The utility of multi-stack alignment and 3D longitudinal image registration to assess bone remodeling in rheumatoid arthritis patients from second generation HR-pQCT scans

Abstract

Background: Medical imaging plays an important role in determining the progression of joint damage in rheumatoid arthritis (RA). High resolution peripheral quantitative computed tomography (HR-pQCT) is a sensitive tool capable of evaluating bone microarchitecture and erosions, and 3D rigid image registration can be used to visualize and quantify bone remodeling over time. However, patient motion during image acquisition can cause a "stack shift" artifact resulting in loss of information and reducing the number of erosions that can be analyzed using HR-pQCT. The purpose of this study was to use image registration to improve the number of useable HR-pQCT scans and to apply image-based bone remodeling assessment to the metacarpophalangeal (MCP) joints of RA patients. Methods: Ten participants with RA completed HR-pQCT scans of the 2nd and 3rd MCP joints at enrolment to the study and at a 6-month follow-up interval. At 6-months, an additional repeat scan was acquired to evaluate reliability. HR-pQCT images were acquired in three individual 1 cm acquisitions (stacks) with a 25% overlap. We completed analysis first using standard evaluation methods, and second with multi-stack registration. We assessed whether additional erosions could be evaluated after multi-stack registration. Bone remodeling analysis was completed using registration and transformation of baseline and follow-up images. We calculated the bone formation and resorption volume fractions with 6-month follow-up, and same-day repositioning as a negative control.

Open-source image analysis tool for the identification and quantification of cortical interruptions and bone erosions in high-resolution peripheral quantitative computed tomography images of patients with rheumatoid arthritis

“…However, both implementations are highly sensitive to motion and stack artifacts. Nonetheless, future studies may need to manually discard erroneous cortical interruptions, implement algorithms to automatically detect the presence of the stack artifact or acquire data with overlapping stacks [36]. This study also compared erosion volume quantification between BAM-Erosion and MIAF, through the manual placement of erosion seed points.…”

Longitudinal time-lapse in vivo micro-CT reveals differential patterns of peri-implant bone changes after subclinical bacterial infection in a rat model

“…The limited sensitivity can also be due to the relatively large voxel size (25 µm), the segmentation inaccuracies resulting from image noise, to partial volume effect or to registration inaccuracies, which can happen with multi-stack in vivo scans that are exposed to misalignments between stacks. The use of stack alignment methods could improve the quality of registration considerably in the future 54 , but at the cost of an increased radiation dose to the study animals. However, multi-stack misalignment is probably not a direct source of errors in our microstructural outcomes, since ROI 1 and ROI 2 are completely within the first stack.…”

Evaluating high-resolution computed tomography derived 3-D joint space metrics of the metacarpophalangeal joints between rheumatoid arthritis and age- and sex-matched control participants

“…High-resolution peripheral quantitative computed tomography (HR-pQCT, XtremeCT II, Scanco Medical, Brüttisellen, Switzerland) scans of the most affected hand were acquired with three 1 cm stacks, with 25% overlap, to encompass the 2nd and 3rd MCP joints (MCP2 and MCP3, respectively) ( 19 ). Each stack was acquired at 68 keV, 1,470 𝜇A, 43 ms dwell time, and with an isotropic 60.7 𝜇m voxel size.…”