Lew Calvin D, Alley Marcus T, Bammer Roland, Spielman Daniel M, Chan Frandics P
Lucas MRS/I Center, Stanford University, 1201 Welch Road, Stanford, CA 94305.
Acad Radiol. 2007 Mar;14(3):258-69. doi: 10.1016/j.acra.2006.11.008.
Phase-contrast (PC) magnetic resonance imaging (MRI) technique has important clinical applications in blood flow quantification and pressure gradient estimation by velocity measurement. Parallel imaging using sensitivity encoding (SENSE) may substantially reduce scan time. We demonstrate the utility of PC-MRI measurements accelerated by SENSE under clinical conditions.
Accuracy and repeatability of a SENSE-PC implementation was evaluated by comparison with a commercial PC sequence with five normal volunteers. Twenty-six patients were then scanned with SENSE-PC at reduction factors (R = 1, 2, and 3). Blood flow and peak velocity were measured in the aorta and pulmonary trunk in 16 patients and peak velocity was measured at the coarctation of 10 patients. Quantitative flow, shunt ratio, and peak velocity measurements obtained with different reduction factors were compared using correlation, linear regression, and Bland-Altman statistics. All studies were approved by an Institutional Review Board, and informed consent was acquired from all subjects.
The correlation coefficients for all comparisons were >0.962 and with high statistical significance (P < .01). Linear regression slopes ranged between 0.96 and 1.11 for flow and 0.88 to 1.05 for peak velocity. For flow, the Bland-Altman statistics yielded a total mean difference ranging from -0.02 to 0.05) L/minute with 2 standard of deviation limits ranging from -0.52 to 0.75 L/minute. For peak velocity, the total mean difference ranged from -0.10 to -0.004) milliseconds with 2-SD limits ranging from -0.062 to 0.46 milliseconds. R = 3 to R = 1 comparisons had greater 2-SD limits than R = 2 to R = 1 comparisons.
SENSE PC-MRI measurements for flow and pressure gradient estimation were comparable to conventional PC-MRI.
相位对比（PC）磁共振成像（MRI）技术在通过速度测量进行血流定量和压力梯度估计方面具有重要的临床应用。使用灵敏度编码（SENSE）的并行成像可大幅减少扫描时间。我们展示了在临床条件下由SENSE加速的PC-MRI测量的实用性。
通过与五名正常志愿者的商用PC序列进行比较，评估了SENSE-PC实施的准确性和可重复性。然后，对26名患者以加速因子（R = 1、2和3）进行SENSE-PC扫描。在16名患者的主动脉和肺动脉主干中测量血流和峰值速度，并在10名患者的缩窄处测量峰值速度。使用相关性、线性回归和布兰德-奥特曼统计方法比较不同加速因子下获得的定量血流、分流比和峰值速度测量值。所有研究均经机构审查委员会批准，并获得所有受试者的知情同意。
所有比较的相关系数均>0.962，具有高度统计学意义（P <.01）。血流的线性回归斜率介于0.96和1.11之间，峰值速度的线性回归斜率介于0.88和1.05之间。对于血流，布兰德-奥特曼统计得出的总平均差异范围为-0.02至0.05）升/分钟，2倍标准差范围为-0.52至0.75升/分钟。对于峰值速度，总平均差异范围为-0.10至-0.004）毫秒，2倍标准差范围为-0.062至0.46毫秒。R = 3至R = 1的比较比R = 2至R = 1的比较具有更大的2倍标准差范围。
用于血流和压力梯度估计的SENSE PC-MRI测量与传统PC-MRI相当。
