Advanced Fetal Imaging

描述(由申请人提供)：胎儿期是大脑发育和发育的最佳时期，可以说是定义未来认知潜力的最重要的时期。因此，当胎儿大脑发育受损时，包括先天性心脏病(CHD)在内的许多疾病都会在宫内出现异常，并导致终身认知障碍，即使在最佳的产后护理下也无法纠正。这导致公共卫生迫切需要在子宫早期发现解剖和生理异常的方法，以便更好地为父母提供建议，并更好地指导胎儿干预措施的发展和优化，以防止或减轻这种长期后果。尽管人们一直乐观地认为胎儿MRI可以发挥这一作用，但它仍然受到妊娠腹部的独特解剖结构、胎儿的小尺寸以及最重要的胎儿运动的严重限制。因此，胎儿大脑核磁共振成像远远落后于出生后的大脑成像。事实上，胎脑MR的评估仍然主要局限于快速单次激发T2序列，这些序列与波谱、扩散和血流灌注相比具有固有的较差的脑对比，不可靠或不可能使用当前的方法。因此，胎儿MRI提供可靠和准确的结构和生理评估的潜力仍然没有实现。我们建议使用一种集成的方法来推进胎儿MRI，该方法解决了从硬件到脉冲序列设计的整个成像采集过程，目标如下：目的1.开发MR硬件和解剖学采集方法。我们建议开发第一个拟人胎儿核磁共振体模，以安全地测试我们开发的可行性，并确保SAR的安全。我们将建立首个128通道孕腹接收相控阵，以促进图像加速和提高信噪比。我们将建立在新兴的并行传输(PTX)领域，并第一个将其应用于胎儿成像，目标是仅刺激胎儿头部的这一区域，以最大限度地减少SAR，实现进一步的加速，并为预期的运动导航提供目标。随着用于胎儿成像的压缩传感(CS)技术的发展，图像采集将获得更快的速度。这些改进将有助于改进解剖图像(TSE和MPRAGE)；目标2.开发生理采集方法。利用目标1中的进展来开发稳健的扩散、光谱和灌注成像；以及目标3.转化为先天性心脏病的活体胎儿脑MRI评估。我们将评估与目前相同受试者的胎儿MRI相比，以及与正常对照组的先进方案相比，我们是否有能力或我们的进展更好地检测CHD的结构和生理脑异常。此外，我们将尝试检测胎儿干预后左心发育不全综合征(HLHS)的生理变化。总之，我们的目标是通过在胎儿MRI实验的采集端开发和使用最先进的进展来改变胎儿MRI领域，以满足随着胎儿干预的出现而对更多信息的日益增长的需求。

DESCRIPTION (provided by applicant): The fetal period is a time of unparalleled brain growth and development and is arguably the most important time for defining future cognitive potential. Therefore, when fetal brain development is impaired, as it is in many disorders including congenital heart disease (CHD), abnormalities emerge in utero and contribute to lifelong cognitive impairment that cannot be corrected even with optimal postnatal care. This has led to an overwhelming public health need for methods that detect early in utero anatomical and physiological abnormalities to better counsel parents and to better guide development and optimization of fetal interventions (surgical or medical) to prevent or mitigate such long-term consequences. Although there has been ongoing optimism that fetal MRI could fulfill this role, it still remains severely limited by the unique anatomy of the gravid abdomen, the small size of the fetus and, most importantly, fetal motion. As a result, fetal brain MRI lags far behind postnatal brain imaging. In fact, fetal brain MR evaluations remain primarily limited to fast single-shot T2 sequences that have inherently poor brain contrast with spectroscopy, diffusion and perfusion unreliable or impossible with the current methods. Thus, the potential of fetal MRI to provide robust and accurate structural and physiological assessments remains unrealized. We propose to advance fetal MRI using an integrated approach that addresses the entire imaging acquisition process from hardware to pulse sequence design with the following aims: Aim 1. Develop MR Hardware and Anatomical Acquisition Methods. We propose to develop the first anthropomorphic fetal MRI phantom to safely test the feasibility of our developments and ensure SAR safety. We will build the first 128-channel receive phased array for the pregnant abdomen to facilitate image acceleration and improve SNR. We will build on the emerging field of parallel transmission (pTx), and be the first to apply it to fetal imaging with the goal of exciting only th region of the fetal head to minimize SAR, enable further acceleration, and provide a target for prospective motion navigation. Additional speed on the image acquisition will be gained with the development of compressed sensing (CS) techniques for fetal imaging. These improvements will enable improved anatomical images (TSE and MPRAGE); Aim 2. Develop Physiological Acquisition Methods. Use advances in Aim 1 to develop robust diffusion, spectroscopy and perfusion imaging; and Aim 3. Translate to In Vivo Fetal Brain MRI assessment in Congenital Heart Disease. We will assess the ability or our advances to better detect structural and physiological brain abnormalities in CHD compared to current fetal MRI in the same subjects and compared to the advanced protocol in normal controls. In addition we will attempt to detect physiological changes after fetal interventions in hypoplastic left heart syndrome (HLHS). In summary, our goal is to transform the field of fetal MRI by developing and employing state-of-the-art advances on the acquisition end of the fetal MRI experiment to meet the growing demand for more information as fetal interventions emerge.