High-resolution CT using thin sections appears to improve detection of perinephric infiltration, although false positives are common [15,16,33]. Various authors have reported an 85% to 93% sensitivity and a 32% to 96% specificity for perinephric invasion [33-35]. In a study involving 117 patients, CT abdomen was reported to have a sensitivity of 59% to 88% and a specificity of 71% to 93% in detecting stage T3a RCC [36]. In particular, CT had a 71% to 88% sensitivity and a 71% to 79% specificity for sinus fat invasion, a 68% to 83% sensitivity and a 72% to 76% specificity for perinephric invasion, and a 59% to 69% sensitivity and a 91% to 93% specificity for renal vein invasion [36]. In a more recent study of 96 patients with 100 pathologically proven RCCs, CT was reported to have an 86% sensitivity and an 88% specificity for renal sinus invasion and an approximately 86% sensitivity and a 97% specificity for renal vein invasion [37]. However, CT only had a modest 77% sensitivity and 72% specificity for detecting perinephric invasion in this study, emphasizing the difficulties in differentiating nontumoral causes for perinephric soft tissue stranding from true tumor perinephric infiltration [37]. It has been reported that presence of enhancing soft tissue nodule in the perinephric fat on CT may be a helpful sign for assessment of perinephric fat invasion. Landman et al [38] reported that the presence of enhancing perinephric soft tissue nodule had an 87% accuracy in predicting perinephric fat invasion compared with the CT finding of perinephric soft tissue stranding, which only had a 56% accuracy. However, the sensitivity of enhancing perinephric soft tissue nodule in detection of perinephric invasion is relatively low (31%) [38]. Staging of Renal Cell Carcinoma CT has excellent sensitivity for detecting ipsilateral adrenal involvement in RCC (T4 tumors), but the specificity varies from 76% to 95%.
Staging of Renal Cell Carcinoma. High-resolution CT using thin sections appears to improve detection of perinephric infiltration, although false positives are common [15,16,33]. Various authors have reported an 85% to 93% sensitivity and a 32% to 96% specificity for perinephric invasion [33-35]. In a study involving 117 patients, CT abdomen was reported to have a sensitivity of 59% to 88% and a specificity of 71% to 93% in detecting stage T3a RCC [36]. In particular, CT had a 71% to 88% sensitivity and a 71% to 79% specificity for sinus fat invasion, a 68% to 83% sensitivity and a 72% to 76% specificity for perinephric invasion, and a 59% to 69% sensitivity and a 91% to 93% specificity for renal vein invasion [36]. In a more recent study of 96 patients with 100 pathologically proven RCCs, CT was reported to have an 86% sensitivity and an 88% specificity for renal sinus invasion and an approximately 86% sensitivity and a 97% specificity for renal vein invasion [37]. However, CT only had a modest 77% sensitivity and 72% specificity for detecting perinephric invasion in this study, emphasizing the difficulties in differentiating nontumoral causes for perinephric soft tissue stranding from true tumor perinephric infiltration [37]. It has been reported that presence of enhancing soft tissue nodule in the perinephric fat on CT may be a helpful sign for assessment of perinephric fat invasion. Landman et al [38] reported that the presence of enhancing perinephric soft tissue nodule had an 87% accuracy in predicting perinephric fat invasion compared with the CT finding of perinephric soft tissue stranding, which only had a 56% accuracy. However, the sensitivity of enhancing perinephric soft tissue nodule in detection of perinephric invasion is relatively low (31%) [38]. Staging of Renal Cell Carcinoma CT has excellent sensitivity for detecting ipsilateral adrenal involvement in RCC (T4 tumors), but the specificity varies from 76% to 95%.