Bonekamp David, Barker Peter B, Leigh Richard, van Zijl Peter C M, Li Xu
The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; FM Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, Maryland.
Magn Reson Med. 2015 Feb;73(2):544-54. doi: 10.1002/mrm.25144. Epub 2014 Feb 25.
An algorithm is developed for the reconstruction of dynamic, gadolinium (Gd) bolus MR perfusion images of the human brain, based on quantitative susceptibility mapping (QSM).
The method is evaluated in five perfusion scans obtained from four different patients scanned at 3 Tesla, and compared with the conventional analysis based on changes in the transverse relaxation rate ΔR2 * and to theoretical predictions. QSM images were referenced to ventricular cerebrospinal fluid (CSF) for each dynamic of the perfusion sequence.
Images of cerebral blood flow and blood volume were successfully reconstructed from the QSM-analysis, and were comparable to those reconstructed using ΔR2 *. The magnitudes of the Gd-associated susceptibility effects in gray and white matter were consistent with theoretical predictions.
QSM-based analysis may have some theoretical advantages compared with ΔR2 *, including a simpler relationship between signal change and Gd concentration. However, disadvantages are its much lower contrast-to-noise ratio, artifacts due to respiration and other effects, and more complicated reconstruction methods. More work is required to optimize data acquisition protocols for QSM-based perfusion imaging.
基于定量磁化率映射（QSM）开发一种算法，用于重建人脑动态钆（Gd）团注磁共振灌注图像。
在从4名不同患者获得的5次3特斯拉灌注扫描中对该方法进行评估，并与基于横向弛豫率ΔR2 *变化的传统分析以及理论预测进行比较。对于灌注序列的每个动态过程，QSM图像均以脑室脑脊液（CSF）为参考。
通过QSM分析成功重建了脑血流量和血容量图像，并且与使用ΔR2 *重建的图像相当。灰质和白质中与钆相关的磁化率效应大小与理论预测一致。
与ΔR2 *相比，基于QSM的分析可能具有一些理论优势，包括信号变化与钆浓度之间的关系更简单。然而，缺点是其对比度噪声比低得多、存在呼吸和其他效应导致的伪影以及重建方法更复杂。需要开展更多工作来优化基于QSM的灌注成像的数据采集协议。
