Is Dual-Time-Point Imaging Necessary for Discrimination of Adrenal Benign Lesions Versus Malignant Masses: A Study Comparing Standard Methods with Dual-Time-Point FDG PET-CT Imaging

Abstract

Objectives: This retrospective study was designed to investigate the clinical role of FDG PET-CT, for the evaluation of adrenal lesions and to compare the standart methods with dual-time-point imaging (DTPI) method to distinguish benign from malignant lesions in various cancer patients. Materials and methods: A total of 60 patients with confirmed primary malignancies underwent PET-CT examinations. Of the 60 patients, 79 adrenal lesions (36 benign and 43 malignant adrenal lesions) were shown by CT. Patients were grouped as benign adrenal group (I), malignant adrenal group (II) and dual-phase-group (III). Results: A total of 20 (33%) patients were included in benign adrenal group (Group I) with 28 adrenal lesions. Mean SUVmax value 2.95 were evaluated. All adrenal lesions in Group I had SUVmax value below cutoff 4.2 except 2. A total of 19 (32%) patients were included in malignant adrenal group (Group II) with 22 adrenal lesions. Mean SUVmax value 8.16 were evaluated. All adrenal lesions in Group II had SUVmax value over cutoff 4.2 except 2. A total of 21 (35%) patients were included in dual phase adrenal group (Group III) with 29 adrenal lesions. For malignant adrenal lesions in group III, all of the 21 malign lesions showed increased FDG uptake and SUVmax value in late imaging. Conclusion: Dual time point imaging of PET-CT seems to be very effective especially in adrenal lesions, addition of dual phase study routinely is not necessary and recommented in only indeterminated lesions.