Efectividad diagnóstica de la tomografía por emisión de positrones con 18fluorodeoxiglucosa asociada a tomografía axial en la discriminación de benignidad o malignidad de las lesiones suprarrenales

Abstract

Introduction The usefulness of 18fluorodeoxyglucose positron emission tomography combined with axial tomography (PET-CT) in diagnosing whether adrenal tumours are benign or malignant is assessed. Material and methods A retrospective study conducted between June 2005 and May 2009 on a consecutive series of patients on whom a PET-CT scan was performed to study suspected malignant adrenal disease. Focal uptakes were assessed, along with the maximum standard uptake value (SUV), and the ratio of the maximum adrenal/hepatic value. The sensitivity, specificity, positive and negative predictive value of the test, the maximum adrenal uptake values and the ratio for those where the diagnostic yield was maximum. Results Fifteen patients were included. The final diagnosis showed malignancy in eight and seven were benign. Ten patients had adrenal uptake: three in benign lesions and seven in neoplasias, with a mean uptake value of 6.3 (3.2 in benign lesions and 9.0 in malignant lesions). The mean adrenal/hepatic ratio was 1.8 (0.9 in benign and 2.6 in malignant lesions). When the presence of adrenal uptake is associated with a final diagnosis of malignancy, we obtained a sensitivity of 87.5%, a specificity of 57.1%, and a positive and negative predictive value of 70% and 80%, respectively. An SUV cut-off value of 6, or an adrenal/hepatic uptake ratio of 2, gave a sensitivity of 75%, a specificity of 100%, and a positive and negative predictive value of 100% and 77.7%, respectively. Conclusions PET-CT has a high ability to discriminate between benign and malignant lesions in the adrenal disease studied.