Non-Invasive Visualisation of the Anteromedial and Posterolateral Bundles of the ACL In-Vivo using Virtual Arthroscopy

Motivation: MRI is often insufficient to assess tendons, ligaments, and the meniscus. Invasive arthroscopy is the diagnostic gold standard. We propose non-invasive methodology to visualise tissue microstructure. Goal(s): To assess the accuracy of our methodology, we sought to differentiate the anteromedial and posterolateral bundles of the ACL. Approach: A rotatable MRI scanner acquired images at multiple orientations relative to a static patient. The magic angle effect in the ACL caused intensity variation across these images. Analysis of the variation enabled collagen fibre direction estimation. Results: The bundles of the ACL were successfully differentiated, thus establishing a lower bound for the accuracy of the methodology. Impact: Our methodology enables non-invasive visualisation of the ACL microstructure in-vivo. Successful differentiation of the anteromedial and posterolateral ACL bundles establishes a lower bound of accuracy. ACL damage can now be assessed in upcoming patient trials with known accuracy.