Cartilage Mapping (T2 & T1rho): Quantitative Joint MRI
Quantitative MRI of cartilage quality as well as thickness, which shows biochemical degeneration before a defect appears.
The idea
Standard MRI shows cartilage morphology (thinning, fissures, defects), which appear relatively late. Quantitative mapping instead measures relaxation times that reflect cartilage composition, changing early in degeneration.
- T2 mapping: sensitive to collagen structure and water content; rises as the collagen matrix breaks down.
- T1rho mapping: sensitive to proteoglycan loss, one of the earliest changes in osteoarthritis.
- dGEMRIC: a contrast-based technique also probing proteoglycan content.
These maps can flag “pre-morphological” disease: cartilage that still looks normal but is biochemically deteriorating.
Where it is used
- Early osteoarthritis research: detecting and tracking degeneration before structural loss.
- Cartilage repair: monitoring the maturation and integration of repair tissue after procedures.
- Injury & overload: assessing cartilage at risk after ligament injury or in athletes.
Practical notes
Largely a research and specialist tool for now: values depend on field strength, sequence and region, and need careful standardisation. Promising for trials of disease-modifying OA therapies.
Sources
- Guermazi A et al. Compositional MRI techniques for evaluation of cartilage degeneration in osteoarthritis. Radiology 2015;277:23–43.
Educational summary; primarily research/specialist use. Not medical advice.
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