Purpose: This study aimed to evaluate the diagnostic performance of multidetector computed tomography (MDCT) for preoperative evaluation of perinephric fat invasion in patients with renal cell carcinomas (RCCs).
Methods: A total of 408 consecutive patients with surgically confirmed RCC who underwent MDCT were included in this study. Image analysis was first performed with axial-only CT images. A second analysis was then performed with both axial and coronal CT images. A qualitative analysis was then conducted by 2 reviewers who reached consensus. The reference standard was pathologic evaluation.
Results: The areas under the curve of the receiver operating characteristic analysis were 0.786 and 0.877 for axial-only images and 0.805 and 0.836 for combined images in both readers. The area under the curve of tumor size was 0.833, a similar value to that of the reviewers. In multivariate analysis, tumor size, a linear-nodular or nodular type of fat infiltration, and an irregular tumor margin were independent predicting factors for perinephric fat invasion.
Conclusions: The MDCT shows relatively high diagnostic performance in detecting perinephric fat invasion of RCC, but suffers from a relatively low positive predictive value. Tumor size, fat infiltration with a nodular appearance, and an irregular tumor margin were predictors for perinephric invasion.