Seidel G, Claassen L, Meyer K, Vidal-Langwasser M
Department of Neurology, University Hospital Lübeck, Ratzeburger Allee 160, D-23538, Lübeck, Germany.
Ultrasound Med Biol. 2001 Aug;27(8):1059-64. doi: 10.1016/s0301-5629(01)00416-1.
By means of harmonic imaging, it is possible to display brain perfusion qualitatively using ultrasound (US) contrast agent (UCA) bolus injection. With UCA continuous infusion reaching a steady state, mean microbubble velocity can be measured, analyzing the reappearance rate after microbubble destruction by US (refill kinetics). We performed an animal pilot study to investigate this new method for the assessment of brain perfusion. Using harmonic grey-scale imaging, five sedated male beagle dogs were investigated through the intact skull with increasing pulsing intervals (250 to 8000 ms) and three UCA infusion rates (0.5, 1.0 and 1.5 mL/min of Optison). Cerebral blood flow was increased by acetazolamide (30 mg/kg BW). Intensity vs. pulsing interval curves were analyzed using an exponential curve fit [I(t) = A(1-e(-beta t))] and parameters of the curve were compared. We found that increasing the pulsing interval above 4000 ms led to no further increase of echo enhancement for infusion rates. Mean beta values were not influenced by infusion rate (p = 0.25 and p = 0.55). Mean F values increased nonsignificantly with rising infusion rate (p = 0.25 and p = 0.86). Acetazolamide led to an increase of mean beta and F values (p = 0.18 and p = 0.025, respectively). It is possible to evaluate changes in brain perfusion through the intact skull by analyzing the UCA refill kinetics after US-induced microbubble destruction.
通过谐波成像，利用超声（US）造影剂（UCA）团注能够定性显示脑灌注情况。在UCA持续输注达到稳态时，可以测量平均微泡速度，通过超声分析微泡破坏后的再出现率（再填充动力学）。我们进行了一项动物初步研究，以探究这种评估脑灌注的新方法。使用谐波灰阶成像，对5只镇静的雄性比格犬通过完整颅骨进行研究，增加脉冲间隔（250至8000毫秒）以及三种UCA输注速率（0.5、1.0和1.5 mL/min的Optison）。通过乙酰唑胺（30 mg/kg体重）增加脑血流量。使用指数曲线拟合[I(t) = A(1 - e^(-βt))]分析强度与脉冲间隔曲线，并比较曲线参数。我们发现，将脉冲间隔增加到4000毫秒以上，对于输注速率而言，回声增强不再进一步增加。平均β值不受输注速率影响（p = 0.25和p = 0.55）。平均F值随输注速率升高无显著增加（p = 0.25和p = 0.86）。乙酰唑胺导致平均β值和F值增加（分别为p = 0.18和p = 0.025）。通过分析超声诱导微泡破坏后的UCA再填充动力学，可以评估通过完整颅骨的脑灌注变化。
