Journal of neuroimaging : official journal of the American Society of Neuroimaging
-
Because clinical evaluation of noncontrast computed tomography (CT) has a poor sensitivity in the evaluation of acute ischemic stroke, computer-aided diagnosis may be able to facilitate the performance. Recently, we introduced a computational method for the detection and localization of visible infarcts. Herein, we aimed to evaluate and extend a previous method, the Stroke Imaging Marker (SIM), to localize nonvisible hyperacute ischemia. ⋯ The improved SIM is a dedicated and potentially useful tool for hyperacute nonvisible brain infarct detection from CT scans and may contribute to reduction of image-to-needle time in patients eligible for revascularization therapy.
-
Differentiation between true acute tandem occlusion involving the extracranial internal carotid artery (ICA) from pseudotandem occlusion with a patent extracranial ICA has important prognostic and therapeutic implications. We explored the utility of perfusion-derived 4-dimensional CT angiogram (4D-CTA) in identifying carotid pseudo-occlusion in a single-center pilot study. ⋯ 4D-CTA is a novel noninvasive technique that can identify carotid pseudo-occlusion in the acute stroke setting. Our preliminary findings suggest that 4D-CTA can be easily incorporated into an existing acute stroke neuroimaging protocol.
-
Multimodality magnetic resonance imaging (MRI) can provide complementary information in the assessment of brain tumors. We aimed to segment tumor in amide proton transfer-weighted (APTw) images and to investigate multiparametric MRI biomarkers for the assessment of glioma response to radiotherapy. For tumor extraction, we evaluated a semiautomated segmentation method based on region of interest (ROI) results by comparing it with the manual segmentation method. ⋯ The semiautomated method of tumor extraction showed greater efficiency and stability than the manual method. Apparent diffusion coefficient, blood flow, and APTw are all useful biomarkers in assessing glioma response to radiotherapy.
-
Review Case Reports
Subclavian Steal Syndrome with or without Arterial Stenosis: A Review.
The subclavian-vertebral artery steal syndrome (SSS) is the hemodynamic phenomenon of blood flow reversal in the vertebral artery due to significant stenosis or occlusion of the proximal subclavian artery or the innominate artery. Occasionally, SSS is diagnosed in patients not harboring arterial stenosis. With the exception of arterial congenital malformations, the limited case reports of SSS with intact subclavian artery are attributed to dialysis arteriovenous fistulas (AVFs). ⋯ In addition, we present a patient with bilateral symptomatic SSS as the result of an arteriovenous graft (AVG) that was introduced after the preexisting AVF in the contralateral arm became nonfunctional. SSS due to subclavian or innominate artery stenosis/occlusion is rarely symptomatic warranting interventional treatment. In contrast, when it is attributed to AVF, surgical correction is frequently necessary.
-
Review Meta Analysis
White Matter Diffusion Abnormalities in Carotid Artery Disease: A Systematic Review and Meta-Analysis.
Abnormalities in apparent diffusion coefficient (ADC), fractional anisotropy (FA), and mean diffusivity (MD) values can be used to assess microstructural damage to white matter tracts and could represent a quantitative marker of chronic ischemia and thereby potentially serve as a stroke risk factor or a measure of existing subclinical ischemic disease burden. We performed a systematic review and 3 separate meta-analyses to evaluate the association between unilateral carotid steno-occlusion and ipsilateral ADC, FA, or MD abnormality. ⋯ Carotid artery disease is associated with significant ADC and FA value changes, suggesting that carotid disease is associated with quantifiable white matter microstructural damage.