Fast-brain MRI in children is quick, without sedation, and radiation-free, but beware of limitations.

Fast-brain MRI is a promising technique for young children who require anesthesia for conventional MRI; however, poor contrast resolution and the use of one type of pulse sequence only has limitations. We aimed to review and document pitfalls of fast-brain MRI in non-sedated children. Fifty fast-brain MRI studies (Fast Imaging Employing sTeady State Acquistion [FIESTA] protocol; 1.5-Tesla Signa Excite HD, GE HealthCare, Milwaukee, WI, USA) performed between January 2008 and August 2010 in 30 non-sedated patients aged 1 day to 5 years of age (mean: 18 months) were reviewed retrospectively and compared to the most recent MRI or CT scan. The indications were: ventriculoperitoneal (VP) shunt insertion or revision or follow-up (20/50, 40%), postoperative follow-up (9/50, 18%), macrocephaly, ventriculomegaly or congenital malformation (15/50, 30%), complications of prematurity (6/50, 12%). The VP shunt position and size of fluid-filled structures were satisfactorily assessed in all patients. Undetected findings in 7/50 studies (14%) were: venous sinus thrombosis (one patient), subdural hematoma (three), failure to differentiate blood products (two), and limited evaluation of extra-axial collections (one). FIESTA fast-brain MRI provides satisfactory assessment of shunt position and the size of fluid-filled structures, but radiologists should be aware of limitations for depiction of venous sinus thrombosis, and bleeding. Modification of fast-brain protocols appears to be indicated.

Chiari 1 malformation and holocord syringomyelia presenting as abrupt onset foot drop.

We present two patients with a Chiari 1 malformation and holocord syringomyelia who presented with abrupt onset unilateral foot drop. Neurophysiologic testing was consistent with a proximal nerve root lesion. This assisted with localization and directed magnetic resonance (MR) imaging to lumbosacral spine and nerve roots. Each child underwent a suboccipital craniectomy and laminectomy with duroplasty to decompress the foramen magnum. Each child also showed rapid and complete clinical recovery despite the significant electromyographic and MRI abnormalities on initial study.

The necessity of shunt series.

OBJECT: This work assessed the value of shunt series in the evaluation of children with CSF shunts, a test that is frequently ordered as part of the assessment of shunt integrity. METHODS: The medical records of all children who underwent shunt series at Children's Hospital of Eastern Ontario between 1975 and 2007 were reviewed. Ancillary studies that were performed within 2 days of the shunt series (brain CT, MR imaging, ultrasonography, and radionuclide shuntography) were noted, as well as the subsequent requirement for a shunt revision. Shunt series and ancillary studies were categorized as either positive (revealing an observable sign that a shunt-related problem was present, such as shunt discontinuity on the shunt series or enlargement of the ventricles on the brain CT scan) or negative (no clear sign of a shunt-related problem). Shunt series were further grouped into shunt series performed for diagnostic reasons, shunt series performed on a routine basis during follow-up in clinic, and shunt series performed postoperatively. The length of time between shunt insertion and shunt fracture was noted. Statistical analyses were performed, including the derivation of sensitivities and specificities. RESULTS: There were 3416 shunt series in 394 patients, of which 3004 were performed with ancillary studies. On average, patients underwent 9 shunt series, with a minimum of 1 and a maximum of 43, during the follow-up period (range 3 weeks to 19 years). A total of 2493 shunt series and ancillary studies (83%) yielded negative results and no surgery was performed. One hundred thirty shunts series were negative with a positive ancillary study (4.3%) and no surgery was required. In 8.7% (261 shunt series negative, ancillary studies positive) shunt revision surgery was necessary. The opposite trend was far less prevalent (17 shunt series positive, ancillary test negative; 0.6%) in which surgery was required. There were 87 patients with 96 shunt fractures (2.8% of shunt series). The average time between shunt insertion and shunt fracture was 7.9 years (range 3 months to 18 years). Shunt series had a sensitivity of 18% and a specificity of 97%. The ancillary studies had a sensitivity of 84% and a specificity of 85%. CONCLUSIONS: The routine utilization of shunt series in the evaluation of a child with a CSF shunt is not necessary. This study showed that a very small number (0.6%) of shunt series helped in surgical decision making. Shunt series can be performed in selected cases, especially preoperatively in the absence of a baseline study to obtain information necessary for surgical planning.

Classification of symptomatic Chiari I malformation to guide surgical strategy.

BACKGROUND: Treatment options for Chiari I malformations include posterior fossa decompression (PFD) with additional techniques including laminectomy, intradural exploration, and duraplasty. Neuroimaging findings of cisterna magna volume, syringomyelia, and intraoperative ultrasonography may tailor surgical intervention. METHODS: We developed an algorithm classifying symptomatic Chiari I patients into three groups to define minimum operation. Without syringomyelia, the presence of cisterna magna defined Group A and the absence defined Group B. Patients with syrinx formed Group C. Mild structural pathology (Group A) or adequate space following PFD (Group B, normal intraoperative ultrasound (IOUS)) should be treated by PFD alone. Conversely, presence of syringomyelia (Group C) or inadequate space following PFD (Group B, abnormal IOUS) should additionally have duraplasty. We applied this algorithm to patients treated at a single institution over 16 years. RESULTS: Twenty-four symptomatic Chiari I malformation patients were divided into three groups that did not differ by age, gender, or extent of tonsillar ectopia. All patients treated by this algorithm experienced clinical and radiographic improvement. This included eight Group B patients who underwent PFD only (n=6) or additional duraplasty (n=2) decided by IOUS. CONCLUSION: Treatment of symptomatic Chiari I malformation may have inadequate outcome with conservative strategy or complications with aggressive strategy. This algorithm utilizes preoperative neuroimaging and intraoperative ultrasound to tailor intervention, with excellent clinical outcome and radiographic syrinx resolution on application to 24 patients. Further validation requires prospective multicenter evaluation with larger patient population.

Treatment of posterior fossa tumors in children.

The most common posterior fossa tumors in children are medulloblastoma, astrocytoma and ependymoma. Atypical rhabdoid teratoid tumors and brain stem gliomas are relatively rare. As the posterior fossa is a limited space, the tumors presenting in this region cause symptoms early on and require prompt treatment to avoid potential morbidity and mortality. Early detection and diagnosis of these tumors and prompt neurosurgical consultation is crucial in the optimum management of pediatric infratentorial brain tumors. Surgery is the mainstay of treatment, as it provides biopsy and decompression of the tumor. Adjuvant therapy is required in the majority of cases. Recent advances in the field of radiation biology and pharmacology have improved dose and delivery techniques of chemoradiation therapy. In the current era, advances in translational research and molecular genetics have assumed a major role in the pursuit of achieving a 'cure' for these potentially malignant tumors.

Postoperative surveillance magnetic resonance imaging for cerebellar astrocytoma.

INTRODUCTION: Patients with low grade astrocytomas generally have good prognosis when total resection can be achieved, but surveillance neuroimaging is commonly performed to detect recurrence or progression. This study evaluated the utility and yield of such strategy for pilocytic and non-pilocytic cerebellar astrocytomas. METHODS: A 20-year retrospective review was performed of patients undergoing resection of cerebellar astrocytoma at a single institution. A negative MRI string (NMS) ratio was computed as the fraction of total follow-up period over which surveillance neuroimaging was negative for recurrence or progression. Chi-squared analysis differentiated NMS ratio by resection extent and lesion histopathology. RESULTS: Twenty-eight patients with pilocytic (n=15) and non-pilocytic (n=13) astrocytoma underwent 34 craniotomies, with total resection in 19 cases. Surveillance MRIs (n=167) among total resection patients were uniformly negative for recurrent disease at average seven years follow-up (NMS ratio = 1.0). The 43 surveillance MRIs among subtotal resection patients revealed disease progression in two patients within six months of operation (NMS ratio = 0.78, p<0.05). No differences in NMS ratio were observed between pilocytic and non-pilocytic astrocytoma subtypes. DISCUSSION: This study illustrates pediatric patients with low-grade cerebellar astrocytomas undergoing total resection may not benefit from routine surveillance neuroimaging, primarily because of low recurrence likelihood. Patients with subtotal resection may benefit from surveillance of residual disease, with further work aimed at exploring the schedule of such follow-up.

Functional outcomes among premature infants with intraventricular hemorrhage.

OBJECTIVE: This work evaluated the mortality and functional outcomes of premature infants sustaining intraventricular hemorrhage (IVH). These outcomes were analyzed for their association with IVH severity, development of hydrocephalus and need for ventriculoperitoneal (VP) shunt insertion. METHODS: A retrospective review was performed of neonates at the Children's Hospital of Eastern Ontario who sustained IVH (1989-2005). Logistic regression tested demographic predictors of IVH severity, development of hydrocephalus and mortality. Chi(2) analysis differentiated functional outcomes and mortality by IVH grade, development of hydrocephalus and intervention for cerebrospinal fluid diversion. All analyses used the 0.05 significance level. RESULTS: Data were available for 284 patients with an average follow-up of 5.1 years. These were distributed as grade I (n = 135), grade II (n = 52), grade III (n = 43) and grade IV (n = 54), with lower gestational age and birth weight predicting disease severity. Hydrocephalus developed in 21% of patients, of whom 39% required VP shunt insertion. Overall mortality of 20% depended on IVH grade and was highest for grade IV patients (59%). Functional independence diminished with IVH severity, and patients with hydrocephalus fared worse than those without this sequel. Outcomes of patients developing hydrocephalus were similar whether or not they eventually required VP shunt insertion. CONCLUSIONS: This study describes a large cohort of neonatal IVH, describing how disease severity affects mortality and functional outcome. The overall mortality of nearly 1 in 5 patients is primarily of grade IV patients, with no difference between grade II and grade III. Further, patients surviving their hydrocephalus exhibited no worse functional deterioration if they required surgical intervention.

Intracranial tumors in first year of life: the CHEO experience.

INTRODUCTION: One seventh of pediatric brain tumors are diagnosed in the first year of life. With more widespread and accessible neuroimaging, these lesions are being diagnosed earlier, but there remains scant literature about their natural history. METHODS: A retrospective review was performed of brain tumor patients presenting to the Children's Hospital of Eastern Ontario (CHEO) through the last 34 years. Patients presenting in the first year of life, including symptoms, management features, and functional outcome, were analyzed using ANOVA and chi (2) statistics. RESULTS: Eighteen cases of brain tumors in the first year of life were identified: 12 suptratentorial, eight with benign histology, and six infratentorial all with malignant histology. Median age of presentation differed by lesion location (p = 0.05) and glial tumors were most common. Raised intracranial pressure was more than twice as prevalent with posterior fossa lesions (p < 0.01) with equivalent likelihood of increasing head circumference (p = 0.74), whereas seizures were more frequent with supratentorial tumors (p = 0.04). Gross total resection was achieved in 47% of patients, cerebrospinal fluid diversion was more frequently necessary among infratentorial lesions (p = 0.02), and adjuvant therapy was more utilized for infratentorial lesions (p < 0.01). Among eight surviving infants, seven had supratentorial tumors, five survived to adulthood, and six are functionally independent. CONCLUSIONS: Brain tumors in the first year of life represent 4.8% of patients treated at CHEO. Mode of presentation, utilization of adjuvant therapy, and survival depend on tumor location and histology, with worse prognosis for infratentorial lesions. One third of patients had acceptable functional outcome requiring no special assistance.

Epilepsy surgery in the first 3 years of life: a Canadian survey.

OBJECTIVE: To determine the clinical characteristics, surgical challenges, and outcome in children younger than 3 years of age undergoing epilepsy surgery in Canada. METHODS: Retrospective data on patients younger than age 3 years who underwent epilepsy surgery at multiple centers across Canada from January 1987 to September 2005 were collected and analyzed. RESULTS: There were 116 patients from eight centers. Seizure onset was in the first year of life in 82%, and mean age at first surgery was 15.8 months (1-35 months). Second surgeries were done in 27 patients, and a third surgery in 6. Etiologies were malformations of cortical development (57), tumor (22), Sturge-Weber syndrome (19), infarct (8), and other (10). Surgeries comprised 40 hemispheric operations, 33 cortical resections, 35 lesionectomies, 7 temporal lobectomies, and one callosotomy. There was one surgical mortality. The most common surgical complications (151 operations in 116 patients) were infection (17) and aseptic meningitis in 13. Of 107 patients with seizure outcome assessed more than one year postoperatively, 72 (67.3%) were seizure free (Engel I), 15(14%) had >90% improvement (Engel II), 12 had >50% improvement (Engel III), and 8 did not benefit from surgery (Engel IV). Development improved in 55.3% after surgery. CONCLUSION: Epilepsy surgery in children younger than 3 years of age is relatively safe and is effective in controlling seizures. Very young age is not a contraindication to surgery in children with refractory epilepsy, and early surgery may impact development positively.

Spinal intradural arteriovenous fistula with unusual presentation: case report and literature review.

OBJECT: The authors present their experience with a Cervical Spinal intradural arteriovenous fistula (AVF) with unusual clinical presentation in a pediatric patient and review of the international literature on this condition. METHODS: A 5-year-old girl was found by her parents in bed screaming and talking inappropriately. Later on, she calmed down and complained of occipital, back and neck pain. She was admitted to the CHEO-ICU for work up and observation. The admission head CT scan showed evidence of SAH. Brain MRI showed blood in the third and fourth ventricles. MRA showed a C2 vascular lesion consistent with spinal cord AVF. Conventional angiogram was done which confirmed the AVF fed by a posterior medullary artery originating from the left vertebral artery. An attempt to embolize the AVF with glue was made but proved to be unsuccessful. On December 4, 2002, direct surgery on the AVF was performed, through a midline posterior approach (C2-C3 laminectomies) and microsurgical technique a complete excision of the intradural extramedullary AVF was achieved. The postoperative course was uneventful and the patient remained neurologically intact. Post-operative angiography confirmed complete excision of the AVF. CONCLUSION: The rarity of a pediatric spinal AVF presenting with spontaneous Intracranial SAH, makes this case very peculiar. This is the first reported pediatric case of cervical cord AVF with this clinical presentation found in the literature.

Inadvertent intracranial insertion of a soft rubber tube in a patient with Treacher-Collins syndrome: case report and review of literature.

CASE REPORT: An inadvertent insertion of a soft rubber tube into the intracranial compartment in a patient with Treacher-Collins syndrome is reported. The neonate was delivered vaginally at 34 weeks gestation, had bilateral choanal atresia and presented with apnea at birth. An emergency orotracheal intubation was performed, and ventilatory support was instituted. Computed tomography scan of the facial bones showed a bilateral bony choanal atresia, with a thick posterior nasal septum, and complete absence of maxillary sinuses, external auditory canal, middle ear and ossicles, and roof of ethmoid bone. There was a central cleft in the frontoethmoidal area. The inner ear and the semicircular canals were present. The patient underwent successful transpalatal repair with nasal stenting. During surgery, two unsuccessful attempts to negotiate a soft rubber tube through the occluded choana were made. Postoperative magnetic resonance imaging revealed a linear hemorrhagic tract created by the soft rubber tube coursing through the anteroinferior basal frontal lobe, thalamus, basal ganglia and terminating in the occipital lobe. The patient developed bacterial meningitis, communicating hydrocephalus followed by cerebrospinal fluid rhinorrhea. A transcranial repair of the anterior cranial fossa was performed followed by ventriculoperitoneal shunt insertion. Subsequently, he underwent shunt revision for suspected shunt malfunction and developed peritoneal abscess for which the shunt was exteriorized and later removed. An endoscopic third ventriculostomy was performed, and the patient is recovering well. DISCUSSION: The potential implications of an inadvertent foreign body penetration into the intracranial compartment in such a rare event are discussed and the relevant literature is briefly reviewed.

Cortical spreading depression releases ATP into the extracellular space and purinergic receptor activation contributes to the induction of ischemic tolerance.

Cortical Spreading Depression (CSD) is a well-studied model of preconditioning that provides a high degree of tolerance to a subsequent ischemic event in the brain. The present study was undertaken in order to determine whether the release of ATP during CSD could contribute to the induction of ischemic tolerance. Direct measurement of ATP levels during CSD indicates that with each CSD wave ATP is released into the extracellular space at levels exceeding 100 microM. Cultures of rat primary cortical neurons exposed to low levels of extracellular ATP developed tolerance to subsequent oxygen-glucose deprivation (OGD) or metabolic hypoxia. The preconditioning effect requires new protein synthesis and develops with time, suggesting that a complex genomic response is required for the induction of tolerance. Multiple purinergic receptors are involved in mediating tolerance, with P2Y receptor activation having the greatest effect. Although extracellular adenosine or glutamate may make a small contribution, most of the tolerance was found to be induced independently of adenosine or glutamate receptor activation. Multiple signal transduction pathways mediate the response to extracellular ATP with the protein kinase A pathway and activation of phospholipase C contributing the most. The results are consistent with the proposal that CSD releases ATP into the extracellular space and the subsequent activation of P2Y receptors makes a major contribution to the induction of ischemic tolerance in the brain.

Transient ventriculoperitoneal shunt malfunction after chronic constipation: case report and review of literature.

BACKGROUND: Significant constipation in patients with shunt-dependent hydrocephalus may often be enough to bring a subclinical shunt malfunction to clinical attention or even to be the cause of temporary distal peritoneal shunt malfunction. The treatment of the constipation may address the symptomatic shunt dysfunction so as to avoid operative intervention. The pathogenesis of distal shunt malfunction and its management in such a situation are discussed, and the relevant literature is briefly reviewed. CASE REPORT: A 16-year-old young boy had shunt-dependent hydrocephalus secondary to prematurity and intraventricular hemorrhage at birth. He was chronic flaccid paraplegic and had a neurogenic bladder and bowel involvement. He presented with acute dull aching intermittent headaches, nausea, and constipation of short duration. There was no underlying shunt infection. CT brain showed dilated lateral ventricles. Shunt survey revealed a convoluted course and kink in the distal peritoneal catheter. After administration of a bowel enema, the headaches and nausea resolved over the next few hours, and the posttreatment CT showed significant decrease in ventricular size. CONCLUSION: Chronic constipation is an important predisposing factor for distal malfunction in shunt-dependent hydrocephalus and should be ascertained in evaluation of a ventriculoperitoneal shunt malfunction. Appropriate treatment of significant constipation can relieve shunt malfunction and reestablish cerebrospinal fluid circulation. A shunt exploration can be avoided in such a situation. A close neurological monitoring of the patient is essential during the course of treatment. An interdisciplinary approach between concerned medical specialties and enhanced awareness is mandatory to ensure appropriate bowel management.

Vascular complications of cranial radiation.

OBJECTIVES: Cerebral vascular disease has been reported as a long-term complication of cranial radiotherapy. The purpose of this study was to examine the frequency and risk factors associated with development of cerebral vascular disease in children after cranial radiation. MATERIALS AND METHODS: A retrospective chart review of all cancer patients treated between 1985 and 2003 who were under the age of 18 years at the time of initial radiotherapy was performed. Variables examined include diagnosis and site of malignancy, age at the time of radiotherapy, sex, total radiation dosage, number of fractions, duration, and whether the patient had proven cerebral vascular event. RESULTS: Two hundred and forty-four patients met the study criteria. One hundred and 13 cases involved tumors of the central nervous system. The remaining patients had systemic neoplastic disease. Post radiation cerebral vascular disease occurred in 11 (5%) patients, and all but one patient had a tumor involving the central nervous system (mainly in the posterior fossa and supratentorial midline). CONCLUSION: There is an increased risk of cerebral vascular disease after radiation therapy in childhood, especially in children who received high dose radiation at the posterior fossa and supratentorial axial region.