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Alexandra D. Beier and Peter B. Dirks

Traumatic brain injuries afflict a large number of pediatric patients. The most severe injuries lead to increased intracranial pressure and herniation, with resultant changes in the brainstem. Traumatic brainstem hemorrhages have previously been associated with poor neurological outcome and fatality. However, this report discusses 2 pediatric patients who sustained severe head trauma with subsequent brainstem hemorrhages, and yet experienced good neurological outcome; the possible mechanism is described.

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Richard J. Edwards and Peter B. Dirks

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Michael J. Ellis, Derek Armstrong and Peter B. Dirks

The management of large and giant arteriovenous malformations (AVMs) in patients presenting with nonhemorrhagic neurological deficits secondary to vascular steal phenomenon is challenging and controversial. In many cases, large AVMs cannot be completely excised or cured, leaving patients with residual or partially treated AVMs, the natural history of which is unknown. Additionally, large, diffuse vascular malformations with multiple, small feeders, slow flow, or so-called cerebral proliferative angiopathy represent a related but distinct clinical and angiographic entity that may require a different therapeutic approach than traditional brain AVMs. The current management of children with other conditions of chronic cerebral hypoperfusion, such as moyamoya disease, involves consideration of surgical revascularization to enhance blood flow to the compromised hemisphere. Here, the authors present the case of a young child with a large thalamic vascular malformation who presented with clinical and radiological features of vascular steal and ischemia. In an effort to augment flow to the hypoperfused brain and protect against future ischemia, the authors treated the child with unilateral pial synangiosis. At 12 months, postoperative angiography demonstrated robust neovascularization, and the child has not sustained any further ischemic events. The authors discuss concept of vascular malformation–related hypoperfusion and the utility of indirect revascularization for inoperable vascular malformations presenting with ischemic symptoms.

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Guillaume Saliou, Peter Dirks, Lee-Anne Slater and Timo Krings

OBJECTIVE

The etiology of jugular bulb stenosis (JBS) or occlusion in the context of vein of Galen aneurysmal malformations (VGAMs) is unknown. It can lead to decompensation of a lesion that was previously clinically stable. The aim of this study was to describe the natural history of JBS or occlusion in VGAM and to determine whether there is an association with bony remodeling of the jugular foramina.

METHODS

The authors identified all cases of JBS greater than 70% bilaterally involving patients seen at The Hospital for Sick Children between January 2007 and June 2014. The foramen diameters were measured on sagittal CT imaging, on a slice passing at the level of the jugular vein. The jugular foramen diameters were also compared to measurements obtained in a matched population of the same age group who had no VGAM and had undergone cerebral CT for a reason other than vascular disease.

RESULTS

Eight patients (6 male and 2 female) with bilateral JBS were included in this series. The median duration of clinical follow-up was 2.5 years (IQR 1.7–4.2 years). JBS was associated with bony narrowing the jugular foramina in 7 of the 8 patients over time. Between 1 and 2 years of age, patients with a VGAM demonstrated jugular foramen narrowing in comparison with a matched population (p = 0.015).

CONCLUSIONS

Jugular bulb stenosis or occlusion in VGAM may be associated with narrowing of the jugular foramina. These conditions seem to have a male predominance. If treatment is required, bony narrowing of the jugular foramina should be taken into account when deciding whether angioplasty and stent placement or surgical bypass might be appropriate therapeutic options.

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James T. Rutka, Masaji Murakami, Peter B. Dirks, Sherri Lynn Hubbard, Laurence E. Becker, Kozo Fukuyama, Shin Jung and Kazuhito Matsuzawa

In the adult human brain, normal astrocytes constitute nearly 40% of the total central nervous system (CNS) cell population and may assume a star-shaped configuration resembling epithelial cells insofar as the astrocytes remain intimately associated, through their cytoplasmic extensions, with the basement membrane of the capillary endothelial cells and the basal lamina of the glial limitans externa. Although their exact function remains unknown, in the past, astrocytes were thought to subserve an important supportive role for neurons, providing a favorable ionic environment, modulating extracellular levels of neurotransmitters, and serving as spacers that organize neurons. In immunohistochemical preparations, normal, reactive, and neoplastic astrocytes may be positively identified and distinguished from other CNS cell types by the expression of the astrocyte-specific intermediate filament glial fibrillary acidic protein (GFAP). This GFAP is a 50-kD intracytoplasmic filamentous protein that constitutes a portion of, and is specific for, the cytoskeleton of the astrocyte. This protein has proved to be the most specific marker for cells of astrocytic origin under normal and pathological conditions. Interestingly, with increasing astrocytic malignancy, there is progressive loss of GFAP production. As the human gene for GFAP has now been cloned and sequenced, this review begins with a summary of the molecular biology of GFAP including the proven utility of the GFAP promoter in targeting genes of interest to the CNS in transgenic animals. Based on the data provided the authors argue cogently for an expanded role of GFAP in complex cellular events such as cytoskeletal reorganization, maintenance of myelination, cell adhesion, and signaling pathways. As such, GFAP may not represent a mere mechanical integrator of cellular space, as has been previously thought. Rather, GFAP may provide docking sites for important kinases that recognize key cellular substrates that enable GFAP to form a dynamic continuum with microfilaments, integrin receptors, and the extracellular matrix.

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Alexandra D. Beier, Samuel H. Cheshier, Aabir Chakraborty and Peter Dirks

The syndrome of inappropriate antidiuretic hormone secretion (SIADH) is occasionally seen after hypothalamic injury or dysfunction, although it typically occurs in association with other endocrine disturbances. It is has never been described as a presenting feature of a suprasellar arachnoid cyst (SAC) in the pediatric population. The authors describe the case of an enlarging SAC resulting in SIADH as the only presenting feature, with an otherwise normal hypothalamic-pituitary axis.

An SAC was diagnosed in utero in this 5-month-old girl who had a normal functioning hypothalamic-pituitary axis on presentation. Because of cyst enlargement and hydrocephalus, the patient was scheduled for surgery; however, preoperative labs revealed SIADH. After stabilizing the serum sodium concentration with fluid restriction and the administration of 3% sodium chloride, the patient underwent endoscopic cyst fenestration. Postoperatively, she had complete resolution of the SIADH.

Syndrome of inappropriate antidiuretic hormone secretion as the presenting symptom of an SAC has not been previously described. In the aforementioned patient, the proposed mechanism for SIADH was enlargement of the suprasellar arachnoid cyst causing compression of the supraoptic and paraventricular nuclei and thus overstimulating the secretion of arginine vasopressin, which resulted in SIADH.

The association of SIADH with an SAC is reportable, as is the resolution of the SIADH via cyst fenestration. The authors suggest that SIADH is an uncommon presenting feature of SACs and that syndrome resolution is possible with cyst decompression.

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Ibrahim H. Al-Ahmed, Mohamed Boughamoura, Peter Dirks, Abhaya V. Kulkarni, James T. Rutka and James M. Drake

Object

Neurenteric cysts (NCs) are endothelium-lined structures of presumed endodermal origin. There have been few pediatric series of intracranial NCs reported previously. The authors present their experience in the management of these lesions.

Methods

A retrospective chart review of all cases of NCs identified between 1977 and 2007 was carried out. Demographics, details of clinical presentation, surgical therapy, and outcome data were extracted.

Results

Eleven cases were identified, involving 6 girls and 5 boys. The patients' average age was 4.6 years (range 1 day–14 years). Limb weakness was the most common presenting symptom. The location of the cysts was cervical in 2 cases, cervicothoracic in 4 cases, and thoracic in 3 cases. One cyst was anterior to the pons with extension to the left cerebellopontine angle and 1 cyst was at the craniocervical junction. Five patients had an apparently complete initial excision, with 1 recurrence. Four patients were initially treated with incomplete excision and/or cyst drainage, usually into an Ommaya reservoir. A neonate with a large cervicothoracic cyst died of multiple congenital anomalies without any intervention. All other patients were alive at last follow-up. One patient with a radiologically identified presumed cyst, which remained stable, was simply followed up. Several patients required multiple procedures and 1 patient developed hydrocephalus after aseptic meningitis and was treated with CSF shunting.

Conclusions

Neurenteric cysts are rare in the pediatric population. Total resection, if possible, provides the best long-term outcome. Incomplete excision may lead to multiple procedures, including cyst drainage, but can lead to long-term stability.

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Pieter Wesseling, Jeroen A. W. M. van der Laak, Henk de Leeuw, Dirk J. Ruiter and Peter C. Burger

✓ Because histologically prominent microvascular proliferation is frequently present in glioblastoma multiforme, it has been hypothesized that this neoplasm is particularly dependent on neovascularization for its continued growth and that antiangiogenic therapy might be especially useful. To quantify the histological aspects of microvascular proliferation in glioma, a feasible and reproducible method was developed for computer-assisted image analysis of the visualized microvasculature in glial tissue. This method was used to compare several vascular parameters in histological whole-tumor sections of untreated human glioblastoma multiforme with those in histologically normal cerebral cortex and white matter. There was a significant increase in mean number, area, and perimeter of blood vessels per microscopic field in glioblastoma multiforme compared to normal cerebral white matter. In a substantial number of tumor fields, however, the vascular density was in the same range as that of normal cerebral white matter. The striking heterogeneity of the microvasculature within glioblastoma multiforme was illustrated by the significantly higher standard deviation for the vascular parameters in tumor tissue. The results of this study suggest that many regions of glioblastomas multiforme are not overtly angiogenesis dependent and may be difficult to treat by antiangiogenic therapy alone.

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Abhaya V. Kulkarni, James M. Drake, Derek C. Armstrong and Peter B. Dirks

Object. The goal of this study was to determine and compare imaging correlates in pediatric patients who underwent successful or failed endoscopic third ventriculostomies (ETVs). To this end, the authors measured ventricular size changes and the presence of cerebrospinal fluid (CSF) flow void in both groups of children following ETV.

Methods. Images obtained in children with hydrocephalus immediately before and at least 30 days after having undergone ETV were reviewed by four independent observers (two blinded and two nonblinded). Each observer independently measured the frontal and occipital horn ratio ([FOR], a reliable and valid measure of ventricular size) and provided a subjective assessment of the presence of a flow void at the ETV site, the degree of periventricular edema, and the amount of CSF over the cerebral hemispheres.

There were 29 children whose mean age was 6.6 years at the time of ETV and who had a mean postoperative follow-up period lasting 1.6 years. Postoperatively, the mean reduction in ventricular size (as measured using the FOR) was 7% (95% confidence interval [CI] 3–11%) in cases that were deemed failures (eight patients) and 16% (95% CI 12–20%) in clinically successful cases (21 patients). This reduction was significantly greater in cases of clinical success compared with those that were deemed failures (p = 0.03, t-test). There were no substantial differences between blinded and nonblinded assessments. Flow void was present in 94% of successes and absent in 75% of failures (p = 0.01, Fisher's exact test). The other subjective assessments were not significantly different between the groups of successes and failures.

Conclusions. Ventricular size appears to be somewhat reduced in both groups of patients who underwent clinically successful and failed ETV; however, the reduction is significantly greater among clinically successful cases. The presence of a flow void also appears to correlate with clinical success and its absence with clinical failure.

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Long Chen, Ivanna Yau, Gabrielle deVeber, Peter Dirks, Derek Armstrong and Timo Krings

Clinical and imaging manifestations of the so-called partially thrombosed aneurysm (PTA) are different from those of the classic intracranial saccular aneurysm. Given some of their peculiar imaging features, it had been hypothesized that some PTAs occur due to repeated intramural hemorrhages. The authors present a case of PTA that evolved from an acute dissecting aneurysm as shown by serial imaging. A previously healthy 5-year-old boy had a sudden onset of left hemiparesis. Initial MRI sequences showed a perforating vessel infarction in the right basal ganglia area secondary to an acute distal middle cerebral artery (MCA) dissection as demonstrated on conventional angiography. Conservative management with close observation of this dissection was chosen, and serial MRI studies revealed layering of blood of various ages within the wall of an aneurysmal outpouching of the MCA, thereby leading to the imaging appearance of a PTA. The findings in this case indicate that some PTAs may be caused by repeated or chronic dissections, with blood entering the wall through an endothelial defect. Understanding the pathological mechanism underlying the formation of these aneurysms will help inform appropriate treatment strategies.