Atypical teratoid-rhabdoid tumor presents at a younger age than medulloblastoma. Although atypical teratoid-rhabdoid tumor and medulloblastoma display similar imaging characteristics on conventional MRI, CPA involvement and intratumoral hemorrhage are more common in atypical teratoid-rhabdoid tumor. If a pediatric posterior fossa mass that displays restricted diffusion is involving the CPA, atypical teratoid-rhabdoid tumor is a more likely consideration than medulloblastoma.

We hypothesized that the silent cerebral infarcts (SCI), which affect up to 40% of children with sickle cell disease (SCD), could occur in the setting of acute anemic events. In a prospective observational study of children with and without SCD hospitalized for an illness associated with acute anemia, we identified acute silent cerebral ischemic events (ASCIE) in 4 (18.2%) of 22 with SCD and in 2 (6.7%) of 30 without SCD, using diffusion-weighted magnetic resonance imaging. Children with ASCIE had lower hemoglobin concentration than those without (median 3.1 vs 4.4 g/dL, P ‫؍‬ .003). The unique temporal features of stroke on diffusionweighted magnetic resonance imaging permit estimation of incidence rates for ASCIE of 421 (95% confidence interval, 155-920) per 100 patient-years during acute anemic events for all patients. For children with SCD, the estimated incidence was 663 (95% confidence interval, 182-1707) which is much higher than previously reported. Acute anemic events are common in children with SCD and prevalence could partially account for the high SCI. Some ASCIE (1 of 4 in our study) may be reversible. Alterations in management may be warranted for children with severe anemia to identify unrecognized ischemic brain injury that may have permanent neurocognitive sequelae. (Blood. 2012;120(19):3891-3897)

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BACKGROUND AND PURPOSE:Children with shunted hydrocephalus have been undergoing surveillance neuroimaging, generally in the form of head CT, for evaluation of ventricular size. As the life expectancy of these children has improved due to better shunt technology and medical care, risks related to the ionizing radiation incurred during multiple head CT examinations that they are expected to undergo throughout their lifetime have become a concern. The purpose of this study is to estimate the LAR of developing fatal cancer due to head CT for ventricular size assessment in children with shunted hydrocephalus and to assess the impact of instituting a rapid brain MR imaging protocol in reducing radiation exposure.

Negative correlation was found between cellularity and ADC metrics of common pediatric cerebellar tumors. Although ADC metrics are useful in the preoperative diagnosis of common pediatric cerebellar tumors and this utility is generally attributed to differences in cellularity of tumors, tumor cellularity may not be the sole determinant of the differences in diffusivity.

Although pilomatricoma is a common tumor of the skin and subcutaneous tissues, imaging is infrequently used in the diagnosis, and therefore, many radiologists are not aware of the lesion. The imaging features of pilomatricoma are consistent in all imaging modalities.

Background/Aims: Different tectal masses have been described; most are low-grade gliomas. Only 20-30% of all lesions grow, as shown on follow-up MRIs, requiring surgical resection at some point. The aim of this study is to describe the experience of a single institution managing pediatric patients with tectal lesions. Methods: We retrospectively studied and analyzed 40 children with tectal lesions managed from 1990 to 2006; the mean age at diagnosis was 9.4 years. A volumetric classification was used to analyze tumor growth trends. More than 1 year of imaging follow-up was available for 23 patients. Results and Conclusion: Medium- and large-volume-size lesions were associated with the need for surgery. About half of the nonsurgical lesions grew at least 50% over a period of 4.5 years and did not require surgical resection.

There is a high incidence of cervical spine injury in pediatric nonaccidental trauma. Positive findings may affect management and suggest a traumatic etiology.