Muacevic A, Peller M, Ruprecht L, Berg D, Fend L, Sroka R, Reulen H J, Reiser M, Tonn J Ch, Kreth F W
Department of Neurosurgery, Ludwig-Maximilians-University, Munich, Germany.
Acta Neurochir (Wien). 2005 Feb;147(2):175-85; discussion 185-6. doi: 10.1007/s00701-004-0409-y.
To determine the applicability and safety of a new canine model suitable for correlative magnetic resonance imaging (MRI) studies and morphological/pathophysiological examination over time after interstitial laser thermotherapy (ILTT) in brain tissue.
A laser fibre (Diode Laser 830 nm) with an integrated temperature feedback system was inserted into the right frontal white matter in 18 dogs using frameless navigation technique. MRI thermometry (phase mapping i.e. chemical shift of the proton resonance frequency) during interstitial heating was compared to simultaneously recorded interstitial fiberoptic temperature readings on the border of the lesion. To study brain capillary function in response to ILTT over time quantitative autoradiography was performed investigating the unidirectional blood-to-tissue transport of carbon-14-labelled alpha amino-isobutyric acid (transfer constant K of AIB) 12, 36 hours, 7, 14 days, 4 weeks and 3 months after ILTT.
All laser procedures were well tolerated, laser and temperature fibres could be adequately placed in the right frontal lobe in all animals. In 5 animals MRI-based temperature quantification correlated strongly to invasive temperature measurements. In the remaining animals the temperature fibre was located in the area of susceptibility artifacts, therefore, no temperature correlation was possible. The laser lesions consisted of a central area of calcified necrosis which was surrounded by an area of reactive brain tissue with increased permeability. Quantitative autoradiography indicated a thin and spherical blood brain barrier lesion. The magnitude of K of AIB increased from 12 hours to 14 days after ILTT and decreased thereafter. The mean value of K of AIB was 19 times (2 times) that of normal white matter (cortex), respectively.
ILTT causes transient, highly localised areas of increased capillary permeability surrounding the laser lesion. Phase contrast imaging for MRI thermomonitoring can currently not be used for reliable temperature readings in vivo. The suggested new canine model proved to be safe, accurate, easy to use, and provides clinical, radiographic, pathological and physiological correlations.
确定一种适用于相关磁共振成像（MRI）研究以及间质激光热疗（ILTT）后脑组织随时间进行形态学/病理生理学检查的新型犬类模型的适用性和安全性。
使用无框架导航技术，将一根集成温度反馈系统的激光光纤（830nm二极管激光）插入18只犬的右侧额叶白质。将间质加热过程中的MRI测温（相位映射，即质子共振频率的化学位移）与病变边界处同时记录的间质光纤温度读数进行比较。为了研究随时间推移ILTT对脑毛细血管功能的影响，在ILTT后12小时、36小时、7天、14天、4周和3个月进行定量放射自显影，研究碳-14标记的α-氨基异丁酸的单向血脑转运（AIB的转运常数K）。
所有激光操作均耐受性良好，所有动物的激光光纤和温度光纤均可充分置于右侧额叶。5只动物基于MRI的温度定量与侵入性温度测量高度相关。其余动物中，温度光纤位于磁敏感伪影区域，因此无法进行温度相关性分析。激光损伤由中央钙化坏死区域组成，周围是反应性脑组织区域，其通透性增加。定量放射自显影显示血脑屏障病变薄且呈球形。ILTT后，AIB的K值从12小时到14天增加，此后降低。AIB的K值平均值分别是正常白质（皮质）的19倍（2倍）。
ILTT导致激光损伤周围出现短暂、高度局部化的毛细血管通透性增加区域。目前，用于MRI热监测的相位对比成像不能用于体内可靠的温度读数。所建议的新型犬类模型被证明是安全、准确、易于使用的，并提供了临床、影像学、病理和生理相关性。
