Master of Science
Musculoskeletal Health Research
First carpometacarpal osteoarthritis is one of the most common forms of OA and is a significant source of pain and disability for patients. Discrepancies between traditional imaging modalities and patient reported outcomes have led galvanized researchers to developing objective point of care based imaging tools for assessing OA progression and treatment response. This thesis aims to describe the development and validation of a semi-submerged mechanical three-dimensional ultrasound device against magnetic resonance imaging. The validation of the 3D US device was conducted on a series of imaging phantoms, as well as ten CMC1 OA patients. Two-raters manually segmented areas of synovial effusion and membrane hypertrophy during two separate sessions to evaluate intra- and inter-rater reliability. The results showed that 3D US had a strong concurrent validity with MRI and that it demonstrated excellent rater reliability, indicating its potential for clinical use. Additionally, this thesis explored the implications of synovitis morphology presented in 3D US images and investigated synovial tissue volume as a possible predictor of CMC1 OA stage as determined by x-ray radiographic grading systems. Eaton-Littler and OMERACT semi-quantitative grading systems were used to indicate OA and synovitis severity. These values were compared to patient reported pain and disability, pinch grip force, synovial tissue volume, age and sex to determine which would be the most significant indicator patient reported pain.US images of CMC1 synovitis were analyzed and three distinct morphologies were identified based on location, volume and features of synovial effusion and hypertrophy.
Summary for Lay Audience
The base of the thumb is a common site of osteoarthritis where patients typically experience symptoms of pain, stiffness, and weakness. An early indicator of thumb osteoarthritis is inflammation of the joint lining, called synovitis, which can be difficult to detect. Currently, x-ray images are the most common form of imaging used to view changes in the joints of patients with thumb osteoarthritis. X-rays are great for imaging bones; however, they are unable to show doctors information about the other joint structures that are affected by arthritis. These include your muscles, joint lining, and joint inflammation. Magnetic resonance imaging is an imaging method that is excellent for visualizing the soft tissue structures affected by osteoarthritis, however it is very expensive, has long waitlists, and is inaccessible to those individuals living in rural areas or cost-constrained healthcare systems. Additionally, neither MRI or x-rays can be used at a patient’s bedside and patient positions for these scans can be uncomfortable maintain for long periods of time. In light of this, there is a serious unmet clinical need for inexpensive, rapid and safe imaging devices that can assess inflammation volumes at a patient’s bedside.
Very little information is available on how synovitis volume, shape and location relate to patient reported outcomes such as pain and functional disability. In this thesis, we describe our novel 3D US device for the hands and how well it performs when compared to more established imaging methods. Additionally, we use 3D US to assess the relationship between different OA imaging grading scales and pain in a group of patients with osteoarthritis at the base of their thumb.
The results of these studies show that 3D US is able to provide accurate and precise measurements of inflammation when compared to MRI. We also showed that the relationship between pain and inflammation in thumb OA patients is not simple and that it may need to be considered within the context of which stage of disease a patient is presenting.
du Toit, Carla, "Three-dimensional Ultrasound Imaging for Characterization of Synovitis in First Carpometacarpal Osteoarthritis" (2022). Electronic Thesis and Dissertation Repository. 8645.
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