Changes in Cerebral Blood Flow from the Acute to the Chronic Phase of Severe Head Injury

Abstract

We studied cerebral blood flow (CBF) in the transition from the acute to the chronic phase of severe head injury in order to determine patterns of change in relation to neurological outcome. We measured CBF with stable xenon-enhanced computed tomography (Xe-CT) in 20 consecutive patients at 1, 2, 3, 4, and 6 weeks after severe head injury, and analyzed the relation between the pattern of change in CBF and neurological outcome at 6 months after injury. CBF values were significantly lower in the brain-injured patients than in 14 healthy volunteers, except at 3 weeks after injury, when CBF increased in the patients to a value that did not differ significantly from that in the normal volunteers. We therefore focused on the change in CBF at 3 weeks after injury. We separated the 20 brain-injured patients into two subgroups, of which the first (subgroup A) consisted of nine patients whose CBF had returned to normal by week 3 post-injury, while the second (subgroup B) consisted of 11 patients whose CBF was subnormal at week 3 post-injury. CBF was significantly higher in subgroup A than in subgroup B at 2 weeks post-injury (p < 0.05). CBF in subgroup B remained significantly lower than that in subgroup A throughout the study period. At 6 months post-injury, subgroup A had a significantly better neurological outcome than did subgroup B (p < 0.05). We conclude that patients whose CBF returns to normal at 2-3 weeks following severe traumatic brain injury after being abnormally low in the acute phase of injury can be expected to achieve a good neurological outcome.

Pediatric Sports-Related Concussion Produces Cerebral Blood Flow Alterations

“…Decreased CBF has been noted in several adult [71][72][73][74][75][76][77][78][79][80][81] and pediatric [82][83][84][85] TBI studies and shows a strong correlation with poorer outcomes; however, these studies have focused largely on adults with moderate and severe injuries. No published investigations have described quantitative CBF values in concussed children.…”

Prophylactic hypothermia for traumatic brain injury: a quantitative systematic review

“…Brain ischemia in this setting results from impaired autoregulation, elevated intracranial pressure (ICP), local and global hypoperfusion, and increased cerebral metabolic demands. 9,10 Reperfusion injury is due to a complex cellular cascade leading to apoptosis. 11 Hypothermia may be beneficial for the injured brain not only by reducing ICP and cerebral metabolic demands, 12 but also by decreasing disruption of the blood-brain barrier 13 and inhibiting the inflammatory cascade that leads to reperfusion injury.…”

Acute Traumatic Brain Injury: A Review of Recent Advances in Imaging and Management

“…This can allow rapid evaluation of clinical interventions (i.e., ICP augmentation) when compared to earlier acquisitions, and herein lies its most tangible future therapeutic use. It may also be used prognostically, as acute reductions in cerebral blood flow post-TBI (demonstrated by xenon CT) have been shown to correlate with a poor clinical outcome [15]. However, xenon has been shown to independently increase ICP and cerebral perfusion, and is difficult to perform on patients with poor respiratory function, which could potentially produce inaccurate estimations of ischemia [10,16].…”

“…Positron emission tomography measures the accumulation of positron-emitting isotopes in the brain using 15 O to assess cerebral blood flow or 18-fluorodeoxyglucose ( 18 FDG) to assess cerebral metabolism. Studies using PET have shown hypometabolism and metabolic stress that, if persistent, can lead to poor functional outcomes, but they have not demonstrated conclusive evidence of cerebral ischemia early after TBI [31,32].…”