Center for Medical Physics and Biomedical Engineering, MR-Centre of Excellence, Medical University of Vienna, Vienna, Austria.
Department of Radiology, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands.
Nephrol Dial Transplant. 2018 Sep 1;33(suppl_2):ii41-ii50. doi: 10.1093/ndt/gfy198.
This systematic review, initiated by the European Cooperation in Science and Technology Action Magnetic Resonance Imaging Biomarkers for Chronic Kidney Disease (PARENCHIMA), focuses on potential clinical applications of magnetic resonance imaging in renal non-tumour disease using magnetic resonance relaxometry (MRR), specifically, the measurement of the independent quantitative magnetic resonance relaxation times T1 and T2 at 1.5 and 3Tesla (T), respectively. Healthy subjects show a distinguishable cortico-medullary differentiation (CMD) in T1 and a slight CMD in T2. Increased cortical T1 values, that is, reduced T1 CMD, were reported in acute allograft rejection (AAR) and diminished T1 CMD in chronic allograft rejection. However, ambiguous findings were reported and AAR could not be sufficiently differentiated from acute tubular necrosis and cyclosporine nephrotoxicity. Despite this, one recent quantitative study showed in renal transplants a direct correlation between fibrosis and T1 CMD. Additionally, various renal diseases, including renal transplants, showed a moderate to strong correlation between T1 CMD and renal function. Recent T2 studies observed increased values in renal transplants compared with healthy subjects and in early-stage autosomal dominant polycystic kidney disease (ADPKD), which could improve diagnosis and progression assessment compared with total kidney volume alone in early-stage ADPKD. Renal MRR is suggested to be sensitive to renal perfusion, ischaemia/oxygenation, oedema, fibrosis, hydration and comorbidities, which reduce specificity. Due to the lack of standardization in patient preparation, acquisition protocols and adequate patient selection, no widely accepted reference values are currently available. Therefore this review encourages efforts to optimize and standardize (multi-parametric) protocols to increase specificity and to tap the full potential of renal MRR in future research.
本系统评价由欧洲科学与技术合作组织磁共振成像慢性肾脏病生物标志物（PARENCHIMA）项目发起，重点关注磁共振弛豫测量（MRR）在肾脏非肿瘤疾病中的潜在临床应用，特别是分别在 1.5T 和 3T 场强下测量独立的定量磁共振弛豫时间 T1 和 T2。健康受试者在 T1 上表现出可区分的皮质-髓质分化（CMD），在 T2 上表现出轻微的 CMD。急性同种异体移植排斥反应（AAR）中皮质 T1 值增加，即 T1CMD 降低，慢性同种异体移植排斥反应中 T1CMD 降低。然而，报道的结果存在差异，AAR 不能与急性肾小管坏死和环孢素肾毒性充分区分。尽管如此，一项最近的定量研究表明，在肾移植中纤维化与 T1CMD 之间存在直接相关性。此外，包括肾移植在内的各种肾脏疾病，T1CMD 与肾功能之间存在中度至强相关性。最近的 T2 研究观察到与健康受试者相比，肾移植中的 T2 值增加，并且在早期常染色体显性多囊肾病（ADPKD）中增加，与单独使用总肾体积相比，这可能有助于改善早期 ADPKD 的诊断和进展评估。肾 MRR 被认为对肾灌注、缺血/氧合、水肿、纤维化、水合作用和合并症敏感，从而降低了特异性。由于患者准备、采集方案和适当的患者选择缺乏标准化，目前没有广泛接受的参考值。因此，本综述鼓励努力优化和标准化（多参数）方案，以提高特异性，并在未来的研究中充分挖掘肾 MRR 的潜力。
