Alayed A, et al. - For the purpose of diagnosing caval wall invasion, researchers assessed MRI in inferior vena cava (IVC) renal cell carcinoma (RCC) tumor thrombus. Using quantitative and subjective analysis, 24 consecutive patients who had thrombectomy for RCC IVC tumor thrombus found at preoperative MRI were evaluated. Invasive tumor thrombus had a larger renal vein and IVC diameters, greater craniocaudal extent, and greater volume than thrombi without invasion. The results obtained from this retrospective case-control study indicate that the highest diagnostic accuracy was achieved by combining the volume of tumor thrombus with entropy and subjective overall impression of IVC wall invasion.