Objective To compare the clinical features between radiological isolated syndrome (RIS) and classical multiple sclerosis (CMS), in order to improve the understanding of the RIS. Methods All 35 patients with RIS and 32 patients with CMS were selected. The epidemiological and clinical findings, cerebrospinal fluid, neural electrophysiological examination and magnetic resonance imaging (MRI) data were analyzed. Results There were no statistical differences in sex ratio and onset age between RIS patients and CMS patients (P>0.05). The main symptoms of in patients with RIS were headache (45.7%, 16/35), dizziness (40.0%, 14/35), hypomnesis (20.0%, 7/35) and psychiatric disorders (11.4%, 4/35). But the main symptoms of in patients with CMS were limb weakness (75.0%, 24/32), sensory abnormalities (68.8%, 22/32) and ocular symptoms (34.4%,11/32). The incidences of limb weakness, sensory abnormalities and ocular symptoms in patients with CMS were significantly higher than those in patients with RIS:75.0%(24/32) vs. 0, 68.8%(22/32) vs. 0 and 34.4%(11/32) vs. 0, and there were statistical differences (P<0.01). The 18 patients with RIS and 21 patients with CMS underwent the examination of cerebrospinal fluid, and there was no significant difference in leukocyte between patients with RIS and patients with CMS (P>0.05). The cerebrospinal fluid protein and the incidences of IgG index>0.7 in patients with RIS were significantly lower than those in patients with CMS:0.175 (0.03-0.69) g/L vs. 0.440 (0.04-1.09) g/L and 3/18 vs. 47.6%(10/21), and there were statistical differences (P<0.05). The 15 patients with RIS and 22 patients with CMS underwent the examination of neural electrophysiological, and the abnormality rates of visual evoked potential (VEP) and brain stem auditory evoked potential (BAEP) in patients with RIS were significantly lower than those in patients with CMS:4/15 vs. 63.6%(14/22) and 3/15 vs. 54.5%(12/22), and there were statistical differences (P<0.05). But there was no statistical difference in the abnormality rate of somatosensory evoked potential (SEP) between patients with RIS and patients with CMS (P>0.05). On MRI, the demyelinating lesions of RIS and CMS were both mainly distributed in the periventricular, semi-oval center, infratentorial white matter, partly involving corpus callosum or cortical. The rates of demyelinating lesions in brainstem and cerebellum in patients with RIS were significantly lower than those in patients with CMS:5.7%(2/35) vs. 34.4% (11/32) and 2.9% (1/35) vs. 25.0% (8/32), and there were statistical differences (P<0.01 or <0.05). Comparison with CMS lesions, RIS lesions mainly showed patching and stippled, and there were statistical differences (P<0.01 or <0.05). The rates of lesions enhancement and spinal cord injury in patients with RIS were significantly lower than those in patients with CMS: 2/17 vs. 45.0% (9/20) and 1/14 vs. 43.5% (10/23), and there were statistical differences (P<0.05). Conclusions There are differences in clinical findings, cerebrospinal fluid, neural electrophysiological examination and MRI appearances between RIS and CMS.

Objective To study whether abnormalities can be detected by MR diffusion tensor imaging (DTI) technology in radiologically isolated syndrome (RIS) patients with normal-appearing white matter (NAWM).Methods Twenty-seven patients who met diagnostic criteria for RIS were collected.Sixteen age-and sex-matched healthy controls with normal neurologic examination findings and no history of neurologic or psychopathic disorders were included.All subjects were examined by both conventional scan and DTI scan on GE Signa 3.0 T MRI.All the images were transmitted to the Advantage Workstation 4.2P and postprocessed using functool software.Anisotropic maps and average diffusion coefficient (ADC) maps were reconstructed.Two ROIs were selected in the genu and splenium of the corpus callosum separately at the trigone of lateral ventricle level.Other 2 ROIs were selected in the anterior and posterior body of the corpus callosum separately at the level of the lateral ventricle body,and 1 ROI was selected in the white matter of bilateral frontal and occipital lobe separately,then the FA and MD values were measured.The diffusion indices (FA and MD)were analysed by SPSS 13.0.Independent-sample t test was performed to examine the group differences in each subregion.Intraclass correlation coefficient analysis was performed to assess the diffusion indices of two measurements in each subregion.Results The ICC of 2 measurements was 0.934-0.989 (P ＜ 0.01),which showed favorable consistency.The FA values were decreased obviously in the genu,anterior and posterior body of the corpus callosum of the RIS patients compared with controls (0.705 ±0.040 vs 0.738 ±0.045,0.632 ±0.043 vs 0.675 ±0.042,0.628 ±0.043 vs 0.666 ± 0.045,t =-3.526,-4.487,-3.890,P ＜0.01),but the FA values of the two groups did not show any significant difference in the splenium,the white matter of the frontal and occipital lobe respectively (t =-1.387,-0.683,-1.243,P ＞0.05).In comparison with controls,the RIS patients had increased MD values in the genu,anterior and posterior body of the corpus callosum.(0.891 ±0.038 vs 0.874 ±0.035,0.839 ± 0.047 vs 0.794 ± 0.031,0.833 ± 0.039 vs 0.792 ± 0.057,t =2.101,5.836,5.146,P ＜ 0.05),but the MD values of the two groups did not show any significant difference in the splenium,the white matter of the frontal and occipital lobe respectively (t =1.671,1.702,1.624,P ＞ 0.05).Conclusion The NAWM abnormalities in the patients with radiologically isolated syndrome could be detected by DTI.