GLOMERULAR FILTRATION RATE & EXTRACTION FRACTION OF GD DTPA IN KIDNEYS W/ MRI

磁共振成像（MRI）已成为一种 重要的成像模式的管理癌症患者，由于 其出色的软组织对比度。 然而，迄今为止， 主要限于癌症的检测，只有有限的 在随后的组织活检中起作用，在治疗中没有直接作用。 这 随着最近一代“开放式”MRI系统的出现， 承诺微创活检和替代的可能性， 全身或全身治疗与局部治疗。 介入 MRI（iMRI）程序涉及使用活检等器械 针、导管或使用射频、激光或 冷冻疗法 由于MRI对干扰非常敏感， 磁场，这些设备的存在往往会产生图像 失真和信号空洞。 努力提高图像质量， 专注于设计能够产生 最小的伪影与传统的成像方法。 我们的目标是 开发先进的MR成像方法，专门用于 在存在介入设备的情况下进行成像，并将这些 方法到一个快速的，交互式的，灵活的系统。 方法/结果：我们开发了一种去除图像的方法， 通过使用视角倾斜的失真。 该方法 取决于梯度的应用，梯度的大小等于 在数据收集期间应用的切片选择梯度的梯度。 额外的梯度确保了非共振自旋看起来是 注册在图像中。 我们还开发了一些方法， 自旋回波图像上的针状伪影， 由于RF重新聚焦而导致的针对比度。 该方法以 靠近针共振远的自旋的优点 非共振 结论：开放式MR系统提供了巨大的 微创治疗的临床机会。 一个基本 快速获得高质量图像的能力将是一个要求 在存在介入器械的情况下。 在这项工作中，我们 开发一个元件阵列， 需要改进和控制的介入设备。

Introduction: Magnetic Resonance imaging (MRI) has become an important imaging modality for the management of cancer patients due to its excellent soft tissue contrast. However, MRI has so far been restricted primarily to the detection of cancer, with only a limited role in subsequent tissue biopsy, and no direct role in therapy. This is all changing with the recent generation of "open" MRI systems which promise less invasive biopsy and the possibility for replacing generalized or systemic therapy with local therapy. Interventional MRI (iMRI) procedures involve the use of devices such as biopsy needles, catheters, or ablation devices using RF, lasers, or cryotherapy. Since MRI is extremely sensitive to perturbations in magnetic field, the presence of these devices often produces image distortions and signal voids. Efforts to improve image quality have focused on designing interventional device materials that produce minimal artifacts with conventional imaging methods. Our goal is to develop advanced MR imaging methods that are designed specifically for imaging in the presence of interventional devices, and integrate these methods into a rapid, interactive, and flexible system. Methods/Results: We have developed a method to remove image distortions by the use of view angle tilting. This method is dependent on the application of a gradient with magnitude equal to that of the slice select gradient, applied during data collection. The additional gradient ensures that off resonance spins appear to be registered in the image. We have also developed methods to increase needle artifacts on spin echo images which have inherently little needle contrast due to the rf refocussing. This method takes advantage of the fact that spins adjacent to the needle resonant far off-resonance. Conclusions: Open MR systems provide tremendous clinical opportunities for minimally invasive therapies. An essential requirement will be the ability to rapidly obtain high quality images in the presence of interventional devices. In this work, we are developing an array of elements that allow the imaging of interventional devices to be improved and controlled.