ECTS2013 Poster Presentations Osteoporosis: evaluation and imaging (31 abstracts)
1Institute of Medical Physics, University of Erlangen-Nuremberg, Erlangen, Germany; 2Institute for Osteology and Biomechanics, University of Hamburg, Hamburg, Germany; 3Molecular Imaging North Competence Center, University of Kiel, Kiel, Germany; 4Institute for Forensic Medicine, University of Hamburg, Hamburg, Germany.
Introduction: QCT of the spine is typically restricted to the BMD analysis of the lumbar vertebrae. However, fractures frequently occur in the thoracolumbar region. Also the load distribution in the spine may depend on the intervertebral disc space (IDS), a good approximation of the intervertebral disc, which itself cannot be reliably assessed by X-ray based methods.
Materials and methods: A QCT 3D acquisition and automated analysis technique (with optional operator interaction) for T6 to L4 was implemented including the segmentation of the IDS defined as the volume between the endplates of two adjacent non-fractured vertebrae and a lateral surface connecting the ridge points of the endplates. QCT data from 12 human cadavers scanned for the purpose of CT acquisition optimization were analyzed. Vertebrae with fractures, injected cement, or internal metal hardware were excluded.
Results: Percentage of changes in vertebral integral volume, integral and trabecular BMD, and IDS volume, all normalized to values of T12, are shown in the table.
The correlation coefficient between IDS volume and volume of the vertebra underneath was r=0.68 for the thoracic and r=0.59 for the lumbar spine (P<0.01 for both r values; Table 1).
% diff. relative to T12 | T7 | T9 | T11 | L1 | L3 |
Volume | −46 | −32 | −11 | +5 | +25 |
Int BMD | +15 | +11 | +8 | −2 | −5 |
Trab BMD | +22 | +5 | +9 | −8 | −17 |
IDS Volume | −62 | −35 | −8 | | +16 |
Conclusion: A largely automatic segmentation of the thoracic and lumbar spine in CT images including the IDS is feasible. Eventually this may improve fracture prediction and amplify finite element models to calculate vertebral strength.