Use of 18F-FDG-positron emission tomography in presurgical evaluation of nonspecific or suspectious adrenal masses in non-oncologic patients

Abstract Background and objective Our purpose was to assess the utility of 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) in pre-surgical characterization of adrenal masses. These masses were incidentally discovered in non-oncologic patients or during the study of endocrine hormone overproduction. These nodular lesions showed nonspecific or suspicious radiological features in the imaging tests routinely performed (CT and/or MRI). Patients and methods This is a cross-sectional and prospective study in 12 patients with adrenal masses which were radiologically non-specific or suspicious for malignancy before adrenalectomy. An 18F-FDG-PET was made and quantitative FDG uptake (SUVmax) in the adrenal region (adrenal SUVmax) and liver (liver SUVmax), and the ratio SUVmax adrenal/liver was calculated. These parameters were related to the pathological findings. We evaluated the accuracy of the test by receive operating curves (ROC). Results The ROC to discriminate between benign and malignant lesions showed that the SUVmax was a better parameter than size or SUVmax adrenal/liver ratio. Using a SUVmax cutoff value ≥3.1, sensitivity, specificity, positive and negative predictive value of the test were 100, 67, 50 and 100%, while a SUVmax adrenal/liver ratio ≥1.8 showed a sensitivity, specificity, positive and negative predictive value of 67, 100, 100 and 90%, respectively. The presence of a SUVmax adrenal/liver ratio ≥1.8 showed a statistically significant association with carcinoma occurrence. Conclusion 18F-FDG-PET may be useful in the characterization of nonspecific or suspicious adrenal masses discovered in patients without a previous history of cancer. Its use in some cases could avoid unnecessary interventions.