Non-contrast quantitative study of brain perfusion changes in multiple sclerosis

BACKGROUND: Non-contrast magnetic resonance perfusion can identify areas of cerebral perfusion changes in patients with multiple sclerosis, even in the absence of focal lesions [1]. This technique offers several advantages, including non-invasiveness [2] and a short data collection time, which allows for repeated examinations and dynamic monitoring without contrast loading on the patient. The use of contrast-free magnetic resonance perfusion in patients with multiple sclerosis may prove to be a valuable diagnostic, management, and evaluation tool for the disease course. Nevertheless, the quantitative assessment of perfusion in multiple sclerosis remains a relatively understudied area in clinical practice [3]. The application of the developed algorithm for postprocessing of non-contrast MR perfusion data allows for the assessment of specific areas of interest and the estimation of absolute perfusion values in milliliters per 100 grams per minute. AIM: The study aims to develop an algorithm and investigate cerebral perfusion changes by non-contrast magnetic resonance perfusion in patients with multiple sclerosis compared with controls. MATERIALS AND METHODS: The study population comprises patients with multiple sclerosis (n=15) and a control group (n=15). The methodology employed in this study is magnetic resonance imaging on a 3.0T Philips Ingenia machine, using the basic study protocol (T1- and T2-weighted images, FLAIR, DIR, and CE_T1) and supplemented with pseudo-continuous arterial spin labeling (pCASL). The statistical analysis employed nonparametric methods. RESULTS: The quantitative processing of non-contrast perfusion data presents significant challenges. To address this, an algorithm was developed, which incorporates the use of the following software: Radiant, MatLAB, FSL (BASIL), MriCroGL, PyCharm. The perfusion in a group of conditionally healthy volunteers, without consideration of liquor-containing spaces and cerebral vessels, was isolated and co-registered with the atlas of T1-weighted images. The average perfusion was found to be 52.8±1.32 mL/(100 g×min), which is consistent with the findings of leading studies worldwide and reflects the efficacy and quality of the algorithm [4, 5]. Furthermore, within the context of the study, values for the demyelination focus [9.7 ± 5.4 mL/(100 g×min)] and for the visually intact white matter of the cerebral hemispheres [46.1 ± 1.7 mL/(100 g×min)] were obtained in the group of patients with multiple sclerosis. Moreover, a diffuse decrease in perfusion indices in visually intact regions of the cerebral hemispheres relative to the control group was revealed. This finding is also widely reported in the scientific literature [6]. CONCLUSIONS: The application of the developed algorithm for the analysis of pseudo-continuous arterial spin labeling in patients with multiple sclerosis allows for the assessment of perfusion in both the focus of demyelination and in the visually intact white matter of the cerebral hemispheres. It was demonstrated that in visually intact areas of the cerebral hemispheres, there is a diffuse decrease in perfusion indices (on average by 13%) relative to the results of the control group. This observation indicates that the use of the pseudo-continuous arterial spin labeling method allows for the suspicion of the appearance of foci before their clinical and morphological verification on other routine sequences.