Automatic Prospective Registration of High-Resolution Trabecular Bone Images of the Tibia

Abstract

Magnetic Resonance Imaging (MRI) longitudinal studies conducted to assess changes in tibia bone quality impose strict requirements on the reproducibility of the prescribed region acquired. Registration, the process of aligning two images, is commonly performed on the images after acquisition. However, techniques to improve image registration precision by adjusting scanning parameters prospectively, prior to image acquisition, would be preferred. We have adapted an automatic prospective mutual information based registration algorithm to a MRI longitudinal study of trabecular bone of the tibia and compared it to a post-scan manual registration. Qualitatively, image alignment due to the prospective registration is shown in 2D subtraction images and 3D surface renderings. Quantitatively, the registration performance is demonstrated by calculating the sum of the squares of the subtraction images. Results show that the sum of the squares is lower for the follow up images with prospective registration by an average of 19.37% +/- 0.07 compared to follow up images with post-scan manual registration. Our study found no significant difference between the trabecular bone structure parameters calculated from the post-scan manual registration and the prospective registration images (p > 0.05). All coefficient of variation values for all trabecular bone structure parameters were within a 2-4.5% range which are within values previously reported in the literature. Results suggest that this algorithm is robust enough to be used in different musculoskeletal imaging applications including the hip as well as the tibia.

Binary Segmentation Masks Can Improve Intrasubject Registration Accuracy of Bone Structures in CT Images

“…2,3,19 Three-dimensional registration is already used in a novel peripheral forearm QCT scanner with a spatial resolution of about 150 lm 14 for human in vivo investigations. However, in this study we did not register serial lCT images but concentrated on multimodality registration of lCT and lMR images of excised bones which can be used, for example, to better quantify damage caused by osteoarthritis in cartilage and corresponding subchondral bone structure 1 or to correlate local inflammatory processes with deterioration of bone tissue.…”

Fast prospective registration of in vivo MR images of trabecular bone microstructure in longitudinal studies

“…During the preparation of this article an article appeared on 3D prospective registration of trabecular bone images of the tibia (23). In that work a localizer-based scheme was used to achieve prospective registration by maximizing mutual information between baseline and follow-up images.…”

“…A technique based on 2D localizer images of the brain aligned with the three principal axes of the scanner has been used to achieve submillimeter and subdegree repositioning accuracy in about 5 min (22). Recently, a mutual information maximization metric optimized for MR spectroscopic imaging of the brain has been demonstrated to yield accurate results in musculoskeletal imaging (23).…”

A Trimodality Comparison of Volumetric Bone Imaging Technologies. Part I: Short-term Precision and Validity

“…Coregistration of pMRI was manually guided by anatomical features and matched slice-by-slice while only orthogonal transformations were applied. However, Blumenfeld et al (26) demonstrated that trabecular bone structural measures calculated from automatic vs manual registration methods did not differ significantly, and test-retest precision error for both methods remained well within 5%.…”