Derek Armstrong

Craniofacial Skeletal Measurements Based on Computed Tomography: Part II. Normal Values and Growth Trends

Current diagnosis and surgical correction of craniofacial anomalies would benefit from accurate quantitative and standardized points of reference. A retrospective study was undertaken to define normal values for a series of craniofacial measurements and to evaluate the growth patterns of the craniofacial complex through axial computed tomography (CT). Fifteen measurements were taken from 542 CT scan series of skeletally normal subjects. The measurement values were then divided into 1-year age categories from 1 to 17 years, and into four age groups for those under 1 year of age. The normal range and growth pattern of measurement values for the cranial vault, orbital region, and upper midface are presented. The overall size of the cranio-orbito-zygomatic skeleton reaches more than 85 percent of adult size by age 5 years. The cranial vault grows rapidly in the first year of life but growth levels off early. The upper midface grows at a slower rate in infancy, but continues to grow later in childhood and early adolescence. Knowledge of the differential growth patterns and normal measurement values in the craniofacial region will help improve diagnostic accuracy, staging of reconstruction, precision of corrective surgery, and follow-up of patients.

Presumed pre- or perinatal arterial ischemic stroke : Risk factors and outcomes

A subgroup of children with arterial ischemic stroke in the pre‐ or perinatal period present with delayed diagnosis. We identified 22 children who met the following criteria: (1) normal neonatal neurological history, (2) hemiparesis and/or seizures first recognized after 2 months of age, and (3) computed tomography or magnetic resonance imaging showing remote cerebral infarct. Laboratory evaluations included protein C, protein S, antithrombin, activated protein C resistance screen (APCR), Factor V Leiden (FVL), prothrombin gene defect, methylene tetrahydrofolate reductase variant (MTHFR), anticardiolipin antibody (ACLA), and lupus anticoagulant. Not all children received all tests. Age at last visit ranged from 8 months to 16.5 years (median 4 years). Twelve were boys. Fourteen had left hemisphere infarcts. Median age at presentation was 6 months. Eighteen had gestational complications. Fourteen children had at least transient coagulation abnormalities (ACLA = 11, ACLA + APCR = 1, APCR = 2 with FVL + MTHFR = 1); 6 of these children had family histories suggestive of thrombosis. Cardiac echocardiogram was unremarkable in the 15 tested. Outcomes included persistent hemiparesis in 22; speech, behavior, or learning problems in 12; and persistent seizures in 5, with no evidence of further stroke in any patient. The persistence and importance of coagulation abnormalities in this group need further study.

Correlation between retinal abnormalities and intracranial abnormalities in the shaken baby syndrome.

PURPOSE To report correlation between retinal and intracranial abnormalities and to evaluate pathogenesis of retinal hemorrhages in the shaken baby syndrome (SBS). DESIGN Observational case series. METHODS Seventy-five children with apparent nonaccidental head trauma consistent with SBS had complete physical examination, complete ophthalmologic examination, neuroimaging by CT or MRI, or both, and skeletal radiographic survey. In this retrospective review, ophthalmoscopic and intracranial abnormalities were correlated. RESULTS The age of patients ranged from 2 to 48 months (mean - SD, 10.6 +/- 10.4 months). Neuroimaging was abnormal in all 75 cases. Findings included subdural hematoma (70 children, 93%), cerebral edema (33 children, 44%), subarachnoid hemorrhage (12 children, 16%), vascular infarction (nine children, 12%), intraparenchymal blood (six children, 8%), parenchymal contusion (six children, 8%), and epidural hemorrhage (one child, 1%). Sixty-four (64/75, 85%) children had retinal abnormalities, mostly (53/64, 82%) confluent multiple hemorrhages that were subretinal, intraretinal, and preretinal in 47/64 (74%) and bilateral in 52/64 (81%). No association was found between anatomic site (left, right, or bilateral) of intracranial and retinal findings (McNemar test kappa = -0.026-0.106) or between any of the intracranial findings mentioned above and the following retinal findings: normal or abnormal retinal examination, multiple (>10) or few retinal hemorrhages (< or =10), symmetric or asymmetric retinal findings, or retinoschisis (kappa = -0.127-0.104). Signs of possible increased intracranial pressure were not correlated with any retinal abnormality (kappa = -0.03-0.073). There was no correlation between evidence of impact trauma to the head and retinal hemorrhages (kappa = 0.058). Total Cranial Trauma Score and Total Retinal Hemorrhage Score, both indicating the severity of injury, were correlated (P =.032). CONCLUSIONS Our study supports previous observations that the severity of retinal and intracranial injury is correlated in SBS. We cannot support the suggestions that in most children with SBS retinal bleeding is caused by sustained elevated intracranial, elevated intrathoracic pressure, direct tracking of blood from the intracranial space, or direct impact trauma. The correlation in severity of both eye and head findings may suggest, however, that retinal abnormalities are the result of mechanical shaking forces.

Dangerous Extracranial–Intracranial Anastomoses and Supply to the Cranial Nerves: Vessels the Neurointerventionalist Needs to Know

SUMMARY: Transarterial embolization in the external carotid artery (ECA) territory has a major role in the endovascular management of epistaxis, skull base tumors, and dural arteriovenous fistulas. Knowledge of the potential anastomotic routes, identification of the cranial nerve supply from the ECA, and the proper choice of embolic material are crucial to help the interventionalist avoid neurologic complications during the procedure. Three regions along the skull base constitute potential anastomotic routes between the extracranial and intracranial arteries: the orbital, the petrocavernous, and the upper cervical regions. Branches of the internal maxillary artery have anastomoses with the ophthalmic artery and petrocavernous internal carotid artery (ICA), whereas the branches of the ascending pharyngeal artery are connected to the petrocavernous ICA. Branches of both the ascending pharyngeal artery and the occipital artery have anastomoses with the vertebral artery. To avoid cranial nerve palsy, one must have knowledge of the supply to the lower cranial nerves: The petrous branch of the middle meningeal artery and the stylomastoid branch of the posterior auricular artery form the facial arcade as the major supply to the facial nerve, and the neuromeningeal trunk of the ascending pharyngeal artery supplies the lower cranial nerves (CN IX–XII).

Posterior fossa medulloblastoma in childhood: Treatment results and a proposal for a new staging system

Seventy-two children with posterior fossa medulloblastoma were diagnosed at the Hospital for Sick Children, Toronto, from 1977 to 1987 and treated by standard methods. The 5- and 10-year survival and disease-free survival rates were 71% and 63%, and 64% and 63%, respectively. Total tumor resection, as determined by the surgeon was the most significant favorable prognostic factor. Post-operative meningitis, a residual enhancing mass lesion on the post-operative, pre irradiation CT scan and dissemination to the brain or cord at diagnosis were unfavorable factors. These four easily definable factors were used to define a staging system with prognostic significance. Five-year disease-free survival rates were for Stage I (total resection, no adverse factor) 100%, Stage II (total resection with one or more adverse factor or less than total resection with no other adverse factor) 78%, and Stage III (less than total resection with one or more adverse factor) 18%. Evaluation of treatment results in medulloblastoma requires that these prognostic factors be known.

Intraorbital Wood: Detection by Magnetic Resonance Imaging

The authors present two cases in which intraorbital wooden foreign bodies remained undetected after initial ophthalmologic examination and radiologic investigation which included plain orbital x-rays, orbital computed tomography (CT) scans, and, in one case, orbital ultrasound. In each case, subsequent magnetic resonance imaging (MRI) showed a well-delineated low-intensity lesion suggestive of a retained foreign body. Investigation of a case of suspected wooden foreign body in the orbit should include an MRI scan if there is no contraindication, and no foreign body has been defined on CT scan, ultrasound, or plain orbital films.

Craniocervical Arterial Dissection in Children: Clinical and Radiographic Presentation and Outcome

Craniocervical arterial dissection is a recognized cause of arterial ischemic stroke in children. Whether children with craniocervical arterial dissection have dissection characteristics different from those of adults is unclear. A retrospective review of children, 1 month to 18 years of age, with dissection from two Canadian pediatric ischemic stroke registry centers was conducted. From 213 patients with arterial ischemic stroke, 16 (7.5%) were identified with dissection, 37.5% had warning symptoms, and 50% had a history of head or neck trauma. The clinical presentation included headache (44%), altered consciousness (25%), seizures (12.5%), and focal deficits (87.5%). Dissection involved extracranial vessels in 75% and anterior circulation in 56%. Follow-up included complete recovery in 43%, mild to moderate deficits in 44%, and severe deficits in 13%. Fourteen (87.5%) children received antithrombotic treatment. Follow-up angiography showed resolution of abnormalities in 60% of vessels. Total occlusion had the worst outcome for recanalization. In conclusion, the etiology of arterial dissection in the majority of children appears to be either trauma or idiopathic. Long-term angiography shows variable outcomes, depending on the initial findings. The relationship of angiographic outcomes with recurrent strokes requires further study in pediatric dissection. ( J Child Neurol 2006;21:8—16).

Post-varicella arteriopathy of childhood Natural history of vascular stenosis

Objective: To determine the course of vascular changes in childhood post-varicella arteriopathy (PVA) and its relationship to recurrent arterial ischemic stroke or TIA (AIS/TIA). Methods: Subjects were children with AIS/TIA occurring <1 year after varicella, ischemic localization consistent with unilateral disease affecting the supraclinoid internal carotid artery or proximal anterior or middle cerebral arteries, and no identified AIS/TIA etiology other than PVA. Charts, brain MRI, and sequential cerebral vessel imaging (selective cerebral angiography or MR angiography [SCA/MRA]) were retrospectively reviewed. Results: Twenty-three children had varicella at age 1.0 to 10.4 years and had single or multiple AIS/TIAs 4 to 47 weeks later. Initial SCA/MRA was performed within 1 month of presentation, and each child had one to five repeat SCA/MRAs during a 4- to 87-month period. There was vascular stenosis in 19 children, maximal on initial studies in 15 of these. Subsequent stenosis regression occurred in 17 children. In 11 of these, one or two additional SCA/MRAs showed further regression as long as 48 months after presentation; there was no restenosis. Eight of 23 children had recurrent AIS/TIA with antithrombotic therapy within 33 weeks of presentation, including 1 of 17 children with documented stenosis regression. Conclusion: Vascular stenosis of childhood post-varicella arteriopathy takes a monophasic course, generally with subsequent stenosis regression and only occasional stenosis progression after arterial ischemic stroke/TIA. Arterial ischemic stroke/TIA rarely recurs with antithrombotic prophylaxis after stenosis regression occurs.

Sagittal synostosis : quantitative assessment of presenting deformity and surgical results based on CT scans

We reviewed our experience with nine consecutive patients with untreated isolated nonsyndromic sagittal synostosis. Using a method of 14 clinically relevant measurements taken from preoperative and postoperative CT scan images of these patients, we documented their presenting skeletal dysmorphology and the results of surgical correction at least 1 year after operation. Significant preoperative findings included an elongated cranial vault length that averaged 103 percent of normal and a narrowed cranial vault width both anteriorly at 92 percent and posteriorly at 86 percent of normal. Results of surgical correction, as documented by CT scan measurements, included normalization of the cranial length to 100 percent and of the anterior width to 101 percent of normal and improvement (but undercorrection) of the posterior width to 94 percent of normal. Quantitative measurement of CT scan images confirmed clinically observed findings in these patients before suture release and reconstruction and proved useful in assessing the surgical results achieved.

Measurement of Ventricular Size: Reliability of the Frontal and Occipital Horn Ratio Compared to Subjective Assessment

Introduction: The frontal and occipital horn ration (FOR) has recently been described as a simple, linear measurement of ventricular size that correlates very well with ventricular volume. This study further characterizes the measurement properties of the FOR by investigating its interobserver reliability and comparing it to a subjective assessment of ventricular size. Methods: Axial images (CT and MR) of children with hydrocephalus taken before and after third ventriculostomy were reviewed by 4 independent observers. Two observers were blinded to patient identity and clinical status and 2 observers were nonblinded. Each observer independently recorded linear measurements from which the FOR was calculated for each image. Each reviewer also made a separate subjective assessment of the degree of hydrocephalus on a 9-point adjectival scale. Reliability was calculated using a repeated-measures analysis of variance (ANOVA) and an intraclass correlation coefficient (ICC) with random image and observer effects. Results: There were 120 separate observations (4 observers, 30 images). The FOR ranged from 0.33 to 0.75 (mean 0.55, standard deviation 0.11). The reliability coefficient was 0.93 (95% confidence interval, CI 0.80–0.97) between the 2 blinded observers and 0.98 (95% CI, 0.95–0.99) between the 2 nonblinded observer. The overall interobserver reliability for all 4 observers was 0.95 (95% CI 0.92–0.98). The mean FOR for each observer was very similar, regardless of the observer’s blinding status. However, the reliability of the observers’ subjective assessment of the hydrocephalus was much lower (ICC = 0.77, 95% CI 0.60–0.88). Conclusions: The FOR demonstrates excellent interobserver reliability (>0.9) and was superior to subjective assessments of hydrocephalus. In this study, excellent reliability was maintained regardless of the blinding status of the observers. This further demonstrates the properties of the FOR as a simple and reproducible measure of ventricular size. It is suitable for use in clinical studies, possibly even in situations in which observer blinding is not possible.