<prompt> The Most important diagnostic investigation in renal cell carcinoma is:CT scan of abdomen and pelvisMRIUSGPET CT  <response>: Ans. a CT scan of abdomen and pelvisRef: Bailey 26thEdition, Page 1306; Campbell Urology 11th Edition, Page 1338 Most important investigation in RCC is CT scan of abdomen. Staging of RCC can be accomplished in most cases with a high quality abdominal CT scan. 