Department of Anesthesiology and Intensive Care, Lund University and Skåne University Hospital, Lund, Sweden -
Minerva Anestesiol. 2016 May;82(5):525-33. Epub 2015 Nov 27.
Brain edema and intracranial hypertension is deleterious after traumatic brain injury (TBI), but the underlying pathophysiology is complex and poorly understood. One major subject of controversy is the time course and extent of blood-brain barrier (BBB) dysfunction following trauma, and previous studies in humans have only provided semi-quantitative data. The objective of the present study was therefore to quantify changes in BBB-permeability in the early course of TBI, when brain edema is still evolving.
Sixteen non-consecutive brain trauma patients and two controls were included. Following i.v. injection of iohexol and CT perfusion scans, patients were scanned eight times from 4 to 25 minutes. Blood to brain transfer constant (Ki) for iohexol (molecular weight 821 D), reflecting permeability and available area for diffusion, was calculated offline by Patlak plot analysis of the enhancement curves of intracerebral large venous vessels and pericontusional brain parenchyma.
In non-ischemic tissue surrounding contusions and hematomas Ki was increased 2- to 10-fold compared to normal tissue, reaching maximal values of 0.5 mL/min/100 g. In non-injured areas and in controls Ki was about 0.06 mL/min/100 g. The increase was more pronounced in the most severely injured patients, and was detectable within 24 hours after trauma and up to five days after.
Our results suggest that traumatic brain injury is associated with early focal increases in small molecular BBB-permeability. The results indicate that in the injured brain, capillary hydrostatic and oncotic pressures may influence edema formation.
脑水肿和颅内高压在创伤性脑损伤（TBI）后是有害的，但潜在的病理生理学是复杂的，理解得还不够。争议的一个主要问题是创伤后血脑屏障（BBB）功能障碍的时间过程和程度，以前的人类研究只提供了半定量数据。因此，本研究的目的是在脑水肿仍在发展的 TBI 早期阶段量化 BBB 通透性的变化。
纳入 16 名非连续脑外伤患者和 2 名对照者。静脉注射碘海醇并进行 CT 灌注扫描后，患者从第 4 分钟到第 25 分钟进行了 8 次扫描。通过对颅内大静脉血管和挫伤周围脑实质的增强曲线进行 Patlak 图分析，计算出碘海醇的血脑转移常数（Ki）（分子量 821D），反映通透性和扩散的可用面积。
在非缺血性挫伤和血肿周围组织中，Ki 与正常组织相比增加了 2 到 10 倍，达到 0.5mL/min/100g 的最大值。在未受伤区域和对照组中，Ki 约为 0.06mL/min/100g。在受伤最严重的患者中，增加更为明显，在创伤后 24 小时内即可检测到，最多可持续 5 天。
我们的结果表明，创伤性脑损伤与早期局灶性小分子 BBB 通透性增加有关。这些结果表明，在受伤的大脑中，毛细血管静水压和渗透压可能会影响水肿的形成。
