Objective: To find a difference in apparent diffusion coefficient (ADC) values of non-enhancing and enhancing lesions in patients with multiple sclerosis (MS) and to find a cutoff ADC value to predict the enhancement of the MS lesion.

Materials and Methods: A retrospective review of magnetic resonance imaging (MRI) of the brain in MS patients between January 2015 and December 2019 was done. The MS plaques in the images were mapped in fluid attenuation inversion recovery (FLAIR) and post-contrast T1- weighted imaging sequences (T1WI). The lesions were categorized into enhancing and non-enhancing lesions based on the presence of enhancement on post-contrast T1WI. The ADC value of each lesion was measured using circular regions of interest (ROI) placed in the enhancing portion. The difference in mean ADC values between the two groups was assessed.

Results: There were 22 patients with 194 MS lesions. The mean ADC values of the enhancing lesions at 0.891±0.164×10⁻³ mm²/s were significantly lower than those of the non-enhancing lesions at 1.303±0.280×10⁻³ mm²/s (p<0.001). A cutoff ADC value of 1.117×10⁻³ mm²/s was used to distinguish between the enhancing and the non-enhancing lesions. The best results were obtained with a sensitivity of 93.9%, specificity of 71.4%, positive predictive value (PPV) of 40.3%, negative predictive value (NPV) of 98.3%, and accuracy of 75.3%.

Conclusion: ADC value measurement can be used to predict the enhancement of the MS plaque, which may be helpful as a screening tool for active demyelinating plaque in MS patients.

Keywords: Multiple sclerosis; Active demyelinating lesion; Active MS; Contrast-enhanced T1-weighted imaging; ADC value

DOI: 10.35755/jmedassocthai.2022.11.13703

Received 27 June 2022 | Revised 30 August 2022 | Accepted 5 September 2022