A new method of inducing selective brain hypothermia with saline perfusion into the subdural space: effects on transient cerebral ischemia in cats.

In this study, we tested brain surface cooling as a new method of inducing selective brain hypothermia, and evaluated its effects on focal cerebral ischemia using a cat model of transient middle cerebral artery (MCA) occlusion. Cats underwent 1 h of MCA occlusion followed by 5 h of reperfusion. Brain surface cooling was induced for 4 h during and after MCA occlusion in the hypothermia group, but not in the normothermia group. Brain surface cooling was performed using saline perfusion into the subdural space. Rectal temperature, brain surface temperature, and deep brain temperature were monitored, and regional cerebral blood flow (rCBF) and somatosensory evoked potential (SEP) were serially measured. After 5 h of reperfusion, water content was also measured. Although the rectal temperature was maintained at about 37 degrees C, the brain surface temperature decreased rapidly to 33 degrees C and was maintained at that temperature. For 3 h following reperfusion, the rCBF was lower in the hypothermia group than in the normothermia group. At 4 and 5 h after reperfusion, the recovery of SEP amplitude was significantly more enhanced in the hypothermia group than in the normothermia group. In the gray matter, the water content was significantly more diminished in the hypothermia group than in the normothermia group. These results demonstrate that our method is useful for protecting the ischemic brain from a transient MCA occlusion. This method may be adapted for neurological surgery.</p

The Usefulness of CT-Diffusion Weighted Image Mismatch in Patients with Mild to Moderate Traumatic Brain Injury

Traumatic brain injury (TBI) has a complex and heterogeneous pathology. It is frequently difficult to predict the neurological deterioration of patients with TBI, and unpredictable change may occur even when TBI is mild to moderate. When computed tomography (CT) findings are considered to be inconsistent with the traumatic origin or with the neurological deterioration of patients observed on admission, magnetic resonance imaging (MRI) is employed based on the standards of our ethical committee. In this retrospective study, we compared CT and diffusion weighted imaging (DWI) of patients with mild to moderate TBI in the very acute phase. When the high-intensity lesions on DWI are larger than the high-density lesions on CT images, we defined the imaging finding as a ʻCT-DWI mismatchʼ. Between January 2010 and December 2013, 92 patients were inspected using both CT and MRI at admission, and we detected a CT-DWI mismatch in 35 patients. CT-DWI mismatch was 92.6 (95 confidence interval 79.8-97.9) sensitive and 84.6 (95 confidence interval 79.3-86.3) specific for the prediction of enlargement of the hemorrhagic lesions on repeat CT. CT-DWI mismatch is considered to be useful as one of the predictors of the enlargement of hemorrhagic lesions in patients with mild to moderate TBI