AJNR. American journal of neuroradiology
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AJNR Am J Neuroradiol · Nov 2012
Controlled Clinical TrialCT-guided lumbar nerve root injections: are we using the correct radiation dose settings?
Selecting a lower tube current for CT fluoroscopic spine injections is a method of radiation dose reduction. Ideally tube current should be tailored to the patient's body habitus, but a greater influence on tube current may be the proceduralist's personal preference. The purpose of this study was to compare tube current and fluoroscopy time of different proceduralists for lumbar spine CT-guided selective nerve root blocks, and to correlate image quality to patient diameter and tube current. ⋯ Wide variability in tube current selection between proceduralists calls for a more objective method of selecting tube current to minimize radiation dose. Body size, measured by AP diameter, had the greatest influence on image quality. This could be used to identify patients for lower tube current selection.
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AJNR Am J Neuroradiol · Nov 2012
Comparative StudyStrengthening the argument for rapid brain MR imaging: estimation of reduction in lifetime attributable risk of developing fatal cancer in children with shunted hydrocephalus by instituting a rapid brain MR imaging protocol in lieu of Head CT.
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. ⋯ Children with shunted hydrocephalus are at increased risk of developing fatal cancer if they are to undergo surveillance using head CT. Implementation of a rapid brain MR imaging protocol with no radiation detriment will reduce this risk.
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AJNR Am J Neuroradiol · Nov 2012
Incidence of cerebellar tonsillar ectopia in idiopathic intracranial hypertension: a mimic of the Chiari I malformation.
IIH is a syndrome of elevated intracranial pressure without hydrocephalus, mass, or identifiable cause. Diagnosis is made by clinical presentation, intracranial pressure measurement, and supportive imaging findings. A subset of patients with IIH may have tonsillar ectopia, meeting the criteria for Chiari malformation type I but not responding to surgical decompression for Chiari I. The purpose of this study was to determine the incidence and morphology of cerebellar tonsillar ectopia in patients with IIH. ⋯ Cerebellar tonsil position in patients with IIH was significantly lower than that in age-matched controls, often times peglike, mimicking Chiari I. A significantly lower obex position suggests an inferiorly displaced brain stem and cerebellum. When tonsillar ectopia of >5 mm is identified, imaging and clinical consideration of IIH are warranted to avoid misdiagnosis as Chiari I.