Is There a Role of the Enhancement Degree of the Lesion on Computerized Tomography for the Characterization of Renal Tumors?

PurposeWe determined the role of tumor enhancement on dynamic enhanced computerized tomography for differentiating pathological characteristics.Materials and MethodsA total of 149 patients with renal tumor underwent dynamic enhanced computerized tomography at our university from June 2007 to November 2011. Tumors were treated surgically and pathological evaluation was done. Precontrast and postcontrast HU values, and the difference were recorded. Postcontrast HU evaluations were done at the nephrographic phase of the procedure. Tumor HU values were compared according to histological subtype, tumor grade and pathological stage.ResultsMean ± SD patient age was 57 ± 13 years and mean tumor size was 4.8 ± 2.7 cm. Postcontrast HU and contrast difference values were significantly lower in the malignant group. A cutoff HU value of 138 HU (mean AUC 0.893 ± 0.027, 95% CI 0.84–0.94) differentiated renal cell cancer from oncocytoma with 88% sensitivity and 87% specificity. Low and high grade cases demonstrated similar precontrast and postcontrast HU, and contrast difference values. These enhancement parameters were significantly lower for higher stage (pT2–3) renal cell cancer than for pT1. We detected higher postcontrast values (mean 62 ± 14 vs 56 ± 39 HU, p = 0.011) and contrast difference values (mean 92 ± 15 vs 82 ± 42 HU, p = 0.034) for high grade than for low grade renal cell cancer in patients with tumors 4 cm or less.ConclusionsThe degree of enhancement on computerized tomography helps differentiate tumor characteristics. These outcomes may help the clinician with prognostic evaluation and may augment the role of computerized tomography in therapeutic planning.