Joel W. Yeakley

Magnetic resonance imaging in relation to functional outcome of pediatric closed head injury: A test of the Ommaya-Gennarelli model

OBJECTIVE To characterize late neuropathological findings of pediatric closed head injury (CHI), to assess depth of brain lesion in relation to acute severity, and to assess long-term outcome to test the Ommaya-Gennarelli model. METHODS Magnetic resonance imaging (MRI) at least 3 months postinjury in a prospective sample (n 5 169) and at least 3 years after CHI in a retrospective sample (n 5 82) was studied. Lesion volume was measured by planimetry. Acute CHI severity was measured by the Glasgow Coma Scale. Patients were classified according to the depth of the deepest parenchymal lesion into no lesion, subcortical, and deep central gray/brain stem groups. The outcomes were assessed by the Glasgow Outcome Scale and the Vineland Adaptive Behavior Scale, which were performed at the time of the MRI in the retrospective sample and up to 3 years postinjury in the prospective sample. RESULTS Focal brain lesions were present in 55.4% of the total sample. Depth of brain lesion was directly related to severity of acute impairment of consciousness and inversely related to outcome, as measured by both the Glasgow Outcome Scale and the Vineland Adaptive Behavior Scale. A rostrocaudal gradient of hemispheric lesion frequency was observed, whereas the posterior lesions of the corpus callosum were particularly common. Total lesion volume could not explain the depth of lesion effect. CONCLUSION Our findings extend support for the Ommaya-Gennarelli model to pediatric CHI, indicating that depth of brain lesion is related to functional outcome. The relative frequency of focal brain lesions revealed by late MRI is higher than that of previous findings using acute computed tomography. Future investigations could explore whether depth of lesion observed using late MRI is sensitive to neuroprotective interventions.

CT evaluation of congenital aural atresia: what the radiologist and surgeon need to know.

PURPOSE The preoperative evaluation of aural atresia and stenosis is strongly dependent upon high resolution CT. We have devised a 10 point surgical rating scale based on high resolution CT of the temporal bone that will provide radiologists with a stepwise method of evaluating these scans and will allow them to communicate these findings to otologic surgeons in a consistent fashion. METHOD We prospectively evaluated 1,500 patients with aural atresia or stenosis for eight critical areas of temporal bone anatomy, each area receiving 1 rating scale point, with the exception of the presence of a stapes, which received 2 points. The appearance of the external ear received the final point on the rating scale since the external ear is formed earlier than the middle ear and helps to predict its deformities. The presurgical score was utilized in selecting surgical candidates and was correlated with the intraoperative findings as well as the postsurgical results by comparing pre- and postoperative speech reception threshold. Patients with a presurgical rating of < or = 5 were not considered surgical candidates. Otherwise, the percentage of successful surgeries corresponded roughly to the rating scale. RESULTS AND CONCLUSION Thus, a presurgical rating of 8 points translates into an 80% chance of restoring hearing to normal or near-normal levels.

Corpus callosum damage and interhemispheric transfer of information following closed head injury in children.

We evaluated the relationship of corpus callosum atrophy and/or lesions on magnetic resonance imaging (MRI) to functional hemispheric disconnection following closed head injury (CHI) in 51 pediatric patients, including mild CHI, moderate to severe CHI with extracallosal lesions, and moderate to severe CHI with callosal atrophy and/or lesions. Interhemispheric transfer of information was assessed using auditory, motor, tactile, and visual tests in patients and in 16 uninjured children. Total and regional callosal areas were measured from the midsagittal MRI slice by morphometry. The corpus callosum lesion group demonstrated a greater right ear advantage on verbal dichotic listening than all other groups. Areas of the posterior corpus callosum were negatively correlated with laterality indices of verbal dichotic listening performance and tachistoscopic identification of verbal material. The relationship of corpus callosum atrophy and/or lesions to asymmetry in dichotic listening is consistent with previous investigation of posttraumatic hemispheric disconnection effects in adults.

Temporal bone fractures : longitudinal or oblique ? The case for oblique temporal bone fractures

Classical descriptions and illustrations of temporal bone fractures are misleading. Both oblique and longitudinal fractures produce a similar fracture line in the middle cranial fossa; however, externally, they are different. Oblique fractures cross the petrotympanic fissure while longitudinal fractures run within it. In a study of 150 temporal bone fractures, the majority were oblique. An array of fracture planes accounts for most of the fractures observed. Depending on the direction of trauma, fracture planes rotate around an anteroposterior axis. When they approach the horizontal (axial) plane, they result in oblique fractures. True longitudinal fractures are rare. They are vertical and perpendicular to the oblique planes.

Magnetic resonance imaging in the diagnosis of the cranio-cervical manifestations of the mucopolysaccharidoses

Sixteen magnetic resonance (MR) studies were performed in eight patients with mucopolysaccharidosis (MPS). In patients with Hunter, Hurler, and Scheie syndromes, multiple areas of increased signal intensity were noted in the periventricular white matter. Computerized tomography (CT) frequently failed to demonstrate these white matter lesions. Other findings included spinal cord compression, hydrocephalus and airway obstruction due to soft tissue thickening around pharynx. In patients with Morquio syndrome, cervical spine dislocation, spinal cord compression and hydrocephalus were diagnosed by MR. MR was superior compared to CT, plain films and plain tomography, as the narrowing caused by bone and soft tissue changes were better seen with MR. Our experience suggests that MR should be the primary imaging modality for the detection of cranial abnormalities in patients with MPS. High resolution surface coil imaging may be preferable to invasive procedures such as myelography and CT with intrathecal contrast agents for the evaluation of cervical spine disease.

Fracture of the Occipital Condyle

Fracture of the occipital condyle is a rare problem. Diagnosis requires a high index of suspicion in a patient with a head injury and abnormalities of function of the lower cranial nerves. The diagnosis is best made by high resolution computed tomographic scanning with sagittal and coronal reconstructions. Although transoral and lateral surgical approaches for decompression and stabilization are possible, these are difficult and frought with danger. We report a case of occipital condyle fracture in which operation was deferred and spontaneous recovery occurred, as has happened in previous cases.

Treacher Collins syndrome: an otologic challenge

Patients with Treacher Collins syndrome have severe middle ear malformations that render operation difficult. We have evaluated 43 patients with Treacher Collins syndrome, on whom only 11 were operated. Computed tomography, the single most important study done preoperatively, routinely showed an underdeveloped temporal bone with islands of bone marrow and absent mastoid pneumatization. The middle ear space was often underdeveloped. Ossicular dysjunction was often noted in which the fused malleus/incus remnant was found 3 to 4 mm distant to the stapes. A common finding was severe dysplasia of the stapes-facial nerve complex that often made the middle ear malformation uncorrectable. Hearing results were much less predictable than in patients with isolated atresia/stenosis of the ear.

Frontal Lobe Changes after Severe Diffuse Closed Head Injury in Children

IN VIEW OF the pathophysiology and biomechanics of severe closed head injury (CHI) in children, we postulated that the frontal lobes sustain diffuse injury, even in the absence of focal brain lesions detected by magnetic resonance imaging (MRI). This study quantitated the morphological effects of CHI on the frontal lobes in children who sustained head trauma of varying severity. The MRI findings of 14 children who had sustained severe CHls (Glasgow Coma Scale score of ≤8) were compared with the findings in a matched group of 14 children having sustained mild head injuries (Glasgow Coma Scale score of 13-15). The patients ranged in age from 5 to 15 years at the time of their MRls, which were acquired at least 3 months postinjury. MRI findings revealed no focal areas of abnormal signal in the frontal lobes. Volumetric analysis disclosed that the total prefrontal cerebrospinal fluid increased and the gray matter volume decreased in the patients with severe CHI, relative to the mildly injured comparison group. Gray matter volume was also reduced in the orbitofrontal and dorsolateral regions of the brains of children with severe CHI, relative to the children who sustained mild head trauma. These volumetric findings indicate that prefrontal tissue loss occurs after severe CHI in children, even in the absence of focal brain lesions in this area. Nearly two-thirds of the children who sustained severe CHls were moderately disabled after an average postinjury interval of 3 years or more, whereas 12 of the 14 patients with mild CHls attained a good recovery (2 were moderately disabled) by the time of study. Although this initial study of brain morphometry after CHI in children was not designed to isolate the contribution of frontal lobe damage to residual disability, further research involving a larger sample is in progress to address this issue.

Rolandic Type Cerebral Palsy in Children as a Pattern of Hypoxic-Ischemic Injury in the Full-Term Neonate:

Magnetic resonance images (MRIS) of the brains of 11 patients aged from 1 week to 12 years with a distinctive type of cerebral palsy were selected based on distribution of cerebral lesions, which were restricted to bilateral perirolandic cortical and subcortical regions, including frequent symmetric involvement of basal ganglia and ventrolateral nucleus of thalami. Retrospectively, the perinatal history and clinical features were reviewed to correlate clinical data with this distinctive pattern of brain injury. Clinically affected neonates had an encephalopathy associated with a severe perinatal asphyxial event. Older children with cerebral palsy survived a similar perinatal course and demonstrated spastic quadriparesis with bulbar or pseudobulbar involvement, lack of verbal speech and variable delays in cognitive development. The distribution of hypoxic-ischemic lesions involving bilateral perirolandic regions, basal ganglia, and thalami, appears to correlate with increased metabolic areas of primary myelination in full-term neonates, but not with arterial border zones nor a single cerebral artery distribution. Myelination is a critical process in maturing brain associated with marked increase in tissue respiration and thus greater susceptibility to oxygen deprivation. It is believed that the extent of hypoxic-ischemic brain injury is determined principally by brain maturity and regional metabolic rates at time of insult and this correlates with active myelination in full-term neonates. This study confirms previous data from neuropathologic literature and recent reports of neuroimaging studies of asphyxiated neonates. In addition, retrospective analysis of the clinical data enables recognition of a type of cerebral palsy that might be the hallmark of hypoxic-ischemic injury in term neonates. (J Child Neurol 1998;13:313-321).

Pediatric temporal bone fractures

Twenty‐seven temporal bone fractures in 25 pediatric patients were evaluated over a 6‐year period. The diagnosis was confirmed with otoscopy and high‐resolution computed tomography scans (HRCT). Three‐dimensional reconstruction of high‐resolution computed tomography scans were used to aid in the diagnosis. The most common fracture was an oblique fracture which is oriented in an axial or horizontal plane with the temporal bone. Facial nerve paralysis was found in 6 of our patients, which is less than the expected incidence when compared to adults. Hearing loss was found in 24 patients, the most common of which was conductive hearing loss, which had a higher incidence than expected when compared with adults.