Effect of partial H2O-D2O replacement on the anisotropy of transverse proton spin relaxation in bovine articular cartilage: part 1 of raw data

Anisotropy of transverse proton spin relaxation in collagen-rich tissues like cartilage and tendon is a well-known phenomenon that manifests itself as the "magic-angle" effect in magnetic resonance images of these tissues. It usually attributed to the non-zero averaging of intra-molecular dipolar interactions in water molecules bound to oriented collagen fibers. One way to manipulate the contributions of these interactions to spin relaxation is by partially replacing the water in the cartilage sample with deuterium oxide. It is known that dipolar interactions in deuterated solutions are weaker, resulting in a decrease in proton relaxation rates.

In this work, the effects of deuteration on the longitudinal and the isotropic and anisotropic contributions to transverse relaxation of water protons in bovine articular cartilage was investigated. The anisotropy of transverse proton spin relaxation in articular cartilage is independent of the degree of deuteration is demonstrated, bringing into question some of the assumptions currently held over the origins of relaxation anisotropy in oriented tissues.

软骨、肌腱等富含胶原蛋白的组织中，横向质子自旋弛豫的各向异性是一种已被广泛认知的现象，该现象在这类组织的磁共振图像中表现为「魔角效应」。该现象通常源于结合在定向胶原纤维上的水分子内分子偶极相互作用的非零平均效应。调控此类相互作用对自旋弛豫贡献的一种手段，是用氘代水（Deuterium Oxide）部分置换软骨样本中的普通水。已知氘代溶液中的偶极相互作用更弱，会导致质子弛豫速率降低。
本研究探究了氘代处理对牛关节软骨内水分子的纵向弛豫，以及横向弛豫的各向同性与各向异性贡献的影响。本研究证实，关节软骨的横向质子自旋弛豫各向异性与氘代程度无关，这一结果对当前关于定向组织中弛豫各向异性起源的部分主流假设提出了质疑。