Comparison of Susceptibility-Weighted Imaging with Contrast Enhancement in Detection of Multiple Sclerosis Active Plaques using 1.5 Tesla Magnetic Resonance Imaging System

Magnetic resonance imaging with contrast enhancement (CE) is an essential method in the detection of active multiple sclerosis (MS) plaques. Nevertheless, in patients who are contraindicated with gadolinium, this method is not possible, and needs to be replaced. Susceptibility-weighted imaging (SWI) has been reported to be effective in detecting MS plaques, but its ability to detect active plaques is unclear.

This cross-sectional study was performed on 147 patients with MS in Shafa Imaging Center, Isfahan, Iran, using 1.5 Tesla magnetic resonance imaging (MRI) System. In addition to conventional MRI sequences including T1</sub>, T2</sub>, FLAIR and CE-T1</sub>W, SWI sequences were also obtained. Then, the images of contrast enhancement, final SWI, and magnitude were examined and signal intensity was measured by drawing return on investment (ROI) in three areas of active plaque, passive plaque, and background.

From 147 patients, 32 had active plaque. There was a direct and significant relationship between final SWI with CE as well as between magnitude and CE (P < 0.001). The final SWI had a sensitivity of 71.87 and a specificity of 91.30; and a magnitude of SWI had a sensitivity of 75 and a specificity of 87.83 in detecting active plaques. Moreover, the accuracy of determination of active plaques was 87.07% for final SWI and 85.03% for large-size ones.

The results of our study show that SWI method is capable of detecting MS plaques with high sensitivity, specificity, and accuracy, and distinguishes active plaques from passive plaques as well.