Multiphase computed tomography of malignant kidney tumors: radiologic-pathologic comparison

The aim of this retrospective study was to evaluate diagnostic test parameters of multiphase spiral computed tomography (CT) of the kidneys in the assessment of malignant renal tumors. Fifty-one patient records were reviewed. The imaging protocol included unenhanced and postcontrast scans during arterial and nephrographic phase. CT findings were compared with pathology findings to assess the value of spiral CT (sensitivity, specificity, negative predictive value, positive predictive value and accuracy) in the detection and characterization of tumors, and in the evaluation of local extension of malignant renal tumors. Spiral CT had a 96.08% sensitivity and accuracy in the detection of tumors. Characterization of renal tumors with CT had a sensitivity of 94.12% and accuracy of 96.08%. In the detection of fibrous capsule penetration, CT reached a sensitivity of 91.97% and specificity of 51.28%. In the evaluation of canal system propagation, the sensitivity was 100% and specificity 90.70%. CT had a sensitivity of 75%, specificity of 95.75% and positive predictive value of 60% in the evaluation of regional lymph node involvement. In the detection of the main renal vein invasion, CT showed 60% sensitivity and 100% specificity. Spearman's rank correlation coefficient between the mean tumor size on CT images and renal specimen was 0.916. In conclusion, multiphase spiral CT has satisfactory diagnostic parameters in the detection, characterization and evaluation of local extension of renal tumors except for detection of the main renal vein invasion.