Clinical applications of neuroimaging with susceptibility-weighted imaging.
ABSTRACT Susceptibility-weighted imaging (SWI) consists of using both magnitude and phase images from a high-resolution, three-dimensional, fully velocity compensated gradient-echo sequence. Postprocessing is applied to the magnitude image by means of a phase mask to increase the conspicuity of the veins and other sources of susceptibility effects. This article gives a background of the SWI technique and describes its role in clinical neuroimaging. SWI is currently being tested in a number of centers worldwide as an emerging technique to improve the diagnosis of neurological trauma, brain neoplasms, and neurovascular diseases because of its ability to reveal vascular abnormalities and microbleeds.
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ABSTRACT: This paper considers the problem of automatic classification of textured tissues in 3D MRI. More specifically, it aims at validating the use of features extracted from the phase of the MR signal to improve texture discrimination in bone segmentation. This extra information provides better segmentation, compared to using magnitude only features. We also present a novel multiscale scheme to improve the speed of pixel based classification algorithm, such as support vector machines. This algorithm dramatically increases the speed of the segmentation process by an order of magnitude through a reduction of the number of pixels that needs to be classified in the image.Medical image computing and computer-assisted intervention : MICCAI ... International Conference on Medical Image Computing and Computer-Assisted Intervention. 02/2006; 9(Pt 2):920-7.
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ABSTRACT: In modern medicine brain imaging is an essential prerequisite not only to acute stroke triage but also to determining the specific therapy indicated. This article reviews the need for imaging the brain in acute stroke, penumbral pathophysiology, penumbral imaging techniques, as well as current status of various imaging modalities that are being employed to select patients for specific therapeutic approaches.Journal of the neurological sciences 10/2009; 288(1-2):13-24. · 2.32 Impact Factor
Article: Chronic cerebrospinal venous insufficiency and iron deposition on susceptibility-weighted imaging in patients with multiple sclerosis: a pilot case-control study.[show abstract] [hide abstract]
ABSTRACT: Chronic cerebrospinal venous insufficiency (CCSVI) is a vascular phenomenon recently described in multiple sclerosis (MS) that is characterized by stenoses affecting the main extracranial venous outflow pathways and by a high rate of cerebral venous reflux that may lead to increased iron deposition in the brain. Aim of this study was to investigate the relationship between CCSVI and iron deposition in the brain of MS patients by correlating venous hemodynamic (VH) parameters and iron concentration in deep-gray matter structures and lesions, as measured by susceptibility-weighted imaging (SWI), and to preliminarily define the relationship between iron measures and clinical and other magnetic resonance imaging (MRI) outcomes. Sixteen (16) consecutive relapsing-remitting MS patients and 8 age- and sex-matched healthy controls (HC) were scanned on a GE 3T scanner, using SWI. All 16 MS patients fulfilled the diagnosis of CCSVI (median VH=4), compared to none of the HC. In MS patients, the higher iron concentration in the pulvinar nucleus of the thalamus, thalamus, globus pallidus, and hippocampus was related to a higher number of VH criteria (P<0.05). There was also a significant association between a higher number of VH criteria and higher iron concentration of overlapping T2 (r=-0.64, P=0.007) and T1 (r=-0.56, P=0.023) phase lesions. Iron concentration measures were related to longer disease duration and increased disability as measured by EDSS and MSFC, and to increased MRI lesion burden and decreased brain volume. The findings from this pilot study suggest that CCSVI may be an important mechanism related to iron deposition in the brain parenchyma of MS patients. In turn, iron deposition, as measured by SWI, is a modest-to-strong predictor of disability progression, lesion volume accumulation and atrophy development in patients with MS.International angiology: a journal of the International Union of Angiology 04/2010; 29(2):158-75. · 1.65 Impact Factor