## 4 Discussion
With reference to conventional MRI findings usually present in neuroradiological reports, our results highlight that, while some MRI biomarkers mainly affect therapeutic decisions, others are more relevant to prognostic evaluations. In particular, information about the inflammatory component of the disease, such as new/enlarging T2w/FLAIR and enhancing lesions, affects clinicians' therapeutic decisions. On the other hand, information related to the degenerative component of MS, such as cerebral atrophy or T1w black holes, mainly affects prognostic evaluations in clinical practice, though in the future could be also associated with treatment decisions. This result is somehow expected, as current immunomodulatory therapies mainly act on the inflammatory component of MS, reducing the frequency and severity of demyelinating events, with a very limited effect on the progressive neurodegenerative features of the disease [10]. Interestingly, the only MRI feature considered useful by all participants was the presence of new/enlarging lesions, which proved to be not only important in terms of therapeutic decisions (conditioning in equal measure the decision to start a new therapy, its type and eventual switches), but also in terms of prognostic assessments. In both cases, the exact number of lesions was preferred compared to a range or even more quantitative information, such as lesion volume expressed in milliliters. This result leads to some considerations, the first one being that the information about enhancing lesions seems to have a less crucial role in driving therapeutic decisions than the one historically attained. This is in line with the most recent literature, as highlighted by the recent MAGNIMS-CMSC-NAIMS consensus guidelines, in which information about new/enlarging lesions has been suggested as a reliable marker of active inflammatory disease, even superior to enhancing lesions in some clinical situations, ultimately leading to a reduction of the use of gadolinium-based contrast agents which are now not recommended in routine follow-up [4]. The second consideration is that new/enlarging T2w lesions emerged as the most important MRI feature relative to prognostic evaluations, with a preference for the exact number of lesions, proving the importance of this parameter for neurologists, as confirmed by its introduction in the definition of \"minimal evidence of disease activity\" (MEDA), which identifies patients at very low risk of disability accumulation [11]. A possible explanation could be found in the clinical relevance of slowly expanding lesions, reflecting a silent inflammatory progression, due to slow-burning inflammation with macrophage/microglia activation and remyelination failure with axonal loss in a context of intact blood-brain barrier [12; 13; 14]. These lesions, known to be better predictors of clinical progression compared to acute ones [15; 16; 17; 18], seem to play a central role in the development of brain atrophy [19], confirming the interest of neurologists in identifying features related to the neurodegenerative component of MS. In this light, atrophy also emerged as another crucial information required by clinicians in neuroradiological reports, with participants preferring software-derived quantitative information to qualitative or semiquantitative estimations. Indeed, among all the possible information that can be provided by the several available software for medical imaging quantification (including, but not limited, to total lesion volume, new lesion volume, cerebral volumes, etc. ), many participants showed interest in receiving information on brain atrophy (alone or in combination with lesion load), with a preference for volumetric data referred to percentile norms. These results, lining up with the wide knowledge of the role of atrophy as one of the main predictors of disability in MS [20; 21; 22], confirm the perceived clinical relevance of this information to neurologists.