only prospective study showed Sensitivity 56%, Specificity 86% Lee et al. J Emerg Med. 2011. Tukeva et al. Rad. 1999.

24. CT for TOA • No studies to evaluate Sens/Spec • Ovarian masses, dilated tubes, free fluid equally seen CT and US • Fat stranding better seen on CT • May be more difficult to differentiate pyosalpinx from T-O complex or abscess by CT Horrow et al. US Quart. 2004.

25. CT for TOA Hiller et al. JRM. 2005.

26. Cat Scan www.cartoonstock.com

27. RLQ Pain in Pregnancy: Is It Appendicitis?

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

29. US for Appendicitis • Systematic review 14 studies (adults) • Sensitivity 81%, Specificity 80% • Appendix not seen 25-35% of time • Positive when diameter >6-7mm • False negatives with perforation, retrocecal or tip inflammation only Eresawa et al. Ann Int Med. 2004. Horn et al. EMCNA. 2011. Kessler et al. Rad. 2004.

30. US for Appendicitis

31. Systematic review • Imaging after normal or inconclusive US in pregnancy • CT: Sensitivity 86%, Specificity 97% • MRI: Sensitivity 80%, Specificity 99% Basaran et al. Ob Gyn Surv. 2009.

32. MRI Appendicitis in Pregnancy

33. MRI vs. CT in Pregnancy • MRI has NPV 98% for acute abd pain • Both show alternative diagnoses • Retrospective study 1998-2005 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. 2009. Goldberg-Stein et al. Am J Roentgenol. 2011.

34. No consensus for imaging algorithm for abd pain in pregnancy • Radiology survey • 96% respondents perform CT when benefit/risk ratio is high • MRI preferred 1st trimester • CT preferred 2nd / 3rd trimesters Jaffe et al. Am J Roentgenol. 2007.

35. Suspected Appendicitis: Is Contrast Needed?

36. 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.

37. 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.

38. 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.

39. 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.

40. Questions www.cartoonstock.com