18F-FDG PET/CT can differentiate vertebral metastases from Schmorl's nodes by distribution characteristics of the 18F-FDG.

Abstract

Differentiation of vertebral metastases from Schmorl's nodes, especially with fluorine-18-fluorodeoxyglucose (18F-FDG) uptake, is very important for the appropriate management of these patients in case they have malignancy. We aimed to evaluate the value of 18F-FDG positron emission tomography/computed tomography (PET/CT) in differentiating vertebral metastases from Schmorl's nodes with 18F-FDG uptake. Fourteen patients with malignancy underwent 18F-FDG PET/CT, which showed abnormal 18F-FDG uptake in 19 Schmorl's nodes. Twenty one patients with vertebral metastases underwent 18F-FDG PET/CT, which showed abnormal 18F-FDG uptake in 28 vertebral metastatic lesions. All these Schmorl's nodes and vertebral metastases were confirmed by pathology or by follow-up. The 18F-FDG PET/CT were retrospectively analyzed, including maximum standardized uptake value (SUVmax), the distribution characteristic of 18F-FDG and the size of these lesions in PET and CT. The mean value of SUVmax of Schmorl's nodes with 18F-FDG uptake were 5.7±2.8, while the mean value of SUVmax of vertebral metastases were 6.6±3.2. There were no significant differences in the SUVmax between Schmorl's nodes and vertebral metastases. However, the 18F-FDG distribution in Schmorl's nodes and vertebral metastases showed some differences. The 18F-FDG uptake in the bordeline area surrounding the nucleus pulposus was highter in Schmorl's nodes. The size of Schmorl's nodes on PET was significantly smaller than that on CT. The size of vertebral metastases on PET was larger or similar with that on CT. Although the SUVmax in the Schmorl's nodes and vertebral metastases was similar, the 18F-FDG distribution characteristic in PET/CT can help differentiating the vertebral metastases from Schmorl's.