Objective：To reconstruct the 3D model of the whole lumbar spine，including vertebral body，annulus fibrosus and nucleus pulposus of intervertebral disc，CAD technique was used to fit CT and thin layer of MR data. Methods：In this study，3D CT scan data and thin -layer MR data were collected from a Chinese male volunteer. Scanning range：L1- S5. MRI was performed using SPCE and STIR sequences with the slice thickness of 0.5 mm. A high-resolution CT spiral scan was acquired with 120 kV radiogenic tube voltage，0.75 mm slice thickness and 512×512 matrix. CT and MR date were stored in DICOM format and imported into MIDIVI to reconstruct the 3D structure of soft and hard tissues respectively. The data of nucleus pulposus and annulus fibrosus of intervertebral disc were measured in Midivi. According to the obtained data，the distribution of nucleus pulposus and annulus fibrosus was depicted in MIDIVI，and registration was performed according to the anatomical marks. Thus，the anatomical model of the whole lumbar spine with the fusion of vertebral body，intervertebral disc annulus and nucleus pulposus was obtained. Results：MR obtained 470 SPCE and 240 STIR images，and CT obtained 738 images. The volumes of the generated vertebral body and sacrum were 47.49，50.92，58.95， 62.86，62.60，218.85 cm3 respectively. The intervertebral disc volumes of L1 - S1 were 11.08，12.30，13.12，13.89，13.55 cm3 respectively. The STL data file of the full lumbar 3D model was 238 M. Conclusion：High - precision 3D anatomical data of intervertebral disc and vertebral body can be obtained by thin-layer MR and CT scanning respectively. These models can be accurately established by the fusion image based on anatomical marks.
