Doppler Ultrasound Examination of Multiple Sclerosis Patients and Control Participants: Inter-observer Agreement and Association with Disease

Objective Chronic cerebrospinal venous insufficiency (CCSVI) has been proposed as a major risk factor for multiple sclerosis (MS). The aim of this study was to assess inter-observer agreement between two ultrasound examiners and to compare findings in MS patients and control participants. Methods A prospective, blinded, controlled study of MS patients diagnosed within 2 years (MS ≤ 2, n = 39), patients diagnosed more than 10 years ago (MS > 10, n = 43) and age- and sex-matched control participants (n = 40). Ultrasound examinations were performed by two independent examiners. CCSVI criteria 1, 3, 4 and 5 as proposed by Zamboni were explored: (1) reflux in the internal jugular (IJV) and vertebral veins (VV), (3) IJV cross-sectional area (CSA) ≤0.3 cm2, (4) absence of flow in IJV and VV, and (5) reverted postural control of venous outflow. Results Criteria 1, 4 and 5 were met in less than 10% of the MS patients and control participants as studied by both examiners. The level of inter-observer agreement was poor for all parameters except assessment of the CSA of IJV at the thyroid level. Findings meeting CCSVI criterion 3 (CSA ≤ 0.3 cm2) were observed in 18/40 (45%) of the control participants, in 24/37 (65%) of MS ≤ 2 patients (p = 0.09 vs. control participants) and in 30/43 (70%) of the MS > 10 patients (p = 0.022 vs. control participants). Conclusions The feasibility of the CCSVI criteria for common use is questionable because of low inter-observer agreement. Small-calibre IJVs meeting the CCSVI criterion 3 appear common in both Finnish control participants and MS patients, but the clinical significance of this finding is questionable.