Virtual Supersampling As Post-Processing Step Preserves The Trabecular Bone Morphometry In Human Peripheral Quantitative Computed Tomography Scans

In the clinical field of diagnosis and monitoring of bone diseases, high-resolution peripheral quantitative computed tomography (HR-pQCT) is an important imaging modality. It provides a resolution where quantitative bone morphometry can be extracted in vivo on patients. It is known that HR-pQCT provides slight differences in morphometric indices compared to the current standard approach micro-computed tomography (micro-CT). The most obvious reason for this is the restriction of the radiation dose and with this a lower image resolution. With advances in micro-CT evaluation techniques such as patient-specific remodeling simulations or dynamic bone morphometry, a higher image resolution would potentially also allow the application of such novel evaluation techniques to clinical HR-pQCT measurements. Virtual supersampling as post-processing step was considered to increase the image resolution of HR-pQCT scans. The hypothesis was that this technique preserves the structural bone morphometry. Supersampling from 82 mu m to virtual 41 mu m by trilinear interpolation of the grayscale values of 42 human cadaveric forearms resulted in strong correlations of structural parameters (R-2: 0.96-1.00). BV/TV was slightly overestimated (4.3%, R-2: 1.00) compared to the HR-pQCT resolution. Tb.N was overestimated (7.47%; R-2: 0.99) and Tb.Th was slightly underestimated (-4.20%; R-2: 0.98). The technique was reproducible with PE yocv between 1.96% (SMI) and 7.88% (Conn.D). In a clinical setting with 205 human forearms with or without fracture measured at 82 mu m resolution HR-pQCT, the technique was sensitive to changes between groups in all parameters (p < 0.05) except trabecular thickness. In conclusion, we demonstrated that supersampling preserves the bone morphometry from HR-pQCT scans and is reproducible and sensitive to changes between groups. Super-sampling can be used to investigate on the resolution dependency of HR-pQCT images and gain more insight into this imaging modality.