Radiologic Monitoring of Hepatocellular Carcinoma Tumor Viability after Transhepatic Arterial Chemoembolization: Estimating the Accuracy of Contrast-enhanced Cross-sectional Imaging with Histopathologic Correlation

Images from follow-up contrast-enhanced CT scans in two patients who have undergone chemoembolization illustrate false-negative and false-positive findings. (a) Noncontrast (top) and contrast-enhanced (middle) CT images demonstrate lack of contrast enhancement in the previously chemoembolized tumor in segment 2/3 (circled). These images suggest adequate treatment without any evidence of residual tumor. However, on explantation (bottom; hematoxylin and eosin stain, magnification ×4), viable tumor cells were visible, with highly pleomorphic nuclei and focal multinucleated tumor giant cells (arrows). (b) Noncontrast (top) and contrast-enhanced (middle) CT images in another patient who had undergone chemoembolization demonstrates an area of contrast enhancement (circles). However, on explantation (bottom; hematoxylin and eosin stain, magnification ×2), this proved to be a macroregenerative nodule with hepatocytes and a rim of fibrosis surrounding the nuclei (arrows).

Images from follow-up contrast-enhanced MR scans in two patients who had undergone chemoembolization illustrate true-negative and true-positive findings. (a) The image obtained before gadolinium enhancement (top) shows T1 bright signal in the lesion typical of hemorrhagic infarction after chemoembolization (circled). LAVA sequence after gadolinium injection (second from top) shows some bright signal in the lesion, which is shine-through from the bright T1 signal before gadolinium administration. Subtraction of the unenhanced image from the enhanced image (third from top) shows no enhancement within the lesion after chemoembolization, indicating no residual tumor. Pathologic examination (bottom; hematoxylin and eosin stain, magnification ×4) shows a necrotic nodule without any viable malignant cells (arrows). Embolic material is present in the vessels (ie, true-negative findings). (b) The image obtained before gadolinium enhancement (top) shows a subtle focus of T1 bright signal in segment 4 typical of hemorrhagic infarction (arrow). LAVA sequence after gadolinium injection (second from top) shows thick irregular enhancement anteriorly and laterally (arrows). Delayed-phase image after gadolinium enhancement (third from top) demonstrates that the arterial-enhancing portion of the tumor washes out (arrows). The combination of arterial enhancement and early washout is characteristic of tumor recurrence, which was confirmed on explantation. Hematoxylin and eosin–stained section on explantation (×10 objective, bottom) demonstrates viable tumor cells growing in a trabecular pattern with a mild degree of pleomorphism, representing a well differentiated tumor (arrows; ie, true-positive findings).