Evaluation of Schmorl's nodes using F-18 FDG PET/CT

To evaluate the image findings of Schmorl's nodes on combined 2-[(18)F]-fluoro-2-deoxy-d-glucose positron-emission tomography/computed tomography (FDG PET/CT).

Twelve patients who were diagnosed with Schmorl's nodes and had undergone magnetic resonance imaging (MRI) and FDG PET/CT were retrospectively recruited for this study. The period between the MRI and the FDG PET/CT examinations was within 1 week. The demographic data and clinical history were reviewed. The relationship between MRI findings and the values of maximum standardized uptake value (SUVmax) on FDG PET/CT was analysed.

The mean values of early and delayed SUVmax of Schmorl's nodes without MRI enhancement were 1.14 ± 0.28 and 1.09 ± 0.32. The mean values of early and delayed SUVmax of Schmorl's nodes with MRI enhancement were 1.73 ± 0.49 and 1.75 ± 0.54. There were significant differences in the early and delayed SUVmax between Schmorl's nodes with and without perifocal enhancement on MRI with Wilcoxon's rank-sum test (p = 0.012; p = 0.006). There was a trend of positive correlation, although not statistically significant, between delayed SUVmax on FDG PET/CT and age in Schmorl's nodes with Spearman's rank correlation (B = 0.86, p = 0.056).

Schmorl's nodes demonstrated low to moderate uptake on FDG PET/CT images. Schmorl's nodes with perifocal enhancement on MRI result in higher FDG uptake. The possibility of false positives caused by Schmorl's nodes should be considered when interpreting FDG PET/CT images of bone metastases, especially in the aging population.