Center for Optoelectronic Biomedicine, College of Medicine, National Taiwan University, Taipei, Taiwan.
J Magn Reson Imaging. 2010 Jun;31(6):1323-30. doi: 10.1002/jmri.22174.
PURPOSE: To optimize the timing of contrast-enhanced magnetic resonance imaging (MRI) that best indicates blood-brain barrier (BBB) disruption induced by focused ultrasound (FUS) along with an ultrasound contrast agent (UCA) and to verify that the contrast-enhanced spin-echo MRI sequence can indicate the degree and location of BBB disruption in the presence of hemorrhage better than a gradient-echo sequence. MATERIALS AND METHODS: Sonication was applied to 12 rat brains with four different doses of UCA to cause variable degrees of hemorrhage. Two imaging sequences were performed to acquire T1-weighted (T1W) images at two time-points after the administration of a T1-shortening contrast agent. The contrast enhancement at the sonicated regions was quantified and correlated against Evans blue (EB) staining. RESULTS: The spin-echo T1W images at 10 minutes post-contrast enhancement showed the best correlation with EB staining in both quantity of EB extravasation (r = 0.812; P < 0.01) and spatial distribution (r = 0.528, P < 0.01). This capability was more robust than the gradient-echo sequence. CONCLUSION: Our results suggest that contrast-enhanced T1W spin-echo sequence acquired in the early phase post-contrast enhancement should be considered to monitor the degree and location of BBB disruption under the possibility of hemorrhage induced by FUS.
目的：优化对比增强磁共振成像（MRI）的时间，以最佳显示聚焦超声（FUS）联合超声造影剂（UCA）引起的血脑屏障（BBB）破坏，并验证对比增强自旋回波 MRI 序列在存在出血的情况下比梯度回波序列能更好地指示 BBB 破坏的程度和位置。 材料与方法：对 12 只大鼠脑进行超声处理，使用四种不同剂量的 UCA 造成不同程度的出血。在给予 T1 缩短造影剂后两个时间点进行两种成像序列以获取 T1 加权（T1W）图像。对超声区域的对比增强进行定量，并与 Evans 蓝（EB）染色进行相关性分析。 结果：增强后 10 分钟的自旋回波 T1W 图像与 EB 外渗的数量（r = 0.812；P < 0.01）和空间分布（r = 0.528，P < 0.01）均具有最佳相关性。这种能力比梯度回波序列更强大。 结论：我们的结果表明，应考虑在增强后早期获取对比增强 T1W 自旋回波序列，以监测 FUS 引起的出血情况下 BBB 破坏的程度和位置。
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