Deep learning-based quantitative visualization and measurement of extraperitoneal hematoma volumes in patients with pelvic fractures: Potential role in personalized forecasting and decision support
Authors: Dreizin David , Zhou Yuyin , Chen Tina , Li Guang , Yuille Alan L. , McLenithan Ashley , Morrison Jonathan J. 
Published: December 2019

INTRODUCTION
Admission computed tomography (CT) is a widely used diagnostic tool for patients with pelvic fractures. In this pilot study, we hypothesized that pelvic hematoma volumes derived using a rapid automated deep learning-based quantitative visualization and measurement algorithm predict interventions and outcomes including (a) need for angioembolization (AE), pelvic packing (PP), or massive transfusion (MT), and (b) in-hospital mortality.

METHODS
We performed a single-institution retrospective analysis of 253 patients with bleeding pelvic fractures who underwent admission abdominopelvic trauma CT between 2008 and 2017. Included patients had hematoma volumes of 30 mL or greater, were 18 years and older, and underwent contrast-enhanced CT before surgical or angiographic intervention. Automated pelvic hematoma volume measurements were previously derived using a deep-learning quantitative visualization and measurement algorithm through cross-validation. A composite dependent variable of need for MT, AE, or PP was used as the primary endpoint. The added utility of hematoma volume was assessed by comparing the performance of multivariable models with and without hematoma volume as a predictor. Areas under the receiver operating characteristic curve (AUCs) and sensitivities, specificities, and predictive values were determined at clinically relevant thresholds. Adjusted odds ratios of automated pelvic hematoma volumes at 200 mL increments were derived.

RESULTS
Median age was 47 years (interquartile range, 29–61), and 70% of patients were male. Median Injury Severity Score was 22 (14–36). Ninety-four percent of patients had injuries in other body regions, and 73% had polytrauma (Injury Severity Score, ≥16). Thirty-three percent had Tile/Orthopedic Trauma Association type B, and 24% had type C pelvic fractures. A total of 109 patients underwent AE, 22 underwent PP, and 53 received MT. A total of 123 patients received all 3 interventions. Sixteen patients died during hospitalization from causes other than untreatable (abbreviated injury scale, 6) head injury. Variables incorporated into multivariable models included age, sex, Tile/Orthopedic Trauma Association grade, admission lactate, heart rate (HR), and systolic blood pressure (SBP). Addition of hematoma volume resulted in a significant improvement in model performance, with AUC for the composite outcome (AE, PP, or MT) increasing from 0.74 to 0.83 (p < 0.001). Adjusted unit odds more than doubled for every additional 200 mL of hematoma volume. Increase in model AUC for mortality with incorporation of hematoma volume was not statistically significant (0.85 vs. 0.90, p = 0.12).

CONCLUSION
Hematoma volumes measured using a rapid automated deep learning algorithm improved prediction of need for AE, PP, or MT. Simultaneous automated measurement of multiple sources of bleeding at CT could augment outcome prediction in trauma patients.

LEVEL OF EVIDENCE
Diagnostic, level IV.