Preliminary study of the optimal b values on diffusion weighted MR imaging of cervical cord

Objective:To investigate the optimal b value on diffusion weighted imaging(DWI) of cervical cord at a 1.5T MR scanner and to obtain the apparent diffusion coefficient(ADC) value of normal spinal cord.Methods:Fifty healthy volunteers were included in this study.Single shot echo-planar pulse sequence was employed for DWI of cervical cord,according to different gradient factors b values=300,500 and 1000s/mm2 were selected and image qualities of the 3 groups were evaluated and their ADC values of cervical cord were measured.The influences of image qualities by various b values were analyzed.Results:Satisfactory DWI and ADC images of the 50 volunteers and ADC values were acquired.As b value increased from 300s/mm2 to 1000s/mm2,the signal intensities of images gradually decreased.The image quality was better as the b value=500s/mm2,with relative high signal noise ratio and contrast,lesser artifacts were found as well.The mean ADC values of the normal cervical cord in these 50 volunteers was(95.7±11.01)×10-5mm2/s.Conclusion:Using the single-shot echo-planar DWI pulse sequence with b value=500s/mm2,satisfactory DWI images and ADC values of normal cervical cord could be obtained.