The lowest HU value on transverse planes: a predictive factor for cranial adjacent vertebral fracture risk after percutaneous vertebroplasty.

Background: Osteoporosis is the major risk factor for adjacent vertebral fracture (AVF). T-Score (DXAsp) cannot eliminate the confounding effect caused by pathological osteogenesis. Hounsfield unit (HU) values are credible predictors of bone density but cannot elucidate its regional differences. Since fracture occurs in the section with the lowest strength, HU values should be reliable predictors for AVF, and the predictive performance of the lowest HU in transverse planes should be better than those of other HU parameters. This study was designed to validate this hypothesis and to introduce an innovative parameter that can more accurately assess the incidence of AVF. Methods: We conducted a retrospective review of prospectively collected imaging data from 103 patients diagnosed with a single segmental osteoporotic vertebral compression fracture (OVCF) who underwent percutaneous vertebroplasty (PVP) between July 2016 and August 2019. The average follow-up period for these patients was 24.1 months. T-Score (DXAsp) and HU values had been used to measure patients' bone density. HU was measured separately in the central transverse plane, the average values of three and four planes, and the lowest HU in transverse planes. Regression analyses identified independent risk factors for the cranial segmental AVF. We also performed receiver operating characteristic (ROC) curve analyses to assess the significant differences in predictive performances for different indicators. Results: The overall incidence rate of AVF was found to be 26.21% (27 out of 103 cases). The HU values were significantly different; however, the T-Score (DXAsp) exhibited an insignificantly lower value in patients with cranial AVF following PVP. The area under the curve (AUC) values for four planes and three planes-average HU value, central transverse plane HU value, lowest HU value, and T-Score (DXAsp)-were recorded as 0.703, 0.705, 0.703, 0.765, and 0.57 respectively. Notably, the AUC of the lowest HU in transverse planes was significantly superior to that of the T-Score (DXAsp) and other HU measurement methods, with the exception of the central transverse plane HU value (P=0.118). Conclusions: Compared to T-Score (DXAsp) and other traditional methods of HU measurement, the lowest HU value obtained from transverse planes demonstrates a superior ability to predict the incidence of AVF. Therefore, measuring this parameter is recommended for a more accurate assessment of AVF risk.