Showing papers by "Maria A. Rocca published in 2004"

Magnetization transfer and diffusion tensor MRI show gray matter damage in neuromyelitis optica.

Abstract: Using magnetization transfer (MT) and diffusion tensor (DT) MRI, the authors assessed the extent of tissue damage of the brain normal-appearing white and gray matter (NAGM) in patients with neuromyelitis optica (NMO) Compared to healthy controls, patients with NMO showed reduced MT ratio and increased mean diffusivity of the NAGM This challenges the classic notion of a sparing of the brain tissue in the course of NMO

Brain tissue loss occurs after suppression of enhancement in patients with multiple sclerosis treated with autologous haematopoietic stem cell transplantation

Abstract: To assess whether brain tissue loss occurs after profound and sustained suppression of magnetic resonance imaging (MRI) enhancement, we measured brain volume changes from 10 patients with rapidly evolving secondary progressive multiple sclerosis (MS) treated with autologous haematopoietic stem cell transplantation and followed up for 24 months. An average yearly decrease of brain volume of about 1.9% was observed despite only five enhancing lesions seen on triple dose follow up scans of two patients. This indicates that, in MS, progressive loss of tissue can occur independently of concomitant MRI-visible inflammation.

Simple and complex movement‐associated functional MRI changes in patients at presentation with clinically isolated syndromes suggestive of multiple sclerosis

Abstract: Using functional magnetic resonance imaging (fMRI), we investigated whether movement-associated functional changes of the brain are present in patients who are, most likely, at the earliest stage of multiple sclerosis (MS). Functional MRI exams were obtained from 16 patients at presentation with clinically isolated syndromes (CIS) suggestive of MS and 15 sex- and age-matched healthy volunteers during the performance of three simple and one more complex motor tasks with fully normal functioning extremities. fMRI analysis was performed using statistical parametric mapping (SPM99). Compared to healthy volunteers, CIS patients had increased activations of the contralateral primary sensorimotor cortex (SMC), secondary somatosensory cortex (SII), and inferior frontal gyrus (IFG), when performing a simple motor task with the dominant hand. The increased recruitment of the contralateral primary SMC was also found during the performance of the same motor task with the non-dominant hand and with the dominant foot. In this latter case, an anterior shift of the center of activation of this region was detected. During the performance of a complex motor task with the dominant upper and lower limbs, CIS patients had an increased recruitment of a widespread network (including the frontal lobe, the insula, the thalamus), usually considered to function in motor, sensory, and multimodal integration processing. The comparison of brain activations during the performance of simple vs. complex motor tasks showed that the movement-associated somatotopic organization of the cerebral and cerebellar cortices was retained in patients with CIS. Cortical reorganization occurs in patients at presentation with CIS highly suggestive of MS. Local synaptic reorganization, recruitment of parallel existing pathways, and reorganization of distant sites are all likely to contribute to the observed functional changes. Hum. Brain Mapping 21:106–115, 2004. © 2003 Wiley-Liss, Inc.

Magnetization transfer magnetic resonance imaging in the assessment of neurological diseases.

Abstract: In several white matter diseases of the central nervous system (CNS), and in particular in multiple sclerosis, conventional magnetic resonance imaging (MRI) has proved to be sensitive for detecting lesions and their changes over time. However, con ventional MRI is not able to characterize and quantify the tissue damage within and outside such lesions. Magnetization transfer MRI (MT-MRI) is a quantitative MRI technique with the potential to overcome this limitation and, as a consequence, to provide additional information about the nature and the extent of tissue damage. Metrics derived from MT-MRI can quantify the structural changes occurring within and outside lesions visible on conventional MRI scans. The present review summarizes the major contributions given by MT-MRI to provide an accurate in vivo picture of the heterogeneity of CNS pathology and, ultimately, to improve our ability to monitor the evolution of various neurological conditions.

Cortical reorganisation in patients with MS

Abstract: Using functional MRI techniques to study patients with MS Over the past decade, modern structural magnetic resonance imaging (MRI) techniques have been extensively used for the study of patients with multiple sclerosis (MS).1 The ultimate goal of this research is to increase the understanding of the mechanisms responsible for the accumulation of irreversible disability. Although important insight into MS pathobiology has been achieved by using modern MR based techniques, the magnitude of the correlation between MRI and clinical findings remains suboptimal. This might be explained, at least partially, by the variable effectiveness of reparative and recovery mechanisms following MS related tissue damage. Resolution of acute inflammation, remyelination, and redistribution of voltage gated sodium channels in persistently demyelinated axons are all likely to limit the clinical impact of damaging MS pathology.2 Cortical reorganisation has been recently suggested, however, as an additional potential contributor to the recovery or to the maintenance of function in the presence of irreversible MS related tissue damage. This is in agreement with what has been seen in other neurological conditions, such as stroke,3 tumours,4,5 and Alzheimer’s disease.6,7 Brain plasticity is indeed a well known feature of the human brain, which is likely to have several different substrates (including increased axonal expression of sodium channels,8 synaptic changes, increased recruitment of parallel existing pathways or “latent” connections, and reorganisation of distant sites), and which might have a major adaptive role in limiting the functional consequences of axonal loss in MS.9 ### What is measured using fMRI? The signal changes seen during functional MRI (fMRI) studies depend on the blood oxygenation level dependent mechanism, which, in turn, involves changes of the transverse magnetisation relaxation time—either T2* in a gradient echo sequence or T2 in spin echo sequence.5 Local increases in neuronal activity result in a rise …

A preliminary diffusion tensor and magnetization transfer magnetic resonance imaging study of early-onset multiple sclerosis.

Abstract: Background Early-onset multiple sclerosis (MS) typically has a more favorable course than adult-onset disease. Objective To assess the extent of microscopic tissue damage in the brain and cervical cord of patients with early-onset MS. Design During a single magnetic resonance imaging session, images of the brain and spinal cord were obtained using diffusion tensor and magnetization transfer magnetic resonance imaging. Patients We studied 13 patients with early-onset MS and 10 healthy volunteers. Results Compared with control subjects, patients with early-onset MS showed only a slight increase of the average mean diffusivity of the normal-appearing brain tissue. Conclusion The relatively modest central nervous system damage detected in these patients might explain why early-onset MS typically has a more favorable clinical course than adult-onset MS.

European Study on Intravenous Immunoglobulin in Multiple Sclerosis Results of Magnetization Transfer Magnetic Resonance Imaging Analysis

Abstract: Background Magnetization transfer magnetic resonance imaging (MT MRI) can provide in vivo markers reflecting the severity of multiple sclerosis–related brain damage occurring within and outside T2-visible lesions. Objective To investigate the effect of intravenous immunoglobulin (IVIG) treatment on the accumulation of brain damage in patients with secondary progressive multiple sclerosis (SPMS), measured using MT MRI. Design, Patients, and Intervention Seventy patients with SPMS participating in the European, multicenter, randomized, double-blind, placebo-controlled trial of IVIG in SPMS underwent brain T2-weighted and MT MRI at baseline and after 12 and 24 months. The MT MRI scans were post-processed and analyzed to obtain MT ratio values from T2-visible lesions and MT ratio histograms from the normal-appearing brain tissue (NABT). Results At baseline, a significant difference was found for NABT MT ratio histogram peak height ( P = .003) between treated patients and patients receiving placebo. No significant differences between treated patients and those receiving placebo were found for any of the considered MT MRI–derived metrics in terms of treatment × time interaction. Nevertheless, over the 24-month period, the placebo patients experienced a 6.75% reduction of the NABT MT ratio histogram peak height, whereas treated patients experienced only a 0.92% reduction of the NABT MT ratio histogram peak height. Conclusions This study did not show any statistically significant effect of IVIG on MT MRI quantities. Nevertheless, the markedly different percentage change of the NABT MT ratio histogram peak height over time between patients receiving placebo and treated patients suggests a possible role of IVIG treatment in preventing the loss of “truly” normal brain tissue in SPMS patients.

MR imaging of Devic’s neuromyelitis optica

Abstract: Devic’s neuromyelitis optica (NMO) is a neurological condition characterized by a severe involvement of the optic nerves and spinal cord in a mono- or multi-phasic manner. Recent pathologic, cerebrospinal fluid and conventional magnetic resonance imaging (MRI) studies have shown abnormalities which might help in differentiating patients with NMO from those with multiple sclerosis. This review article summarizes the main results obtained using conventional MRI in NMO, which has contributed to the definition of internationally-accepted diagnostic criteria, and those obtained from the application of modern quantitative MR techniques which are significantly changing our views on NMO pathobiology.

Imaging primary progressive multiple sclerosis: the contribution of structural, metabolic, and functional MRI techniques

Abstract: Patients with primary progressive multiple sclerosis (PPMS) typically experience a progressive disease course from onset, leading to the accumulation of severe neurological disability. This is in contrast with the observation that the burden and activity of lesions on conventional magnetic resonance imaging (MRI) scans of the brain are much lower in patients with PPMS than in those with other less disabling forms of the disease. Studies with structural and functional MRI techniques are providing relevant contributions to the understanding of the mechanisms underlying the accumulation of irreversible neurological deficits in patients with PPMS. The results of these studies underpin that the main factors possibly explaining the clinical/MRI discrepancy observed in patients with PPMS include the presence of a diffuse tissue damage that is beyond the resolution of conventional imaging, the extent of cervical cord damage, and the impairment of the adaptive capacity of the cortex to limit the functional consequences of subcortical pathology.

Multiparametric MRI in a patient with adult-onset leukoencephalopathy with vanishing white matter

Abstract: This is a multiparametric MR study of the first reported patient with adult-onset genetically confirmed vanishing white matter (VWM) disease. It shows that, despite the presence of a severe and diffuse damage of the brain WM, brain gray matter, and cervical cord tissue, the cortical adaptive capacities were relatively preserved. Interpatient variability of brain plasticity may contribute to the known phenotypic variation of patients with VWM disease.

Brain plasticity in multiple sclerosis.

Abstract: Accessible online at: www.karger.com/ene The last two decades have witnessed an increased effort in understanding the mechanisms responsible for the accumulation of irreversible disability in multiple sclerosis (MS). In this context, the clinical application of magnetic resonance imaging (MRI) techniques has progressively increased our ability to achieve an accurate quantification of the overall burden of the disease and to monitor its course objectively. More recently, the use of functional MRI in the assessment of MS patients has shown a modified recruitment of cortical areas during motor, cognitive and sensory tasks in MS patients [1]. Functional cortical changes have been demonstrated during the acute phase of the disease [2] and in clinically stable patients with different disease phenotype and clinical impairment [1]. It has also been shown that cortical adaptive changes might be elicited and/or modulated by different substrates, including the extent of T2-visible lesions and the severity of their intrinsic damage, the amount of normal-appearing white matter and gray matter damage, the extent of axonal loss/dysfunction and the severity of spinal cord involvement [1]. Up to now, the role of brain atrophy on cortical functional changes has not been fully elucidated yet. Conversely, this variable has been carefully controlled in all the previous studies in order to avoid a possible bias in functional MRI results. The single case report of Roelcke et al. [3] presented in this issue may be considered as a preliminary view on this important topic. The progressive development of brain atrophy is a well-known feature of MS patients [4]. Using different measurement techniques, many studies have shown that atrophy of the brain is present from the earliest stages of the disease and tends to progress with disease evolution [4]. In their report, Roelke et al. [3] compared the movement-associated pattern of cortical activations between the atrophic and the normal hemisphere in an MS patient with unilateral brain atrophy and found no differences in the location, extent and significance of the cluster of activations between the two hemispheres. In some longitudinal follow-up studies of MS patients with a subcortical lesion affecting the corticospinal tracts, we invariably found during self-paced movements an increased activation of the contralateral primary motor cortex associated with increased activation of the supplementary motor area and ipsilateral primary motor cortex. During the follow-up, the overactivation both in the contralateral and ipsilateral areas always decreased if a good recovery of motor function was achieved. However, also in patients with good recovery, some increased activation of cortical motor areas persisted, indicating that cortical reorganization contributed to the recovery. Interestingly enough, in the more advanced phases of the disease, in patients with severe motor deficits, the overactivation of cortical motor areas (both contralateral and ipsilateral) disappeared, suggesting that the decrease in motor ability

Diffusion tensor and magnetization transfer MR imaging of early-onset multiple sclerosis.

Abstract: Multiple sclerosis (MS) is a chronic, demyelinating disease of the central nervous system (CNS) with the onset of symptoms typically occurring between the age of 20 and 40 years. However, in about 3% to 12% of the cases, the onset of the disease is before 16 years of age. This review summarizes the main results obtained by the application of conventional and non-conventional MRI techniques to the assessment of patients with early-onset MS, which showed that the overall amount of CNS damage in these subjects is mild, compared to that typically detected in the adult-form of the disease. This fits with the notion that an early onset of the disease is associated with a more favourable clinical evolution.