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Conventional MRI (conventional + mri)
Selected AbstractsConventional MRI in Multiple SclerosisJOURNAL OF NEUROIMAGING, Issue 2007Massimo Filippi MD ABSTRACT During the past 10 years, conventional magnetic resonance imaging (cMRI) has become an established tool for the assessment of patients with multiple sclerosis (MS) and to monitor treatment trials. This is mainly due to the sensitivity and reproducibility of cMRI in the detection of MS-related damage. A large effort has also been devoted to develop imaging strategies capable of providing accurate estimates of the extent of disease-related damage not only in the brain, but also in the spinal cord and optic nerve. Guidelines have been defined to integrate MR findings in the diagnostic evaluation of patients at presentation with clinically isolated syndromes suggestive of MS, and specific acquisition protocols have been offered for monitoring longitudinal changes in patients with established disease. Despite the fact that the role of cMRI in MS has been profoundly obviated by the advent of modern and quantitative MR techniques, several issues are still unresolved. Technical development in acquisition and postprocessing, as well as the introduction of high-field magnets in the clinical arena, are likely to increase our understanding of disease pathobiology, mainly through an increased ability to quantify the extent of gray matter damage. [source] Magnetic Resonance Imaging Monitoring of Multiple Sclerosis Lesion EvolutionJOURNAL OF NEUROIMAGING, Issue 2005Matilde Inglese MD ABSTRACT The characteristic feature of multiple sclerosis (MS) pathology is the demyelinated plaque distributed throughout the central nervous system. Although MS is a primary demyelinating disease, acute axonal injury is common in actively demyelinating MS lesions and it is considered one of the major determinants of neurological deficit. Magnetic resonance imaging (MRI) has had a dramatic impact on MS in both the clinical practice and basic science settings. Techniques such as T2-weighted and gadolinium-enhanced T1-weighted MRI are very sensitive in detecting lesions and, thus, increase the level of certainty of MS diagnosis. Conventional MRI has also improved our understanding of the pathogenesis of the disease and has provided objective and reliable measures to monitor the effect of experimental treatments in clinical trials. However, conventional MR,I does not provide specific information on the heterogeneous pathologic substrate of MS lesions. Advanced MRI techniques, such as magnetization transfer imaging, diffusion tensor imaging, and proton MR spectroscopy, offer the unprecedented ability to observe and quantify pathological changes in lesions and normal-appearing brain tissue over time. The present review will discuss the major contributions of conventional MRI and quantitative MRI techniques to understand how individual MS lesions evolve. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 14JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003A Toscano Transthyretin-derived familial amyloid polyneuropathy (TTR-FAP) is the most common form of hereditary amyloidosis, often associated with multisystemic involvement and a poor prognosis. We studied four patients, aged between 43 and 68 yrs, with TTR-FAP. A severe somatic and autonomic polyneuropathy was seen in three patients, whereas one was at onset of the disease. In addition 2/4, aged 43 and 63 years old, had a mild central nervous system (CNS) involvement. Neurophysiological studies showed an axonal polyneuropathy and amyloid deposits were found in all sural nerve biopsies. Combined conventional MRI and proton MR spectroscopic imaging (MRSI) were performed in our patients and in 14 age-matched normal controls. Conventional MRI was normal in two patients and showed minimal white matter and subcortical lesions in the other two, who were 63 and 68 years old. Proton MRSI of the periventricular brain regions showed a large reduction in N-acetylaspartate/creatine (NAA/Cr) resonance intensity (mean NAA/Cr in patients: 2.45 ± 0.04; mean NAA/Cr in normal controls: 2.9 ± 0.1; p < 0.003). Our findings suggest that, despite minimal or no abnormalities on conventional MRI, evidence of diffuse axonal damage can be demonstrated in brain of patients with TTR-FAP by proton MRSI examination, even in patients with no or mild CNS involvement. [source] Apparent diffusion coefficient of the superior cerebellar peduncle differentiates progressive supranuclear palsy from Parkinson's disease,MOVEMENT DISORDERS, Issue 16 2008Giuseppe Nicoletti MD Abstract The early diagnosis of progressive supranuclear palsy (PSP) may be challenging, because of clinical overlapping features with Parkinson's disease (PD) and other parkinsonian syndromes such as the Parkinsonian variant of multiple system atrophy (MSA-P). Conventional MRI can help in differentiating parkinsonian disorders but its diagnostic accuracy is still unsatisfactory. On the basis of the pathological demonstration of superior cerebellar peduncle (SCP) atrophy in patients with PSP, we assessed the SCP apparent diffusion coefficient (ADC) values in patients with PSP, PD, and MSA-P in order to evaluate its differential diagnostic value in vivo. Twenty-eight patients with PSP (14 with possible-PSP and 14 with probable-PSP), 15 PD, 15 MSA-P, and 16 healthy subjects were studied by using diffusion weighted imaging (DWI). ADC was calculated in regions of interest defined in the left and right SCP by two clinically blinded operators. Intrarater (r = 0.98, P < 0.001) and interrater reliability (r = 0.97; P < 0.001) for SCP measurements were high. Patients with PSP had higher SCP rADC values (median 0.98 × 10,3mm2/s) than patients with PD (median 0.79 × 10,3 mm2/s, P < 0.001), MSA-P (median 0.79 × 10,3 mm2/s, P < 0.001), and healthy controls (median 0.80 × 10,3 mm2/s, P < 0.001). DWI discriminated patients with PSP from PD and healthy subjects on the basis of SCP rADC individual values (100% sensitivity and specificity) and from patients with MSA-P (96.4% sensitivity and 93.3% specificity). The higher values of rADC in SCP of patients with PSP correspond with the in vivo microstructural feature of atrophy detected postmortem and provide an additional support for early discrimination between PSP and other neurodegenerative parkinsonisms. © 2008 Movement Disorder Society [source] Assessing optic nerve pathology with diffusion MRI: from mouse to humanNMR IN BIOMEDICINE, Issue 9 2008Junqian Xu Abstract The optic nerve is often affected in patients with glaucoma and multiple sclerosis. Conventional MRI can detect nerve damage, but it does not accurately assess the underlying pathologies. Mean diffusivity and diffusion anisotropy indices derived from diffusion tensor imaging have been shown to be sensitive to a variety of central nervous system white matter pathologies. Despite being sensitive, the lack of specificity limits the ability of these measures to differentiate the underlying pathology. Directional (axial and radial) diffusivities, measuring water diffusion parallel and perpendicular to the axonal tracts, have been shown to be specific to axonal and myelin damage in mouse models of optic nerve injury, including retinal ischemia and experimental autoimmune encephalomyelitis. The progression of Wallerian degeneration has also been detected using directional diffusivities after retinal ischemia. However, translating these findings to human optic nerve is technically challenging. The current status of diffusion MRI of human optic nerve, including imaging sequences and protocols, is summarized herein. Despite the lack of a consensus among different groups on the optimal sequence or protocol, increased mean diffusivity and decreased diffusion anisotropy have been observed in injured optic nerve from patients with chronic optic neuritis. From different mouse models of optic nerve injuries to the emerging studies on patients with optic neuritis, directional diffusivities show great potential to be specific biomarkers for axonal and myelin injury. Copyright © 2008 John Wiley & Sons, Ltd. [source] Cognitive visual dysfunctions in preterm children with periventricular leukomalaciaDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 12 2009ELISA FAZZI MD PHD Aim, Cognitive visual dysfunctions (CVDs) reflect an impairment of the capacity to process visual information. The question of whether CVDs might be classifiable according to the nature and distribution of the underlying brain damage is an intriguing one in child neuropsychology. Method, We studied 22 children born preterm (12 males, 10 females; mean age at examination 8y, range 6,15y; mean gestational age 30wks, range 28,36wks) with periventricular leukomalacia, spastic diplegia, normal intelligence (mean Full-scale IQ 84; mean Verbal IQ 97; mean Performance IQ 74), and normal visual acuity, focusing on higher visual functions. Brain magnetic resonance images (MRI) were analysed to establish the presence of lesions along the primary optic pathway, in the occipitoparietal and occipitotemporal regions. Results, Most children displayed an uneven cognitive profile, with deficits in visual object recognition, visual imagery, visual,spatial skills, and visual memory, and sparing of visual associative abilities, non-verbal intelligence, and face and letter recognition. Conventional brain MRI did not document major alterations of parietal and temporal white matter, or cortical alteration of areas involved in visual associative functions. Interpretation, We suggest a widespread involvement of higher visual processing systems, involving both the ventral and dorsal streams, in preterm children with periventricular leukomalacia. The lack of major alterations on conventional MRI does not exclude the possibility of malfunctioning of higher visual processing systems, expressing itself through discrete CVDs. Possible mechanisms underlying these neuropsychological deficits are discussed. [source] Automated normalized FLAIR imaging in MRI-negative patients with refractory focal epilepsyEPILEPSIA, Issue 6 2009Niels K. Focke Summary Background:, Patients with focal epilepsy that is refractory to medical treatment are often considered candidates for resective surgery. Magnetic resonance imaging (MRI) has a very important role in the presurgical work-up of these patients, but is unremarkable in about one-third of cases. These patients are often deferred from surgery or have a less positive outcome if surgery is eventually undertaken. The aim of this study was to evaluate our recently described voxel-based technique using routine T2-FLAIR (fluid-attenuated inversion-recovery) scans in MRI-negative patients and to compare the results with video-EEG (electroencephalography) telemetry (VT) findings. Methods:, We identified 70 epilepsy patients with refractory focal seizures who underwent VT and had a normal routine MRI. T2-FLAIR scans were bias-corrected, and intensity and spatially normalized (nFSI) using Statistical Parametric Mapping 5 (SPM5) as previously described. Individual scans were then compared against a set of 25 normal controls using a voxel-based method. Results:, SPM5 identified 10 patients with suprathreshold clusters (14.3%). In 50% of these there was concordance between the lobe of the most significant cluster and the presumed lobe of seizure onset, as defined by VT. All cases were concordant with respect to lateralization of the putative focus. Conclusion:, Using nFSI we identified focal structural cerebral abnormalities in 11.4% of patients with refractory focal seizures, and normal conventional MRI, that were fully or partially concordant with scalp VT. This voxel-based analysis of FLAIR scans, which are widely available, could provide a useful tool in the presurgical evaluation of epilepsy patients. Ongoing work is to compare these imaging findings with the results of intracranial EEG and histology of surgical resections. [source] EFNS guidelines on the use of neuroimaging in the management of multiple sclerosisEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2006M. Filippi Magnetic resonance (MR)-based techniques are widely used for the assessment of patients with suspected and definite multiple sclerosis (MS). However, despite the publication of several position papers, which attempted to define the utility of MR techniques in the management of MS, their application in everyday clinical practice is still suboptimal. This is probably related, not only, to the fact that the majority of published guidelines focused on the optimization of MR technology in clinical trials, but also to the continuing development of modern, quantitative MR-based techniques, that have not as yet entered the clinical arena. The present report summarizes the conclusions of the ,EFNS Expert Panel of Neuroimaging of MS' on the application of conventional and non-conventional MR techniques to the clinical management of patients with MS. These guidelines are intended to assist in the use of conventional MRI for the diagnosis and longitudinal monitoring of patients with MS. In addition, they should provide a foundation for the development of more widespread but rational clinical applications of non-conventional MR-based techniques in studies of MS patients. [source] Linking structural, metabolic and functional changes in multiple sclerosisEUROPEAN JOURNAL OF NEUROLOGY, Issue 4 2001Massimo Filippi In patients with multiple sclerosis (MS), conventional magnetic resonance imaging (MRI) has markedly improved our ability to detect the macroscopic abnormalities of the brain and spinal cord. New quantitative magnetic resonance (MR) approaches with increased sensitivity to subtle normal-appearing white matter (NAWM) and grey matter changes and increased specificity to the heterogeneous pathological substrates of MS may give information complementary to conventional MRI. Magnetization transfer imaging (MTI) and diffusion-weighted imaging (DWI) have the potential to provide important information on the structural changes occurring within and outside T2-visible lesions. Magnetic resonance spectroscopy (MRS) adds information on the biochemical nature of such changes. Functional MRI might quantify the efficiency of brain plasticity in response to MS injury and improve our understanding of the link between structural damage and clinical manifestations. The present review summarizes how the application of these MR techniques to the study of MS is dramatically changing our understanding of how MS causes irreversible neurological deficits. [source] Imaging biomarkers in multiple sclerosisJOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2010M. Filippi MD Abstract Recent years have witnessed impressive advances in the use of magnetic resonance imaging (MRI) for the assessment of patients with multiple sclerosis (MS). Complementary to the clinical evaluation, conventional MRI provides crucial pieces of information for the diagnosis of MS. However, the correlation between the burden of lesions observed on conventional MRI scans and the clinical manifestations of the disease remains weak. The discrepancy between clinical and conventional MRI findings in MS is explained, at least partially, by the limited ability of conventional MRI to characterize and quantify the heterogeneous features of MS pathology. Other quantitative MR-based techniques, however, have the potential to overcome such a limitation of conventional MRI. Indeed, magnetization transfer MRI, diffusion tensor MRI, proton MR spectroscopy, and functional MRI are contributing to elucidate the mechanisms that underlie injury, repair, and functional adaptation in patients with MS. Such techniques are likely to benefit from the use of high-field MR systems and thus allow in the near future providing additional insight into all these aspects of the disease. This review summarizes how MRI is dramatically changing our understanding of the factors associated with the accumulation of irreversible disability in MS and highlights the reasons why they should be used more extensively in studies of disease evolution and clinical trials. J. Magn. Reson. Imaging 2010;31:770,788. ©2010 Wiley-Liss, Inc. [source] Guidelines for using quantitative magnetization transfer magnetic resonance imaging for monitoring treatment of multiple sclerosis,JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 4 2003Mark A. Horsfield PhD Abstract Quantitative evaluation of brain magnetic resonance imaging (MRI) scans is now an accepted part of the trial of new putative treatments for multiple sclerosis (MS). However, conventional MRI is not pathologically specific, and it does not reveal the details of the pathological processes that underlie the progression of the disease. Magnetization transfer (MT) imaging is a relatively new quantitative technique that appears to offer some pathological specificity, and can be used to monitor the changes over time in both individual lesions and the central nervous system as a whole. This paper considers the case for incorporating MT imaging into new clinical trials, so that the utility of MT for monitoring the modification of MS progression by treatment can be assessed. Specific guidelines for implementing MT imaging as part of a large multicenter clinical trial are given, and practical considerations when planning such a trial are detailed. It is anticipated that MT imaging will be incorporated into many new trials in the near future. J. Magn. Reson. Imaging 2003;17:389,397. © 2003 Wiley-Liss, Inc. [source] Magnetic Resonance Imaging Monitoring of Multiple Sclerosis Lesion EvolutionJOURNAL OF NEUROIMAGING, Issue 2005Matilde Inglese MD ABSTRACT The characteristic feature of multiple sclerosis (MS) pathology is the demyelinated plaque distributed throughout the central nervous system. Although MS is a primary demyelinating disease, acute axonal injury is common in actively demyelinating MS lesions and it is considered one of the major determinants of neurological deficit. Magnetic resonance imaging (MRI) has had a dramatic impact on MS in both the clinical practice and basic science settings. Techniques such as T2-weighted and gadolinium-enhanced T1-weighted MRI are very sensitive in detecting lesions and, thus, increase the level of certainty of MS diagnosis. Conventional MRI has also improved our understanding of the pathogenesis of the disease and has provided objective and reliable measures to monitor the effect of experimental treatments in clinical trials. However, conventional MR,I does not provide specific information on the heterogeneous pathologic substrate of MS lesions. Advanced MRI techniques, such as magnetization transfer imaging, diffusion tensor imaging, and proton MR spectroscopy, offer the unprecedented ability to observe and quantify pathological changes in lesions and normal-appearing brain tissue over time. The present review will discuss the major contributions of conventional MRI and quantitative MRI techniques to understand how individual MS lesions evolve. [source] Water Apparent Diffusion Coefficient and T2 Changes in the Acute Stage of Maple Syrup Urine Disease: Evidence of Intramyelinic and Vasogenic-Interstitial EdemaJOURNAL OF NEUROIMAGING, Issue 2 2003Andrea Righini MD ABSTRACT Background. The acute phase of the neonatal classical form of maple syrup urine disease (MSUD) is usually associated with generalized brain edema. Methods and Results. The authors present the case of a newborn infant in the acute stage of the classical form of MSUD in whom a remarkable decrease in the water apparent diffusion coefficient (ADC) in advanced myelinating white matter areas was associated with an increase in the T2 signal. This diffusion magnetic resonance imaging (MRI) pattern appears to be compatible with a rare kind of cytotoxic edema, the so-called intramyelinic edema. At the same time, an increase in the ADC was seen in unmyelinated areas together with an increase in the T2 signal, a sign of a coexistent vasogenic-interstitial edema. Conclusions. ADC measurements in MSUD provide more specific information than conventional MRI about the pathophysiology of white matter changes. [source] Abstracts of the 8th Meeting of the Italian Peripheral Nerve Study Group: 14JOURNAL OF THE PERIPHERAL NERVOUS SYSTEM, Issue 1 2003A Toscano Transthyretin-derived familial amyloid polyneuropathy (TTR-FAP) is the most common form of hereditary amyloidosis, often associated with multisystemic involvement and a poor prognosis. We studied four patients, aged between 43 and 68 yrs, with TTR-FAP. A severe somatic and autonomic polyneuropathy was seen in three patients, whereas one was at onset of the disease. In addition 2/4, aged 43 and 63 years old, had a mild central nervous system (CNS) involvement. Neurophysiological studies showed an axonal polyneuropathy and amyloid deposits were found in all sural nerve biopsies. Combined conventional MRI and proton MR spectroscopic imaging (MRSI) were performed in our patients and in 14 age-matched normal controls. Conventional MRI was normal in two patients and showed minimal white matter and subcortical lesions in the other two, who were 63 and 68 years old. Proton MRSI of the periventricular brain regions showed a large reduction in N-acetylaspartate/creatine (NAA/Cr) resonance intensity (mean NAA/Cr in patients: 2.45 ± 0.04; mean NAA/Cr in normal controls: 2.9 ± 0.1; p < 0.003). Our findings suggest that, despite minimal or no abnormalities on conventional MRI, evidence of diffuse axonal damage can be demonstrated in brain of patients with TTR-FAP by proton MRSI examination, even in patients with no or mild CNS involvement. [source] Accelerating SENSE using compressed sensingMAGNETIC RESONANCE IN MEDICINE, Issue 6 2009Dong Liang Abstract Both parallel MRI and compressed sensing (CS) are emerging techniques to accelerate conventional MRI by reducing the number of acquired data. The combination of parallel MRI and CS for further acceleration is of great interest. In this paper, we propose a novel method to combine sensitivity encoding (SENSE), one of the standard methods for parallel MRI, and compressed sensing for rapid MR imaging (SparseMRI), a recently proposed method for applying CS in MR imaging with Cartesian trajectories. The proposed method, named CS-SENSE, sequentially reconstructs a set of aliased reduced-field-of-view images in each channel using SparseMRI and then reconstructs the final image from the aliased images using Cartesian SENSE. The results from simulations and phantom and in vivo experiments demonstrate that CS-SENSE can achieve a reduction factor higher than those achieved by SparseMRI and SENSE individually and outperform the existing method that combines parallel MRI and CS. Magn Reson Med, 2009. © 2009 Wiley-Liss, Inc. [source] Optimized interleaved whole-brain 3D double inversion recovery (DIR) sequence for imaging the neocortexMAGNETIC RESONANCE IN MEDICINE, Issue 6 2004P.A. Boulby Abstract For a substantial number of individuals with neurological disorders, a conventional MRI scan does not reveal any obvious etiology; however, it is believed that abnormalities in the neocortical gray matter (GM) underlie many of these disorders. Attempts to image the neocortex are hindered by its thin, convoluted structure, and the partial volume (PV) effect. Therefore, we developed a 3D version of the double inversion recovery (DIR) sequence that incorporates an optimized interleaved (OIL) strategy to improve efficiency and allow high-quality, high-resolution imaging of GM. Magn Reson Med 51:1181,1186, 2004. © 2004 Wiley-Liss, Inc. [source] Temporal alterations in brain water diffusivity in neonatal meningitisACTA PAEDIATRICA, Issue 9 2009Gyanendra K Malik Abstract Aim:, To compare changes in apparent diffusion coefficient (ADC) in neonatal meningitis using serial diffusion-weighted imaging (DWI). Method:, Thirty neonates with meningitis and 12 age/sex-matched controls were studied using DWI. ADC was quantified by placing region of interest(s) on periventricular white matter during acute illness and again at 21 days. Three groups of patients were studied: those with normal findings on both conventional MRI and DWI, those with abnormal DWI only and those with abnormal conventional MRI as well as DWI. Neurodevelopment assessment was performed in controls and patients at 3 months using Indian adaptation of Bayley scales of infant development (BSID) kit. Results:, Patients with neonatal meningitis with normal imaging (n = 8) showed no significant difference in ADC compared to controls. Patients showing abnormality only on DWI (n = 10) and on both conventional magnetic resonance imaging (MRI) as well as DWI (n = 12) had significantly reduced ADC (p = 0.001) than controls at baseline study. Follow-up study showed no significant differences in ADC in controls compared to any patient group. Significantly reduced neurodevelopmental scores were observed in patient groups compared to controls. Conclusion:, We conclude that quantitative ADC may detect meningitis-induced hypoxia early in brain parenchyma, which may be associated with abnormal motor and mental development. [source] | ||||||||||||||||||||||