Klem Igor, Rehwald Wolfgang G, Heitner John F, Wagner Anja, Albert Timothy, Parker Michele A, Chen Enn-Ling, Kim Raymond J, Judd Robert M
Duke Cardiovascular Magnetic Resonance Center, Durham, NC 27710, USA.
Circulation. 2005 Mar 1;111(8):1033-9. doi: 10.1161/01.CIR.0000156332.56894.22. Epub 2005 Feb 21.
Magnetic resonance global coherent free precession (GCFP) is a new technique that produces cine projection angiograms directly analogous to those of x-ray angiography noninvasively and without a contrast agent. In this study, we compared GCFP blood flow with "gold standards" to determine the accuracy of noninvasive GCFP blood flow measurements.
The relationship between GCFP blood flow and true blood flow defined by invasive ultrasonic flow probe and by phase contrast velocity encoded MRI (VENC) was studied in anesthetized dogs (n=6). Blood flow was controlled by use of a hydraulic occluder around the left iliac artery. GCFP images were acquired by selectively exciting the abdominal aorta and visualizing temporal blood flow into the iliac arteries. GCFP flow was similar to ultrasonic blood flow at baseline (131.3+/-44.8 versus 114.8+/-34.2 mL/min), during occlusion (10.8+/-5.1 versus 6.5+/-7.2 mL/min), during reactive hyperemia (191.4+/-100.7 versus 260.3+/-138.7 mL/min), during the new resting state (135.5+/-52.4 versus 117.8+/-24.1 mL/min), and during partial occlusion (61.4+/-36.4 versus 49.3+/-13.1 mL/min, P=NS for all). Results comparing GCFP flow with VENC were similar. Statistical analysis revealed that GCFP flow was related to mean blood flow assessed by the flow probe (P<0.0001) and by VENC (P<0.0001). In the control right iliac artery, conversely, GCFP measurements were unaffected throughout all left iliac interventions (P=NS).
GCFP blood flow is linearly related to true blood flow for a straight, cylindrical blood vessel without branches. Although more complex geometries imply a qualitative rather than a quantitative relationship, the data nevertheless suggest that GCFP may serve as the basis for a new form of noninvasive stress testing.
磁共振整体相干自由进动（GCFP）是一项新技术，可无创且无需使用造影剂直接生成与X线血管造影类似的电影投影血管造影。在本研究中，我们将GCFP血流与“金标准”进行比较，以确定无创GCFP血流测量的准确性。
在麻醉犬（n = 6）中研究了GCFP血流与通过侵入性超声血流探头和相位对比速度编码MRI（VENC）定义的真实血流之间的关系。通过使用围绕左髂动脉的液压闭塞器来控制血流。通过选择性激发腹主动脉并观察流入髂动脉的瞬时血流来获取GCFP图像。在基线时（131.3±44.8对114.8±34.2 mL/min）、闭塞期间（10.8±5.1对6.5±7.2 mL/min）、反应性充血期间（191.4±100.7对260.3±138.7 mL/min）、新的静息状态期间（135.5±52.4对117.8±24.1 mL/min）以及部分闭塞期间（61.4±36.4对49.3±13.1 mL/min，所有P值均无统计学意义），GCFP血流与超声血流相似。比较GCFP血流与VENC的结果相似。统计分析显示，GCFP血流与通过血流探头评估的平均血流相关（P<0.0001），与VENC评估的平均血流也相关（P<0.0001）。相反，在对照右侧髂动脉中，在所有左侧髂动脉干预过程中，GCFP测量均未受影响（P值无统计学意义）。
对于无分支的直圆柱形血管，GCFP血流与真实血流呈线性相关。尽管更复杂的几何形状意味着是定性而非定量关系，但这些数据仍表明GCFP可作为一种新型无创应激测试的基础。
