Evaluation of fracture lines in adolescent lumbar spondylolysis using MR bone imaging as an alternative to computed tomography.

PURPOSE: The diagnosis of adolescent lumbar spondylolysis typically requires computed tomography (CT) imaging; however, concerns regarding medical radiation exposure have emerged. With recent advancements in magnetic resonance imaging (MRI), it has become possible to acquire CT-like images using an MR bone imaging approach. This study aimed to investigate whether MR bone imaging can be utilised as a substitute for CT in evaluating the fracture line in patients with adolescent spondylolysis.

METHODS

We included 24 patients (28 levels) diagnosed with adolescent lumbar spondylolysis between June and August 2023. In addition to the usual MRI, MR bone imaging and CT scans of the affected area were performed. Two raters evaluated the fracture lines on sagittal images and determined their presence or absence. For statistical analysis, we calculated the sensitivity, specificity, and accuracy of MR bone imaging using CT as the reference standard. Furthermore, we assessed intra- and inter-observer agreement using Cohen's Kappa coefficient.

RESULTS

This study included 42 fractured pars and 14 non-fractured pars interarticularis controls. The sensitivity, specificity, and accuracy of MR bone imaging were 0.846, 1.00, and 0.893, respectively, for rater A and 0.789, 1.00, and 0.857, respectively, for rater B. The intra-observer agreement rates were 0.841 and 0.769 for raters A and B, respectively. Inter-observer agreement rates were 1.00 for CT and 0.875 for MR bone imaging.

CONCLUSION

Our results show that MR bone imaging can detect fracture lines in adolescent lumbar spondylosis at a level comparable to that of CT in clinical settings.