3-D Subject-Specific Shape and Density Estimation of the Lumbar Spine From a Single Anteroposterior DXA Image Including Assessment of Cortical and Trabecular Bone

• Published in: IEEE transactions on medical imaging Vol. 37; no. 12; pp. 2651 - 2662
• Main Authors: Lopez Picazo, Mirella, Magallon Baro, Alba, Del Rio Barquero, Luis M, Di Gregorio, Silvana, Martelli, Yves, Romera, Jordi, Steghofer, Martin, Gonzalez Ballester, Miguel A., Humbert, Ludovic
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.12.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Absorptiometry, Photon - methods; Accuracy; Adult; Aged; Algorithms; Biocompatibility; Biomedical materials; Bone density; Bone Density - physiology; Bone mineral density; Bones; Cancellous bone; Compartments; Computed tomography; Correlation coefficients; Cortical bone; cortical thickness; Diagnosis; Dual energy X-ray absorptiometry; DXA; Female; Fractures; Fragility; Humans; image registration; Imaging, Three-Dimensional - methods; lumbar spine; Lumbar Vertebrae - diagnostic imaging; Male; Mathematical models; Medical imaging; Middle Aged; Models, Statistical; Osteoporosis; Osteoporosis - diagnostic imaging; Patients; Radiation; Radiation dosage; Risk assessment; Shape; Solid modeling; Spine; Spine (lumbar); statistical model; Three dimensional models; Three-dimensional displays; Tomography, X-Ray Computed - methods; Training; Vertebrae
• ISSN: 0278-0062; 1558-254X; 1558-254X
• DOI: 10.1109/TMI.2018.2845909

Dual Energy X-ray Absorptiometry (DXA) is the standard exam for osteoporosis diagnosis and fracture risk evaluation at the spine. However, numerous patients with bone fragility are not diagnosed as such. In fact, standard analysis of DXA images does not differentiate between trabecular and cortical bone; neither specifically assess of the bone density in the vertebral body, which is where most of the osteoporotic fractures occur. Quantitative computed tomography (QCT) is an alternative technique that overcomes limitations of DXA-based diagnosis. However, due to the high cost and radiation dose, QCT is not used for osteoporosis management. We propose a method that provides a 3-D subject-specific shape and density estimation of the lumbar spine from a single anteroposterior (AP) DXA image. A 3-D statistical shape and density model is built, using a training set of QCT scans, and registered onto the AP DXA image so that its projection matches it. Cortical and trabecular bone compartments are segmented using a model-based algorithm. Clinical measurements are performed at different bone compartments. Accuracy was evaluated by comparing DXA-derived to QCT-derived 3-D measurements for a validation set of 180 subjects. The shape accuracy was 1.51 mm at the total vertebra and 0.66 mm at the vertebral body. Correlation coefficients between DXA and QCT-derived measurements ranged from 0.81 to 0.97. The method proposed offers an insightful 3-D analysis of the lumbar spine, which could potentially improve osteoporosis and fracture risk assessment in patients who had an AP DXA scan of the lumbar spine without any additional examination.