Comprehensive Motion-Robust Pediatric MR Imaging Using Radial Acquisitions

描述（由申请人提供）：越来越多的人意识到与儿科患者诊断成像相关的辐射的有害影响。虽然在许多情况下，腹部MRI可以作为CT的可行替代方案，但由于 a）对运动伪影的高灵敏度，B）需要在全身麻醉或深度镇静下执行这些检查以获得可接受的诊断图像质量，以及c）诊断准确性的限制，因为在镇静下的患者的暂停呼吸期间不能采集数据。在拟议的项目中，我们将开发和评估基于径向k空间采集和高级非线性重建的新型运动鲁棒MRI技术，以克服这些限制。这些发展将补充我们现有的用于运动鲁棒MRI的放射状技术，其仅提供脂肪饱和的T1加权对比度，因此，到目前为止还不能用于全面的诊断检查。技术发展包括一种新的脂肪/水分离技术，用于径向3D多梯度回波采集，可用于评估病变的脂肪含量，并解决目前在T1加权径向采集和频谱脂肪饱和度中看到的伪影。为了获得T2加权图像对比度，将开发稳健的径向3D TSE序列，并与定制的压缩感知重建相结合，以实现临床可接受的扫描时间。此外，一种新的时间效率的图像稳定技术将开发的基础上，k空间的一致性评估和自适应数据重新扫描。它将被集成到我们所有的径向序列中，以防止大量患者运动导致的数据不一致。所有开发的技术将进行评估，首先，在镇静的儿童硬化症患者和临床成像标准进行比较。将在盲态阅片人研究中通过定量估计病变检出率来评估图像质量的改善。然后，这些技术将用于实施儿科腹部MRI的全径向诊断检查策略，这将使儿科患者的运动稳健检查无需使用深度镇静或全身麻醉。将在脑硬化患者中评价无镇静成像方法，并根据在全身麻醉或深度镇静下进行的儿科腹部MRI的临床标准，在图像质量、检测准确性和检查时间方面进行基准测试。这种新的简化检查策略不仅有望改变儿科患者的诊断身体MRI的方式，而且还将影响无法充分暂停呼吸的老年人和患病患者的临床成像。

DESCRIPTION (provided by applicant): There is growing awareness of the detrimental effect of radiation associated with diagnostic imaging in pediatric patients. Although in many cases abdominal MRI can serve as a viable alternative to CT, it is underutilized in clinical practice due to a) high sensitivity to motion artifacts, b) need to perform these exams under general anesthesia or deep sedation to obtain acceptable diagnostic image quality, and c) limitations in the diagnostic accuracy, as data cannot be acquired during suspended respiration in patients who are under sedation. In the proposed project, we will develop and evaluate novel motion-robust MRI techniques based on radial k-space acquisition and advanced non-linear reconstruction to overcome these limitations. The developments will complement our existing radial techniques for motion-robust MRI, which provide only fat- saturated T1-weighted contrast and, thus, cannot be utilized for comprehensive diagnostic exams so far. The technical developments include a new fat/water-separation technique for radial 3D multi-gradient-echo acquisitions, which can be used to assess the fat content of lesions and to resolve artifacts currently seen in T1-weighted radial acquisitions with spectral fat saturation. To obtain T2-weighted image contrast, a robust radial 3D TSE sequence will be developed and combined with a tailored compressed-sensing reconstruction to achieve clinically acceptable scan times. In addition, a novel time-efficient image-stabilization technique will be developed based on k-space consistency assessment and adaptive data rescanning. It will be integrated into all our radial sequences to prevent data inconsistencies from bulk patient motion. All developed techniques will be evaluated, first, in sedated pediatric patients with Tuberous Sclerosis and compared to the clinical-imaging standard. The improvement in image quality will be assessed in blinded-reader studies and by quantitatively estimating the lesion detection rate. The techniques will then be used to implement a full-radial diagnostic exam strategy for pediatric abdominal MRI, which will enable motion-robust examination of pediatric patients without the use of deep sedation or general anesthesia. The sedation-free imaging approach will be evaluated in patients with Tuberous Sclerosis and benchmarked in terms of image quality, detection accuracy, and exam time against the clinical standard for pediatric abdominal MRI performed under general anesthesia or with deep sedation. This new simplified exam strategy promises not only to change the way diagnostic body MRI is done in pediatric patients but it will also impact clinical imaging of elderly and sick patients who cannot adequately suspend respiration.