The impact of preoperative magnetic resonance images on outcome of cemented vertebrae

Abstract

Refracture of cemented vertebrae is often seen after percutaneous vertebroplasty. The purpose of this prospective study was to evaluate pre-procedural magnetic resonance images (MRI) for the prediction of further collapse and vertebral height loss after vertebroplasty. This study included 81 consecutive patients (73 women and 8 men) with osteoporotic compression fractures. MR studies were performed 1-5 days before vertebroplasty. Patients were followed to evaluate refracture for a minimum of 6 months after treatment. Cox proportional hazards model was used to evaluate relationships between clinical data, covariates on pre-procedural MRI, and the presence of cemented vertebrae refracture. The mean refracture rate was estimated with the Kaplan-Meier method. After a mean follow-up of 23.0 ± 8.2 months, 46 cemented vertebrae (57%) experienced refracture, and the mean loss of anterior vertebral height was 11.3%. The 1-year refracture rate after vertebroplasty was 7%, and rapid increased to 76% in the third year. Cox proportional analysis showed that any 1% decrease in signal intensity on T2-weighted images of the injured vertebra will increase the refracture rate by 0.74% (OR = 0.26, 95% CI 0.08-0.81, p = 0.02), and a 1% increase in the poorly enhanced volume ratio will increase the refracture rate by 4.3% (OR = 5.32, 95% CI 1.22-23.14, p = 0.03). Quantitative pre-procedural MRI appears to be useful in exploring vertebrae with poor bone marrow integrity, which effectively predicts the subsequent refracture of cemented vertebra.

Fig. 1

The signal intensity (SI) ratio and volume ratio of the region of interest (ROI) was calculated as follows. The poorly enhanced rate = a/(a + b + c). The well-enhanced rate = (b + c)/(a + b + c)

Fig. 2

The refracture-free rate of cemented vertebrae at different time intervals after vertebroplasty

Fig. 3

Images of a 62-year-old man. T2-weighted images (a) and T1-weighted-enhanced fat-suppression images (b) show a large, poorly enhanced zone in the L1 vertebra (arrow). c Plain radiographic image immediately after vertebroplasty. (d) Follow-up MRI 1 month after the procedure showed a recurrent fracture with increased enhancement of the inferior-posterior vertebra. e Further collapse of the treated vertebra was found 6 months after vertebroplasty