Introduction:
Multiple   sclerosis   (MS)   is   the   most   common
demyelinating disease in adults, leading to wide disability inthecommunity. Theactivity of MS disease is significantly associated with the development of new lesions. The purpose of this study is to introduce a method which can detect the new MS plaques without performing  contrast-enhanced  MRI  and  so that without use of contrast-agents and to assess the relationship between the demyelinated plaque’s signals and contrast-enhancement and restriction of DWI signal.
 
Material and Method:
34 patients with acute attack of MS participated in this study. FLAIR, DWI, and T1 (post-contrast) pulse sequences were performed for the patients. LNR and LWR were calculated using signal intensity of brain lesions in FLAIR images. Sensitivity, specificity, accuracy, ppv and npv of LNR and LWR determined. Contrast-enhancement and diffusion restriction of lesions has been also evaluated. Finally, a cutoff value determined for LNR and LWR.
 
Results:
There was a significant difference between the LWR and LNR of the MS plaques, in FLAIR images, which were enhanced or were not enhanced in T1 contrast imaging. Also a significant difference was seen between the LWR and LNR of the MS plaques which were not restricted in DWI comparing with the LWR and LNR of the plaques which showed DWI restriction. The cutoff value for LWR and LNR were between 0.9 to 1 and 24 to 28 respectively.
 
Conclusion:
The Flair images can also be used to detect new MS plaques by calculating LWR and LNR. LWR is a better index in diagnosis of new plaques due to its higher sensitivity and specificity. DWI images can also have a role in the detection of new plaques, however, its sensitivity is less than the application of LWR and LNR in FLAIR images.