If the bone scan shows areas of abnormal radiotracer uptake suspicious for osseous metastases, single-photon emission CT (SPECT) fused with CT can be used to provide detailed anatomic localization of the abnormal radiotracer uptake and further improve the characterization of the nature of the abnormality [14]. CT Abdomen Preoperative imaging of RCC provides critical information on staging and serves as a roadmap to the surgeon. Both CT and MRI are comparable in staging of the primary tumor [15,16]. CT of the abdomen with IV contrast is considered in all major guidelines as an adequate method for staging of RCC, including the guidelines from the EAU and NCCN [5,13]. Use of IV contrast helps in the diagnosis and staging of the RCC [14,15,17-27]. Acquisition of nephrographic phase images is vital and most important in the detection and characterization of RCC. Corticomedullary phase images and excretory phase images are optional and may be helpful in differentiating RCC subtypes, distinguishing RCC from urothelial tumors and in providing complementary information on the vasculature and tumor extension into pelvicalyceal system. Extension into the perinephric fat is difficult to discriminate from nonspecific perinephric stranding due to edema, vascular engorgement, or fibrosis. 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 85% to 93% sensitivity and 32% to 96% specificity for the detection of perinephric invasion on IV contrast-enhanced CT abdomen [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].
Staging of Renal Cell Carcinoma. If the bone scan shows areas of abnormal radiotracer uptake suspicious for osseous metastases, single-photon emission CT (SPECT) fused with CT can be used to provide detailed anatomic localization of the abnormal radiotracer uptake and further improve the characterization of the nature of the abnormality [14]. CT Abdomen Preoperative imaging of RCC provides critical information on staging and serves as a roadmap to the surgeon. Both CT and MRI are comparable in staging of the primary tumor [15,16]. CT of the abdomen with IV contrast is considered in all major guidelines as an adequate method for staging of RCC, including the guidelines from the EAU and NCCN [5,13]. Use of IV contrast helps in the diagnosis and staging of the RCC [14,15,17-27]. Acquisition of nephrographic phase images is vital and most important in the detection and characterization of RCC. Corticomedullary phase images and excretory phase images are optional and may be helpful in differentiating RCC subtypes, distinguishing RCC from urothelial tumors and in providing complementary information on the vasculature and tumor extension into pelvicalyceal system. Extension into the perinephric fat is difficult to discriminate from nonspecific perinephric stranding due to edema, vascular engorgement, or fibrosis. 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 85% to 93% sensitivity and 32% to 96% specificity for the detection of perinephric invasion on IV contrast-enhanced CT abdomen [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].