Early optical detection of cerebral edema in vivo
Early optical detection of cerebral edema in vivo
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DOI：
10.3171/2010.2.jns091017
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发表时间：
2011-02-01
影响因子：
4.1
通讯作者：
Binder, Devin K.
中科院分区：
文献类型：
--
作者：
Gill, Amandip S.;Rajneesh, Kiran F.;Binder, Devin K.
Object.脑水肿是多种疾病状态下发病率和死亡率的重要原因。目前，检测体内进行性脑水肿的方法包括使用颅内压（ICP）监测仪和/或系列放射学研究。然而，ICP测量值显示出高度的可变性，ICP监测仪仅在水肿足以显著升高ICP后才检测到水肿。作者报道了两种不同的微创光纤近红外（NIR）技术的发展，能够直接检测早期脑水肿。通过腹膜内水给药（腹膜内注射30%体重），通过水中毒在成年CD 1小鼠中诱导细胞毒性脑水肿。将可植入的双光纤探头立体定位地放置到大脑皮层中，并连接到光源和检测器硬件。光源由宽带卤素照明或单波长NIR激光二极管组成，检测器是灵敏的NIR光谱仪或光功率计。在一个动物亚组中，进行左侧颅骨切除术，以获得皮质活检，用于含水量测定，以验证脑水肿。在另一组动物中，ICP传感器被放置在对侧皮层，与计算机同步并打上时间戳。无论是使用宽带照明与近红外光谱或单波长激光二极管照明与光功率计检测，作者检测到减少在早期脑水肿的近红外光学反射率。计算了注水（时间点0）、光学触发（定义为光学反射率相对于基线的2-SD变化）和规定的阈值ICP值（10、15和20 mm Hg）之间的时间间隔。NIR反射率的降低明显早于任何ICP阈值（p < 0.001）。注射盐水的对照小鼠表现出稳定的基线光学信号。皮质活检的反射率变化和组织比重之间存在显著相关性，进一步验证了双光纤探头作为脑水肿的直接测量方法。与传统的ICP监测相比，上述微创NIR技术允许显著更早地检测脑水肿，这可能在识别并因此早期治疗脑水肿方面具有临床实用性。(DOI：10.3171/2010.2.JNS091017）
Object. Cerebral edema is a significant cause of morbidity and mortality in diverse disease states. Currently, the means to detect progressive cerebral edema in vivo includes the use of intracranial pressure (ICP) monitors and/or serial radiological studies. However, ICP measurements exhibit a high degree of variability, and ICP monitors detect edema only after it becomes sufficient to significantly raise ICP. The authors report the development of 2 distinct minimally invasive fiberoptic near-infrared (NIR) techniques able to directly detect early cerebral edema.Methods. Cytotoxic brain edema was induced in adult CD1 mice via water intoxication by intraperitoneal water administration (30% body weight intraperitoneally). An implantable dual-fiberoptic probe was stereotactically placed into the cerebral cortex and connected to optical source and detector hardware. Optical sources consisted of either broadband halogen illumination or a single-wavelength NIR laser diode, and the detector was a sensitive NIR spectrometer or optical power meter. In one subset of animals, a left-sided craniectomy was performed to obtain cortical biopsies for water-content determination to verify cerebral edema. In another subset of animals, an ICP transducer was placed on the contralateral cortex, which was synchronized to a computer and time stamped.Results. Using either broadband illumination with NIR spectroscopy or single-wavelength laser diode illumination with optical power meter detection, the authors detected a reduction in NIR optical reflectance during early cerebral edema. The time intervals between water injection (Time Point 0), optical trigger (defined as a 2-SD change in optical reflectance from baseline), and defined threshold ICP values of 10, 15 and 20 mm Hg were calculated. Reduction in NIR reflectance occurred significantly earlier than any of the ICP thresholds (p < 0.001). Saline-injected control mice exhibited a steady baseline optical signal. There was a significant correlation between reflectance change and tissue specific gravity of the cortical biopsies, further validating the dual-fiberoptic probe as a direct measure of cerebral edema.Conclusions. Compared with traditional ICP monitoring, the aforementioned minimally invasive NIR techniques allow for the significantly earlier detection of cerebral edema, which may be of clinical utility in the identification and thus early treatment of cerebral edema. (DOI: 10.3171/2010.2.JNS091017)