Comparison of quantitative T₁ mapping and multi-phase enhanced MRI in evaluating pathological grading of clear cell renal cell carcinoma

Objective To compare the value of quantitative T₁ mapping and multi-phase enhanced MRI in differentiating between low- and high-grade clear cell renal cell carcinoma (ccRCC).

Methods Clinical data of ninety-four patients with ccRCC approved by pathological examination were respectively analyzed. All patients underwent T₁ mapping and multi-phase enhanced MRI examination before operation. According to the International Society of Urological Pathology (ISUP) classification criteria, 64 patients were grade Ⅰ-Ⅱ (low-grade group), and 30 patients were grade Ⅲ-Ⅳ (high-grade group). The enhancement rate of corticomedullary phase and nephrographic phase, T₁ values of pre-and post-contrast imaging as well as the T₁ reduction rate were compared between the two groups. The receiver operating characteristic (ROC) analysis was used for the evaluation.

Results The enhancement rate of ccRCC in the high-grade group in corticomedullary phase and nephrographic phase were lower than those in the low-grade group, but there was no significant difference between the two groups. The post-contrast T₁ value increased and T₁ reduction rate decreased in the high-grade group compared with those in the low-grade group (P < 0.001). The areas under the ROC curves for the post-contrast T₁ and T₁ reduction rate values to distinguish low- and high-grade ccRCC were 0.855 and 0.828, respectively.

Conclusions Quantitative T₁ mapping is superior to conventional multi-phasic enhanced MRI scanning in differentiating between low- and high-grade ccRCC.