Hepatobiliary phase enhancement of liver metastases on gadoxetic acid MRI: assessment of frequency and patterns.

To assess for and characterize patterns of hepatobiliary phase (HBP) enhancement in hepatic metastases of various malignancies on gadoxetic acid–enhanced MRI. Eighty gadoxetic acid–enhanced MRI studies performed between July 2012 and November 2019 in patients with hepatic metastases from 13 different primary malignancies were assessed. Most (n = 60) were from colorectal cancer (CRC), pancreatic ductal adenocarcinoma (PDAC), or neuroendocrine tumor (NET) primaries. Two radiologists quantitatively evaluated the dominant lesion on each MRI. A lesion was considered enhancing when HBP enhancement relative to muscle exceeded 20%. Lesions were classified by pattern of enhancement. Quantitative enhancement metrics and patterns of enhancement were compared between CRC, PDAC, and NET using non-parametric statistical tests. Most dominant metastatic lesions > 1 cm (77%, 54/70) demonstrated HBP enhancement. HBP enhancement was identified in hepatic metastases from 10 different primary malignancies, including CRC, PDAC, and NET. PDAC metastases demonstrated a lower degree of HBP enhancement (26%) than CRC (44%, padj = 0.04) and NET (51%, padj = 0.01) metastases. Three discrete enhancement patterns were identified: peripheral, central (target), and diffuse heterogeneous. Patterns of HBP enhancement varied between CRC, PDAC, and NET, with secondary analysis demonstrating that PDAC had the highest proportion of peripheral pattern (73%, padj < 0.001), CRC the highest proportion of diffuse heterogeneous pattern (32%, padj < 0.01), and NET the highest proportion of central pattern (89%, padj < 0.001). Liver metastases from several primary malignancies, including PDAC, demonstrate mild HBP enhancement in variable patterns. Correlation with OATP1B3 expression and prognosis is required. • Hepatobiliary phase (HBP) enhancement was identified in 77% of hepatic metastases in several different primary malignancies. • Discrete patterns of HBP enhancement exist (peripheral, central, diffuse heterogeneous) and varied between CRC, PDAC, and NET. CRC and PDAC metastases demonstrated mostly non-central patterns (diffuse and peripheral), and NET mostly a central pattern. • Relationship between HBP enhancement, enhancement pattern, OATP1B3 expression, and prognosis requires further dedicated exploration for each malignancy.