ObjectiveComparison of predictive performance for pedicel screw loosening (PSL) between CT-based Hounsfield units (HU) and MRI-based vertebral bone quality score (VBQ) following lumbar surgery MethodsA retrospective study was conducted on patients who received transforaminal lumbar interbody fusion (TLIF) continuously at our institution from May 2018 to September 2020. Based on 12 months follow-up lumbar X-ray, screw loosening was defined as a clear zone of minimal thickness of ≥ 1 mm around the pedicle screw on radiography. VBQ score and HU value were measured using preoperative MRI and CT, respectively. Then, we evaluated the predictive performance of these two parameters by comparing the receiver operating characteristic (ROC) curve. ResultsIn all patients, area under the curve (AUC) of the VBQ score (AUC = 0.752; 95% confidence interval (CI): 0.663-0.841; P < 0.001) was larger than those of the CT HU value (AUC = 0.652; 95% CI: 0.558-0.746; P = 0.005), but there was no significant difference between them (PAUC = 0.076). In patients with lumbar spinal stenosis (LSS), AUC of VBQ score (AUC = 0.863; 95% CI: 0.764-0.961; P < 0.001) was larger than those of the CT HU value (AUC = 0.673; 95% CI: 0.513-0.833; P = 0.043), with significant difference (PAUC = 0.003). ConclusionMRI-based VBQ score, and CT-based HU value have similar performance in predicting PSL after lumbar surgery. Furthermore, in patients with LSS, VBQ score demonstrated better predictive ability than HU value.