Biggi Marianna, Dyson Sue J
Am J Vet Res. 2018 Mar;79(3):299-310. doi: 10.2460/ajvr.79.3.299.
OBJECTIVE To use high-field and low-field MRI to describe the anatomy of the proximal portion of the tarsal region (proximal tarsal region) of nonlame horses. SAMPLE 25 cadaveric equine tarsi. PROCEDURES The proximal portion of 1 tarsus from each of 25 nonlame horses with no history of tarsal lameness underwent high-field (1.5-T) and low-field (0.27-T) MRI. Resulting images were used to subjectively describe the anatomy of that region and obtain measurements of the collateral ligaments of the tarsocrural joint. RESULTS Long and short components of the lateral and medial collateral ligaments of the tarsocrural joint were identified. Various bundles of the short collateral ligaments were difficult to delineate on low-field images. Ligaments typically had low signal intensity in all sequences; however, multiple areas of increased signal intensity were identified at specific locations in most tarsi. This signal intensity was attributed to focal magic angle effect associated with orientation of collagen fibers within the ligaments at those locations. Subchondral bone of the distal aspect of the tibia was uniform in thickness, whereas that of the medial trochlear ridge of the talus was generally thicker than that of the lateral trochlear ridge. In most tarsi, subchondral bone of the talocalcaneal joint decreased in thickness from proximal to distal. CONCLUSIONS AND CLINICAL RELEVANCE Results generated in this study can be used as a reference for interpretation of MRI images of the proximal tarsal region in horses.
目的 使用高场和低场MRI描述无跛行马匹跗骨区域近端（近端跗骨区域）的解剖结构。样本 25 具马尸体跗骨。方法 对25匹无跗骨跛行病史的无跛行马匹的每只跗骨近端进行高场（1.5T）和低场（0.27T）MRI检查。所得图像用于主观描述该区域的解剖结构，并获取跗横关节侧副韧带的测量值。结果 确定了跗横关节外侧和内侧副韧带的长、短部分。短副韧带的不同束在低场图像上难以描绘。韧带在所有序列中通常具有低信号强度；然而，在大多数跗骨的特定位置发现了多个信号强度增加的区域。这种信号强度归因于与这些位置韧带内胶原纤维取向相关的局部魔角效应。胫骨远端的软骨下骨厚度均匀，而距骨内侧滑车嵴的软骨下骨通常比外侧滑车嵴厚。在大多数跗骨中，距跟关节的软骨下骨厚度从近端到远端逐渐减小。结论和临床意义 本研究产生的结果可作为解释马匹近端跗骨区域MRI图像的参考。
