Comparison of brain magnetic resonance sequences with and without contrast for the detection of active brain lesions in patients with multiple sclerosis during the attack period

Introduction and Objective: Multiple sclerosis (MS) is a demyelinating and axonal disease that progresses with attacks and is one of the leading causes of neurological disability in the population. Magnetic resonance imaging (MRI) is the most valuable test used in almost every stage of MS. Although contrast-enhanced T1-weighted sequences are standard examinations to evaluate active and inactive MS lesions, there are drawbacks to the administration of contrast agents due to their side effects. In this study, we aimed to evaluate active lesions in patients with relapsing remitting MS (RRMS) presenting with an attack using the new 'intravoxel incoherent motion' (IVIM) MR scan based on noninvasive conventional and diffusion weighted imaging (DAG) without contrast. Materials and Methods: Between July 2021 and February 2022, 34 patients who were diagnosed with RRMS according to McDonald 2017 criteria in Ondokuz Mayıs University Multiple Sclerosis Outpatient Clinic and service, and who were evaluated as an attack and whose active plaque was selected on MR were included in the study. Neurologic examinations of the patients were performed by a neurologist and conventional MR examinations were evaluated by a neuroradiologist specialized in DAG imaging in IVIM protocol. MR signal characteristics and contrast enhancement patterns of actively contrast enhancing and non-contrast enhancing newly developed plaques were determined. Measurements were made by manually creating a region of interest (ROI) in the center of the plaques. The correlation between conventional MR and IVIM-DAG image parameters of the patients' contrast enhancing lesions was analyzed. Results: Of the 34 patients included in our study, 11 were excluded due to incomplete MRI, steroid use before MRI and other reasons. Thirteen of the remaining 23 patients had 30 plaques with active contrast enhancement. The rate of detection of contrast enhancing lesions was 56,5% (13/23) for MS patients in the attack period. Of the 23 patients included in the study, 15 were female and 8 were male. The female/male ratio was 1,88. The ages of the patients ranged between 19,6 and 53,8 years with a mean age of 29,648,53 years. Disease duration ranged between 0,67 and 15,75 years with a mean disease duration of 6,234,85 years. The EDSS values of the patients ranged between 0 and 5 and the mean EDSS was 1,871,1. The total number of attacks varied between 2 and 14 with a mean total number of 4,782,91. The time of MR imaging ranged between 2 days and 14 days after the onset of the attack symptom, but the mean MR imaging time was 6,74,1 days after the onset of the attack. Contrast enhancing lesion localization is often periventricular. In IVIM evaluation of active and chronic plaques, no significant difference was found in ADC-ratio, ADClow-ratio, ADCdiff-ratio, f1-ratio, f2-ratio, D1-ratio, D2-ratio parameters. A significant difference (p=0,037) was found in the Dstar-ratio parameter for the differentiation of active and chronic plaques, and the sensitivity of the Dstar-Ratio value for differentiating active and chronic plaques was 0,625 with a sensitivity of 0,626. There was no difference in age, EDSS, disease duration between patients with contrast enhancing lesions and patients with non- contrast enhancing lesions (p0,05). Conclusion: Not all MS patients in the attack phase have contrast-enhancing lesions. Dstar-ratio value was found to be effective for the detection of active plaques. ADC- ratio, ADClow-ratio, ADCdiff-ratio, f1-ratio, f2-ratio, D1-ratio, D2-ratio parameters of IVIM sequence examination did not provide sufficient information to detect active plaques.