In particular, CT had a 71% to 88% sensitivity and 71% to 79% specificity for renal sinus fat invasion, a 68% to 83% sensitivity and a 72% to 76% specificity for perinephric fat invasion, and a 59% to 69% sensitivity and a 91% to 93% specificity for renal vein invasion [36]. In a more recent study, 96 patients with 100 pathologically proven RCC, CT was reported to have an 86% sensitivity and 88% specificity for renal sinus fat invasion and an approximately 86% sensitivity and 97% specificity for renal vein invasion [37]. However, CT only had a modest 77% sensitivity and 72% specificity for detecting perinephric fat invasion in this study, emphasizing the difficulties in differentiating nontumoral causes for perinephric soft tissue stranding, from true tumor perinephric fat invasion [37]. Staging of Renal Cell Carcinoma It has been reported that the presence of enhancing soft tissue nodule in the perinephric fat on CT may be a helpful sign for the 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 fat invasion is relatively low (31%) [38]. CT has an excellent sensitivity for detecting ipsilateral adrenal involvement in RCC (T4 tumors), but the specificity varies from 76% to 95%. One study involving 229 patients with RCC reported that CT had a 100% sensitivity for ipsilateral adrenal involvement in RCC, but only a 76% specificity [39]. However, Blakely et al [40] reported a 100% sensitivity and a 94% specificity for CT in identifying adrenal involvement. Similar findings have been reported by other authors.
Staging of Renal Cell Carcinoma. In particular, CT had a 71% to 88% sensitivity and 71% to 79% specificity for renal sinus fat invasion, a 68% to 83% sensitivity and a 72% to 76% specificity for perinephric fat invasion, and a 59% to 69% sensitivity and a 91% to 93% specificity for renal vein invasion [36]. In a more recent study, 96 patients with 100 pathologically proven RCC, CT was reported to have an 86% sensitivity and 88% specificity for renal sinus fat invasion and an approximately 86% sensitivity and 97% specificity for renal vein invasion [37]. However, CT only had a modest 77% sensitivity and 72% specificity for detecting perinephric fat invasion in this study, emphasizing the difficulties in differentiating nontumoral causes for perinephric soft tissue stranding, from true tumor perinephric fat invasion [37]. Staging of Renal Cell Carcinoma It has been reported that the presence of enhancing soft tissue nodule in the perinephric fat on CT may be a helpful sign for the 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 fat invasion is relatively low (31%) [38]. CT has an excellent sensitivity for detecting ipsilateral adrenal involvement in RCC (T4 tumors), but the specificity varies from 76% to 95%. One study involving 229 patients with RCC reported that CT had a 100% sensitivity for ipsilateral adrenal involvement in RCC, but only a 76% specificity [39]. However, Blakely et al [40] reported a 100% sensitivity and a 94% specificity for CT in identifying adrenal involvement. Similar findings have been reported by other authors.