Browsing by Author "Manske, Sarah L"

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    Four-Dimensional Computed Tomography to Determine Normal Syndesmotic Motion and to Compare Motion after Rigid and Flexible Fixation of Syndesmotic Injuries
    (2020-11-27) Wong, Murray T; Schneider, Prism S; Edwards, W Brent; Wiens, Charmaine AS; Manske, Sarah L; LaMothe, Jeremy M
    Syndesmotic injuries occur in up to one-quarter of all ankle fractures. Despite mitigating efforts, malreduction of the syndesmosis is common after both rigid and flexible fixation methods, causing inferior patient function. Conventional assessments of syndesmotic reduction do not account for normal syndesmotic motion with ankle range-of-motion (ROM). The aims of this thesis were to use four-dimensional computed tomography (4DCT) to determine normal syndesmotic motion and to investigate the impact of rigid and flexible fixation on postoperative syndesmotic kinematics. Fifty-eight uninjured ankles were imaged to quantify normal syndesmotic kinematics. Thirteen patients after rigid or flexible fixation underwent bilateral ankle 4DCT to evaluate postoperative syndesmotic kinematics. Measures of syndesmotic width including anterior, middle, and posterior syndesmosis distances as well as tibiofibular clear space and tibiofibular overlap were automatically extracted from 4DCT data. Sagittal translation and fibular rotation were also recorded. Linear mixed effects models were used to determine the position of the syndesmosis at neutral dorsiflexion as well as syndesmotic motion, defined as the change in syndesmotic measurements with ankle ROM.In uninjured ankles, various measures of syndesmotic width decreased by 0.7-1.1 mm as ankles moved from dorsiflexion to plantarflexion (p < 0.001). The fibula externally rotated by 1.2° with plantarflexion (p < 0.001). There was no significant motion in the sagittal plane (p = 0.43). Rigid fixation increased syndesmotic width compared to uninjured ankles when measured by middle syndesmotic distance and tibiofibular clear space only (p = 0.039 and 0.032 respectively). Rigid fixation demonstrated reduced motion compared to uninjured ankles in middle and posterior syndesmotic distance, tibiofibular clear space, and tibiofibular overlap (p < 0.01). There were no differences in syndesmotic position or motion between flexible fixation and uninjured ankles.Ankle plantarflexion leads to decreased syndesmotic width and fibular external rotation in uninjured ankles, indicating ankle position must be accounted for when performing syndesmotic imaging and fixation. Flexible fixation better restores syndesmotic position and motion compared to rigid fixation. These findings may be used to decrease the rate of syndesmotic malreduction and, consequently, improve post-surgical outcomes.
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    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
    (2020-04-07) Brunet, Scott C; Kuczynski, Michael T; Bhatla, Jennifer L; Lemay, Sophie; Pauchard, Yves; Salat, Peter; Barnabe, Cheryl; Manske, Sarah L
    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. Results 13/57 (23%) of erosions could not be analyzed from raw images due to a stack shift artifact. All erosions could be volumetrically assessed after multi-stack registration. We observed that there was a median bone formation fraction of 2.1% and resorption fraction of 3.8% in RA patients over the course of 6 months. In contrast to the same-day rescan negative control, we observed median bone formation and resorption fractions of 0%. Conclusions Multi-stack image registration is a useful tool to improve the number of useable scans when analyzing erosions using HR-pQCT. Further, image registration can be used to longitudinally assess bone remodeling. These methods could be implemented in future studies to provide important pathophysiological information on the progression of bone damage.