Lumbar Spine Bone MRI: A Radiation-Free Approach Utilizing CT-Like Imaging for Diagnosing Pars Defects in the Adolescent Spine.

Background and purpose: This is a retrospective cohort study to assess the quality of a synthetic bone MRI protocol by using the spoiled GRE (SPGRE) sequence and determine its usability in detecting pars defects in adolescent patients for orthopedic surgeons and radiologists.

Materials and methods: This retrospective study included 30 adolescent patients with lumbar spondylolysis and low back pain. Patients underwent a clinical lumbar spine MRI at 3T that included a 3D SPGRE sequence; 5 patients also underwent a CT for comparison. An orthopedic spine surgeon and an attending radiologist analyzed inverted SGPR and CT images, assessing the presence of a lumbar pars defect and image quality using a 5-point Likert scale. The interreader agreement was calculated.

Results: Thirty patients were identified with pars defects seen in all patients on the SPGRE MRI. Image quality scores on a 5-point Likert scale measured an overall average of 4.53 ± 0.60, corresponding to good to perfect image quality, with a substantial interrater agreement with a Gwet AC2 of 0.79 [0.71, 0.88], without significant difference between the orthopedic surgeon and the radiologist (orthopedic surgeon's score 4.50 ± 0.63, radiologist's score 4.53 ± 0.57; P = .91).

Conclusions: A synthetic bone MRI protocol using SPGRE is a viable, nonionizing alternative to CT for visualizing pars defects in adolescent patients, providing sufficient image quality for radiologists and orthopedic surgeons.