Solitary hypovascular hepatic nodules: comparison and differentiation between peripheral nodular cholangiocarcinoma and atypical liver hemangioma with MRI

BACKGROUND: Peripheral nodular cholangiocarcinoma (PCC) and hepatic hemangioma (HG) significantly differ in treatment strategies and prognosis. However, they can present similar imaging characteristics, making them difficult to distinguish. The distinction between PCC and atypical HG using pre-operative dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) holds substantial significance. METHODS: Fifty-four cases of solitary hypovascular hepatic nodules (nodules ≤3 cm in diameter and enhancement not exceeding the hepatic parenchyma) confirmed pathologically were collected, including 25 cases of PCC and 29 cases of HG. The clinical and DCE-MRI features were observed, and the apparent diffusion coefficient (ADC) values were compared. The t-test or Fisher’s exact test was used to compare the differences between the two groups. Receiver operating characteristic (ROC) curve analysis was performed on the diagnostic results of the two readings before and after the study by three diagnostic physicians. RESULTS: The signal of PCC was more heterogeneous and could be shown as a ring hyperintensity signal on diffusion weighted imaging (DWI). The T2-weighted imaging (T2WI) signal of HG lesions showed a more homogeneous high-intense signal. The ADC value of PCC patients was lower than that of HG patients. Most of the patients in the two groups presented marginal enhancement in the arterial phase with infrequent abnormal perfusion around. The intratumoral vascular traversal signs in the PCC group showed a diagnostic significance. Among the lesions with marginal enhancement at arterial stage, the enhancement in PCC group was more likely to have annular enhancement with the main manifestation of delay reduction and nebulous or separated/astral center. On the other hand, HG tended to be more likely to have nodular enhancement in the arterial phase with delayed invariance at the margins and with no significant enhancement at the center. The area under the curves (AUC) of the three radiologists before and after the two readings were 0.645 and 0.888, respectively. CONCLUSIONS: In the differentiation of PCC and atypical liver hemangioma, the presence of a circular hyper-intense signal in DWI, the ADC values, and the pattern and extent of enhancement of marginal and central lesions were of diagnostic significance.