Journal of neuroimaging : official journal of the American Society of Neuroimaging
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An organized hematoma shows a heterogeneous signal intensity on T1-and T2-weighted images on MR imaging, reflecting variable stages of hemorrhage. Although rather nonspecific, precontrast CT images of an organized hematoma demonstrate inhomogeneous hyperdense mass with or without calcification. ⋯ Computed tomography and magnetic resonance imaging findings of the organized hematoma are shown and discussed. We believe that recognition of the characteristic imaging findings of the organized hematoma as well as consideration of the history of surgery or anticoagulation treatment assists in its correct diagnosis enabling an inappropriate surgery to be avoided.
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Randomized Controlled Trial Multicenter Study
Derivation and evaluation of thresholds for core and tissue at risk of infarction using CT perfusion.
Computed tomography perfusion provides information on tissue viability according to proposed thresholds. We evaluated thresholds for ischemic core and tissue at risk and subsequently tested their accuracy in independent datasets. ⋯ Time-based perfusion thresholds perform well as predictors of tissue at risk of infarction with DT the best predictor. Relative CBF was the best predictor of ischemic core. Evaluation in larger populations is needed to confirm the performance of tissue viability thresholds.
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Comparative Study
Cerebral blood flow reduction associated with orientation for time in amnesic mild cognitive impairment and Alzheimer disease patients.
Impairment of orientation for time (OT) is a characteristic symptom of Alzheimer disease (AD). However, the brain regions underlying OT remain to be elucidated. Using single photon emission computed tomography (SPECT), we examined the brain regions exhibiting hypoperfusion that were associated with OT. ⋯ Our SPECT study suggested that hypoperfusion in the left SPL and bilateral IPL was AD specific, and reduced rCBF in the left PCC was specifically associated with OT.
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Studies of brain tumors have identified altered tissue metabolism and water diffusion in MRI normal appearing tissue regions. In this retrospective study the relationship of these imaging measures with tumor grade in gliomas was investigated. ⋯ This study supports previous observations of altered tissue metabolism and water diffusion in normal-appearing white matter while additionally finding differences of metabolite values in gray matter and an association with tumor grade.
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The events leading up to the development of new multiple sclerosis (MS) lesions on conventional imaging are unknown. The purpose of this study is to use diffusion tensor imaging (DTI) to investigate prelesional changes in MS to better understand the pathological changes that lead to lesion development. ⋯ A significant change in diffusion measures can be seen prior to gadolinium enhancement. Changes in TD drove changes in FA and MD, providing evidence for impaired myelin integrity prior to gadolinium enhancement. DTI may be a sensitive measure for early detection of inflammatory disease activity in MS.