Detection of Hepatic Hypovascular Metastases: 3D Gradient Echo MRI Using a Hepatobiliary Contrast Agent

Purpose: To assess the diagnostic performance of gadobenate dimeglumine-enhanced 3D gradient echo (3D-GRE) magnetic resonance imaging (MRI) for the detection of hepatic hypovascular metastases. Materials and Methods: We retrospectively analyzed the initial radiologic reports of MRI of 41 patients with suspected hepatic metastases. Seventy-nine metastatic lesions were confirmed by histopathology or intraoperative ultrasound (IOUS). The sensitivity and positive predictive values for the diagnosis of hepatic metastasis were determined among each MRI set (hepatobiliary phase, precontrast images, dynamic Imaging). The diagnostic performance of dynamic image set and combined dynamic and hepatobiliary image set was also evaluated by two radiologists using alternative free response receiver operating characteristic (ROC) analysis. Results: The overall detection rate and positive predictive value of MR were 96.2% (76/79) and 96.2% (76/79), respectively. Images obtained with hepatobiliary phase 3D-GRE showed a significantly better detection rate compared to those with precontrast sequences or dynamic imaging (P = 0.008 and 0.016, respectively). Regarding lesions I cm or smaller, the detection rate was 90.3% (28/31). Each reader showed a higher Az value of the combined hepatobiliary image set than those of the dynamic image set. Conclusion: 3D-GRE MRI using a hepatobiliary contrast agent is an accurate tool in the detection of hepatic hypovascular metastases and improves detection rate compared with precontrast and dynamic imaging.