Mani Laila-Yasmin, Seif Maryam, Nikles Florence, Tshering Vogel Dechen W, Diserens Gaëlle, Martirosian Petros, Burnier Michel, Vogt Bruno, Vermathen Peter
Department of Nephrology and Hypertension, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland.
Departments of Biomedical Research and Radiology, University of Bern, Bern, Switzerland.
Front Med (Lausanne). 2021 Aug 10;8:697055. doi: 10.3389/fmed.2021.697055. eCollection 2021.
Kidney perfusion and oxygenation are two important determinants of kidney graft function. In kidney transplantation, repeated graft hypoperfusion may occur during hip flexion, for example in the sitting position, due to the progressive development of fibrotic tissue around iliac arteries. The aim of this study was to assess the changes in oxygenation and perfusion of kidney grafts during hip flexion and extension using a new functional magnetic resonance imaging (fMRI) protocol. Nineteen kidney graft recipients prospectively underwent MRI on a 3T scanner including diffusion-weighted, blood oxygenation level dependent (BOLD), and arterial spin labeling sequences in hip positions 0° and >90° before and after intravenous administration of 20 mg furosemide. Unexpectedly, graft perfusion values were significantly higher in flexed compared to neutral hip position. Main diffusion-derived parameters were not affected by hip position. BOLD-derived cortico-medullary R2 ratio was significantly modified during hip flexion suggesting an intrarenal redistribution of the oxygenation in favor of the medulla and to the detriment of the cortex. Furthermore, the increase in medullary oxygenation induced by furosemide was significantly blunted during hip flexion ( < 0.001). Hip flexion has an acute impact on perfusion and tissue oxygenation in kidney grafts. Whether these position-dependent changes affect the long-term function and outcome of kidney transplants needs further investigation.
肾脏灌注和氧合是肾移植功能的两个重要决定因素。在肾移植中，例如在坐姿时髋关节屈曲过程中，由于髂动脉周围纤维化组织的逐渐发展，可能会反复出现移植肾灌注不足。本研究的目的是使用一种新的功能磁共振成像（fMRI）方案评估髋关节屈伸过程中移植肾的氧合和灌注变化。19名肾移植受者在3T扫描仪上接受了MRI检查，包括在静脉注射20mg呋塞米前后，在髋关节0°和>90°位置进行扩散加权、血氧水平依赖（BOLD）和动脉自旋标记序列扫描。出乎意料的是，与髋关节中立位相比，髋关节屈曲时移植肾灌注值显著更高。主要的扩散衍生参数不受髋关节位置的影响。髋关节屈曲期间，BOLD衍生的皮质-髓质R2比值显著改变，提示肾内氧合重新分布，有利于髓质而不利于皮质。此外，呋塞米诱导的髓质氧合增加在髋关节屈曲期间显著减弱（<0.001）。髋关节屈曲对移植肾的灌注和组织氧合有急性影响。这些与位置相关的变化是否会影响肾移植的长期功能和结果需要进一步研究。
