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Biomedical subjects

M Filippi

Publications and source records attributed to M Filippi.

At least 37 records · Page 2Linked to original sources
PubMed2002

Contribution of cervical cord MRI and brain magnetization transfer imaging to the assessment of individual patients with multiple sclerosis: a preliminary study.

This study was performed to assess how established diagnostic criteria for brain magnetic resonance imaging (MRI) interpretation in cases of suspected multiple sclerosis (MS) (Barkhofs criteria) would perform in the distinction of MS from other diseases and whether other MR techniques (cervical cord imaging and brain magnetization transfer imaging [MTI]), might help in the diagnostic work-up of these patients. We retrospectively identified 64 MS and 59 non-MS patients. The latter group included patients with systemic immune-mediated disorders (SID; n=44) and migraine (n=15). All patients had undergone MRI scans of the brain (dual echo and MTI) and of the cervical cord (fast short-tau inversion recovery). The number and location of brain T2-hyperintense lesions and the number and size of cervical cord lesions were assessed. Brain images were also postprocessed to quantify the total lesion volumes (TLV) and to create histograms of magnetization transfer ratio (MTR) values from the whole of the brain tissue. Barkhofs criteria correctly classified 108/123 patients, thus showing an accuracy of 87.8%. "False negative" MS patients were 13, while 2 patients with systemic lupus erythematosus (SLE) were considered as "false positives". Using brain T2 TLV, nine of the "false negative" patients were correctly classified. Correct classification of 10 MS patients and both the SLE patients was possible based upon the presence or absence of one cervical cord lesion. Two MS patients with negative Barkhofs criteria and no cervical cord lesions were correctly classified based on their brain MTR values. Overall, only one MS patient could not be correctly classified by any of the assessed MR quantities. These preliminary data support a more extensive use of cervical cord MRI and brain MTI to differentiate between MS and other disorders in case of incondusive findings on T2-weighted MRI scans of the brain.

Adolescent↗
PubMed2002

Two-year follow-up study of primary and transitional progressive multiple sclerosis.

This study documents changes in clinical and magnetic resonance imaging (MRI) characteristics in a large cohort of patients with primary and transitional progressive multiple sclerosis (PP and TPMS) over 2 years. Patients with PPMS and TPMS were recruited from six European centres and underwent clinical and MRI examination at three time points: baseline, year one and year two. Of the 190 patients recruited clinical data were available on 125 patients (66%, five centres) and MRI data were available on 113 patients (59%, four centres) at 2 years. Significant increases were seen in T2 load and T1 hypointensity, while brain and cord volume decreased. In PPMS significantly higher lesion loads were found in those who presented with non-cord syndromes when compared to cord presentation and there was a trend to greater brain atrophy in those who deteriorated clinically over the course of the study compared to those who remained stable. Significant cord atrophy was only seen in those with a cord presentation. Measurable changes in MRI parameters can be detected in PPMS patients over a relatively short period of time. MRI quantification is likely to be useful in elucidating disease mechanisms in PPMS and in the execution of clinical trials.

Adult↗
PubMed2001

The effect of IFNbeta-1b on the evolution of enhancing lesions in secondary progressive MS.

BACKGROUND: After the resolution of contrast enhancement, the majority of new MS lesions become isointense with surrounding white matter on T1-weighted MRI. Less commonly, a hypointense T1 lesion develops, representing the development of more severe focal tissue damage. Interferon beta (IFNbeta) reduces both the number of new enhancing lesions and the duration of contrast enhancement. OBJECTIVE: To determine if IFNbeta affects the degree of tissue damage within new lesions and if its effects are related to lesion size. METHODS: One hundred twenty-five patients with secondary progressive MS from seven European sites were randomized to receive either IFNbeta-1b or placebo. Monthly, contrast-enhanced T1-weighted MR images were acquired at baseline, at months 1 to 6, and at months 19 to 24. The size of all new enhancing lesions developing between months 1 and 6 was recorded and their appearance at follow-up documented. RESULTS: In the first 6 months, fewer new enhancing lesions occurred in the IFNbeta-1b arm. This difference was greater for small (70% decrease) than for large (46% decrease) lesions. Hypointense T1 lesions were more likely to form from large (25%) than from small (9%) enhancing lesions in both treatment arms. Patients taking IFNbeta-1b developed fewer hypointense T1 lesions; however, the proportion of enhancing lesions developing into hypointense T1 lesions was similar in both arms. CONCLUSION: IFNbeta-1b reduced the number of new enhancing lesions, with a greater effect on small lesions. However, when a new enhancing lesion did become established, treatment with IFNbeta-1b did not alter its subsequent course.

Adult↗
PubMed2001

Clinical-MRI correlations in a European trial of interferon beta-1b in secondary progressive MS.

BACKGROUND: The recently completed placebo-controlled multicenter randomized trial of interferon beta-1b (Betaferon) in 718 patients with secondary progressive MS shows significant delay of disease progression and reduction of relapse rate. This study provides an opportunity to assess the level of relationship between clinical and MRI outcomes in this cohort of patients with secondary progressive MS. METHODS: Brain T2-weighted lesion volume was measured annually in all available patients, with visual analysis to identify any new or enlarging (active) T2 lesions at each annual time point. A subgroup of 125 patients had monthly gadolinium-enhanced, T1-weighted imaging at months 0 to 6 and 18 to 24. Relapses were documented and expanded disability status scale (EDSS) was measured every 3 months. RESULTS: For the annual MRI outcomes, a significant but modest correlation was identified between the change in T2 lesion volume from baseline to the final scan and the corresponding change from baseline in EDSS (r = 0.17, p < 0.0001). There were significant correlations between the cumulative number of active T2 lesions and 1) change in EDSS (r = 0.18, p < 0.0001) and 2) relapse rate (r = 0.24, p < 0.0001). In the subgroup of 125 patients undergoing monthly imaging, MRI lesion activity was correlated with relapse rate over months 0 to 24 (r = 0.24, p = 0.006) but not with change in EDSS. CONCLUSIONS: These results confirm that the clinical-MRI relationships previously identified in relapsing-remitting MS still are apparent in the secondary progressive phase of the disease and support the use of MRI as a relevant outcome measure. In view of the relatively modest nature of the correlations, it seems unwise to rely on such MRI measures alone as primary efficacy variables in secondary progressive MS trials.

Brain↗
PubMed2001

Single-cell analysis of cytokine production shows different immune profiles in multiple sclerosis patients with active or quiescent disease.

Peripheral blood mononuclear cells of multiple sclerosis (MS) patients were stimulated with myelin basic protein (MBP) together with anti-CD28 monoclonal antibody and staphylococcal enterotoxin B to optimize cytokine production by antigen-specific cells. Type 1 (IL-2, IL-12, IFNgamma) and pro-inflammatory (TNFalpha, IL-1beta, IL-6) cytokines were augmented in CD4+, CD8+, and CD14+ cells of acute MS patients and of patients undergoing disease reactivation. These cytokines were reduced in IFNbeta-treated and in stable MS patients; type 2 cytokines (IL-4, IL-10) were increased in these patients. Similar immune profiles are seen in MS patients in whom remission is naturally or pharmacologically (IFNbeta) achieved. Cytokine alterations are particularly evident in CD14+ cells, underlying their critical role in the modulation of the immune response.

Adjuvants, Immunologic↗
PubMed2001

Sample size estimations for MRI-monitored trials of MS comparing new vs standard treatments.

The authors estimated the sample sizes needed for exploratory trials of MS assessing the efficacy of new treatments in reducing the number of new enhancing lesions vs those of interferon-beta or glatiramer acetate. The sample sizes per arm ranged from 868 (effect: 20%) to 94 (effect: 50%) for patients with relapsing-remitting MS and from 2,484 (effect: 20%) to 361 (effect: 50%) for patients with secondary progressive MS. In MS, exploratory trials of new vs available therapies require large numbers of patients, even when MR end-points are used.

Adjuvants, Immunologic↗
PubMed2001

Quantification of tissue damage in AD using diffusion tensor and magnetization transfer MRI.

The authors measured mean diffusivity (D) and magnetization transfer ratio (MTR) of the brain from 18 patients with AD and 16 healthy control subjects. The peak heights of cortical gray matter (cGM) D (p < 0.001) and MTR (p < 0.001) histograms were lower and average cGM D (p < 0.01) higher in patients with AD than in control subjects. A composite MR score based on brain volume and cGM MTR peak height was correlated with patient cognitive impairment (r = 0.65, p = 0.003). This preliminary study presents a novel approach to quantify AD-related tissue damage in-vivo.

Aged↗
PubMed2001

Glatiramer acetate reduces the proportion of new MS lesions evolving into "black holes".

The authors evaluated whether glatiramer acetate (GA) modifies the severity of tissue damage in 1,722 new lesions from 239 patients with MS enrolled in a placebo-controlled trial monitored with monthly cerebral MRI. The percentage of new lesions that evolved into "black holes" was lower in GA-treated than in placebo patients on scans at 7 (18.9 and 26.3%; p = 0.04) and 8 (15.6 and 31.4%; p = 0.002) months after lesion appearance. GA has a favorable effect on tissue disruption in MS lesions once they are formed.

Adolescent↗
PubMed2001

Magnetization transfer and diffusion tensor MR imaging of the optic radiations and calcarine cortex from patients with Leber's hereditary optic neuropathy.

Optic nerve abnormalities are easily detectable in patients with Leber's hereditary optic neuropathy (LHON), using magnetic resonance imaging (MRI). However, the presence of structural changes in the optic radiations and calcarine cortex of these patients is still an unresolved issue. In this study, we obtained magnetization transfer (MT) and diffusion tensor (DT) MRI to investigate the integrity of these structures in patients with LHON. Dual echo, MT- and DT-MRI scans of the brain were obtained from 10 men with LHON and 10 healthy sex- and age-matched controls. After image co-registration, we obtained MT ratio (MTR), average diffusivity (D) and fractional anisotropy (FA) maps. MTR, D and FA values for the white matter of the optic radiations and MTR and D values for the calcarine cortex were obtained using a region of interest (ROI) analysis. No macroscopic abnormalities were detected in any of the scans from LHON patients and controls. No statistically significant differences of MTR, D or FA values were found for any of the regions studied in LHON patients and healthy controls. Our results suggest that, in patients with LHON, the optic radiations and the calcarine cortex are spared from structural damage, both at a macroscopic and a microscopic level.

Adult↗
PubMed2001

Autologous hematopoietic stem cell transplantation suppresses Gd-enhanced MRI activity in MS.

BACKGROUND: Autologous hematopoietic stem cell transplantation (ASCT) has been recently utilized with encouraging results in patients with poorly controlled MS. OBJECTIVE: To determine in severe cases of MS the effect of ASCT on gadolinium (Gd)-enhanced MRI and to obtain information on clinical course and safety. METHODS: In a cooperative study, 10 patients with rapidly evolving secondary progressive MS were transplanted, after BEAM conditioning regimen (carmustine, etoposide, cytosine-arabinoside, and melphalan), with unmanipulated autologous peripheral blood SC mobilized with high-dose cyclophosphamide (CY; 4 g/m2) and granulocyte-colony-stimulating factor. Triple-dose Gd-enhanced scans were performed monthly for a pretreatment period of 3 months and compared with serial monthly Gd-enhanced MRI for the following 6 months and then once every 3 months. RESULTS: The median follow-up is now 15 months (range 4 to 30 months). The number of Gd-enhancing lesions decreased immediately after mobilization with CY and finally dropped to zero in all cases after the conditioning regimen. The number of new T2-weighted positive lesions paralleled data obtained for Gd-enhanced MRI. Clinically, patients improved slightly or remained stable. CONCLUSION: These results demonstrate that the therapeutic sequence CY-BEAM-ASCT has the capacity to completely suppress MR-enhancing activity, an effect that is sustained with time. The final impact of this procedure on disease course remains to be established.

Adult↗
PubMed2001

Correlates of MS disability assessed in vivo using aggregates of MR quantities.

OBJECTIVES: To assess the magnitude of the correlations between disability and composite MRI scores in patients with MS. METHODS: T2- and T1-weighted MRI, magnetization transfer imaging, diffusion tensor imaging, and MRS imaging scans of the brain from 23 patients with MS were obtained. T2 lesion volume, T1 lesion volume, brain magnetization transfer ratio, average brain diffusivity (D), and brain N-acetylaspartate/creatine ratio were measured. RESULTS: The correlations between the Expanded Disability Status Scale (EDSS) score and each of the MR quantities taken in isolation were not significant, with the exception of the correlation between EDSS and the NAA/creatine ratio (r = -0.50; p = 0.01). In contrast, three of the composite MR scores computed using regression models were strongly correlated with the EDSS scores (r range, 0.58 to 0.73; p range, 0.004 to 0.0001). The model that included T2 and T1 lesion volumes and brain D explained 34% of the EDSS variance; the model that included T2 and T1 lesion volumes and brain N-acetylaspartate/creatine ratio explained 36% of the EDSS variance; the model that included T1 lesion volume, brain D, and brain N-acetylaspartate/creatine ratio explained 53% of the EDSS variance. CONCLUSIONS: The results suggest that multiparametric MR models have the potential to provide powerful measures to monitor MS evolution.

Adult↗
PubMed2001

A magnetic resonance imaging study of the cervical cord of patients with CADASIL.

The authors obtained MR and magnetization transfer (MT) imaging of the cervical cord from 25 patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL). They found no conventional MR abnormalities, but a reduced peak height of the MT ratio (MTR) histogram. This suggests a reduced amount of "truly" normal cord tissue in CADASIL. A significant correlation was found between the extent of brain lesions and cord MTR, suggesting wallerian degeneration as the substrate of the cord MTR changes.

Adult↗
PubMed2001

Effect of early interferon treatment on conversion to definite multiple sclerosis: a randomised study.

BACKGROUND: Interferon beta reduces activity in multiple sclerosis as measured clinically and by magnetic resonance imaging (MRI). We assessed the effect of interferon beta-1a on the occurrence of relapses in patients after first presentation with neurological events, who are at high risk of conversion to clinically definite multiple sclerosis. METHODS: Eligible patients had had a first episode of neurological dysfunction suggesting multiple sclerosis within the previous 3 months and had strongly suggestive brain MRI findings. Patients were randomly assigned interferon beta-1a 22 microg or placebo subcutaneously once weekly for 2 years. Neurological and clinical assessments were done every 6 months and brain MRI every 12 months. Analyses excluded one patient assigned placebo who received no study injections. FINDINGS: 241 (78%) of 308 randomised patients received study treatment for 2 years; 278 (90%) remained in the study until termination. 57 (85%) of 67 who stopped therapy did so after conversion to clinically definite multiple sclerosis. Fewer patients developed clinically definite multiple sclerosis in the interferon group than in the placebo group (52/154 [34%] vs 69/154 [45%]; p=0.047). The time at which 30% of patients had converted to clinically definite multiple sclerosis was 569 days in the interferon group and 252 in the placebo group (p=0.034). The annual relapse rates were 0.33 and 0.43 (p=0.045). The number of new T2-weighted MRI lesions and the increase in lesion burden were significantly lower with active treatment. INTERPRETATION: Interferon beta-1a treatment at an early stage of multiple sclerosis had significant positive effects on clinical and MRI outcomes.

Adolescent↗
PubMed2001

The role of non-conventional MR techniques to study multiple sclerosis patients.

Conventional magnetic resonance imaging (MRI) lacks pathological specificity to the heterogeneous substrates of multiple sclerosis (MS) lesions and is not able to detect subtle, disease-related changes in the normal-appearing white matter (NAWM). As a consequence, the correlation between MRI findings and the long-term evolution of MS is moderate at best. To overcome the limitations of conventional MRI, new quantitative magnetic resonance (MR) techniques, such as cell-specific imaging, magnetization transfer imaging (MTI), proton magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI) and functional MR imaging (fMRI) have all been recently applied to the study of MS. These techniques should provide more accurate and pathologically specific estimates of the MS lesion burden than conventional MR and should improve our understanding of the mechanisms leading to MS-related irreversible disability.

Humans↗
PubMed2001

Overview of diffusion-weighted magnetic resonance studies in multiple sclerosis.

Diffusion-weighted magnetic resonance imaging (DW-MRI) provides a unique form of MR contrast that enables the diffusional motion of water molecules to be quantitatively measured. As a consequence, DW-MRI provides information about the size, shape, integrity, and orientation of brain structures. Pathological processes able to alter tissue integrity by removing or modifying some of the structural barriers that normally restrict water molecular motion in biological tissues cause changes in water diffusion characteristics, which can be measured in-vivo using DW-MRI. Although DW-MRI has been shown to be of great clinical utility in the assessment of patients with cerebral ischemia, it is also increasingly being used to quantify in-vivo the extent and severity of multiple sclerosis (MS) pathology. The pathological elements of MS have the potential to alter the permeability or geometry of structural barriers to water molecular motion in the brain, optic nerve and spinal cord. The present review outlines the major contributions given by DW-MRI for the quantification of MS-related damage and for the understanding of MS pathophysiology.

Animals↗
PubMed2001

Diffusion tensor magnetic resonance imaging in multiple sclerosis.

OBJECTIVES: To quantify, using diffusion tensor imaging (DTI), the tissue damage in lesions and normal-appearing white matter (NAWM) from a large cohort of patients with MS and to investigate the magnitude of the correlation between DTI-derived metrics and clinical disability. METHODS: Dual-echo and DTI scans were obtained from 78 patients with relapsing-remitting, secondary progressive, or primary progressive MS and from 20 normal control participants. Post-contrast T1-weighted images were also obtained from the patients. After creating mean diffusivity (D) and fractional anisotropy (FA) images and image coregistration, D and FA values were measured for 4846 lesions (3207 nonenhancing T1-isointense, 1511 nonenhancing T1-hypointense, and 128 enhancing), 497 NAWM areas from patients, and 160 white matter areas from the controls. RESULTS: The average lesion D was higher and the average lesion FA was lower than the corresponding quantities of the NAWM (p < 0.001). The values of enhancing and nonenhancing lesions were not different, whereas enhancing lesions had lower FA (p < 0.001). T1-hypointense lesions had higher D and lower FA than T1-isointense lesions (p < 0.001). NAWM of patients had higher and lower FA than white matter of controls (p = 0.01). Significant correlations were found between T1 and T2 lesion volume and and FA of lesions and NAWM. In the overall patient sample, a moderate correlation was also found between lesion D and the Expanded Disability Status Scale score (r = 0.28, p = 0.01). However, the r value of this correlation was 0.48 in patients with secondary progressive MS, whose disability was also correlated with average lesion FA (r = -0.50). CONCLUSIONS: The results of this study show that DTI is able to identify MS lesions with severe tissue damage and to detect changes in the NAWM. They also indicate that DTI-derived measures are correlated with clinical disability, especially in patients with secondary progressive MS, thus suggesting a role for DTI in monitoring advanced phases of the disease.

Adult↗