Feasibility of blood oxygenation level-dependent MRI at 3T in the characterization of hepatic tumors

Purpose: To determine the feasibility of using blood oxygenation level-dependent (BOLD) MRI in the characterization of hepatic tumors. Methods: A total of 100 patients with 43 hepatocellular carcinomas (HCCs), 36 metastases, 17 cholangiocarcinomas, and 23 hemangiomas underwent gadoxetic acid-enhanced and BOLD MRI at 3T. BOLD MRI was performed using a multiple fast-field echo sequence (TR/TE, 290/10-28; slice thickness 5 mm) to generate 20 T2*-weighted images. The T2*value of each tumor were calculated. On a color-coded T2*map, tumors were classified into five categories of high signal intensity (strong, moderate, rim, mild) and iso-intensity, which was correlated with the enhancement pattern on dynamic phases by two observers. Results: The mean T2* value (ms) of hemangiomas (97.3 ± 20.2) was the highest, followed by HCCs (48.4 ± 12.7), metastases (37.1 ± 10.5), and cholangiocarcinomas (36.6 ± 11.1). These values were significantly different (hemangioma vs. others tumors and HCC vs. metastasis or cholangiocarcinoma) (P ≤ 0.001). The agreement between the T2*color map and dynamic images was moderate for all tumors (k = 0.544), good for tumors >2.0 cm (k = 0.666), and fair for tumors ≤2.0 cm (k = 0.334). With the gadoxetic acid-enhanced MRI used as a reference, the sensitivities of BOLD MRI (T2*color map) for displaying hypervascularity of HCC (categories of 1-3) were 81.0 % (n = 34/42) and 78.6 % (n = 33/42) for both observers. Conclusion: Liver BOLD MRI has a potential to predict the vascular pattern of hepatic tumors.