Quantitative Lung Function Assessment in 2-year old children after Congenital Diaphragmatic Hernia using Fourier Decomposition Magnetic Resonance Imaging

先天性膈疝（CDH）导致腹部器官突出进入胸腔，从而导致肺发育受损，随后出现肺发育不全。已知肺发育不全和肺动脉高压是CDH病例存活结果的主要决定因素，如果没有严重的附加畸形或综合征存在。肺发育不全不仅与气道结构畸形有关，还与微血管系统功能失调有关。在健康儿童中，肺泡的数量增加到大约三岁，此后肺的生长是基于先前存在的肺泡的扩大。因此，对于CDH修复后的儿童，儿童时期肺组织的产后发育可能是可能的。到目前为止，很少有人知道受影响的肺会在多大程度上恢复。目前的灌注加权肺磁共振成像（MRI）方法要么基于动态对比增强（DCE） MRI，要么基于动脉自旋标记（ASL）技术。尽管DCE-MRI提供比ASL技术更高的信噪比（SNR），但在使用造影剂方面的额外努力及其潜在的副作用是缺点，特别是在患有肾脏疾病（即NSF）的受试者中。最近，也出现了一个主要的争论，即长期的副作用可能与钆造影剂在大脑中的积累有关。因此，尤其在儿童中重复使用造影剂（例如，对于CDH患儿参加随访计划）应进行严格和单独的评估。MRI可以通过FD技术测量肺灌注和肺通气，而不需要电离辐射。我们的研究组先前已经证明，在CDH后的2岁儿童中进行dce测量是可能的，并且可以检测肺灌注值的侧差异。此外，在无辐射和无造影剂的成人患者中，通过fd技术对灌注和通气进行量化，从而实现V/Q成像已被证明是可行的。因此，MRI是儿童CDH后随访的合适工具，因为它能够显示肺形态和肺功能。本研究计划的目的是将傅里叶分解技术应用于2岁儿童的肺部成像，探讨通气和灌注图对先天性膈疝儿童的临床价值。这包括实施2D和3D成像技术，在1.5T下进行后处理并将其转换为3T，以及将灌注图与DCE-MRI相关联。临床方面，所开发的技术的诊断价值，其检测对侧和同侧肺间灌注/通气变化的能力，并最终描述CDH儿童定量灌注和通气联合成像对患者治疗和各自随访的意义。

Congenital diaphragmatic hernia (CDH) leads to herniation of abdominal organs into the thoracic cavity and consequently to impaired lung development, followed by lung hypoplasia. Lung hypoplasia and pulmonary hypertension are known to be the main determinants of survival outcome in cases of CDH if no severe additional malformations or syndromes are present. Lung hypoplasia is not only attributed to malformed airway structures but also to a dysfunctional micro vascular system. In healthy children the amount of alveoli increases until the age of about three and afterwards lung growth is based on the enlargement of preexistent alveoli. Therefore, postnatal development of lung tissue during childhood may be possible for children after CDH repair. Up to now, little is known to which extent the affected lung catches up.Current methods for perfusion weighted lung magnetic resonance imaging (MRI) are either based on dynamic contrast enhanced (DCE) MRI or arterial spin labeling (ASL) techniques. Although DCE-MRI offers much higher signal to noise ratio (SNR) than ASL techniques, the additional efforts in administering the contrast agent and its potential side-effects are disadvantages, especially in subjects with kidney disease (i.e. NSF). Recently, also a major debate has arisen which long-term side-effects may be associated to accumulation of gadolinium based contrast-agents in the brain. Therefore, especially in children the repetitive usage of contrast agent (e.g. for children with CDH enrolled into a follow-up program) should be evaluated critically and individually.With MRI lung perfusion and lung ventilation can be measured via the FD technique without the need for ionizing radiation. Our study group has demonstrated previously that DCE-measurements in 2-year old children after CDH are possible and detect side differences in lung perfusion values. Besides, in adult patients radiation free and contrast agent free quantification of perfusion and ventilation and thereby, V/Q imaging has been proven to be feasible by FD-techniques. Therefore, MRI is a suitable tool for follow-up of children after CDH, as being capable to visualize both lung morphology and lung function. The objectives of this research proposal is to implement the Fourier Decomposition technique for lung imaging in 2-year old children and to investigate the clinical value of the ventilation and perfusion maps for children with congenital diaphragmatic hernia. This comprises implementing 2D and 3D imaging techniques and post processing at 1.5T and its translation to 3T as well as correlation of the perfusion maps to DCE-MRI. Clinically, diagnostic value of the developed techniques, its power to detect changes in perfusion/ ventilation between contra- and ipsilateral lung and eventually describe implication of combined quantitative perfusion and ventilation imaging in CDH children on patient treatment and respectively follow-up procedure.