Understanding Radiocarpal Rotation Through In Vivo Pronation and Supination of the Hand: A Single Case Study

Background: Studies have not clearly defined the motion of the distal radius in relation to the carpus in vivo. We hypothesized that 1) with the hand fixed by grasping a handle to prevent hand and wrist motion, the resulting load in torsion generated by extrinsic muscle in vivo would create motion at the radiocarpal joint; and 2) the motion measured will be between the distal radius and the proximal row of the carpus. Methods: The data was acquired from the senior author external to our institution; in the current study, we quantify the resulting radiocarpal motion. A K-wire was placed into the second metacarpal, and a second wire was placed in the distal radius. The shoulder was abducted to 90° and the hand was pronated, held stationary gripping a fixed object. The forearm was pronated and supinated to simulate radiocarpal rotation. Photographs were obtained at three points: 1) initial position showing the wire in vertical alignment; 2) same perspective in maximum internal radiocarpal rotation; and 3) same perspective in maximum external radiocarpal rotation. ImageJ (open source) was used to quantify the angle between the wires. Results: Superimposition of the three photographs in vivo allowed us to approximate two angle measurements. The measurements with maximal internal and external rotations were 16° and 24°, respectively. Conclusions: Radiocarpal rotation should be considered in addition to flexion and extension motions and radial ulnar deviations when treating degenerative changes in the wrist

Evaluating the reliability of four-dimensional computed tomography scans of the wrist

Introduction: Four-dimensional CT (or 4D CT) scans are a novel approach to diagnosing musculoskeletal pathology. Although still in its infancy, there has been a surge of interest in identifying clinical applications for musculoskeletal 4D CT. The scapholunate joint has received the most attention thus far due to the complex articulations and challenges faced with prompt diagnosis of scapholunate injuries. The objective of this thesis is to review current literature on musculoskeletal 4D CT and to evaluate the inter- and intra-rater reliability of the assessment of scapholunate stability in 4D CT wrist scans. Methodology: 4D CT scans of thirteen healthy volunteers and four patients were prepared. Seven orthopaedic and plastic surgeons were recruited to qualitatively assess the stability of the scapholunate joint in the 4D CT scans. Statistical analysis included percent agreement, Fleiss’ kappa, and Gwet’s AC1 coefficient. Results: The percent agreement amongst all raters was 0.80392 (95% CI: 0.675 - 0.932). Fleiss’ Kappa was 0.54895 (95% CI: 0.252 - 0.846) and Gwet’s AC₁ was 0.54895 (95% CI: 0.391 - 0.915). The intraclass correlation coefficient (ICC) for intra-rater reliability was 0.71631 (95% CI: 0.5567 – 0.8423). Conclusion: Our pilot study suggests good inter- and intra-rater reliability for the qualitative assessment of scapholunate instability in 4D CT scans. Although further studies are required, this thesis highlights the vast potential of 4D CT as a non-invasive diagnostic technique of dynamic musculoskeletal injuries

Brain Activation During Passive and Volitional Pedaling After Stroke

Background: Prior work indicates that pedaling-related brain activation is lower in people with stroke than in controls. We asked whether this observation could be explained by between-group differences in volitional motor commands and pedaling performance. Methods: Individuals with and without stroke performed passive and volitional pedaling while brain activation was recorded with functional magnetic resonance imaging. The passive condition eliminated motor commands to pedal and minimized between-group differences in pedaling performance. Volume, intensity, and laterality of brain activation were compared across conditions and groups. Results: There were no significant effects of condition and no Group × Condition interactions for any measure of brain activation. Only 53% of subjects could minimize muscle activity for passive pedaling. Conclusions: Altered motor commands and pedaling performance are unlikely to account for reduced pedaling-related brain activation poststroke. Instead, this phenomenon may be due to functional or structural brain changes. Passive pedaling can be difficult to achieve and may require inhibition of excitatory descending drive

Brain Tumour Classification Using Deep Features from Structural MRI

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Automated motion analysis of bony joint structures from dynamic computer tomography images: A multi-atlas approach

Dynamic computer tomography (CT) is an emerging modality to analyze in-vivo joint kinematics at the bone level, but it requires manual bone segmentation and, in some instances, landmark identification. The objective of this study is to present an automated workflow for the assessment of three-dimensional in vivo joint kinematics from dynamic musculoskeletal CT images. The proposed method relies on a multi-atlas, multi-label segmentation and landmark propagation framework to extract bony structures and detect anatomical landmarks on the CT dataset. The segmented structures serve as regions of interest for the subsequent motion estimation across the dynamic sequence. The landmarks are propagated across the dynamic sequence for the construction of bone embedded reference frames from which kinematic parameters are estimated. We applied our workflow on dynamic CT images obtained from 15 healthy subjects on two different joints: thumb base (n = 5) and knee (n = 10). The proposed method resulted in segmentation accuracies of 0.90 ± 0.01 for the thumb dataset and 0.94 ± 0.02 for the knee as measured by the Dice score coefficient. In terms of motion estimation, mean differences in cardan angles between the automated algorithm and manual segmentation, and landmark identification performed by an expert were below 1◦. Intraclass correlation (ICC) between cardan angles from the algorithm and results from expert manual landmarks ranged from 0.72 to 0.99 for all joints across all axes. The proposed automated method resulted in reproducible and reliable measurements, enabling the assessment of joint kinematics using 4DCT in clinical routine