MRI Scanning (mri + scanning)

Distribution by Scientific Domains

Selected Abstracts

Brain MRI in late-onset multiple sclerosis

J. de Seze
Multiple sclerosis (MS) with clinical onset after 50 years of age is unusual (between 1 and 6%) and is frequently misdiagnosed. Furthermore, brain magnetic resonance imaging (MRI) abnormalities are frequently observed in subjects over 50 years of age. The aim of this study was to describe brain MRI in late-onset MS to evaluate the sensitivity and specificity of radiological MS criteria in patients aged over 50 years. We evaluated the brain MRI of 20 patients with onset of MS after 50 years of age. We compared these MRI with 26 controls matched for age, sex and vascular risk factors. MRI were blindly analysed by two neuroradiologists according to Paty et al.'s [Neurology38 (1988) 180] criteria, Fazekas et al.'s [Neurology38 (1988) 1822] criteria and Barkhof et al.'s [Brain120 (1997) 2059] criteria. The mean age at MRI scanning was 58 years. Sensitivity was 90% for Paty et al.'s criteria, 80% for Fazekas et al.'s criteria and 85% for Barkhof et al.'s criteria. Specificity was 54% for Paty et al.'s criteria, 69% for Fazekas et al.'s criteria and 65% for Barkhof et al.'s criteria. Barkhof et al.'s criteria are less specific in older patients than in young patients. We suggest that spinal cord MRI and cerebrospinal fluid analysis should be systematically performed in suspected late-onset MS in order to increase the specificity of the diagnosis. [source]

Feasibility of Magnetic Resonance Imaging in Patients with an Implantable Loop Recorder

Background: The implantable loop recorder (ILR) is a useful tool in the diagnosis of syncope. Our understanding of their functional and safety profile in interfering environments such as magnetic resonance imaging (MRI) becomes increasingly important as they become more prevalent. Methods: We report four patients with an ILR who underwent MRI. The ILR memory was cleared before MRI and no changes were made to programmed settings. Device interrogation took place immediately after the scan. Patients were surveyed for device movement and heating, in addition to cardiopulmonary symptoms after their MRI. Results: Following MRI scanning, all patients were asymptomatic and no device movement or heating was observed. In addition, the functionality of the device remained unaffected. Artifacts mimicking arrhythmias were seen in all ILR patients regardless of the type of MRI scan. Conclusions: MRI scanning of ILR patients can be performed without harm to patient or device, but artifacts that could be mistaken for a tachyarrhythmia are seen frequently. [source]

Neuroanatomy of the Subadult and Fetal Brain of the Atlantic White-sided Dolphin (Lagenorhynchus acutus) from in Situ Magnetic Resonance Images

Eric W. Montie
Abstract This article provides the first anatomically labeled, magnetic resonance imaging (MRI) -based atlas of the subadult and fetal Atlantic white-sided dolphin (Lagenorhynchus acutus) brain. It differs from previous MRI-based atlases of cetaceans in that it was created from images of fresh, postmortem brains in situ rather than extracted, formalin-fixed brains. The in situ images displayed the classic hallmarks of odontocete brains: fore-shortened orbital lobes and pronounced temporal width. Olfactory structures were absent and auditory regions (e.g., temporal lobes and inferior colliculi) were enlarged. In the subadult and fetal postmortem MRI scans, the hippocampus was identifiable, despite the relatively small size of this structure in cetaceans. The white matter tracts of the fetal hindbrain and cerebellum were pronounced, but in the telencephalon, the white matter tracts were much less distinct, consistent with less myelin. The white matter tracts of the auditory pathways in the fetal brains were myelinated, as shown by the T2 hypointensity signals for the inferior colliculus, cochlear nuclei, and trapezoid bodies. This finding is consistent with hearing and auditory processing regions maturing in utero in L. acutus, as has been observed for most mammals. In situ MRI scanning of fresh, postmortem specimens can be used not only to study the evolution and developmental patterns of cetacean brains but also to investigate the impacts of natural toxins (such as domoic acid), anthropogenic chemicals (such as polychlorinated biphenyls, polybrominated diphenyl ethers, and their hydroxylated metabolites), biological agents (parasites), and noise on the central nervous system of marine mammal species. Anat Rec, 2007. 2007 Wiley-Liss, Inc. [source]

Brain magnetic resonance imaging abnormalities in neuromyelitis optica

Y. Li
Objective,,, Brain abnormalities in neuromyelitis optica (NMO) attracted much attention. Our study was to identify the brain magnetic resonance imaging (MRI) abnormalities in Chinese NMO patients. Methods,,, Patients who fulfilled the latest diagnostic criteria of NMO proposed by Wingerchuk et al. [Neurology 66 (2006) 1485] and whose brain MRI did not meet the multiple sclerosis (MS) criteria of McDonald et al. [Ann Neurol 50 (2001) 121] were selected to perform MRI scanning of the brain, spinal cord and optic nerves. Results,,, Twenty-eight of 33 patients (84.8%) had abnormal MRI findings. Twenty-two patients (66.7%) presented with well-defined brain parenchymal lesions and the other six patients (18.2%) with macroscopic symmetrical diffuse hyperintensities in deep white matter. Fifteen of 22 patients had more than one lesion (,2 lesions) and the other seven patients had single lesion. In the supratentorium, most lesions were punctate or small round dot and non-specific in juxtacortical, subcortical and deep white matter regions, a few were patchy atypical confluent lesions. Brainstem was easily involved (14/33, 42.4%) especially in medulla (7/33, 21.2%). Conclusions,,, This study demonstrates the characteristics of brain MRI abnormalities in Chinese NMO patients, which are helpful to the revision of diagnostic criteria for NMO. [source]