Use Of Combined Conventional And Quantitative MRI To Quantify Pathology Related To Cognitive Impairment In Multiple Sclerosis
Lin X, Tench CR, Morgan PS, Constantinescu CS
J Neurol NeuroSurg Psychiatry 2008 Apr;79(4):437-41
University of Nottingham, Rehabilitation Research Unit, Derby City General Hospital, Derby, UK
Cognitive Impairment is one of the frequent and early findings in Multiple Sclerosis (MS).
To determine the relation between Cognitive abnormalities and the extent of macroscopic and microscopic tissue damage in the Corpus Callosum (CC), revealed by conventional Magnetic Resonance Imaging (MRI), Magnetization Transfer Imaging (MTI) and Diffusion Tensor Imaging (DTI).
Conventional dual-echo, DTI and MTI of the Brain were obtained from 36 patients with Relapsing/Remitting (RR) MS, and 13 age and gender matched normal controls.
Voxels from CC were identified using a Tractography based algorithm. Mean Apparent Diffusion Coefficient (mean trace ADC(av)) and MT Ratio were measured for the CC as defined by Tractography.
Corpus Callosum Area (CCA) was measured using edge detection on the mid-sagittal slice on high resolution MRI images.
The Expanded Disability Status Scale (EDSS) and Paced Auditory Serial Addition Test (PASAT) were scored.
Nine patients (25%) were found to be Cognitively Impaired.
The CCA was not significantly different in the whole cohort of patients from controls (608.2 (428.6-713.0) mm2 vs 674.2 (585.8-754.4) mm2, p = 0.1).
But, was smaller in Cognitively Impaired than unimpaired group (417 (290-634) mm2 vs 652 (511-718) mm2, p = 0.04).
The mean MT Ratio of CC in patients was lower than in controls (0.41 (0.39-0.042) vs 0.43 (0.42-0.43), p < 0.001).
The mean trace ADC(av) in the CC in patients was higher than in controls (0.94 (0.89-0.99) vs 0.87 (0.85-0.89), p < 0.001).
PASAT was correlated with mean MT Ratio (r = 0.47, p = 0.0046), ADC(av) (r = -0.53, p = 0.0012), CCA (r = 0.42, p = 0.01) and total T2 lesion load (r = -0.4, p = 0.017).
But, not with T2 lesion load within the CC (r = -0.24, p = 0.16), disease duration (r = -0.2, p = 0.24) or EDSS (r = -0.27, p = 0.12).
mean trace ADC(av), MTR and Atrophy measures in the CC may offer a sensitive method detecting subtle macroscopic and microscopic changes associated with Cognitive Impairment in MS.
Corpus Callosum Damage And Cognitive Dysfunction In Benign MS
Mesaros S, Rocca MA, Riccitelli G, Pagani E, Rovaris M, Caputo D, Ghezzi A, Capra R, Bertolotto A, Comi G, Filippi M
Hum Brain Mapp 2009 Aug;30(8):2656-66
Scientific Institute and University Ospedale San Raffaele, NeuroImaging Research Unit, Milan, Italy
Corpus Callosum (CC), the largest compact White Matter fiber bundle of the human Brain involved in InterHemispheric transfer, is frequently damaged in the course of Multiple Sclerosis (MS).
Cognitive Impairment is one of the factors affecting quality of life of patients with Benign MS (BMS).
The aim of this study was to investigate the relationship between the Cognitive profile of BMS patients and the extent of tissue damage in the CC.
Brain conventional and DT MRI scans were acquired from 54 BMS patients and 21 healthy controls. NeuroPsychological Tests (NPT) exploring Memory, Attention, and Frontal Lobe Cognitive Domains were administered to the patients.
DT Tractography was used to calculate the Mean Diffusivity (MD) and Fractional Anisotropy (FA) of the CC Normal-Appearing White Matter (NAWM). An index of CC Atrophy was also estimated.
Nine (17%) BMS patients fulfilled criteria for Cognitive Impairment. Compared with controls, BMS had significantly different CC Diffusivity and Volumetry (P < 0.001).
Compared with Cognitively Preserved patients, those with CI had significantly higher CC lesion volume (LV) (P = 0.02) and NAWM MD (P = 0.02).
The scores obtained at PASAT were significantly correlated with CC T2 LV, and NAWM FA and MD (r values ranging from -0.31 to 0.66, P values ranging from 0.04 to < 0.001).
Cognitive Impairment in BMS is associated with the extent of CC damage in terms of both focal lesions and diffuse fiber bundle injury.
MRI assessment of topographical distribution of tissue damage may represent a rewarding strategy for understanding the subtle clinical deficits of patients with BMS.
Hum Brian Mapp 2009. (c) 2008 Wiley-Liss, Inc.
Cognitive Impairment And Structural Brain Damage In Benign Multiple Sclerosis
Rovaris M, Riccitelli G, Judica E, Possa F, Caputo D, Ghezzi A, Bertolotto A, Capra R, Falautano M, Mattioli F, Martinelli V, Comi G, Filippi M
Neurology 2008 Nov 4;71(19):1521-6
From the NeuroImaging Research Unit (M.R., G.R., M. Filippi) and Department of Neurology (M.R., E.J., F.P., M. Falautano, V.M., G.C., M. Filippi), Scientific Institute and University Ospedale San Raffaele, Milan; Department of Neurology (D.C.), Scientific Institute Don Gnocchi, Milan; Multiple Sclerosis Center (A.G.), Ospedale di Gallarate, Gallarate; Multiple Sclerosis Center (A.B.), Ospedale di Orbassano, Orbassano; and Multiple Sclerosis Center (R.C., F.M.), Spedali Civili, Brescia, Italy
Although in Benign Multiple Sclerosis (BMS) locomotor disability is absent or only minimal, subclinical Cognitive Impairment seems to occur in many cases.
Diffusion Tensor (DT) MRI enables us to quantify the extent of "actual" tissue damage, which goes undetected when using conventional MRI.
Against this background, we investigated the extent of structural Brain damage underlying Cognitive Dysfunction in BMS, with the ultimate aim to move a first step toward a more reliable definition of this disease phenotype.
Conventional and DT MRI scans of the Brain were acquired from 62 BMS patients. Thirty-six Secondary/Progressive Multiple Sclerosis (SPMS) patients and 19 healthy subjects served as controls.
In BMS patients, NeuroPsychological tests exploring Memory, Attention, and Frontal Lobe functions were administered.
Normalized Brain Volume (NBV), Mean Diffusivity (MD), and Fractional Anisotropy (FA) of the Normal-Appearing White Matter (NAWM) and MD of the Gray Matter (GM) were computed.
Twelve BMS patients (19%) fulfilled predefined criteria for Cognitive Impairment. BMS patients had abnormal MD and FA values from both NAWM and GM.
Whereas BMS patients without Cognitive Impairment had lower T2 LV (p = 0.03), higher NBV (p = 0.006), and lower average GM MD (p = 0.03) than SPMS patients, BMS patients with Cognitive Impairment did not significantly differ from SPMS patients for any MRI-derived metric.
In Benign Multiple Sclerosis (BMS), Cognitive Dysfunction is associated with severe structural Brain damage, which resembles that of patients with a much more disabling disease course.
A reliable definition of BMS should, therefore, include the preservation of Cognitive functioning as an additional requisite.
Structural And Functional MRI Correlates Of Stroop Control In Benign MS
Rocca MA, Valsasina P, Ceccarelli A, Absinta M, Ghezzi A, Riccitelli G, Pagani E, Falini A, Comi G, Scotti G, Filippi M
Hum Brain Mapp 2009 Jan;30(1):276-90
University Ospedale San Raffaele, NeuroImaging Research Unit, Milan Italy
The objective of this study was to assess the functional and structural substrates of Cognitive Network changes in patients with Benign Multiple Sclerosis (BMS), using an analysis of effective connectivity and MR Tractography.
Using a 3-Tesla scanner, we acquired Dual-Echo, Diffusion Tensor (DT) and Functional MRI during the performance of the Stroop task from 15 BMS patients and 19 healthy controls.
DT MR Tractography was used to calculate DT derived metrics from several White Matter (WM) fiber bundles, thought to be involved in Cognitive performance.
DT MRI metrics from WM fiber bundles not directly related with Cognitive performance were also derived. Effective connectivity analysis was performed using statistical parametric mapping.
MS patients had significantly abnormal DT MRI metrics in all the structures analyzed. Compared with controls, MS patients had more significant activations of several areas of the Cognitive Network involved in Stroop performance, bilaterally.
Compared with controls, BMS patients also had increased connectivity strengths between several Cortical Areas of the SensoriMotor Network and the Right (R) Inferior Frontal Gyrus and the R Cerebellum, as well as decreased connectivity strengths with the Anterior Cingulate Cortex.
Coefficients of altered connectivity were moderately correlated with structural MRI metrics of tissue damage within Intra- and Inter-Hemispheric Cognitive-related WM fiber bundles.
While no correlations were found with the remaining fiber bundles studied, suggesting that Functional Cortical Changes in patients with BMS might represent an adaptive response driven by damage of specific WM structures.
(c) 2007 Wiley-Liss, Inc.