Split-bolus single-pass CT in splenic injury: does it miss relevant vascular injury? : Article type: original research.

Purpose: To evaluate diagnostic performance of split-bolus single-pass CT (SBSP-CT) for splenic vascular injury (SVI) and clinically relevant splenic vascular injury requiring treatment (CR-SVI) in trauma patients with splenic injury.

Methods: This retrospective observer study included 111 consecutive trauma patients (76% male), mean age 37 years (9-81), median ISS 27 (interquartile range (IQR) 26-33), with splenic injury and primary SBSP-CT at a level-1 trauma center between December 2012 and December 2018. Four radiologists independently scored CTs for SVI presence and likelihood. Consensus reference standards for SVI and CR-SVI were based on clinical, imaging and 3-month follow-up data. Image adequacy was assessed quantitively and qualitatively and diagnostic performance and interobserver agreement analyzed.

Results: 37 of 111 (33.3%) patients had SVI and 27 (24.3%) had CR-SVI requiring treatment. Five patients died prior to SVI treatment from unrelated injuries; no mortality was attributed to undetected SVI. Two patients had delayed splenic rupture, both survived. Median attenuation was 292 HU (IQR 250-348) in the aorta and 130 HU (IQR 114-150) in splenic parenchyma. Images were adequate in 107 of 111 (96.4%) patients. Interobserver agreement for SVI was substantial (0.741; 95% CI: 0.67-0.82). NPV for SVI ranged from 89.2 to 94.4% (95% CI: 89.2-97.4) and for CR-SVI from 94.4 to 97.1% (95% CI: 88.5-98.9). AUROC for SVI ranged from 0.825 to 0.862 and for CR-SVI from 0.825 to 0.862.

Conclusion: SBSP-CT provides adequate image quality and high diagnostic confidence for evaluating splenic vascular injury with high negative predictive value for relevant splenic vascular injuries.