Quantitative assessment of active bleeding on contrast-enhanced computed tomography in primary postpartum hemorrhage

This study aimed to evaluate whether computed tomography (CT)-derived extravasation rate from dynamic contrast-enhanced CT is associated with invasive hemostatic intervention and clinical severity in primary postpartum hemorrhage.

This retrospective single-center study included 36 patients with active intrauterine arterial bleeding on contrast-enhanced CT among 135 patients who underwent CT for primary postpartum hemorrhage between January 2020 and December 2025. The extravasation rate was calculated as the increase in extravasation volume from arterial to delayed phase divided by the interphase interval. Associations with hysterectomy and transcatheter arterial embolization (TAE), and correlations with clinical variables, were assessed.

The median extravasation rate was 3.7 mL/min. In the overall cohort, the extravasation rate was higher in patients who underwent hysterectomy than in those who did not, although the difference was not statistically significant (21.71 vs. 3.37 mL/min, P = 0.083). After exclusion of laparotomy cases, the extravasation rate tended to be higher in patients who underwent TAE than in those managed conservatively (4.07 vs. 0.90 mL/min, P = 0.075). Exploratory receiver operating characteristic curve analyses yielded areas under the curve of 0.705 and 0.764 for hysterectomy and TAE, respectively, although the corresponding confidence intervals were wide. The extravasation rate showed weak negative correlations with hemoglobin level (ρ = -0.356, P = 0.033) and hematocrit (ρ = -0.343, P = 0.040), whereas the correlations with systolic and diastolic blood pressure did not reach statistical significance.

CT-derived extravasation rate showed exploratory associations with hemorrhagic severity and invasive hemostatic intervention. These preliminary findings require validation in larger studies using standardized CT acquisition and measurement protocols.

Quantitative assessment of contrast extravasation on dynamic CT provides a continuous imaging measure beyond the binary presence or absence of active bleeding.