The apparent diffusion coefficient does not reflect cytotoxic edema on the uninjured side after traumatic brain injury

After traumatic brain injury, vasogenic and cytotoxic edema appear sequentially on the involved side. Neuroimaging investigations of edema on the injured side have employed apparent diffusion coefficient measurements in diffusion tensor imaging. We investigated the changes occurring on the injured and uninjured sides using diffusion tensor imaging/apparent diffusion coefficient and histological samples in rats. We found that, on the injured side, that vasogenic edema appeared at 1 hour and intracellular edema appeared at 3 hours. Mixed edema was observed at 6 hours, worsening until 12–24 hours post-injury. Simultaneously, microglial cells proliferated at the trauma site. Apparent diffusion coefficient values increased at 1 hour, decreased at 6 hours, and increased at 12 hours. The uninjured side showed no significant pathological change at 1 hour after injury. Cytotoxic edema appeared at 3 hours, and vasogenic edema was visible at 6 hours. Cytotoxic edema persisted, but vasogenic edema tended to decrease after 12–24 hours. Despite this complex edema pattern on the uninjured side with associated pathologic changes, no significant change in apparent diffusion coefficient values was detected over the first 24 hours. Apparent diffusion coefficient values accurately detected the changes on the injured side, but did not detect the changes on the uninjured side, giving a false-negative result.

Recent advances and future directions in preclinical research of argininevasopressin(AVP) receptor blocker conivaptan in the context of stroke

Stroke is a major cause of mortality and permanent disability.The onset of stroke is followed by life-threatening pathophysiological responses including brain edema,elevation of intracranial pressure,disruption of blood-brain barrier（BBB）,brain infarct and permanent tissue damage.Brain edema develops due to accumulation of water in intracellular and extracellular compartments of the brain,

Atypical clinical and pathological findings in a patient with isolated cortical vein thrombosis

Isolated cortical vein thrombosis often produces a focal lesion. Because of the rapid development of collateral circulation, increased intracranial pressure has never been reported in a patient with isolated cortical vein thrombosis. The diagnosis of isolated cortical vein thrombosis is based mainly on MRI, catheter digital subtraction angiography, and histological findings, but may be challenging. We report a patient who presented with intermittent seizures and left-sided limb weakness. Her symptoms gradually progressed, and she eventually developed signs of increased intracranial pressure. Imaging studies showed a space-occupying lesion in the right frontal lobe of the brain. As we could not diagnose isolated cortical vein thrombosis based on the preoperative findings, surgical excision of the lesion was performed under general anesthesia. Histological examination showed destruction of the brain parenchyma with infiltration of macrophages, proliferation of reactive astrocytes and small vessels, and foci of hemorrhage. Further examination found that a number of small vessels in both the subarachnoid space and brain parenchyma were filled with thrombus, some of which was organized. Elastic fiber staining showed that the obstructed vessels were veins. We diagnosed isolated cortical vein thrombosis with atypical clinical features.