The diagnostic value of axially loaded magnetic resonance imaging in patients with degenerative disorders of lumbar spine

Abstract

Objeetive To evaluate the diagnostic value of axially loaded MR imaging with supine position in patients with degenerative disorders of lumbar spine.Methods Thirty asymptomatic volunteers and 89 patients were examined in psoas-relaxed position(PRP)and axially compressed supine position(ACE)of the lumbar spine.Sixty-one patients with low back pain,19 with sciatica and 9 with neurogenic claudication were included in the symptomatic study group.The disc levels from L3 to S1 were examined.Results In 30 asymptomatie volunteers,a significant decrease in dural sac cross-sectional area(DSCA)was found at 14 disc levels(15.6%)in 10 individuals(33.3%)during ACE(>15 mm2).In 89 patients.a significant decrease in DSCA was found at 55 disc levels(20.6%)in 38 patients(42.7%)during ACE(>15 mm2),and the mean decrease was 28 mm2.During ACE,32 disc levels with an increasing severity of disc herniation were noted in 26 patients.16 disc levels with neural foramen stenosis were found in 12 patients,11 disc levels with ligamentum flavum thickening were observed in 10 patients,3 cases facet dislocation and 3 cases lumbar spondylolisthesis were also seen.In 22 of the 89 patients(24.7%).additional valuable information(AVI)was found during ACE,including 7 patients(7/9)with neurogenic claudication,8 patients(8/19)with sciatica,and 11.5%(7/61)of the patients with low back pain.Conclusion As compared with conventional imaging methods,axially loaded imaging provides AVI,and more occult lesions can be found during ACE.ACE MRI is a valuable tool in diagnosing degenerative disorders of lumbar spine. Key words: Lumbar vertebrae; Magnetic resonance imaging: Biomechanics