[Solitary hypovascular hepatic nodules: MR characterization and differential diagnosis]

The purpose of this study was to compare MRI findings of solitary hypovascular hepatic nodules, benign and malignant, to identify their MRI characteristics.

We retrospectively assessed solitary hypovascular hepatic nodules ≤ 3 cm in 135 patients, among them there were 55 malignant nodules [29 peripheral nodules of cholangiocarcinoma, PCC, and 26 hepatic metastases, HM] and 80 benign nodules [48 inflammatory myofibroblastic tumors, IMT, and 32 hepatic hemangioma, HG], proved by surgery, biopsy or follow-up imaging. Unenhanced and dynamic enhanced MRI findings of the 135 patients were analyzed retrospectively. Statistical analysis included Chi-square test or Fisher's exact test, and receiver operating characteristic (ROC) curve.

There was significant difference (P < 0.05) between the malignant group and benign group in terms of location, margin, T2WI signal intensity, heterogeneity or homogeneity of the nodule, and type and degree of peritumoral and intratumoral enhancement. Area under the curve at the first film reading by three radiologists was 0.678 ± 0.047, 0.920 ± 0.022 at the second time, and there was a significant difference (Z = 5.22, P < 0.05) between them.

Our data indicated that solitary hypovascular hepatic nodules show unenhanced and dynamic enhanced MRI features. Therefore, MR imaging combined with clinical and biochemical data does provide reliable information for a proper diagnosis of such hepatic lesions and differentiation of malignant from benign nodules.