Correlation between CT morphologic appearance and histologic findings in colorectal liver metastasis after preoperative chemotherapy

Purpose: Radiological evaluation of the efficacy of preoperative chemotherapy for colorectal liver metastasis (CRLM) is the most important tool for determining treatment strategies. The aim of this study was to identify a correlation between morphologic appearance on computed tomography (CT) and histologic findings of CRLM after preoperative chemotherapy. Methods: We examined 47 patients who had undergone a first hepatic resection for CRLM after preoperative chemotherapy and had received contrast-enhanced CT scans. We assessed the morphologic appearance of the overall attenuation based on metastases changing from heterogeneous to mixed and homogenous lesions, the tumor–liver interface, and the peripheral rim enhancement on CT. Histologic parameters included usual necrosis (UN), infarct-like necrosis (ILN), three-zonal change, dangerous halo, mucous lake, shape of ILN, dominant type of necrosis, and presence of viable tumor cells. The relationship between morphologic appearance and histologic findings was evaluated. Results: CT overall attenuation revealed that UN predominance was more common in the heterogeneous group than in the mixed and homogeneous groups (P = 0.011). The frequency of ILN increased sequentially from ill-defined to variable and sharp at the tumor–liver interface (P = 0.038), and the frequency of UN decreased sequentially from present to partially resolved and completely resolved in the peripheral rim enhancement (P = 0.023). The histologic presence of viable tumor cells was closely associated with the tumor–liver interface (P = 0.0003) and the peripheral rim enhancement (P = 0.004). Conclusions: CT morphologic appearance of CRLM after preoperative chemotherapy is correlated with histologic findings regarding necrosis.