Transcranial Doppler ultrasonography reveals impaired cerebral vasomotor reactivity in patients with active neuro-Behçet’s disease

Abstract Cerebral vasomotor reactivity (CVR) reflects changes in cerebral blood flow or velocity in response to vasodilatory stimuli. This study aimed to evaluate CVR using transcranial Doppler ultrasonography (TCD) in patients with Behçet’s disease without neurological involvement (BDWONI) and neuro-Behçet’s disease (NBD), and to examine its association with disease activity. Patients with BD and NBD evaluated between 2022 and 2024 were included. Disease activity was assessed using the Behçet’s Disease Current Activity Form-2006 (BDCAF-2006). CVR was measured by TCD using breath-holding and hyperventilation tests. Peak systolic velocity (PSV), end-diastolic velocity (EDV), mean flow velocity (MFV), pulsatility index (PI), and resistance index (RI) were recorded in the M1 segment of the middle cerebral artery (MCA). The study included 33 BDWONI patients, 28 NBD patients, and 40 healthy controls. MCA PSV, EDV, and MFV values were significantly lower in the NBD group ( p < 0.05). Breath-holding index (BHI) and hyperventilation index (HVI) were significantly reduced in NBD patients with high disease activity. HVI showed a significant negative correlation with BDCAF scores (rs =-0.573, p = 0.002). Exploratory ROC analysis showed AUC values of 0.78 for BHI and 0.86 for HVI for discriminating higher from lower disease activity. Reduced BHI and HVI were associated with higher disease activity within the NBD group. These indices may represent exploratory candidate markers, but require validation in larger longitudinal cohorts.