MRI investigation of the threshold for thermally induced blood-brain barrier disruption and brain tissue damage in the rabbit brain
MRI investigation of the threshold for thermally induced blood-brain barrier disruption and brain tissue damage in the rabbit brain
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DOI：
10.1002/mrm.20060
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发表时间：
2004-05-01
影响因子：
3.3
通讯作者：
Hynynen, K
中科院分区：
文献类型：
--
作者：
McDannold, N;Vykhodtseva, N;Hynynen, K
测试了MRI衍生的测温法预测脑中热诱导组织变化的能力，并估计了血脑屏障（BBB）破坏和脑组织损伤的热阈值。此外，标准MRI检测阈值水平效应的能力得到证实。正在研究这些安全阈值，以提供大脑中临床热消融研究的指南。MRI监测的聚焦超声加热被输送到26只家兔的63个部位。在T2加权成像和T1加权成像（有或无造影剂）和光学显微镜下检测组织变化。作为累积热剂量、达到的峰值温度、施加的声能和峰值声功率的函数的组织损伤的概率用概率单位回归来估计。采用受试者工作特征曲线（ROC）下的面积比较这些参数的区分能力。在MRI中，在超声暴露后不久的对比增强T-1加权成像中观察到BBB破坏，有时伴随T-2加权成像的变化。两天后，观察到T-2加权成像的变化，有时伴有T-1加权成像的变化。在组织学中，在观察到MRI变化的每个位置都观察到组织损伤，范围从小的（直径< 1.0 mm）组织坏死区域到严重的血管损伤和相关的出血性梗死。在一个位置，MRI未检测到小（直径：0.8 mm）损伤。热剂量和峰值温度阈值分别在43 ℃和48.0- 50.8 ℃时为12.3-40.1等效min之间，估计43 ℃和48.4 ℃时的17.5等效min值导致组织损伤的概率为50%。热剂量和峰值温度是较声能量和峰值声功率更好的预测因子（P < 0.01）。血脑屏障破坏总是伴随着组织损伤。温度信息比施加的声功率或能量更好地预测损伤，而不是超声参数。MRI对阈值损伤敏感。Magn Reson Med 51：913-923，2004年。(C)2004 Wiley-Liss，Inc.
The ability of MRI-derived thermometry to predict thermally induced tissue changes in the brain was tested, and the thermal thresholds for blood-brain barrier (BBB) disruption and brain tissue damage were estimated. In addition, the ability of standard MRI to detect threshold-level effects was confirmed. These safety thresholds are being investigated to provide guidelines for clinical thermal ablation studies in the brain. MRI-monitored focused ultrasound heating was delivered to 63 locations in 26 rabbits. Tissue changes were detected in T-2-weighted imaging and T-1-weighted imaging (with and without contrast) and with light microscopy. The probability for tissue damage as a function of the accumulated thermal dose, the peak temperature achieved, the applied acoustic energy, and the peak acoustic power was estimated with probit regression. The discriminative abilities of these parameters were compared using the areas under the receiver operator characteristic (ROC) curves. In MRI, BBB disruption was observed in contrast-enhanced T-1-weighted imaging shortly after the ultrasound exposures, sometimes accompanied by changes in T-2-weighted imaging. Two days later, changes in T-2-weighted imaging were observed, sometimes accompanied by changes in T-1-weighted imaging. In histology, tissue damage was seen at every location where MRI changes were observed, ranging from small (diameter < 1.0 mm) areas of tissue necrosis to severe vascular damage and associated hemorrhagic infarct. In one location, small (diameter: 0.8 mm) damage was not detected in MRI. The thermal dose and peak temperature thresholds were between 12.3-40.1 equivalent min at 43degreesC and 48.0-50.8degreesC respectively, and values of 17.5 equivalent min at 43degreesC and 48.4degreesC were estimated to result in tissue damage with 50% probability. Thermal dose and peak temperature were significantly better predictors than the applied acoustic energy and peak acoustic power (P < 0.01). BBB disruption was always accompanied by tissue damage. The temperature information was better than the applied acoustic power or energy for predicting the damage than the ultrasound parameters. MRI was sensitive in detecting threshold-level damage. Magn Reson Med 51:913-923, 2004. (C) 2004 Wiley-Liss, Inc.