Oral Contrast for CT of abdomen/pelvis necessary?  

-Study #1: In a single center cohort study, there was no statistically significant difference between study and control in clinical diagnoses, technical adequacy of the scans, or specific bowel related pathology (such as fat stranding)

-Study #2: In a retrospective study of 1992 patients who received CT with IV contrast only, only 4 patients required repeat imaging due to lack of PO contrast on initial evaluation

-PO contrast was identified as most useful in:
     •Patients with BMI < 25
     •Suspected bowel perforation
     •Focal bowel abnormalities

Bottom Line:
-Both studies suggest that PO contrast is NOT necessary in most cases of acute abdominal pain
-However, PO contrast can benefit reading radiologists and learners in identifying structures and pathology
-PO contrast use is often institution dependent
-Clinical suspicion of bowel perforation, fistulas, or in some cases bowel obstruction are most likely to benefit from PO contrast administration

Resources:
1) Kessner R, Barnes S, Halpern P, Makrin V, Blachar A. CT for Acute Nontraumatic Abdominal Pain—Is Oral Contrast Really Required? Academic Radiology. 2017;24(7):840-845. doi:10.1016/j.acra.2017.01.013. Uyeda JW, Yu H, Ramalingam V, Devalapalli AP, Soto JA, Anderson SW.
2) Evaluation of Acute Abdominal Pain in the Emergency Setting Using Computed Tomography Without Oral Contrast in Patients With Body Mass Index Greater Than 25. Journal of Computer Assisted Tomography. 2015;39(5):681-686. doi:10.1097/rct.0000000000000277