Dynamic Composite Multi-Gradient Systems for Advanced MRI

摘要：本项目将使用一种新型的复合梯度系统来测试由磁共振成像（MRI）获得的内耳和中耳解剖精细结构图像，并最终通过梯度性能大大提高内耳和中耳病理的诊断，该梯度性能比传统的典型振幅40至45 mT/m和旋转速率200T/m/s提高。梯度系统将同时将系统体梯度与插入头梯度结合起来，以实现梯度性能，其速度和幅度几乎是单独体梯度的3倍。由于内耳病变需要非常高的空间分辨率，这通常超出了传统MRI扫描仪的能力，因此本研究中提出的检测这些病变的实验是改进复合梯度性能的理想测试。通过确定突发性感音神经性听力损失的原因，可以在疾病管理的早期指定适当的治疗方法。对内淋巴积液的客观检测将有助于改善梅尼埃氏病和相关疾病的诊断和治疗监测。通过对中耳残余胆脂瘤和其他非肿瘤组织的准确区分，可以省去许多不必要的手术。据我们所知，这是第一个系统地评估非常高梯度性能在中耳和内耳诊断研究中的价值的工作。在本研究中，体梯度和局部梯度将同时使用，并具有等效波形形状和时序。这项工作将通过证明：1)复合梯度系统相对于传统的单一梯度系统的灵活性和潜在性能改进，以及2)仅使用插入梯度的身体梯度时不会丢失图像质量，从而推进临床MRI可用的技术。因此，插入梯度可以保持在临床全脑研究的位置，并可用于需要增加梯度性能的序列。这些观察结果以前从未被证实过。

DESCRIPTION (provided by applicant): Dynamic composite multi-gradient systems for advanced MRI Abstract: This project will use a novel composite gradient system to test that images of the fine structure of inner and middle ear anatomy obtained with magnetic resonance imaging (MRI) and, ultimately, the diagnosis of inner and middle ear pathology can be greatly improved by gradient performance that is increased over the conventional typical amplitudes of 40 to 45 mT/m and slew rates of 200T/m/s. The gradient system will combine the system body gradients simultaneously with an insert head gradient to achieve gradient performance that is nearly a factor of 3 greater in speed and amplitude than the body gradients alone. Because pathologies of the inner ear require very high spatial resolution that is often beyond the capabilities of conventional MRI scanners, the experiments proposed in this study to detect these pathologies are ideal tests for the improved performance of composite gradients. By determining the cause of sudden sensorineural hearing loss the appropriate treatment could be specified early in the disease management. An objective test for endolymphatic hydrops would allow improved diagnosis and monitoring of therapy in Meniere's and related disorders. By accurately discriminating between residual cholesteatoma and other non-tumor tissues of the middle ear, this project could eliminate many unnecessary surgeries. To the best of our knowledge, this is the first work to systematically evaluate the value of very high gradient performance in diagnostic studies of the middle and inner ear. In this study, the body and local gradients will be used simultaneously with equivalent waveform shapes and timing. This work will advance the technology available for clinical MRI by demonstrating: 1) the flexibility and potential performance improvement of composite gradient systems over conventional single gradient systems and 2) that no image quality is lost when using only the body gradients with the insert gradients in position. Thus, the insert gradients can be kept in position for clinical whole brain studies and be available for use on sequences that require increased gradient performance. These observations have never before been demonstrated. PUBLIC HEALTH RELEVANCE: This project will be the first to improve MRI imaging of the middle and inner ear by operating insert gradient coils, which give high temporal and spatial resolution, in concert with conventional whole-body gradients which are slower, but more uniform.