Incidental findings during workup for trauma patients is commonplace. A third of patients with incidental findings on CT work up have the potential to cause morbidity if not further evaluated. In one study ¹, hepatic lesions were the 6th most common incidental finding during work-up.
The differential diagnosis for this patient's liver lesion is a traumatic lesion vs hemangioma.
Typically, hemangiomas appear hypoattenuating relative to the surrounding liver parenchyma on noncontrast CT ². With IV contrast, the arterial phase shows peripheral lesion enhancement, followed by centripetal enhancement on the venous phase CT.
In comparison, traumatic hepatic lesions feature the following characteristics ³:

• periportal tracking - hypoattenuation at the right hepatic lobe
• hepatic contusion - irregular hypoattenuating area due to interstitial bleeding
• subcapsular hematoma - biconvex collection, with mass effect on the hepatic parenchyma
• complex laceration - single or multiple linear streaking areas, involving the liver parenchyma
• fragmentation/avulsion of hepatic pedicle - hypoattenuating region, with unmodified enhancement after IV contrast

Case contributed by A/Prof. Pramit Phal.