A non-ionizing technique for three-dimensional measurement of the lumbar spine

作者：Koo Terry K^*; Kwok Wingchi Edmund

来源：Journal of Biomechanics, 2016, 49(16): 4073-4079.

DOI：10.1016/j.jbiomech.2016.10.048

• Ultrasound
• Magnetic resonance imaging
• Registration
• Lumbar spine
• Segmental kinematics

Comprehensive assessments of scoliotic deformity and spinal instability require repetitive three-dimensional (3D) measurements of motion segments at different functional postures. However, accurate 3D measurement of the spine is a challenging task. In this paper, we present a novel, non-invasive, non-ionizing technique to quantify 3D poses of lumbar motion segments in terms of clinically meaningful anatomical coordinates. The technique used ultra-short echo time (UTE) magnetic resonance (MR) images to construct subject-specific geometrical models of individual vertebrae and registered them with 3D ultrasound dataset acquired during pose measurements. A hierarchical registration approach was used to minimize the detrimental effects of speckle noise and artifacts within soft tissues on registration accuracy. The technique was validated using a human dry bone specimen as well as a fresh porcine cadaver. Registration errors were determined by comparing with a gold standard fiducial-based registration. Results showed that the technique is accurate and reliable with bias in sub-degree and sub millimeter level (except for the flexion-extension of the porcine cadaver experiment, which was -1.74 degrees), and average precision of 1.11 degrees in rotation and 0.86 mm in position for the human dry bone experiment, and 1.26 degrees and 1.23 mm for the porcine cadaver experiment. Given its non-ionizing nature, the UTE MR ultrasound registration technique is particularly useful for repeated measurements and longitudinal follow-up. With further refinement and validation, it could be a powerful tool for 3D spinal assessment.

• 出版日期2016-12-8