Markl Michael, Fluckiger Jacob, Lee Daniel C, Ng Jason, Goldberger Jeffrey J
From the *Department of Radiology, Feinberg School of Medicine, Northwestern University, Chicago; †Department of Biomedical Engineering, McCormick School of Engineering, Northwestern University, Evanston, IL; ‡Division of Cardiology, and §Section of Cardiac Electrophysiology, Northwestern University, Chicago, IL.
J Comput Assist Tomogr. 2015 May-Jun;39(3):422-7. doi: 10.1097/RCT.0000000000000207.
To systematically investigate the impact of beat-to-beat variations on electrocardiography (ECG)-gated multibeat flow imaging with phase contrast (PC) magnetic resonance imaging (MRI) based on real time in vivo transesophageal echocardiography (TEE) data in patients with known arrhythmia.
Real-time 2-dimensional Doppler TEE was performed in five patients with atrial fibrillation (4 men, age = 64 ± 8.7 years). The TEE data provided real-time left atrial (LA) and left ventricular (LV) flow velocities in consecutive cardiac cycles with different RR interval durations. The PC MRI acquisitions were simulated from the TEE velocity measures by constructing time-resolved k-space data for segmented sampling schemes typically used for ECG-gated 2-dimensional PC MRI. Each simulation was repeated 100 times to minimize effects from data that may be weighted to a particular beat in the center of k-space. The resulting LA and LV velocities were compared to the average TEE velocities and data from individual cardiac cycles.
Despite beat-to-beat variations of velocities in TEE data, ECG-gated flow imaging with MRI could reproduce persistent average LA and LV mean velocities within 7.0% to 7.4% compared to TEE.
The PC MRI velocity measurements in patients with varying RR interval durations are not significantly different from time-averaged real-time velocity data for a typical segmented k-space data acquisition schemes. Though beat-to-beat variations in atrial velocities that were observed with TEE cannot be detected with ECG-gated multibeat PC MRI, it can reliably assess average flow patterns across multiple beats.
基于已知心律失常患者的实时体内经食管超声心动图（TEE）数据，系统研究逐搏变化对心电图（ECG）门控多搏相位对比（PC）磁共振成像（MRI）血流成像的影响。
对5例心房颤动患者（4例男性，年龄=64±8.7岁）进行实时二维多普勒TEE检查。TEE数据提供了不同RR间期持续时间的连续心动周期中的实时左心房（LA）和左心室（LV）流速。通过构建通常用于ECG门控二维PC MRI的分段采样方案的时间分辨k空间数据，从TEE速度测量值模拟PC MRI采集。每个模拟重复100次，以最小化可能加权到k空间中心特定搏动的数据的影响。将所得的LA和LV速度与平均TEE速度以及单个心动周期的数据进行比较。
尽管TEE数据中存在流速的逐搏变化，但与TEE相比，MRI的ECG门控血流成像能够在7.0%至7.4%的范围内重现持续的平均LA和LV平均速度。
对于不同RR间期持续时间的患者，PC MRI速度测量与典型分段k空间数据采集方案的时间平均实时速度数据无显著差异。虽然ECG门控多搏PC MRI无法检测到TEE观察到的心房流速逐搏变化，但它可以可靠地评估多个搏动的平均血流模式。
