Diagnostic value of a new axial loading MRI device in patients with suspected lumbar spinal stenosis.

Abstract

This study was carried out to investigate a new device for axial loading MRI (alMRI) in the diagnosis of lumbar spinal stenosis (LSS). A total of 87 patients with suspected LSS sequentially underwent conventional MRI and alMRI using a new device with pneumatic shoulder-hip compression mode. Four quantitative parameters of dural sac cross-sectional area (DSCA), sagittal vertebral canal diameter (SVCD), disc height (DH), and ligamentum flavum thickness (LFT) at L3-4, L4-5, and L5-S1 in both examinations were measured and compared. Eight qualitative indicators were compared as valuable diagnostic information. Image quality, examinee comfort, test-retest repeatability, and observer reliability were also assessed. Using the new device, all 87 patients successfully completed alMRI with no statistically significant differences in image quality and examinee comfort from conventional MRI. Statistically significant changes were observed in DSCA, SVCD, DH, and LFT after loading (p < 0.01). SVCD, DH, LFT, and DSCA changes were all positively correlated (r = 0.80, 0.72, 0.37, p < 0.01). Eight qualitative indicators increased from 501 to 669 after axial loading, for a total increase of 168 (33.5%). Nineteen patients (21.8%, 19/87) developed absolute stenosis after axial loading and 10 of them (11.5%, 10/87) also had a significant reduction in DSCA (> 15 mm2). The test-retest repeatability and observer reliability were good to excellent. The new device is stable for performing alMRI and can exacerbate the severity of spinal stenosis, providing more valuable information for diagnosing LSS and reducing missed diagnoses. •The new axial loading MRI (alMRI) device could detect a higher frequency of patients with lumbar spinal stenosis (LSS). •The new device with pneumatic shoulder-hip compression mode was used to investigate its applicability in alMRI and diagnostic value for LSS. •The new device is stable for performing alMRI and can provide more valuable information for diagnosing LSS.