BACKGROUND Monitoring brain tissue PO2 (PbtO2) is part of multimodality monitoring of patients with traumatic brain injury (TBI). However, PbtO2 measurement is a sampling of only a small area of tissue surrounding the sensor tip. OBJECTIVE To examine the effect of catheter location on the relationship between PbtO2 and neurological outcome. METHODS A total of 405 patients who had PbtO2 monitoring as part of standard management of severe traumatic brain injury were studied. The relationships between probe location and resulting PbtO2 and outcome were examined. RESULTS When the probe was located in normal brain, PbtO2 averaged 30.8 ± 18.2 compared with 25.6 ± 14.8 mm Hg when placed in abnormal brain (P< .001). Factors related to neurological outcome in the best-fit logistic regression model were age, PbtO2 probe position, postresuscitation motor Glasgow Coma Scale score, and PbtO2 trend pattern. Although average PbtO2 was significantly related to outcome in univariate analyses, it was not significant in the final logistic model. However, the interaction between PbtO2 and probe position was statistically significant. When the PbtO2 probe was placed in abnormal brain, the average PbtO2 was higher in those with a favorable outcome, 28.8 ± 12.0 mm Hg, compared with those with an unfavorable outcome, 19.5 ± 13.7 mm Hg (P = .01). PbtO2 and outcome were not related when the probe was placed in normal-appearing brain. CONCLUSION These results suggest that the location of the PbtO2 probe determines the PbtO2 values and the relationship of PbtO2 to neurological outcome.

Working memory deficits are present in patients with mild traumatic brain injury (MTBI). Functional connectivity of different brain regions is required for adequate working memory. Brain injury is associated with disrupted connectivity due to microscopic axonal damage. In this investigation, we sought to investigate functional brain connectivity during working memory in MTBI patients. A sample of 30 MTBI patients and 30 age-, education-, and gender-matched normal controls were studied. Working memory was assessed with the Sternberg's verbal and visuo-spatial working memory tasks. Electro-encephalography (EEG) was recorded from 128 channels while subjects performed working memory tasks and during eyes closed resting condition. EEG coherence was computed in theta; lower and upper alpha; and lower and upper beta frequency bands during the encoding, retention, and retrieval stages of working memory as well as during eyes-closed rest. We found that the MTBI patients had impaired verbal and visuo-spatial working memory. The different stages of working memory were associated with poor intrahemispheric coherence in long-range (fronto-parietal) and mid-range (fronto-temporal and temporo-parietal) regions as well as poor interhemispheric coherence in the frontal and temporal regions in the MTBI patients. The deficit in coherence was present in theta, alpha, and beta frequency bands. However, the MTBI and the control group had comparable coherence values in intra- and inter-hemispheric regions during eyes closed rest. We suggest that the inter- and intra-hemispheric functional connectivity is impaired in MTBI during working memory performance.

The purpose of this study was to investigate the increased susceptibility of the brain, after a controlled mild cortical impact injury, to a secondary ischemic insult. The effects of the duration and the timing of the secondary insult after the initial cortical injury were studied. Rats anesthetized with isoflurane underwent a 3 m/sec, 2.5-mm deformation cortical impact injury followed by hypotension to 40 mm Hg induced by withdrawing blood from a femoral vein. The duration of hypotension was varied from 40 to 60 min. The timing of 60 min of hypotension was varied from immediately post-injury to 7 days after the injury. Outcome was assessed by behavioral tasks and histological examination at 2 weeks post-injury. A separate group of animals underwent measurement of the acute physiology including mean blood pressure (MAP), intracranial pressure (ICP), and cerebral blood flow (CBF) using a laser Doppler technique. Increasing durations of hypotension resulted in marked expansion of the contusion, from 6.5±1.8 mm³ with sham hypotension to 27.1±3.9 mm³ with 60 min of hypotension. This worsening of the contusion was found only when then hypotension occurred immediately after injury or at 1 h after injury. CA3 neuron loss followed a similar pattern, but the injury group differences were not significant. Motor tasks, including beam balance and beam walking, were significantly worse following 50 and 60 min of hypotension. Performance on the Morris water maze task was also significantly related to the injury group. Studies of the acute cerebral hemodynamics demonstrated that CBF was significantly more impaired during hypotension in the animals that underwent the mild TBI compared to those that underwent sham TBI. The perfusion deficit was worst at the impact site, but also significant in the pericontusional brain. With 50 and 60 min of hypotension, CBF did not recover following resuscitation at the impact site, and recovered only transiently in the pericontusional brain. These results demonstrate that mild TBI, like more severe levels of TBI, can impair the brain's ability to maintain CBF during a period of hypotension, and result in a worse outcome.

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About a third of the infants diagnosed with brain tumors (34%) had a good functional outcome and approximately a quarter of them (28%) were able to attend regular school or take up a skilled job. After tissue diagnosis, histological grade of tumor is the only independent predictor associated with outcome.

Working memory deficits are present in patients with mild traumatic brain injury (MTBI). Functional connectivity of different brain regions is required for adequate working memory. Brain injury is associated with disrupted connectivity due to microscopic axonal damage. In this investigation, we sought to investigate functional brain connectivity during working memory in MTBI patients. A sample of 30 MTBI patients and 30 age-, education-, and gender-matched normal controls were studied. Working memory was assessed with the Sternberg's verbal and visuo-spatial working memory tasks. Electro-encephalography (EEG) was recorded from 128 channels while subjects performed working memory tasks and during eyes closed resting condition. EEG coherence was computed in theta; lower and upper alpha; and lower and upper beta frequency bands during the encoding, retention, and retrieval stages of working memory as well as during eyes-closed rest. We found that the MTBI patients had impaired verbal and visuo-spatial working memory. The different stages of working memory were associated with poor intrahemispheric coherence in long-range (fronto-parietal) and mid-range (fronto-temporal and temporo-parietal) regions as well as poor interhemispheric coherence in the frontal and temporal regions in the MTBI patients. The deficit in coherence was present in theta, alpha, and beta frequency bands. However, the MTBI and the control group had comparable coherence values in intra- and inter-hemispheric regions during eyes closed rest. We suggest that the inter- and intra-hemispheric functional connectivity is impaired in MTBI during working memory performance.

Early and non-invasive evaluation of hydatid infestation of brain and spine is of paramount importance, especially in endemic areas. We present a spectrum of imaging findings in neurohydatidosis with a brief review of literature.