Three-dimensional ultrasound for monitoring knee inflammation and cartilage damage in osteoarthritis and rheumatoid arthritis

The most common chronic inflammatory and chronic joint diseases in Canada are rheumatoid arthritis (RA) and osteoarthritis (OA) respectively. The current methods for monitoring the development of these diseases and their response to treatment involve acquiring x-ray and magnetic resonance imaging (MRI) images and comparing the results to the patient's symptoms during examination However, x-ray imaging is associated with difficulties when trying to interpret 3D anatomy, and MRI is associated with high operating costs, long waitlists, long scan times, and is inaccessible to mobility-impaired patients. Our solution to these limitations is the use of three-dimensional ultrasound (3D US) imaging for providing bedside monitoring of RA and OA progression and their response to treatment. This project validates two 3D US acquisition devices: tilt acquisition and linear acquisition scanning methods. The linear and volumetric measurement capabilities were validated through scanning phantoms and segmenting resulting images at repeated time points. A proof-of-concept volunteer scan was conducted to compare the capabilities of 3D US against MRI for measuring articular cartilage volumes. Results indicated that the linear measurement errors for both the tilt and linear scanners were <5% of the known phantom dimensions. The volumetric measurement errors were <5% for the linear scanner and >10% (29.84%) for the tilt scanner. The percent difference between the volumes of the articular cartilage measured using 3D US and MRI of a healthy volunteer's knee was 6.46%. The linear scanner is therefore better suited for clinical scanning than the tilt scanner due to its smaller linear and volumetric errors.