CESAR SOTO PGY -2 STONY BROOK UNIVERSITY HOSPITAL Non-traumatic abdominal pain CT imaging review

Abdominal pain 28 year old male with no significant past medical history comes to ED 2 days worsening, migrating lower abdominal pain, low grade fevers and nausea, no vomiting, no dysuria/discharge, no travel history. The patient looks uncomfortable, tachycardic and was found to be febrile. What kind of imaging do you want to order?

ACR recommendations Meta-analysis of 7 studies Non-Contrast Abd CT  Sensitivity of 92% and Specificity of 96% Oral and IV Contrast CT  Sensitivity of 100% and Specificity 98% No Oral, ONLY IV contrast  Sensitivity of 100% and Specificity of >97%

What about in the ER? 311 patients, retrospective study 16 had acute appendicitis 0 patients needed repeat CT scan 30 day follow up identified no cases significant surgical problems identified, NO cases of appendicitis were missed

1992 patients retrospective study

4 patients (0.2%) – required repeat CT (with oral contrast) 1193 (59.8%) were interpreted as “negative” 113 (17.6%) were acute appendicitis  Sensitivity of CT without oral was 100% with specificity of 99.5%

What about in perforation? In same study 111 cases of diverticulitis (17.9%) 1 case out of those 1992 (0.05%) required repeat CT with oral contrast as well as rectal contrast. Contrast was only used to CONFIRM perforation

Abdominal pain w/ fever What about someone same patient with LLQ abdominal pain and fevers? Still want oral contrast? What do you worry about?

Diverticulitis

What about IBD? What about a patient who may have inflammatory bowel disease? Many similar complications when compared to diverticulitis

More words…

Last Case What about a patient who has history of abdominal surgeries, is on opioids for chronic back pain, sent from outside NH who has not had a BM in 11 days, no vomiting, no fevers, mild abdominal distention and mild general abdominal tenderness. Oral contrast important? Is it needed to rule out complications of SBO?

99 patients with suspected SBO, retrospective study 105 CT scans (6 patients had 2 CT scans) – 56% had SBO Non Contrast CT –  Sensitivity 88.1% and specificity 77% Contrast enhanced CT  Sensitivity 87.6% and specificity of 82.6%

Last study I promise Why not just give oral contrast, only 2 additional hours! From the Emergency Radiology Journal, Leverson at al study  1014 ED patient oral contrast CT vs 987 IV only contrast CT  Found no statistical difference between the two groups (p<0.001) – no patient had repeat CT with oral contrast  ED length of stay dropped by 97.7 minutes  Average ED visit– about $ 500 each additional 30 mins  That’s more than $1500 per patient

Summary Oral contrast is generally not required, however, if there’s time, it may add to the diagnosis In non acute patients, saves time, money and resources May be appropriate in 1-4% of cases for more “detailed anatomical discrepancy” – but NOT significantly better at making the diagnosis

References American College of Radiology. Atri, M, et al. Multidetector helical CT in the evaluation of acute small bowel obstruction: comparison of non-enhanced (no oral, rectal or IV contrast) and IV enhanced CT. Eur J Radiol Jul;71(1): Eur J Radiol. Glauser J, et al. Emergency department experience with nonoral contrast computed tomography in the evaluation of patients for appendicitis. J Patient Saf Sep;10(3):154-8.J Patient Saf. Levenson, RB, et al. Eliminating routine oral contrast use for CT in the Emergency Department: Impact on patient throughput and diagnosis. Emergency Radiology Dec; 19 (6): Payor A, et al. Efficacy of Noncontrast Computed Tomography of the Abdomen and Pelvis for Evaluating Nontraumatic Acute Abdominal Pain in the Emergency Department. J Emerg Med Aug 22. pii: S (15) J Emerg Med. Rawson, J.V, et al. When to Order Contrast-Enchanced CT. Am Fam Physician Sep 1;88(5): Stafford RE, et al. Oral contrast solution and compute d tomography for blunt abdominal trauma: a randomized study. Arch Surg Jun;134(6):622-6.Arch Surg. Uyeda JW, et al. Evaluation of Acute Abdominal Pain in the Emergency Setting Using Computed Tomography Without Oral Contrast in Patients with Body Mass Index Greater Than 25. J Comput Assist Tomogr Sep-Oct;39(5):681-6.J Comput Assist Tomogr.