Contrast Without Clarity: The Questionable Role of Oral Contrast in Detecting Missed Hollow Viscus Injury

Background Delayed diagnosis of hollow viscus injury (HVI) after blunt abdominal trauma is life-threatening and may be missed on initial CT imaging. Unexplained free fluid can signal HVI, yet the optimal diagnostic approach, particularly the role of repeat imaging with oral (PO) contrast, remains controversial. This study evaluates whether repeat CT with PO improves detection of missed HVI. Methods A single-center retrospective cohort study was performed at a level I trauma center (2017-2023) examining patients who presented with blunt abdominal trauma and free fluid on initial CT. Cohorts were grouped based on imaging modality: IV contrast only (CT IV) and IV plus PO contrast (CT IV + PO). The primary outcome was identification of new or previously missed findings prompting management changes. Secondary outcomes included postoperative complications and mortality. Results 300 patients met inclusion criteria (130 CT IV; 170 CT IV + PO). New findings appeared in 34.3% overall, with no significant difference between groups (38.5% vs 31.4%, P = 0.20). Rates of operative intervention (11.5% vs 15.9%, P = 0.32), positive operative findings (8.5% vs 12.9%, P = 0.27), and postoperative complications (7.7% vs 8.2%, P = 1.00) were similar. Unadjusted mortality was higher in patients who underwent CT IV (10.8% vs 4.1%, P = 0.038); however, no difference was observed after adjusting for Injury Severity Score ( P = 0.59). Delayed time to intervention strongly correlated with complications and mortality. Discussion Repeat CT can assist in detecting missed HVI, but adding PO contrast does not improve diagnostic yield, alter management, or affect outcomes.