MR Spectroscopic imaging of collagen: Tendons and knee menisci

Abstract

Water molecules associated with collagen have short transverse (T₂) relaxation times. Projection-reconstruction techniques are able to achieve an echo time (TE) much shorter than conventional techniques, allowing imaging of tissues with T₂ < 5 ms. Using these techniques, a conventional 1.5-T MRI human imaging system can directly image collagen-associated water from knee menisci and tendons in normal volunteers and patients. Long-T₂ suppression improves the contrast between these structures and the surrounding tissue with long-T₂ relaxation times. Spectroscopic imaging provides improved lipid/water registration and information about chemical composition and relaxation times. Direct imaging of tendons and menisci may provide more information about these structures and provide a new way to assess both injury and repair.