von Morze Cornelius, Purcell Derk D, Banerjee Suchandrima, Xu Duan, Mukherjee Pratik, Kelley Douglas A, Majumdar Sharmila, Vigneron Daniel B
Department of Radiology, University of California, San Francisco, CA 94143-2512, USA.
Magn Reson Imaging. 2008 Dec;26(10):1329-33. doi: 10.1016/j.mri.2008.04.002. Epub 2008 May 27.
Greater spatial resolution in intracranial three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) is possible at higher field strengths, due to the increased contrast-to-noise ratio (CNR) from the higher signal-to-noise ratio and the improved background suppression. However, at very high fields, spatial resolution is limited in practice by the acquisition time required for sequential phase encoding. In this study, we applied parallel imaging to 7T TOF MRA studies of normal volunteers and patients with vascular disease, in order to obtain very high resolution (0.12 mm(3)) images within a reasonable scan time.
Custom parallel imaging acquisition and reconstruction methods were developed for 7T MRA, based on generalized autocalibrating partially parallel acquisition (GRAPPA). The techniques were compared and applied to studies of seven normal volunteers and three patients with cerebrovascular disease.
The technique produced high resolution studies free from discernible reconstruction artifacts in all subjects and provided excellent depiction of vascular pathology in patients.
7T TOF MRA with parallel imaging is a valuable noninvasive angiographic technique that can attain very high spatial resolution.
在颅内三维时间飞跃（TOF）磁共振血管造影（MRA）中，由于较高场强下信噪比对提高对比度噪声比（CNR）及改善背景抑制的作用，可实现更高的空间分辨率。然而，在非常高的场强下，实际空间分辨率受到顺序相位编码所需采集时间的限制。在本研究中，我们将并行成像应用于正常志愿者和血管疾病患者的7T TOF MRA研究，以便在合理的扫描时间内获得超高分辨率（0.12 mm³）图像。
基于广义自校准部分并行采集（GRAPPA）开发了用于7T MRA的定制并行成像采集和重建方法。将这些技术进行比较并应用于7名正常志愿者和3名脑血管疾病患者的研究。
该技术在所有受试者中均产生了无明显重建伪影的高分辨率研究，并能很好地显示患者的血管病变。
采用并行成像的7T TOF MRA是一种有价值的无创血管造影技术，可实现非常高的空间分辨率。
