Non-enhancing black holes (neBHs) are more common in multiple sclerosis (MS) patients with longer disease durations and progressive disease subtypes.

Our aim was to analyse the added value of neBHs in patients with clinically isolated syndromes (CISs) for predicting conversion to clinically definite MS (CDMS).

Patients were classified based on the presence or absence of neBHs and on the number of Barkhof–Tintoré (B-T) criteria fulfilled. Dissemination in space (DIS) was defined as the presence of at least three of the four B-T criteria. Dissemination in time (DIT)₁ was defined by simultaneous presence of enhancing and non-enhancing lesions. DIT₂ was defined by simultaneous presence of neBHs and T2 lesions not apparent on T1-weighted images.

Focal T2-hyperintense brain lesions were identified in 87.7% of the 520 CIS patients, and 41.4% of them presented at least one neBH. Patients meeting DIS, DIT₁, and DIT₂ had a significantly higher rate of conversion to CDMS. After adjusting for DIS, only patients who fulfilled DIT₁ preserved a significant increase in CDMS conversion.

Non-enhancing black holes in CIS patients are associated with a higher risk of conversion to CDMS. However, the predictive value of this finding is lost when added to the DIS criteria.