Hackenbroch M, Meyer C, Beck G, Nehrke K, Gieseke J, Yang A, Tiemann K, Schmitz C, Schild H, Sommer T
Radiologische Klinik, Universitätsklinik Bonn.
Rofo. 2005 Mar;177(3):350-7. doi: 10.1055/s-2005-857882.
A major problem of free breathing coronary MR angiography (MRA) with respiratory navigator gating is low navigator efficiency and prolonged scan time due to irregular breathing patterns. 3D motion adapted gating (MAG) is a new adaptive navigator technique, which adapts in real time to changes of the end-expiratory position of diaphragm. This study evaluates the influence of 3D MAG on coronary MRA.
In 3D MAG, two additional gating windows are grouped around the conventional window. Additionally, each gating window is divided into three bands assigned to different portions of the k-space. The scan is terminated when three consecutive bands are filled and one complete image data set is collected. Free breathing navigator-gated coronary MRA was performed on 48 patients with suspected coronary artery disease. In random order, each patient underwent an ECG-gated, a 3D segmented k-space gradient echo sequence using 3D MAG and a conventional navigator technique. The coronary MRA was evaluated and compared using the following parameters: 1. navigator efficiency and scan time; 2. visualized coronary artery length; 3. qualitative assessment of image quality; and 4. detection of stenoses > 50 % in comparison with catheter angiography.
Coronary MRA with 3D MAG had a significant increase in the average navigator efficiency (46 % +/- 12 % vs. 38 % +/- 12 %, p < 0.05), resulting in a significantly shorter scan time (mean: 18 % +/- 4 %, p < 0.05) for coronary MRA with 3D MAG compared to conventional navigator technique. Scans with and without 3D MAG had no significant differences in the continuously visualized vessel lengths, in the assessed image quality and in the sensitivity and specificity (83 % and 89 % vs. 83 % and 88 %, p > 0.05) of detecting coronary artery stenoses > 50 %.
The 3D MAG technique improves the navigator efficiency and significantly (p < 0.05) shortens the scan time of navigator gated coronary MRA while maintaining image quality and diagnostic accuracy in the detection of coronary artery stenoses.
采用呼吸导航门控的自由呼吸冠状动脉磁共振血管造影（MRA）的一个主要问题是，由于呼吸模式不规则，导航效率低下且扫描时间延长。三维运动自适应门控（MAG）是一种新的自适应导航技术，可实时适应膈肌呼气末位置的变化。本研究评估三维MAG对冠状动脉MRA的影响。
在三维MAG中，在传统窗口周围增加两个门控窗口。此外，每个门控窗口分为三个条带，分别对应于k空间的不同部分。当三个连续条带被填充且收集到一个完整的图像数据集时，扫描结束。对48例疑似冠心病患者进行自由呼吸导航门控冠状动脉MRA检查。患者按随机顺序分别接受心电图门控、使用三维MAG的三维分段k空间梯度回波序列和传统导航技术检查。使用以下参数对冠状动脉MRA进行评估和比较：1.导航效率和扫描时间；2.可视化冠状动脉长度；3.图像质量的定性评估；4.与导管血管造影相比，检测>50%的狭窄。
与传统导航技术相比，采用三维MAG的冠状动脉MRA平均导航效率显著提高（46%±12%对38%±12%，p<0.05），扫描时间显著缩短（平均：18%±4%，p<0.05）。采用和不采用三维MAG的扫描在连续可视化血管长度、评估的图像质量以及检测>50%冠状动脉狭窄的敏感性和特异性（83%和89%对83%和88%，p>0.05）方面无显著差异。
三维MAG技术提高了导航效率，显著（p<0.05）缩短了导航门控冠状动脉MRA的扫描时间，同时在检测冠状动脉狭窄时保持了图像质量和诊断准确性。
