Objective:To study the differences of apparent diffusion coefficient(ADC) values among different lesions

normal-appearing white matter(NAWM) areas in multiple sclerosis(MS) and white matter areas in healthy volunteers

and to explore the correlation between ADC values and expanded disability status scale(EDSS) scores.Methods:44 patients with relapsing-remitting MS(RRMS) and 20 healthy volunteers underwent both conventional magnetic resonance imaging(MRI) and diffusion-weighted imaging(DWI) of brain.The mean ADC values were measured for the acute and chronic lesions

NAWM areas of MS patients and white matter areas of the controls

respectively.The statistical data were performed to determine the mean ADC value differences among various lesions of MS

and to analyze the correlation between ADC values of lesions and EDSS scores.Results:(1) The mean ADC values were(112.02±15.16)×10-5 mm2/s for all lesions

(79.33±4.83)×10-5 mm2/s for NAWM areas of MS

and(77.32±3.55)×10-5 mm2/s for white matter areas of the controls

respectively

there were significant differences(P<0.01).(2) The mean ADC of acute lesions ((136.43±7.72)×10-5 mm2/s) was significantly higher than that of chronic lesions((110.66±3.45) ×10-5 mm2/s)(P<0.01).(3)In the chronic lesions

the ADC values of isointense lesions on T1-weighted images(T1WI) were lower than that of hypointense lesions(P<0.01)

the ADC values were (102.65±4.14)×10-5 mm2/s and(128.89±6.97)×10-5 mm2/s

respectively.(4)No significant correlation was found between ADC values and EDSS scores(P>0.05).Conclusion:Quantitative ADC values are useful to identify the changes of pathology in different phases and signal lesions

and to detect the occult damage in the NAWM areas of MS patients.