Walter D. Obrist

Computed Tomography of Pediatric Head Trauma: Acute General Cerebral Swelling

General cerebral swelling was the most common CT finding in 100 pediatric patients with acute head injury, and was demonstrated by CT as absence or compression of the lateral and third ventricles and perimesencephalic cisterns. Up to 50% of the children who die from head injury are conscious on admission. The most common pathological findings are diffuse cerebral swelling, loss of cerebrospinal fluid spaces, and venous congestion of the cortex.

Noninvasive Method of Estimating Human Newborn Regional Cerebral Blood Flow

A noninvasive method of estimating regional cerebral blood flow (rCBF) in premature and full-term babies has been developed. Based on a modification of the xenon-133 inhalation rCBF technique, this method uses eight extracranial NaI scintillation detectors and an i. v. bolus injection of xenon-133 (∼0.5 mCi/kg). Arterial xenon concentration was estimated with an external chest detector. Cerebral blood flow was measured in 15 healthy, neurologically normal premature infants. Using Obrists method of two-compartment analysis, normal values were calculated for flow in both compartments, relative weight and fractional flow in the first compartment (gray matter), initial slope of gray matter blood flow, mean cerebral blood flow, and initial slope index of mean cerebral blood flow. The application of this technique to newborns, its relative advantages, and its potential uses are discussed.

Correlation of Cerebral Blood Flow with Outcome in Head Injured Patients

In order to determine the relationship of cerebral blood flow (CBF) to the clinical outcome of head injury, serial determinations of CBF were performed by the intravenous Xenon technique in 24 patients. The patients were of mixed injury severity and were classified into four groups depending on the neurological exam at the time of each CBF study. All eight patients who were lethargic on admission demonstrated increases in their minimally depressed CBF as they unproved to normal status. Eleven patients in deep stupor or coma ultimately recovered. Ten of these patients initially had moderate to profound decreases in CBF which improved as recovery occurred. The single exception was an adolescent whose initial CBF was high but became normal at recovery. Five comatose patients died. In four of these, already depressed CBF fell even lower, while one adolescent with initially increased CBF developed very low CBF preterminally. The data presented in this report demonstrated a good correlation between CBF and clinical outcome. In every one of the adult survivors, depressed CBF increased as the patient recovered to normal status. All adults who died showed a deteriorationof CBF as the neurological status worsened. The only exceptions were two adolescents who initially showed high CBF values. In the adolescent who died, CBF dropped to low levels while in the survivor a normal CBF was achieved. Thus in adults a traumatic brain injury was associated with depressed CBF which increased with recovery or decreased further with deterioration while the reaction to injury was quite different in the younger brain.

Superficial temporal‐middle cerebral artery anastomosis Effects on vascular, neurologic, and neuropsychological functions

In 44 patients, we studied the effects of superficial temporal-middle cerebral artery anastomosis on cerebral blood flow (CBF), neurologic examination, and cognitive functions. At 3 months, there was significant improvement in all variables. At 9 months, CBF was no longer significantly greater, but neurologic examination and cognitive functions had further improved. Patients with TIA had significant postoperative decreases in TIA frequency and did not progress to stroke, but had no significant changes in any variable. In stroke patients, we could not separate the effects of surgery from the natural evolution of changes in CBF and examination after stroke. None of the preoperative measurements predicted postoperative clinical improvement.

Regional variations in human newborn cerebral blood flow

Regional differences in the local cerebral metabolic rate of glucose have been reported in newborn infants. This study was performed to determine if comparable differences exist in neonatal regional cerebral blood flow (rCBF). In 21 infants, rCBF was measured with a modified xenon 133 (133Xe) clearance technique by means of eight extracranial detectors positioned over four homologous regions (frontal, parietal, temporal, and occipital). The rCBF was lowest in the frontal region, higher in the parietal region, and highest in the temporal and occipital regions. Regional differences in rCBF may be caused by regional differences in brain development and function.

Factors Relating to Intracranial Hypertension in Acute Head Injury

It is well established that ICP monitoring plays an important role in the management of patients with acute head injury. The present paper describes the relationship between ICP and several variables assumed to be correlated with intracranial hypertension; namely, neurological outcome, CT findings and cerebral blood flow (CBF).

Relation of visual field defects to neuropsychological outcome after closed head injury

SummaryNeuropsychological outcome within two years after injury was determined in 159 head injured patients who were classified into three groups according to the presence of either unilateral, bilateral, or no visual field defects (VFDs). The VFDs occurred irrespective of injury severity as determined by the Glasgow coma scale, or social outcome as determined by the Glasgow outcome scale. Differences among the three visual field groups were obtained for several neuropsychological functions: intelligence, memory, learning, acquired verbal skills, visuospatial skills, and visuomotor speed. Patients with bilateral VFDs were more severely impaired neuropsychologically than those with unilateral or no VFDs. Occurrences of secondary complications (brain swelling, intracranial hypertension, and hyperemia) were more prevalent among the bilateral VFD cases. The findings suggested that bilateral VFDs may be indicators of increased brain damage from secondary insults.

Correlation of Acute ICP and CBF with CT Scan and Neuropsychological Recovery in Severe Head Injury

There is increasing evidence that intracranial pressure is a significant determinant of outcome following acute head injury (Marshall et al. 1979, Pitts et al. 1980, Narayan et al. 1982). Although the mechanism for this is not fully understood, recent reports on the relationship between CT scan and outcome (Van Dongen et al. 1983, Toutant et al. 1984), and between ICP and CT scan (Murphy et al. 1983), suggest that brain swelling accompanied by compression of the basal cisterns plays an important role. Evidence that cerebral circulatory factors contribute to brain swelling and elevations of ICP has also been reported (Bruce et al. 1981, Obrist et al. 1984). The present paper examines the interrelationship of ICP, cerebral blood flow (CBF) and CT scan evidence of brain swelling, with special emphasis on the correlation of these variables to neuropsychological outcome.

Cerebral Circulatory and Electroencephalographic Changes in Aging and Dementia

A full understanding of senescent behavioral changes requires information from in vivo physiologic studies, including both the electroencephalogram (EEG) and cerebral blood flow (CBF). The purpose of the present paper is to review some of the recent findings on cerebral physiology in the dementias of old age. Earlier EEG and CBF findings have been extensively reviewed elsewhere (Obrist 1972; Obrist 1975) and will only be summarized here.