Quantitative MRI and MR Elastography in Renal Transplants

肾移植是恢复肾功能的唯一治疗方法。急性移植排斥反应的检测，发生在35%的所有肾脏接受者，是一个主要的挑战，在早期移植后阶段。急性排斥反应的特征在于受体对供体肾的强烈免疫应答，并且经常亚临床地进展。急性排斥反应的早期发现对于及时启动免疫抑制性休克治疗以防止移植物完全破坏是至关重要的。侵入性活检是目前诊断急性排斥反应的参考标准。非侵入性生物标志物，如来自血清和尿量的肌酐，已被证明仅在晚期对结构性肾组织变化敏感，通常会延迟临床干预。相反，定量磁共振成像（qMRI），包括通过动脉自旋标记（ASL）确定灌注，通过血氧水平依赖性（BOLD）MRI确定氧合，通过扩散加权成像（DWI）确定扩散，以及通过磁共振弹性成像（MRE）确定粘弹性，可以无创评估体内肾移植物的结构-功能特性。因此，将首次收集自体和移植肾的创新qMRI和MRE参数，并进行测试，用于疑似急性肾移植排斥反应的肾受者的临床评价。为此，将通过ASL、BOLD-MRI、DWI和MRE研究移植前健康志愿者和活体供体的自体肾以及移植后和急性移植排斥反应受者的移植肾。我们的方案获得的定量MRI数据的多参数分析将允许得出关于肾移植早期病理功能-结构变化的结论，从而改善肾移植后急性排斥反应的治疗决策和临床管理。

Kidney transplantation is the only treatment that restores kidney function. The detection of acute transplant rejection, which occurs in 35% of all kidney recipients, is a major challenge during the early post-transplantation phase. Acute rejection is characterized by a strong immune response of the recipient against the donor kidney and often progresses subclinically. Early detection of acute rejection is essential for prompt initiation of immunosuppressive shock therapy to prevent complete transplant destruction. Invasive biopsy is the current reference standard for diagnosis of acute rejection. Noninvasive biomarkers such as creatinine from blood serum and urine output have been shown to be sensitive to structural renal tissue changes only at a late stage, often delaying clinical intervention. Conversely, quantitative magnetic resonance imaging (qMRI), including determination of perfusion by arterial spin labeling (ASL), oxygenation by blood-oxygenation-level-dependent (BOLD) MRI, diffusion by diffusion-weighted imaging (DWI), and viscoelasticity by magnetic resonance elastography (MRE), allows noninvasive assessment of the structural-functional properties of kidney transplants in vivo. For this reason, innovative qMRI and MRE parameters of native and transplant kidneys will be collected for the first time and tested for the clinical evaluation of kidney recipients with suspected acute kidney transplant rejection. For this purpose, native kidneys in healthy volunteers and living donors before explantation as well as transplant kidneys after implantation and in recipients with acute transplant rejection will be investigated by ASL, BOLD-MRI, DWI, and MRE. It is expected that the multiparametric analysis of the quantitative MRI data obtained with our protocols will allow conclusions to be drawn about early pathological functional-structural changes in kidney transplants and to thus improve therapeutic decision-making and clinical management of acute rejection episodes after kidney transplantation.