What are the advantages of 3D over 2D QCT?
• Faster patient setup and scan time with 3D QCT. 3D QCT requires the acquisition of a simple set of evenly spaced, parallel planes encompassing two vertebral bodies. 2D QCT requires gantry tilt adjustments to acquire 3 or 4 axial scans through the mid planes of 3 or 4 vertebral bodies. An implication of faster patient setup and scan time is that there is less chance of problems induced by patient motion. • 3D QCT bone volumes to be analyzed are determined retrospectively, while 2D QCT volumes are nearly completely determined at the time the axial data is acquired. Retrospective volume determination provides great latitude for handling common clinical situations, such as herniated disc, scoliosis or mild compression fractures, that may not be fully appreciated at the time the QCT data is acquired. A 2D QCT analysis provides limited options for reducing measurement errors induced by such clinical realities, while a 3D analysis provides much greater latitude in choosing the volume of bon
