Comparison of the diagnostic efficacies of 18F-FDG PET/MRI versus contrast-enhanced MRI in the detection of brain metastases

Purpose: The aim of our study was to determine which imaging method was superior in detecting brain metastases by comparing contrast-enhanced MRI and 18F FDG PET / MRI which were obtained simultaneously. Methods: From August 2015 to December 2018, 480 consecutive patients with histopathologic proven primary malignancy (188 men and 292 women; mean age+ standard deviation, 45 years+ 25,4) were retrospectively evaluated. All patients underwent 18F-FDG PET/MRI during follow-up of their malignancies. Results: Brain metastases (BM) were found in 33 (25 Female and 8 Male) of 480 patients. Contrast-enhanced MRI revealed 190 brain metastases (BM) in 33 patients (100%), while 18F-FDG PET data was accurately identified 50 (26.3%) BM lesions in 16 (48.5%) patients. Based on measurements on contrast-enhanced MR images, the maximum BM lesion size was 40.1mm (mean: 6.64mm±6.39mm, range: 0.9mm-40.1mm). Mean lesion size ± SD was 12.88±8.13mm in 18F-FDG PET/MRI detectable lesions. Conclusion: Contrast-enhanced brain MR is more likely to detect brain metastases than 18F-FDG PET / MRI, and is still the gold standard imaging method for the detection of brain metastases.