Prevalence of imaging findings of acute pancreatitis in emergency department patients with elevated serum lipase.

PURPOSE: To assess the association of imaging features of acute pancreatitis (AP) with the magnitude of lipase elevation in Emergency Department (ED) patients.

METHODS: This Institutional Review Board-approved retrospective study included 509 consecutive patients presenting from 9/1/13-8/31/15 to a large academic ED with serum lipase levels ≥3× the upper limit of normal (ULN) (≥180 U/L). Patients were excluded if they did not have imaging (n = 131) or had a history of trauma, abdominal metastases, altered mental status, or transfer from an outside hospital (n = 190); the final study population was 188 patients. Imaging exams were retrospectively evaluated, and a consensus opinion of two subspecialty-trained abdominal radiologists was used to diagnose AP. Primary outcome was presence of imaging features of AP stratified by lipase level (≥3×-10× ULN and > 10× ULN). Secondary outcome was rate of discordant consensus evaluation compared to original radiologist's report.

RESULTS: 25.0% of patients (47/188) had imaging features of AP. When lipase was >10× ULN (n = 94), patients were more likely to have imaging features of AP (34%) vs. those with mild elevation (16%) (p = 0.0042). There was moderately strong correlation between lipase level and presence of imaging features of AP (r = 0.48, p < 0.0001). Consensus review of CT and MRI images was discordant with the original report in 14.9% (28/188) of cases.

CONCLUSION: Prevalence of imaging signs of AP in an ED population with lipase ≥3× ULN undergoing imaging is low. However, the probability of imaging features of AP increases as lipase value increases.