What is the standard imaging modality for evaluating a renal mass suspected to be RCC?

• A. PET-CT
• B. Ultrasound
• C. X-ray
• D. CT abdomen with contrast; MRI if contrast contraindicated

Answer: (D)

When a renal mass is suspected to be RCC, contrast-enhanced CT of the abdomen is the standard imaging approach because it gives detailed anatomy and how the lesion enhances, which helps distinguish malignant solid tumors from benign cysts and guides staging. A multiphase CT study (often arterial/corticomedullary and nephrographic phases, sometimes with an excretory phase) shows how the mass takes up contrast relative to normal kidney tissue. This enhancement pattern, along with size, location, and relationships to the renal vein and IVC, is crucial for planning treatment (such as partial versus radical nephrectomy) and for assessing spread to lymph nodes or distant sites.

If iodinated contrast cannot be used, the best alternative is MRI with gadolinium, which provides excellent soft-tissue contrast and staging information, including assessment of local invasion and complex cysts via specific sequences. Ultrasound is useful for initial detection or guiding biopsy but does not give the comprehensive staging information CT provides. X-ray is not sensitive for renal masses, and PET-CT is not part of standard initial RCC evaluation due to variable uptake.