Search results for "diffusion magnetic resonance imaging"
showing 10 items of 61 documents
Mathematical models for the diffusion magnetic resonance signal abnormality in patients with prion diseases
2014
In clinical practice signal hyperintensity in the cortex and/or in the striatum on magnetic resonance (MR) diffusion-weighted images (DWIs) is a marker of sporadic Creutzfeldt–Jakob Disease (sCJD). MR diagnostic accuracy is greater than 90%, but the biophysical mechanisms underpinning the signal abnormality are unknown. The aim of this prospective study is to combine an advanced DWI protocol with new mathematical models of the microstructural changes occurring in prion disease patients to investigate the cause of MR signal alterations. This underpins the later development of more sensitive and specific image-based biomarkers. DWI data with a wide a range of echo times and diffusion weightin…
Whole-body diffusion-weighted MR and FDG-PET/CT in Hodgkin Lymphoma: Predictive role before treatment and early assessment after two courses of ABVD
2017
Abstract Purpose To evaluate whether imaging features of pathologic lymph nodes on whole-body diffusion-weighted MR have a predictive role before treatment and may assess the response after two courses of chemotherapy in comparison to FDG-PET/CT in Hodgkin Lymphoma. Materials and methods We reviewed the whole-body MR and FDG-PET/CT performed on 41 patients with Hodgkin Lymphoma before and after two Doxorubicin-Bleomycin-Vinblastine-Dacarbazine (ABVD). Responder and non-responder lesions were identified on interim-FDG-PET/CT performed after two ABVD. We used Multivariate Generalized Estimating Equations model to assess statistical association between being-responder and baseline-Maximum Stan…
Comparison between whole-body MRI with diffusion-weighted imaging and PET/CT in staging newly diagnosed FDG-avid lymphomas.
2015
Abstract Objectives To compare whole body-MRI (WB-MRI) with diffusion-weighted imaging and FDG-PET/CT in staging newly diagnosed FDG-avid lymphomas. Methods 68 patients (37 males, 31 females; median age 42 years; range 15–86 years) with histologically confirmed lymphoma (37 Classical Hodgkin, 16 Diffuse large B-cell, 10 Follicular, 5 Mantle cell) underwent both MRI and FDG-PET/CT before treatment. Ann Arbor stages obtained with WB-MRI and FDG-PET/CT were compared using Cohen’s k statistics. Moreover WB-MRI and FDG-PET/CT stages were compared with the pathological stages obtained after the diagnostic iter using also bone marrow and available biopsies if clinically indicated. Results The agre…
Metabolic changes in vestibular and visual cortices in acute vestibular neuritis
2004
Five right-handed patients with a right-sided vestibular neuritis were examined twice with fluorodeoxyglucose positron emission tomography while lying supine with eyes closed: once during the acute stage (mean, 6.6 days) and then 3 months later when central vestibular compensation had occurred. Regional cerebral glucose metabolism (rCGM) was significantly increased (p <0.001 uncorrected) during the acute stage in multisensory vestibular cortical and subcortical areas (parietoinsular vestibular cortex in the posterior insula, posterolateral thalamus, anterior cingulate gyrus [Brodmann area 32/24], pontomesencephalic brainstem, hippocampus). Simultaneously, there was a significant rCGM decrea…
Bilateral Wallerian degeneration of the medial cerebellar peduncles after ponto-mesencephalic infarction
2003
Three patients with acute large paramedian ponto-mesencephalic infarctions developed a bilateral retrograde degeneration of the medial cerebellar peduncles within 4 months after the insult. In an initial magnetic resonance imaging (MRI) within the first 2 weeks, the medial cerebellar peduncles showed normal intensities, but a control MRI after 4 months showed bright hyperintensities in the T2-TSE weighted images, and moderately increased signal intensities in echo planar imaging-diffusion weighted imaging were seen, possibly representing bilateral Wallerian degeneration of the cerebellar-pontine fibers.
Bilateral Hypoglossal Nerve Palsy in an Adult Patient With Repaired Tetralogy of Fallot
2018
Introduction Spontaneous cervical artery dissection (sCAD) is a major cause of ischemic stroke in young and middle-aged adults, but the occurrence of multiple sCADs could suggest the presence of an underlying arteriopathy. Bilateral hypoglossal nerve palsy caused by extracranial internal carotid artery dissections have been rarely described. We present the case of a 3-vessel sCAD in a patient with repaired tetralogy of Fallot (ToF). Case report A 50-year-old man was admitted to our stroke unit for a sudden onset of left cervical pain, mild left ptosis, dysarthria, and dysphagia. His medical history was remarkable for surgically repaired ToF. Neurological examination showed left Claude-Berna…
Functional relevant loss of long association fibre tracts integrity in early Alzheimer's disease.
2007
Abstract The aim of our study was to quantify the structural integrity of the long association fibre tracts in early Alzheimer's disease (AD) and to correlate the findings with the cognitive performance of the patients. We conducted region-of-interest-based analyses of color-coded diffusion-tensor imaging in 12 patients with early AD (age 69.8 ± 8.0 years; MMSE 25.3 ± 1.8) and 16 age- and education-matched healthy controls. Early AD patients showed significantly decreased fractional anisotropy (FA) of the cingulate bundles and the inferior fronto-occipital fascicles bilaterally, whereas FA values of the superior longitudinal fascicles (second division) did not differ significantly between p…
Functional implications of hippocampal volume and diffusivity in mild cognitive impairment.
2005
Abstract Hippocampal atrophy has been related to mild cognitive impairment (MCI) and early Alzheimer disease (AD), but the diagnostic significance of cross-sectionally determined hippocampal volumes is still ambiguous. Diffusion-Tensor-Imaging (DTI) in MCI patients revealed an association of microstructural changes in hippocampal areas with verbal memory decline. MRI volumetry and DTI were combined to investigate 18 MCI patients attending a memory clinic, and 18 carefully age- and gender-matched healthy controls. Neuropsychological testing, high resolution T1-weighted volume MRI scans, and DTI scans with regions-of-interest in hippocampal areas were applied. Left hippocampal volume was sign…
Predicting conversion to dementia in mild cognitive impairment by volumetric and diffusivity measurements of the hippocampus.
2005
In our prospective study of diffusion tensor imaging (DTI), we measured hippocampal mean diffusivity (MD) and volumes in amnestic mild cognitive impairment (MCI). Thirteen MCI patients were followed-up by clinical assessment over a mean 112-year period. MCI patients who converted to dementia (6 of 13) during the observation period had slightly elevated left hippocampal mean diffusivity at baseline compared with MCI patients who remained clinically stable. Hippocampal volumes as well as baseline verbal memory and MMSE did not differ significantly between stable MCI patients and converters. Hippocampal diffusivity was superior to hippocampal volumes for prediction of conversion to dementia in…
MRI patient selection for endovascular thrombectomy in acute ischemic stroke: correlation between pretreatment diffusion weighted imaging and outcome…
2018
Introduction: Eligibility for endovascular treatment (EVT) in patients with acute ischemic stroke (AIS) depends, amongst other factors, on CT- or MR-based scores. The aim of this study was to investigate the role of Alberta Stroke Program Early CT score based on diffusion weighted imaging (MR-ASPECT) in the assessment of brain damage pre-EVT, patient selection for EVT and outcome. Materials and methods: We included in this study patients with National Institute of Health stroke score (NIHSS) at admission ≥ 8, MR-ASPECT ≥ 5 and anterior AIS, who were treated with EVT in our hospital. All patients were clinically evaluated at admission, post-EVT, discharge and at 3-month follow-up. We used MR…