Application of superb microvascular imaging in focal liver lesions

AIM: To explore the ability of superb microvascular imaging (SMI) in differential diagnosis of focal liver lesions (FLLs) and to compare SMI morphology findings to those of color Doppler ultrasound and enhanced imaging. METHODS: Twenty-four patients with 31 FLLs were included in our study, with diagnoses of hemangioma (HE) (n = 17), hepatocellular carcinoma (HCC) (n = 5), metastatic lesions (n = 5), primary hepatic lymphoma (n = 1), focal nodular hyperplasia (FNH) (n = 2), and adenoma (n = 1). Nine lesions were pathologically diagnosed, and 22 lesions were radiologically confirmed, all of which were evaluated by at least two types of enhanced imaging techniques. All patients had undergone SMI. Patients were divided into subgroups based on pathological and radiological diagnoses to analyze SMI manifestations. We also compared the SMI manifestations of the most common malignant FLLs (HCCs and metastatic lesions) with those of the most common benign FLLs (HEs). RESULTS: HEs were classified into three SMI subgroups: diffuse dot-like type (n = 6), strip rim type (n = 8), and nodular rim type (n = 3). The sizes of the three types of HEs were significantly different (P = 0.00, < 0.05). HCCs were classified into two subgroups: diffuse honeycomb type (n = 2) and non-specific type (n = 3). Four of the metastatic lesions were the strip rim type, and the other metastatic lesion was the thick rim type, which is the same as that of lymphoma. FNH was described as a spoke-wheel type, and adenoma as a diffuse honeycomb type. The SMI types of HCCs and metastatic lesions were significantly different from those of HEs (P = 0.048, < 0.05). CONCLUSION: SMI technology enables microvascular evaluation of FLLs without using any contrast agent. For HEs, lesion size may affect SMI performance. SMI is able to provide useful information for differential diagnosis of HCCs and metastatic lesions from HEs.