• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Three-dimensional rotational micro-angiography.
【24h】

Three-dimensional rotational micro-angiography.

机译：三维旋转微血管造影。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Computed tomography (CT) is state-of-the-art for 3D imaging in which images are acquired about the patient and are used to reconstruct the data. But the commercial CT systems suffer from low spatial resolution (0.5-2 lp/mm). Micro-CT (microCT) systems have high resolution 3D reconstruction (>10 lp/mm), but are currently limited to small objects, e.g., small animals. To achieve artifact free reconstructions, geometric calibration of the rotating-object cone-beam microCT (CBmicroCT) system is performed using new techniques that use only the projection images of the object, i.e., no calibration objects are required. Translations (up to 0.2 mm) occurring during the acquisition in the horizontal direction are detected, quantified, and corrected based on sinogram analysis. The parameters describing the physical axis of rotation determined using our image-based method (aligning anti-posed images) agree well (within 0.1 mm and 0.3 degrees) with those determined using other techniques that use calibration objects. Geometric calibrations of the rotational angiography (RA) systems (clinical cone-beam CT systems with fluoroscopic capabilities provided by flat-panel detectors (FPD)) are performed using a simple single projection technique (SPT), which aligns a known 3D model of a calibration phantom with the projection data. The calibration parameters obtained by the SPT are found to be reproducible (angles within 0.2° and x- and y-translations less than 2 mm) for over 7 months. The spatial resolution of the RA systems is found to be virtually unaffected by such small geometric variations. Finally, using our understanding of the geometric calibrations, we have developed methods to combine relatively low-resolution RA acquisitions (2-3 lp/mm) with high resolution microCT acquisitions (using a high-resolution micro-angiographic fluoroscope (MAF) attached to the RA gantry) to produce the first-ever 3D rotational micro-angiography (3D-RmicroA) system on a clinical gantry. Images of a rabbit with a coronary stent placed in an artery were obtained and reconstructed. To eliminate artifacts due to image truncation, lower-dose (compared to the MAF acquisition) full-FOV (FFOV) FPD RA sequences are also obtained. To ensure high-quality high-resolution reconstruction, the high-resolution images from the MAF are aligned spatially with the lower-dose FPD images (average correlation coefficient before and after alignment: 0.65 and 0.97 respectively), and the pixel values in the FPD image data are scaled (using linear regression) to match those of the MAF. Greater details without any visible truncation artifacts are seen in 3D RmicroA (MAF-FPD) images than in those of the FPD alone. The FWHM of line profiles of stent struts (100 micron diameter) are approximately 192 +/- 21 and 313 +/- 38 microns for the 3D RmicroA and FPD data, respectively. Thus, with the RmicroA system, we have essentially developed a high resolution CBmicroCT system for clinical use.
机译：计算机断层扫描（CT）是3D成像的最新技术，其中获取有关患者的图像并用于重建数据。但是商用CT系统的空间分辨率较低（0.5-2 lp / mm）。 Micro-CT（microCT）系统具有高分辨率3D重建（> 10 lp / mm），但目前仅限于小型物体，例如小型动物。为了实现无伪影的重建，使用仅使用物体的投影图像，即不需要校准物体的新技术来执行旋转物体锥束微CT（CBmicroCT）系统的几何校准。基于正弦图分析，可以检测，量化和校正水平采集过程中发生的平移（最大0.2毫米）。使用我们基于图像的方法（对齐反摆图像）确定的描述旋转物理轴的参数与使用其他使用校准对象的技术确定的参数吻合良好（在0.1毫米和0.3度以内）。旋转血管造影（RA）系统（由平板探测器（FPD）提供的具有荧光检查功能的临床锥形束CT系统）的几何校准是使用简单的单投影技术（SPT）进行的，该技术可以对已知的3D模型进行校准带有投影数据的校准体模。发现通过SPT获得的校准参数可重复7个月以上（角度在0.2°范围内，x和y平移小于2 mm）。发现RA系统的空间分辨率实际上不受这种小的几何变化的影响。最后，利用对几何标定的理解，我们开发了将相对低分辨率的RA采集（2-3 lp / mm）与高分辨率的microCT采集（使用附有高分辨率的微血管造影荧光镜（MAF））相结合的方法RA龙门架），以在临床龙门架上生产出首个3D旋转微血管造影（3D-RmicroA）系统。获得并重建了冠状动脉支架置入动脉的兔子的图像。为了消除由于图像截断而造成的伪影，还可以获得较低剂量（与MAF采集相比）的全FOV（FFOV）FPD RA序列。为了确保高质量的高分辨率重建，将MAF的高分辨率图像与小剂量FPD图像进行空间对齐（对齐前后的平均相关系数分别为0.65和0.97），以及FPD中的像素值图像数据按比例缩放（使用线性回归）以匹配MAF的图像数据。与单独的FPD相比，在3D RmicroA（MAF-FPD）图像中可以看到更大的细节，而没有任何可见的截断伪像。对于3D RmicroA和FPD数据，支架撑杆（直径为100微米）的线轮廓的FWHM分别约为192 +/- 21和313 +/- 38微米。因此，借助RmicroA系统，我们已从根本上开发出了用于临床的高分辨率CBmicroCT系统。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号