Cristian Lorenz, Principal Scientist, Philips
Musculoskeletal imaging – an overview
Musculoskeletal imaging starts with fetal screening and growth control using echography and then touches a variety of clinical questions including congenital musculoskeletal disorders, chronic and acute diseases of the musculoskeletal system, primary and secondary bone cancer, fractures in the context of polytrauma, etc.
This presentation aims at an overview on how medical imaging is used in the context of the above clinical questions from the perspective of medical image analysis.
Punam Kumar Saha, Professor, University of Iowa
Topologic and Geometric Approaches for In Vivo Quantitative Assessment of Trabecular Bone Micro-Architecture
Osteoporosis is an adult bone disease associated with an increased risk of fractures. The cost of osteoporotic fracture to the world healthcare system as well as its impact on an individual basis are both extremely high, and its incidence increases progressively with age. Clinically osteoporosis is linked to low bone mineral density (BMD), which accounts for 60 to 70% of the variability in bone-strength. The remainder is due to the cumulative and synergistic effects of various factors, including trabecular bone (TB) micro-architecture. Thus, reliably measuring TB micro-architecture is of clinical significance; particularly as TB is more susceptible to hormonal, pharmacologic, and toxic effects. Recent advances with medical imaging, such as magnetic resonance (MR), high resolution peripheral quantitative computed tomography (HR-pQCT), and multi-row detector computed tomography (MD-CT), allow in vivo segmentation of individual TB structures for characterization of their micro-architectural integrity and assessment of bone strength and fracture risk. Different groups have applied various methods for topologic and geometric characterization of TB micro-architecture related to TB volume, network area, spacing, number, star volume measure, structure model index, connectivity number etc.
This talk presents topologic and geometric methods developed by our research group for in vivo quantitative assessment of TB plate-rod and longitudinal-transverse micro-architecture. There is histologic evidence confirming the relationship between the gradual conversion of trabecular plates to rods and increased fracture-risk. Digital topological analysis is applied to characterize individual trabecular plates, rods, edges, and junctions in skeletal representations derived from in vivo imaging. Volumetric topological analysis (VTA) and tensor-scale algorithms allow characterization of the topology of individual trabeculae on the continuum between a perfect plate and a perfect rod. Also, tensor-scale allows characterization of longitudinal and transverse trabeculae. This talk describes basic principles of these methods, and presents experimental results evaluating fidelity, generalizability, their impact on bone strength, fracture risk, and treatment-effects on these micro-architectural properties.