Transient response harmonic imaging -: An ultrasound technique related to brain perfusion
Transient response harmonic imaging -: An ultrasound technique related to brain perfusion
复制标题
DOI：
10.1161/01.str.29.9.1901
复制
发表时间：
1998-09-01
期刊：
影响因子：
8.3
通讯作者：
Büttner, T
中科院分区：
文献类型：
--
作者：
Postert, T;Muhs, A;Büttner, T
背景和目的-灰度谐波成像是第一种在静脉注射造影剂后用超声可视化血液灌注和毛细血管血流的方法。本研究的目的是评估瞬态响应二次谐波成像（TRsHI）通过经颅超声评估不同脑区正常回声对比特征的潜力。方法：在 18 例无脑血管疾病的患者中，应用 6.5 mt 半乳糖微泡悬浮液（400 mg/mL）后，采用经颞叶入路进行双侧 TRsHI 检查。传播率为每4个心动周期一次。目视评估局部脑对比度，然后使用时间强度曲线进行离线量化。在 4 个不同的感兴趣区域 (ROI)（丘脑后部 [ROIa]、丘脑前部 [ROIb]、豆状核 [ROIc] 和白质 [ROId]）中，评估以下参数：峰值强度、曲线下面积 (AUC) 和峰值强度时间。计算 ROIc/a、d/a、c/b 和 d/b 的 AUC 比率。 结果-在所有患者中，肉眼可检测到实质对比度增强。 144 个 ROI 中可显示 131 条特征时间强度曲线（基线阶段、峰值对比度强度、缓慢冲洗阶段）。在 ROIc 和 ROId 中，可以最频繁地观察到特征对比度曲线（68/72 次检查），而 ROIa 和 ROIb 中的时间-强度曲线无法评估，因为 72 次检查中有 9 次对比度增强不充分。达到峰值强度的时间在 20 到 52 个心动周期之间变化； 1 名患者的心动周期为 88 个。在所有个体中，以及 18 名受试者中的 16 名受试者中，ROIc 和 ROId 的峰值强度与 ROIa 和 ROIb 相比增加了 2 至 10 倍。在任何检查中，无论 ROI 如何，AUC 比率均未显示 >2 倍的侧向差异。结论 - 本研究首次证明 TRsHI 在不同大脑区域产生准确的对比度，并代表与大脑灌注相关的超声工具。定量参数的绝对值显示出由不同颞骨厚度引起的高度变化以及回波对比浓度和光学强度测量之间的复杂关系。不同 ROI 之间的比率有助于比较不同大脑区域的对比度增强情况。此外，由于 TRsHI 中对比度增强的衰减严格取决于声波深度，因此脑灌注的谐波成像研究不能直接与其他成像技术（例如正电子发射断层扫描）进行比较。
Background and Purpose-Gray-scale harmonic imaging is the first method to visualize blood perfusion and capillary blood flow with ultrasound after intravenous contrast agent application. The purpose of the present study was to evaluate the potential of transient response second harmonic imaging (TRsHI) to assess normal echo contrast characteristics in different brain areas by transcranial ultrasound.Methods-In 18 patients without cerebrovascular diseases, TRsHI examinations were performed bilaterally with the use of the transtemporal approach after application of 6.5 mt of a galactose-based microbubble suspension (400 mg/mL). The transmission rate was once every 4 cardiac cycles. Regional cerebral contrast was visually assessed and then quantified off-line with the use of time-intensity curves. In 4 different regions of interest (ROI) (posterior part of the thalamus [ROIa], anterior part of the thalamus [ROIb], lentiform nucleus [ROIc], and white matter [ROId]), the following parameters were evaluated: peak intensity, area under the curve (AUC), and time to peak intensity. AUC ratios for ROIc/a, d/a, c/b, and d/b were calculated.Results-In all patients parenchymal contrast enhancement was visually detectable. One hundred thirty-one characteristic time-intensity curves (baseline phase, peak contrast intensity, slow washout phase) were demonstrable in 144 ROIs. In ROIc and ROId characteristic contrast curves could be observed most frequently (68/72 examinations), whereas time-intensity curves in ROIa and ROIb could not be evaluated because of inadequate contrast enhancement in 9 of 72 examinations. Time to peak intensity varied between 20 and 52 cardiac cycles; in 1 patient it was 88 cardiac cycles. In all individuals AUCs and in 16 of 18 subjects peak intensity in ROIc and ROId showed a 2- to 10-fold increase compared with ROIa and ROIb. In no examination did AUC ratios show a >2-fold side difference irrespective of the ROI.Conclusions-The present study demonstrates for the first time that TRsHI produces accurate contrast in different brain areas and represents an ultrasonic tool related to brain perfusion. Absolute values of quantitative parameters show high variations caused by different temporal bone thicknesses and a complex relationship between echo contrast concentrations and measurements of optic intensities. Ratios between different ROIs help to compare contrast enhancement in different brain areas. Furthermore, because of the fact that attenuation of contrast enhancement in TRsHI depends strictly on the insonation depth, harmonic imaging studies of brain perfusion cannot be compared directly with other imaging techniques such as positron emission tomography.