Search results for " MRI"
showing 10 items of 290 documents
Metabolic and structural connectivity within the default mode network relates to working memory performance in young healthy adults.
2012
Abstract Studies of functional connectivity suggest that the default mode network (DMN) might be relevant for cognitive functions. Here, we examined metabolic and structural connectivity between major DMN nodes, the posterior cingulate (PCC) and medial prefrontal cortex (MPFC), in relation to normal working memory (WM). DMN was captured using independent component analysis of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) data from 35 young healthy adults (27.1 ± 5.1 years). Metabolic connectivity, a correlation between FDG uptake in PCC and MPFC, was examined in groups of subjects with (relative to median) low (n = 18) and high (n = 17) performance on digit span backward te…
Diffusion-tensor MR imaging at 1.5 and 3.0 T: initial observations.
2001
Diffusion-tensor MR imaging was compared at 1.5 and 3.0 T. With sufficient signal-to-noise ratio, we found no differences in fractional anisotropy. With a 40% higher signal-to-noise ratio at 3.0 T, higher resolution could be obtained without introduction of noise-related errors, albeit at the cost of increased geometric distortions caused by 3.0-T magnetic field inhomogeneities.
Is There an Indication for Intraoperative MRI in Subtotal Resection of Glioblastoma? A Multicenter Retrospective Comparative Analysis.
2017
Objective Surgery in patients with highly eloquent glioblastoma (GB) remains challenging. The aim of this study was to evaluate influence of use of intraoperative magnetic resonance imaging (iMRI) on extent of resection (EOR), clinical outcome, and survival in patients with preoperatively intended subtotal resection of GB. Methods Retrospective assessment was performed in 3 neurosurgical centers (2008–2013). All patients with primary GB, unilocular growth, and adjuvant radiochemotherapy in whom subtotal resection was intended were included. Imaging data were pseudonymized and volumetrically assessed by a central reviewer. Clinical outcome was evaluated based on complications, new permanent …
Solid bone tumors of the spine: Diagnostic performance of apparent diffusion coefficient measured using diffusion-weighted MRI using histology as a r…
2017
Purpose To assess the diagnostic performance of mean apparent diffusion coefficient (mADC) in differentiating benign from malignant bone spine tumors, using histology as a reference standard. Conventional magnetic resonance imaging (MRI) sequences have good reliability in evaluating spinal bone tumors, although some features of benign and malignant cancers may overlap, making the differential diagnosis challenging. Materials and Methods In all, 116 patients (62 males, 54 females; mean age 59.5 ± 14.1) with biopsy-proven spinal bone tumors were studied. Field strength/sequences: 1.5T MR system; T1-weighted turbo spin-echo (repetition time / echo time [TR/TE], 500/13 msec; number of excitatio…
Meniscal ramp lesions: diagnostic performance of MRI with arthroscopy as reference standard
2021
Abstract Background The posteromedial meniscal region is gaining interest among orthopedic surgeons, as lesions of this area has been reported to be significantly associated with anterior cruciate ligament tears. The current imaging literature is unclear. Purpose To evaluate the diagnostic performance of MR in the detection of meniscal ramp lesions having arthroscopy as reference standard. Materials and methods We retrospectively included 56 patients (mean age of 25 ± 7 years; 14 females) from January to November 2017 with a arthroscopically proved ACL tear and posterior meniscocapsular separation. On preoperative MRI, two radiologists with 13 and 2 years’ experience in musculoskeletal imag…
Red Ear Syndrome and Migraine: Report of Eight Cases
2002
We describe eight idiopathic cases of red ear syndrome in seven children and one adult. All were migraineurs with a history of paroxysmally painful and red ear, unilateral or alternating, in isolation or associated with migraine attacks. The reported duration of these episodes varied from 30 minutes to 1 hour. Neurologic examination, brain MRI and CT scans, and x-rays of the cervical spine were normal. The close temporal relationship between the "red ear episodes" and migraine attacks suggests an association between the two conditions.
Broad disruption of brain white matter microstructure and relationship with neuropsychological performance in male patients with severe alcohol depen…
2012
Aims In the last years, refined magnetic resonance diffusion tensor imaging (DTI) methods have become available to study microstructural alterations in the human brain. We investigated to what extent white matter tissue abnormalities are present in male patients after chronic, excessive alcohol consumption and if these alterations are correlated with measures of alcohol consumption and neuropsychological performance. Methods Twenty-four detoxified adult male patients with severe alcohol dependence and 23 healthy male control subjects were included in the study. Neuropsychological tests were assessed for executive function, attention, memory and visuospatial function. DTI was acquired and pr…
Disruption of White Matter Integrity in Bipolar Depression as a Possible Structural Marker of Illness
2011
Background: Diffusion tensor imaging allows the study of integrity of white matter (WM) tracts. Literature suggests that WM integrity could be altered in bipolar disorder. Heterogeneity of brain imaging methods, the studied samples, and drug treatments make localization, nature, and severity of the WM abnormalities unclear. Methods: We applied tract-based spatial statistics of diffusion tensor imaging measures to compare fractional anisotropy (FA), mean, and radial diffusivity of the WM skeleton in a group of 40 consecutively admitted inpatients affected by a major depressive episode without psychotic features with a diagnosis of bipolar disorder type I and 21 unrelated healthy volunteers f…
VBM-DTI correlates of verbal intelligence: a potential link to Broca's area.
2012
Abstract Human brain lesion studies first investigated the biological roots of cognitive functions including language in the late 1800s. Neuroimaging studies have reported correlation findings with general intelligence predominantly in fronto-parietal cortical areas. However, there is still little evidence about the relationship between verbal intelligence and structural properties of the brain. We predicted that verbal performance is related to language regions of Broca's and Wernicke's areas. Verbal intelligence quotient (vIQ) was assessed in 30 healthy young subjects. T1-weighted MRI and diffusion tensor imaging data sets were acquired. Voxel-wise regression analyses were used to correla…
Resovist enhanced MR imaging of the liver: Does quantitative assessment help in focal lesion classification and characterization?
2009
Purpose: To improve characterization of focal liver lesions by a prospective quantitative analysis of percentage signal intensity change, in dynamic and late phases after slow (0.5 mL/s) Resovist administration. Materials and Methods: Seventy-three patients were submitted on clinical indication to MR examination with Resovist. Signal intensity of 92 detected focal lesions (5–80 mm) were measured with regions of interest and normalized to paravertebral muscle in arterial, portal, equilibrium and T1/T2 late phases, by two observers in conference. Five values of percentage variations per patient were obtained and statistically evaluated. Results: The enhancement obtained on dynamic study is mo…