Imaging findings of 18F-FDG PET/CT in patients with primary AL amyloidosis

1958 Objectives Although there were several case reports and cases series of 18F-FDG PET/CT in amyloidosis, the value of PET/CT for diagnosing amyloidosis was not clarified. We investigated the imaging findings of 18F-FDG PET/CT in patients with primary AL amyloidosis. Methods Subjects were 10 patients (M:F = 8:2; age, 62 ± 4 y) with histologically and laboratorily confirmed primary AL amyloidosis, who underwent pretreatment 18F-FDG PET/CT to rule out the possibility of malignancy. For involved organs, visual and semiquantitative analyses were performed on PET/CT images. Results Three patients had associated multiple myeloma with amyloidosis. There were no malignancies in the remaining 6 patients. Thirteen organs (heart in 6, kidney in 3, stomach in 1, ileum in 1, pancreas in 1, and liver in 1) were histologically and laboratorily confirmed with primary AL amyloidosis. 18F-FDG uptake was significantly increased in the 9 of 13 organs (69%; heart in 6, 1 in kidney, 1 in ileum, and 1 in liver; SUVmax = 8.4 ± 3.6, range 3.5 - 14.3). However, in 5 of 9 PET positive organs (4 in heart, 1 in ileum), it was difficult to differentiate from physiological uptake. PET was negative for pancreas and stomach lesions. Conclusions Significant high 18F-FDG uptake may be present in patients with AL amyloidosis. However, careful patients’ preparation to reduce physiological uptake may be necessary. Further prospective studies are needed to evaluate the role of 18F-FDG PET/CT in AL amyloidosis.