Value of noncontrast CT immediately after transarterial chemoembolization of hepatocellular carcinoma with drug-eluting beads

Purpose: To retrospectively evaluate the presence and distribution patterns of contrast agent retention in the liver on noncontrast computed tomography (CT) immediately following chemoembolization with drug-eluting beads (DEBs). Materials and Methods: From 2008 to 2010, 95 patients with 224 liver lesions had chemoembolization performed with DEBs and a noncontrast CT examination of the liver performed immediately after embolization. Of these, 85 patients with 193 lesions were included. The postembolization CT scan was reviewed by a diagnostic radiologist, and the presence of contrast agent retention within the lesion was assessed. Varying patterns of contrast agent retention were defined. Results: Of the 193 lesions included, 146 (76%) retained contrast medium. Aside from some contrast medium in vessels, very little if any contrast medium was seen in the surrounding liver. Various patterns of contrast agent retention were noted within lesions. In a single case, repeat imaging was obtained 6 hours later, which demonstrated washout of contrast agent in a lesion that had retained contrast agent on the postprocedure CT scan. Of significance, 13 additional foci of contrast agent retention were identified on postchemoembolization CT scans that, on retrospective review of preprocedure imaging, represented enhancing lesions not previously identified. Conclusions: Noncontrast CT after chemoembolization with DEBs demonstrates contrast agent retention in 76% of cases, without significant contrast medium seen in the adjacent liver parenchyma. The presence or absence of contrast agent retention may prove to be useful in evaluating accurate targeting of a lesion.