Comparing Spinopelvic Angles and Magnification on Supine MRI With Standing Radiographs in Lumbar Spinal Stenosis

Area of Science:

• Spine imaging and biomechanics
• Radiology and diagnostic imaging
• Orthopedic surgery

Background:

• Supine MRI is standard for lumbar spinal stenosis (LSS) diagnosis.
• Standing radiographs are used for spinopelvic angle measurement.
• Limited research exists on LL and SS consistency between supine MRI and standing X-rays in non-deformity LSS.

Purpose of the Study:

• To compare lumbar lordosis (LL) and sacral slope (SS) measurements between supine MRI and standing radiographs in LSS patients without deformity.
• To quantify image magnification on standing lumbar radiographs.

Main Methods:

• Radiologic cross-sectional study of 211 LSS patients (non-deformity).
• Measured LL, segmental LL (sLL), and SS on supine MRI and standing radiographs.
• Assessed interobserver reliability and performed correlation analysis.

Main Results:

• Good to excellent interobserver reliability (ICC 0.77-0.94).
• Statistically significant differences found in LL and SS between modalities.
• Mean LL: 48.9° (radiographs) vs. 46.0° (MRI); Mean SS: 37.3° (radiographs) vs. 38.1° (MRI).
• L3 vertebral body magnification ranged from 21-23%.

Conclusions:

• Supine MRI is a potential alternative for LL and SS measurement in LSS follow-up without spinal deformity.
• Standing radiographs are recommended for initial LSS investigation.
• Standing lumbar radiographs can exhibit significant magnification.