Dynamic changes in bleeding sites: Evaluating contrast extravasation on computed tomography and angiography in pelvic fractures.

Background: Contrast extravasation ("blush") on contrast-enhanced computed tomography (CECT) indicates active bleeding, but diagnostic angiography (AG) following CECT sometimes differs from the CECT findings in patients with pelvic fractures. This study aimed to evaluate the concordance rate between blush on CECT and AG based on pelvic anatomical location.

Methods: This retrospective single-center study included patients (18 years or older) with pelvic fractures between 2015 and 2023 who had AG after CECT. Angiography was performed in patients with blush or hematoma on CECT, or unstable hemodynamics due to pelvic fracture. Pelvic bleeding regions were categorized separately into left and right as anterior internal iliac artery and posterior internal iliac artery based on pelvic arterial anatomy. The concordance rate between blush on CECT and AG was assessed using the k statistic.

Results: A total of 87 patients with pelvic fractures were included. Among these, 75 (86%) had blush on CECT, and 12 (14%) had no blush on CECT. The concordance rate was 83% (95% confidence interval, 0.03-0.57; k = 0.30) when assessed on an individual patient basis and 53% (95% confidence interval, 0.24-0.44; k = 0.34) when evaluated by anatomical regions on a unilateral half of the pelvis. The concordance rate for the anatomical hemipelvis evaluation was significantly lower compared with the individual evaluation ( p < 0.001). Thirty-three percent of patients with unilateral blush on CECT showed new contralateral blushes during AG.

Conclusion: The location of active bleeding often differs between CECT and AG, indicating that bleeding may change intermittently and at various sites over time. This suggests the importance of evaluating both sides of the pelvic arteries during AG rather than solely relying on CECT findings.

Level of evidence: Prognostic and Epidemiological; Level IV.