BOLD MRI: Application to Intra-renal Oxygenation

放射性造影剂肾病（RCN）是医院获得性肾衰竭的第三大常见原因， 11%的发病率。随着诊断成像程序数量的持续增加， 医院获得性综合征，预防的必要性是最迫切的。然而，背后的机制 RCN的发展仍然没有完全理解。基于动物试验提出的许多干预措施 在人体试验中失败了这种脱节的可能原因可能是：（1）动物模型没有 充分代表人类生理学，（2）动物模型中使用的结果测量与那些 用于临床;（3）无效假设等。 在过去的二十年里，在理解氧合方面取得了重大进展， 并且现在很好地理解，肾内的区域在缺氧条件下存活， 条件为了使肾脏在缺氧环境中存活，进化出了强大的控制机制 其即使在外部刺激的威胁下也能保持氧气充足， 造影剂据信，肾脏激活这些控制机制的能力的损害 可能是在诸如造影剂的刺激之后发生肾衰竭的原因 媒体 基于这些假设，已经提出并验证了新的动物模型。这些比较简单 与需要手术操作的先前模型相比，更重要的是， 人类状况的功能方面。此外，可用于监测肾内 氧合不断改善。血氧水平依赖（BOLD）MRI技术具有以下优点： 已被证明是敏感和有效的评价肾氧合在大鼠和人的肾脏。在 此外，对氧合状态的更好了解也带来了新的干预目标。 基于这一背景，该建议扩展了我们目前在健康和高血压肾脏中的发现， BOLD MRI，以更好地了解造影剂给药后的急性血流动力学反应， RCN和RCN易感糖尿病大鼠的功能模型。我们还将获得用于 在诊所里我们还将测试针对缓解缺氧的新干预措施的有效性。我们将进一步 使用钠MRI监测造影剂后的急性变化，并将其与BOLD MRI相关联 测量. 成功的结果应该对制定RCN的预防战略产生重大影响。放射性造影剂诱导的肾功能衰竭是一种常见的医院获得性综合征， 严重的可能包括死亡，预防策略是非常受欢迎的。随着 诊断程序的数量，这个问题的相关性和重要性越来越大。我们提出的 这项研究将有助于更好地了解这种综合征发展背后的机制， 制定新的预防策略。

Radiocontrast nephropathy (RCN) is a third common cause of hospital acquired renal failure, accounting for 11% of incidence. With the continuing rise in the number of diagnostic imaging procedures and because it is a hospital acquired syndrome, the need for prevention is most compelling. However, the mechanisms behind the development of RCN remain not fully understood. Many interventions proposed based on animal testing have failed in human trials. The possible reasons for this disconnect may be due to: (1) animal models not adequately representing the human physiology, (2) outcome measures used in animal models differ from those used in the clinic, (3) invalid hypothesis etc.. Over the last two decades significant progress has been made in terms of understanding the oxygenation status within the kidney and it is now well appreciated that regions within the kidney survive under hypoxic conditions. In order for the kidney to survive in the hypoxic milieu, powerful control mechanisms have evolved that maintain oxygen sufficiency even under the threat of external stimuli such as during administration of contrast media. It is believed that compromise in the ability of the kidney to activate these control mechanisms during a "stress" may be the cause for the development of renal failure following stimuli such as contrast media. Based on these hypotheses, novel animal models have been proposed and validated. These are simpler compared to previous models that necessitate surgical manipulations, and more importantly better represent the functional aspect of the human condition. Additionally, the techniques available for monitoring intra-renal oxygenation have continuously improved. Blood oxygenation level dependent (BOLD) MRI technique has been shown to be sensitive and efficacious in evaluating renal oxygenation both in rat and human kidneys. In addition, better understanding of the oxygenation status has given rise to new targets for intervention. Based on this background, this proposal extends our present findings in healthy and hypertensive kidneys with BOLD MRI to better understand the acute hemodynamic responses following contrast administration in functional models of RCN and in RCN prone diabetic rats. We will additionally acquire markers that are used in the clinic. We will also test the efficacy of novel interventions targeted at relieving hypoxia. We will further use sodium MRI to monitor acute changes following contrast media and correlate them with BOLD MRI measurements. Successful outcome should have a significant impact on the development of preventive strategies for RCN. Radiocontrast induced renal failure is a common hospital acquired syndrome and because the consequences could be severe including death, preventive strategies are highly sought after. With the continuous increase in the number diagnostic procedures, the relevance and significance of this problem is growing. Our proposed study will allow for better understanding of the mechanisms behind the development of this syndrome and develop novel preventive strategies.