F-18 FDG PET in detecting renal cell carcinoma

Purpose: To assess the role of F-18 FDG imaging with a dual head coincidence mode gamma camera (Co-PET) in the detection of renal cell carcinoma (RCC) in patients with renal masses.

Material and Methods: An F-18 FDG Co-PET study was performed in 19 patients (7 F, 12 M; mean age 58.15±2.5 years, age range 45-79 years) with suspected primary renal tumors based on conventional imaging techniques, including computed tomography (CT) and ultrasonography (US) before nephrectomy or surgical resection of the mass.

Results: Histologically documented RCC was present in 15 patients. Of the 19 patients with suspected primary renal tumors, F-18 FDG Co-PET was true-positive in 13, false-negative in 2, true-negative in 3, and false-positive in 1 patient. Two angiomyolipomas and one renal mass due to infarction and hemorrhage showed a true-negative Co-PET result. The patient with false-positive FDG Co-PET study was diagnosed as xantogranulomatous pyelonephritis. Overall sensitivity, specificity, and accuracy of FDG Co-PET for RCC were 86% (13/15), 75% (3/4), and 84% (16/19), respectively. Positive predictive value for RCC was 92% and negative predictive value 60%.

Conclusion: These findings suggest that F-18 FDG Co-PET may have a role in the diagnostic evaluation of patients with RCC and primary staging of disease. Positive F-18 FDG study may be predictive of the presence of RCC. However, a negative study does not exclude the RCC.