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

Abstract

Background: 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.

Subjects and methods: 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.

Results: 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.

Conclusion: 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.