ABSTRACT
PURPOSE: To compare the estimated quantity of intratumor gadoxetic acid retention using T1 mapping of gadoxetic acid-enhanced magnetic resonance imaging (MRI) versus conventional processing methods for the differential diagnosis of focal liver lesions. METHODS: Seventy patients with hepatic lesions (colorectal metastasis (CRM) [nâ¯=â¯28], hepatocellular carcinoma (HCC) [nâ¯=â¯20], hemangioma [nâ¯=â¯12], and intrahepatic cholangiocarcinoma (ICC) [nâ¯=â¯10]) underwent gadoxetic acid-enhanced MRI, including pre- and post-contrast T1-weighted imaging and T1 mapping. Quantitative analyses included the lesion-to-liver signal intensity ratio (SIR) on hepatobiliary phase images, the pre- and post-contrast lesion T1 value difference (ΔT1 [ms]), and the lesion retention index (LRI [%]), which was the estimated intralesional gadoxetic acid retention calculated on pre- and post-contrast T1 maps using a two-compartment pharmacokinetic model. Results were compared between the four subcategories of focal liver lesions using the Kruskal-Wallis test, followed by the post-hoc Dunn's test and receiver operating characteristic (ROC) analysis to distinguish between pairs of the four lesion subcategories. RESULTS: This study identified significant differences in the LRI of the four lesion subcategories (pâ¯<⯠0.01), without significant differences in ΔT1 or SIR. Post-hoc analysis demonstrated significant differences in CRM vs. hemangioma (pâ¯<⯠0.01), hemangioma vs. ICC (pâ¯<⯠0.01), and HCC vs. ICC (pâ¯=⯠0.047) for the LRI. CONCLUSIONS: The quantity of intratumor gadoxetic acid retention estimated using pre- and post- contrast T1 mapping could distinguish focal liver lesions, unlike conventional processing methods, and captured unique lesion characteristics.