在多发性硬化症早期阶段弥散张量MRI检测到的正常表现白质的损害与疾病短期内的活动度无关

Background: Diffusion-tensor (DT) magnetic resonance imaging (MRI) has the po tential to elucidate some characteristics of tissue microstructure inaccessible to other MRI techniques. Objective: To investigate whether normal-appearing bra in tissue abnormalities occur in patients with multiple sclerosis at the earlies t clinical stage and whether their severity is predictive of a short-term disea se evolution by using DT MRI. Design: Forty-five patients and 22 healthy contro l subjects were studied. All patients had had a clinically isolated syndrome wit hin the 3 months preceding study enrollment and paraclinical evidence of disease dissemination in space. During a single session, dual-echo, pulsed-gradient s pin-echo echo-planar, and postgadolinium T1-weighted images of the brain were obtained from each subject. In patients, dual-echo and enhanced images were ob tained after 3 and 12 months, to detect MRI signs of disease dissemination in ti me. An on-study neurological examination was also conducted to ascertain the oc currence of clinical relapses. Mean diffusivity and fractional anisotropy maps w ere derived from DT images. Normal-appearing white matter (N-AWM) and normal- appearing gray matter mean diffusivity and fractional anisotropy histograms were produced and analyzed. Results: During the study period, 29 patients showed MRI evidence of disease dissemination in time. When compared with healthy controls, patients showed higher average NAWM mean diffusivity (P=.01), lower average NAW M mean diffusivity peak height (P < .001), and fractional anisotropy (P < .001). The DT MRI characteristics of patients did not differ between those with and those without disease dissemina tion in time at follow-up. Conclusions: In patients with multiple sclerosis at the earliest clinical stage, the severity of NAWM damage does not predict new le sion formation in the short term, suggesting that the “diffuse”component of ti ssue damage is, at least partially, independent of the “discrete,”predominantl y inflammatory aspects of the disease since its clinical onset.

应用弥散张量MRI定量分析原发进展型MS的颈髓病变

Objective: To investigate the extent and severity of cervical cord damage usin g diffusion tensor MRI (DT-MRI) and histogram analysis in patients with primary progressive MS (PPMS). Methods: Diffusion-weighted sensitivity-encoded (SENSE ) echoplanar images of the cervical cord and brain dual-echo and diffusion-wei ghted scans were acquired from 24 patients with PPMS and 13 healthy controls. Cord and brain mean diffusivity and fractional anisotropy histograms were produced. An analysis of variance mod el, adjusting for cord volume, was used to compare cord DT-MRI parameters from controls and patients. Results: Compared to healthy controls, PPMS patients had reduced cervical cord cross-sectional area and average cord fractional anisotro py (p= 0.007), and increased cord mean diffusivity (p = 0.024). No correlations were found between DT-MRI metrics of the cord and quantities obtained from conv entional and DT-MRI of the brain. Conclusions: DT-MRI of the cervical cord can quantify the extent of diffuse cord pathology in patients with PPMS. Such cord diffusivity changes in patients with PPMS are likely to reflect irreversible axo nal injury and reactive gliosis and seem to be independent of brain damage.

干扰素β-1b对多发性硬化症患者疗效的磁共振成像分布

Whereas the effect of interferons (IFNs) on magnetic resonance imaging (MRI) outcome measures in patients with multiple sclerosis (MS) has been convincingly shown, little work has been done to define the between-patient heterogeneity of treatment response. Our aim was to assess the distribution of the effect of IFNβ - 1b in terms of reduction of active T2 lesions in patients with MS. Using a fixed and a random effects model, we investigated the distribution of active T2 lesions reduction over a three-year follow up in response to treatment with 250 mcg IFNβ -1b every other day in 695 patients with a complete MRI data-set of the 718 (97 % ) enrolled in the European, multicenter, randomised, double-blind, placebo-controlled trial of secondary progressive MS. The two statistical models consistently showed that the between-patient response to IFNβ -1b, in terms of reduction of active T2 lesions, is highly heterogeneous. Whereas treated patients have a high probability (more than 65 % ) of showing an active T2 lesion reduction equal to or greater than 60 % , there is also a 7 % probability for treated patients not to show any reduction of MRI-detected disease activity during the course of the trial or even to have an increase of T2 active lesions. This study might be regarded as a first step toward the definition of markers potentially useful to identify IFNβ treatment responders and non-responders with regard to T2 lesion activity.

可进展为多发性硬化的临床横断综合征患者颈髓磁转移磁共振研究

Cervical cord magnetization transfer ratio (MTR) histograms were obtained from 45 patients at presentation with clinically isolated syndromes (CIS) suggestive ofmultiple sclerosis (MS). The mean values of MTR histogram derived metrics were not different between CIS patients and healthy control subjects or between patients with and without evidence of disease dissemination in time. Only three patients showed significantly lower cord MTR values than control subjects. These findings suggest the absence of intrinsic structural damage of the cervical cord soon after the onset of CIS suggestive of MS, even in those patients with an early evolution to MS.