AJNR. American journal of neuroradiology
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AJNR Am J Neuroradiol · Dec 2012
Age-related changes of cerebral autoregulation: new insights with quantitative T2'-mapping and pulsed arterial spin-labeling MR imaging.
Cerebral perfusion and O(2) metabolism are affected by physiologic age-related changes. High-resolution motion-corrected quantitative T2'-imaging and PASL were used to evaluate differences in deoxygenated hemoglobin and CBF of the gray matter between young and elderly healthy subjects. Further combined T2'-imaging and PASL were investigated breathing room air and 100% O(2) to evaluate age-related changes in cerebral autoregulation. ⋯ T2'-mapping and PASL in the cerebral cortex of healthy subjects revealed a significant decrease of deoxygenated hemoglobin and of CBF with age. The constant deoxyHb level breathing 100% O(2) compared with normoxia in young and elderly GM suggests an age-appropriate cerebral autoregulation. At the younger age, hyperoxic-induced CBF decrease may protect the brain from hyperoxemia.
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AJNR Am J Neuroradiol · Dec 2012
Decreased fractional anisotropy evaluated using tract-based spatial statistics and correlated with cognitive dysfunction in patients with mild traumatic brain injury in the chronic stage.
The relationship between white matter disruption and cognitive dysfunction of patients with mTBI in the chronic stage remains unclear. The aim of this study was to identify white matter integrity by using DTI in patients with mTBI without morphologic traumatic abnormalities seen with conventional imaging and to evaluate the association of such regions with cognitive function. ⋯ The present study shows that patients with mTBI in the chronic stage have certain regions with abnormally reduced white matter integrity in the brain. Although the clinical and pathologic-anatomic correlation of these findings remains to be elucidated, these brain regions are strongly suggested to be related to chronic persistent cognitive impairments in these patients.
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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.