Quantitative meniscus imaging and analysis: A narrative review

In this review, we summarize the literature on the evolution of magnetic resonance imaging (MRI), segmentation, and quantitative analysis (qMRI) of the meniscus, while bearing in mind the pivotal role of the meniscus in the development (incidence) and progression of symptomatic and structural knee osteoarthritis (KOA).

We performed a literature search across PubMed and Google Scholar, spanning 35 years (1989-2024). We utilized keywords such as "meniscus", "fibrocartilage", "imaging", "magnetic resonance", "radiography", "morphometry", "quantitative analysis", "knee", "osteoarthritis", "symptoms", "pain", "structure", "progression", "radiographic", and "reproducibility".

Technological advances in image acquisition, segmentation, and derivation of quantitative analytic endpoints pertinent to meniscus morphometry (e.g., height, width, and volume) and position (e.g., tibial coverage, extrusion area, and distance) within the joint are highlighted in the literature. Three-dimensional qMRI of the meniscus has emerged as a reliable and reproducible non-invasive measurement technology, offering enhanced efficacy for assessing the relationship of the meniscus with radiographic joint space width (JSW), knee pain, structural (radiographic) KOA status, and with symptomatic and structural progression of KOA. Quantitative measures of meniscal extrusion were found to be robust predictors of various imaging endpoints, including osteophyte formation, subchondral bone changes, cartilage loss, as well as significant clinical outcomes.

The emergence of quantitative meniscus measurement technology has revamped the field of meniscal imaging research, providing accurate 3D analysis of both morphometric and positional measures. The systematic application of this methodology has unveiled significant insights into a better understanding of the incidence and symptomatic and structural progression of KOA.