Early Diagnosis of Growth Disorders Uing MR Imaging

描述（由申请人提供）：本研究的目的是检测 骨骺缺血和预测其生长后遗症使用新的 非侵入性磁共振（MR）方法。在动物模型中，我们建议 以确定缺血的最早变化，区分早期和晚期 缺血导致缺血性坏死;并预测 生长停滞除了常规的MR测量（质子密度和T2 松弛），我们将研究灌注相关的变化，早期钆 (Gd)增强成像和弥散相关改变行弥散扫描 和扩散张量成像。我们还将评估 软骨基质，包括糖胺聚糖耗竭，显示延迟 GD增强成像和磁化传递成像的胶原含量。 主要假设是MR参数可以1）检测早期缺血，2） 区分早期和晚期缺血导致的后遗症，和3）预测 通过反映组织结构的MR参数， 未成熟骨骺的血管化。 骨骺缺血是一种常见的致病途径， 紊乱缺血导致股骨头缺血性坏死 常导致儿童髋关节畸形和残疾。一个长出来的臀部 在成年人中也异常地易患退行性关节疾病;超过 所有患有髋关节骨关节炎的成年人中有一半患有髋关节疾病， 孩子软骨疾病的成像用于指导早期治疗， 预防或尽量减少畸形，并检测易患早产儿的儿童 成年后软骨退化。 具体目的是：1）确定正常人的MR组织特征 骺软骨具体地说，我们希望测试， 未成熟骺软骨的细胞结构和血管化导致 不同的MR组织特征; 2）在早期缺血，确定时间 以及扩散成像、T2图和Gd增强之间的空间差异 3）在长期缺血中，确定哪些MR参数最能预测 不可逆转的损伤;以及4）在缺血性坏死模型中，确定哪一个 MR参数预测异常生长。

DESCRIPTION (provided by applicant): The goal of this research is the detection of epiphyseal ischemia and prediction of its growth sequelae using novel non-invasive magnetic resonance (MR) approaches. In animal models, we propose to determine the earliest changes in ischemia, to differentiate early from late ischemia leading to avascular necrosis; and to predict the deverlopment of growth arrest. In addition to conventional MR measures (proton density and T2 relaxation), we will investigate perfusion-related changes by early gadolinum (Gd) enhanced imaging; and diffusion related changes by line diffusion scanning and diffusion tensor imaging. We will also evaluate disturbances of the cartilaginous matrix including glycosaminoglycan depletion revealed by delayed GD enhanced imaging, and collagen content by magnetization transfer imaging. The major hypotheses are that MR parameters can 1) detect early ischemia, 2) differentiate early from late ischemia leading to sequelae, and 3) predict growth deformity through MR parameters that reflect tissue structure and vascularization of the immature epiphysis. Epiphyseal ischemia is a pathogenic pathway shared by many common pediatric disorders. Ischemia leading to avascular necrosis of the femoral head frequently causes hip deformity and disability in childhood. A hip that grows abnormally also predisposes to degenerative joint disease in adult; more than half of all adults with osteoarthritis of the hip suffered hip diseases as children. Imaging of cartilaginous disorders serves to guide early therapy, prevent or minimize deformity, and detect children predisposed to premature cartilage degeneration in adulthood. The specific aims are to: 1) determine the MR tissue characteristics of normal epiphyseal cartilage. Specifically, we wish to test whether the greater cellularity and vascularization of immature epiphyseal cartilage result in different MR tissue characteristics; 2) in early ischemia, determine temporal and spatial differences between diffusion imaging, T2 maps and Gd-enhanced imaging; 3) in prolonged ischemia, determine which MR parameters best predict irreversible damage; and 4) in a model of avascular necrosis, determine which MR parameters predict abnormal growth.