Distribution Characteristics of Vertebral CT Hounsfield Unit Values in Patients With Degenerative Lumbar Scoliosis

Study DesignRetrospective study.ObjectiveThis study aims to identify how CT HU values vary in degenerative lumbar scoliosis (DLS) patients with different scoliotic apexes and in those with different degree of scoliosis.MethodsWe included 222 DLS patients and 140 lumbar spinal stenosis (LSS) patients, dividing the DLS patients into 2 groups based on scoliotic apex location. Patients were further categorized by T scores into osteoporotic and non-osteoporotic groups, and by Cobb angle into mild (<20°) and severe (>20°) scoliosis. We analyzed CT value distribution in these groups and compared the area under the curve (AUC) for predicting osteoporosis based on HU values from different vertebrae.ResultsCT HU values for L1 and L2 were significantly lower in the DLS group compared to LSS group (<i>P</i> < 0.05). The lowest HU values in patients with a scoliotic apex at L2 or L2-3 were observed at the scoliotic apex region, while those with the scoliotic apex at L3, L3-4, and L4 had the lowest values at L3. This pattern was more pronounced in patients with a Cobb angle >20°. In the mild scoliosis group, the lowest CT value was found at L3 when the scoliotic apex was between L2 and L4. Additionally, L4 CT HU thresholds were better at distinguishing osteoporosis than other levels (<i>P</i> < 0.05), swhen the scoliotic apex was located at L2 or L2-3.ConclusionsCT HU values in DLS patients, particularly with a Cobb angle >20°, decrease at the scoliotic apex. Caution is required when using HU values from L1, L2, and L3 to assess osteoporosis in patients with a scoliotic apex at L2 and L2-3.