The maximum number of enhancing plaques in MS patients was detected 15 min after contrast agent administration and the size and signal intensity of the lesions also increased remarkably at this time.

Objective: The use of an appropriate contrast agent performs a major role in brain magnetic resonance imaging (MRI) of multiple sclerosis (MS) patients. The present study aimed to make a comparison between the diagnostic values of Gadovist and Magnevist considering the successive imaging times in contrast-enhanced brain MRI of MS patients. Materials and Methods: A total of 62 relapsing-remitting MS patients (56 females, mean age of 31 years) were enrolled in the present study. All of them underwent two sessions of standard contrast-enhanced brain MRI upon enrollment and 48 h later. The participants were randomly assigned to each contrast agent. T1-weighted (T1W) images were taken 30 sec, as well as 5, 10, 15, and 30 min after the contrast injection. For all of the images, two neuro-radiologists who were blinded to the contrast type counted the number of plaques in the brain. In addition, for the enhanced plaques larger than 10 mm, the signal intensity (SI) was determined using its region of interest. Results: The mean plaque number significantly increased from 30 sec to 15 min for both contrasts separately (P<0.001). Nonetheless, the slight increases in the mean plaque number from 15-30 min for both Gadovist and Magnevist were not statistically significant (both P-Values>0.25). The mean plaque number in the Gadovist group was higher, compared to that in the Magnevist group at both 15 and 30 min, and the differences were statistically on the borderline (both P-Values=0.07). The mean SI of enhanced plaques gradually increased in the course of imaging in both contrast groups. Except for 30 sec, in all other time sessions, the mean SI was higher in Gadovist-enhanced MR images, compared to Magnevist-enhanced MR images (P<0.01). Conclusion: As evidenced by the obtained results, Gadovist showed a relatively better diagnostic value for brain MRI of MS patients. Furthermore, the findings suggested that it is cost-effective to take MRI only up to 15 min (instead of 30 min) after contrast injection in both agents.