H double-quantum filtered MR imaging of joints tissues: bound water specific imaging of tendons, ligaments and cartilage

The ¹H double-quantum filtered (DQF) NMR and DQF MRI is applied to the joint tissues of rabbits for selective visualization of tendons, menisci and articular cartilage. The ¹H DQF NMR selectively filters double-quantum coherence arising from the ¹H dipolar interaction of the “bound” water in these tissues. The double-quantum creation time dependency of the DQF signal intensity is determined by the molecular environment of the “bound” water. Therefore, each tissue has a unique creation time at which the DQF signal reaches its maximum intensity, τ_max (Achilles tendon: 0.46 ± 0.02 ms, patella: 0.55 ± 0.8 ms, anterior cruciate ligament: 0.60 ± 0.05 ms, meniscus: 0.78 ± 0.02 ms, skin: 0.81 ± 0.07 ms). We have presented the creation-time-contrasted DQF images of the meniscus, patella, foot, and knee joint. Compared with conventional T₂*-weighted gradient-echo (GRE) MR images, tendons, ligaments, menisci, and articular cartilage were more clearly seen in the DQF MR images. All these tissues were distinctly discriminated from each other by their creation times. DQF MR images of foot and knee joints can selectively demonstrated tendons, ligaments, and cartilage, which make it easier to understand the complicated anatomic structure of joints. Because the DQF NMR signal intensity and τ_max are sensitive to the order structure of the “bound” water, it might be possible to introduce the creation-time dependent-contrast of ¹H DQF MR images as a new tool for analyzing the changes in the ordered structure of the tissue.