Despite the higher sensitivity of CT, there are some concerns about the risk of false-positive findings (ie, intrapulmonary lymph nodes and granulomas), particularly in patients with T1a RCC, which can lead to further unnecessary and potentially invasive investigations [9]. Additionally, some authors suggest that CT of the chest may not be necessary to identify most cases of pulmonary recurrence after nephrectomy for RCC when CT of the abdomen with coverage of the lung bases at the T7 thoracic level is performed [26]. The use of IV contrast is optional for CT of the chest but it may be beneficial for detection and characterization of the hilar lymph nodes. In patients undergoing active surveillance with CT of the abdomen who are receiving IV contrast, chest CT can also be performed after IV contrast administration. Unlike CT of the abdomen, in which images without and with IV contrast may be appropriate in some circumstances, CT of the chest without and with IV contrast does not provide additional information in these patients and is considered inappropriate. CT Head Most patients with metastases to the central nervous system are symptomatic. Thus, active surveillance protocols for small localized renal masses have not supported routine imaging of the brain to search for metastases in asymptomatic patients. Brain imaging should be performed only in cases with suggestive signs or symptoms [2,9,11]. MRI Abdomen MRI of the abdomen without and with IV contrast is an accurate method for the detection and characterization of small localized renal masses. Different sequences, including T2-weighted, chemical shift T1-weighted, contrast- enhanced T1-weighted, and diffusion-weighted images, can help distinguish RCC from other benign and malignant lesions and distinguish the clear-cell subtype from other subtypes of RCC.
Post Treatment Follow up and Active Surveillance of Renal Cell Carcinoma. Despite the higher sensitivity of CT, there are some concerns about the risk of false-positive findings (ie, intrapulmonary lymph nodes and granulomas), particularly in patients with T1a RCC, which can lead to further unnecessary and potentially invasive investigations [9]. Additionally, some authors suggest that CT of the chest may not be necessary to identify most cases of pulmonary recurrence after nephrectomy for RCC when CT of the abdomen with coverage of the lung bases at the T7 thoracic level is performed [26]. The use of IV contrast is optional for CT of the chest but it may be beneficial for detection and characterization of the hilar lymph nodes. In patients undergoing active surveillance with CT of the abdomen who are receiving IV contrast, chest CT can also be performed after IV contrast administration. Unlike CT of the abdomen, in which images without and with IV contrast may be appropriate in some circumstances, CT of the chest without and with IV contrast does not provide additional information in these patients and is considered inappropriate. CT Head Most patients with metastases to the central nervous system are symptomatic. Thus, active surveillance protocols for small localized renal masses have not supported routine imaging of the brain to search for metastases in asymptomatic patients. Brain imaging should be performed only in cases with suggestive signs or symptoms [2,9,11]. MRI Abdomen MRI of the abdomen without and with IV contrast is an accurate method for the detection and characterization of small localized renal masses. Different sequences, including T2-weighted, chemical shift T1-weighted, contrast- enhanced T1-weighted, and diffusion-weighted images, can help distinguish RCC from other benign and malignant lesions and distinguish the clear-cell subtype from other subtypes of RCC.