Søndergaard L, Ståhlberg F, Thomsen C, Stensgaard A, Lindvig K, Henriksen O
Danish Research Center of Magnetic Resonance, Hvidovre Hospital.
J Magn Reson Imaging. 1993 Mar-Apr;3(2):433-7. doi: 10.1002/jmri.1880030220.
Reliability of magnetic resonance (MR) velocity mapping to assess severity of stenosis was assessed in vitro. Steady flow at different flow rates through five stenoses with a central orifice area ranging from 17 to 176 mm2 was measured with velocity mapping performed perpendicular to the stenotic jet. Besides determination of the stenotic cross-sectional area and flow rate, the pressure gradient was calculated with the modified Bernoulli equation and compared with manometer measurements. Cross-sectional areas were measured with an accuracy of > or = 76%, a precision of > or = 91%, and an error of < or = 19 mm2. Flow rates had an accuracy of > or = 72%, a precision of > or = 94%, and an error of < or = 1.4 L/min. The modification of the Bernoulli equation limited its reliability to stenoses with areas of 35-113 mm2. Pressure gradients were calculated with an accuracy of > or = 80%, a precision of > or = 88%, and an error of < or = 15 mm Hg. The method was applied in a single patient with aortic stenosis and gave estimates that agreed with those obtained by heart catheterization.
在体外评估了磁共振（MR）速度映射用于评估狭窄严重程度的可靠性。通过垂直于狭窄射流进行速度映射，测量了通过五个中央孔面积范围为17至176平方毫米的狭窄处不同流速下的稳定血流。除了确定狭窄横截面积和流速外，还使用修正的伯努利方程计算压力梯度，并与压力计测量值进行比较。测量的横截面积的准确度≥76%，精密度≥91%，误差≤19平方毫米。流速的准确度≥72%，精密度≥94%，误差≤1.4升/分钟。伯努利方程的修正将其可靠性限制在面积为35 - 113平方毫米的狭窄处。计算的压力梯度的准确度≥80%，精密度≥88%，误差≤15毫米汞柱。该方法应用于一名主动脉狭窄患者，所得估计值与心导管检查获得的估计值一致。
