Caruthers Shelton D, Lin Shiow Jiuan, Brown Peggy, Watkins Mary P, Williams Todd A, Lehr Katherine A, Wickline Samuel A
Cardiovascular Magnetic Resonance Laboratories, Barnes-Jewish Hospital, Cardiovascular Division, Washington University School of Medicine, St Louis, MO 63110, USA.
Circulation. 2003 Nov 4;108(18):2236-43. doi: 10.1161/01.CIR.0000095268.47282.A1. Epub 2003 Oct 20.
Valvular pathology can be analyzed quickly and accurately through the use of Doppler ultrasound. For aortic stenosis, the continuity equation approach with Doppler velocity-time integral (VTI) data is by far the most commonly used clinical method of quantification. In view of the emerging popularity of cardiac magnetic resonance (CMR) as a routine clinical imaging tool, the purposes of this study were to define the reliability of velocity-encoded CMR as a routine method for quantifying stenotic aortic valve area, to compare this method with the accepted standard, and to evaluate its reproducibility.
Patients (n=24) with aortic stenosis (ranging from 0.5 to 1.8 cm2) were imaged with CMR and echocardiography. Velocity-encoded CMR was used to obtain velocity information in the aorta and left ventricular outflow tract. From this flow data, pressure gradients were estimated by means of the modified Bernoulli equation, and VTIs were calculated to estimate aortic valve orifice dimensions by means of the continuity equation. The correlation coefficients between modalities for pressure gradients were r=0.83 for peak and r=0.87 for mean. The measurements of VTI correlated well, leading to an overall strong correlation between modalities for the estimation of valve dimension (r=0.83, by means of the identified best approach). For 5 patients, the CMR examination was repeated using the best approach. The repeat calculations of valve size correlated well (r=0.94).
Velocity-encoded CMR can be used as a reliable, user-friendly tool to evaluate stenotic aortic valves. The measurements of pressure gradients, VTIs, and the valve dimension correlate well with the accepted standard of Doppler ultrasound.
通过使用多普勒超声可以快速准确地分析瓣膜病变。对于主动脉瓣狭窄，采用多普勒速度时间积分（VTI）数据的连续方程法是目前最常用的临床量化方法。鉴于心脏磁共振成像（CMR）作为一种常规临床成像工具日益普及，本研究的目的是确定速度编码CMR作为量化狭窄主动脉瓣面积的常规方法的可靠性，将该方法与公认标准进行比较，并评估其可重复性。
对24例主动脉瓣狭窄（面积范围为0.5至1.8 cm²）患者进行了CMR和超声心动图检查。采用速度编码CMR获取主动脉和左心室流出道的速度信息。根据这些血流数据，通过改良的伯努利方程估算压力阶差，并计算VTI，通过连续方程估算主动脉瓣口尺寸。压力阶差各模式之间的相关系数，峰值时r = 0.83，平均值时r = 0.87。VTI测量结果相关性良好，导致各模式之间在瓣膜尺寸估计方面总体具有很强的相关性（通过确定的最佳方法，r = 0.83）。对5例患者采用最佳方法重复进行CMR检查。瓣膜大小的重复计算相关性良好（r = 0.94）。
速度编码CMR可作为评估狭窄主动脉瓣的可靠、用户友好的工具。压力阶差、VTI和瓣膜尺寸的测量结果与多普勒超声的公认标准相关性良好。
