Retrospective comparative study between 3T WB-MRI including WB-DWI and 18F-FDG-PET/CT in detection of metastatic disease

Abstract

Purpose: To retrospectively compare the diagnostic accuracy of 18F-FDG-PET/CT (PET-CT) and WB-MRI with WB-DWI (WB-MRI) in various types of metastatic diseases. Materials and methods:There were 26 patients who underwent WB-MRI and PET-CT within a period of one month. The WB-MRI protocols were: sagittal T1WI (Turbo Spin Echo) with TR/TE: 600/ 9.4 (msec), STIR with TR/ TE: 6000/85/240 (msec), coronal T1WI (FLASH) with TR/TE of 120/2.46 (msec) and axial DWI (b-0 and 800) based on STIR with TR/TE/TI of 14000/60/240 (msec). Three radiologists with various lengths of experience were assigned to review the WB-MRI images. The PET-CT reports were reviewed by radiologists with more than 10 years of experience in diagnostic PET-CT images. All patients had a follow-up of more than 6 months by MRI, computed tomography (CT) or PET-CT.Results: A total of 124 gold standard malignant lesions were identified. Regarding WB-MRI, the sensitivity was 68-78% (p=0.059-1.00) and the positive predicted value was 76-84%. With PET-CT, 98 lesions were detected correctly in total and the sensitivity and positive predictive values were 79% and 65%. Concerning only skeletal metastasis, the number of gold standard lesions was 80 in total. Regarding WB-MRI, the sensitivity was 85-93% (p=0.002-0.02) and the positive predicted value was 79-95%. With PET-CT, 61 lesions were detected correctly in total and the sensitivity and positive predictive values were 76% (61/80), 75% (61/81) respectively Conclusion: Although PET-CT and WB-MRI yielded similar overall results in detection of malignant lesions, the performance of WB-MRI in detection of bone metastasis was significantly higher.