Clinical value of 18FDG PET/MRI in muscle-invasive, locally advanced, and metastatic bladder cancer
A. Cahid Civelek, Scot A. Niglio, Ashkan A. Malayeri, Jeffrey Lin, Sandeep Gurram, Heather J. Chalfin, Barış Türkbey, Vladimir Valera, Seth M. Steinberg, Andrea B. Apolo
Abstract
Objective Metastatic bladder cancer is an aggressive disease that can often be difficult to diagnose and stage with conventional cross-sectional imaging. The primary objective of this study was to determine the clinical value of fluorine-18 2-fluoro-2-deoxy-D-glucose ( 18 F-FDG) PET/MRI for surveillance and restaging of patients with muscle-invasive, locally advanced, and metastatic bladder cancer compared to conventional imaging methods. Materials and Methods This retrospective study enrolled patients with muscle-invasive, locally advanced and metastatic bladder cancer in a single institute evaluated with 18 F-FDG PET/MRI. All patients also underwent conventional imaging with CT. Additional imaging may also have included 18 F-FDG PET/CT ( 18 F-FDG PET), or sodium fluoride (NaF) PET/CT in some patients. Images were reviewed by a diagnostic radiologist/nuclear medicine physician. Number of lesions and sites of disease were captured and compared between 18 F-FDG PET/MRI and conventional imaging. Lesions were confirmed by sequential imaging or lesion biopsy. All patients were followed for survival. Results Fifteen patients (4 for surveillance; 11 for restaging) underwent 34 18 F-FDG PET/MRI scans. Each patient received a corresponding conventional CT around the time of the 18 F-FDG PET/MRI (median 6 days). The 15 patients (11 male; 4 female) had a median age of 61.5 years (range 37–73) and histologies of urothelial carcinoma ( n = 13) and small-cell carcinoma of the bladder ( n = 2) diagnosed as stage 4 ( n = 13), stage 3 ( n = 1), or stage 2 ( n = 1). 18 F-FDG PET/MRI detected 82 metastatic malignant lesions involving lymph nodes ( n = 22), liver ( n = 10), lung ( n = 34), soft tissue ( n = 12), adrenal glands ( n = 1), prostate ( n = 1), and bone ( n = 2) with a resultant advantage of 36% for lesion visibility in comparison with CT. Serial imaging or biopsy confirmed these lesions as malignant. Conclusion 18 F-FDG PET/MRI can detect metastatic lesions which cannot be identified on conventional CT, and this can allow for better treatment planning and improved disease monitoring during therapy.