Data from: A reliability study of colour-Doppler sonography for the diagnosis of chronic cerebrospinal venous insufficiency shows low inter-rater agreement

Objective: Chronic cerebrospinal venous insufficiency (CCSVI) has been
extremely variable associated with multiple sclerosis in color-Doppler
sonographic studies. We aimed to evaluate inter-rater agreement in color
doppler sonograpy venous examination. Design: Inter-rater agreement study.
Setting: First-referral multiple sclerosis centre. Participants:
thirty-eight multiple sclerosis patients, and 55 age-matched (± 5 years)
controls. Intervention: sonography was carried out in accordance with
Zamboni's five criteria by 8 sonographers with different expertise,
blinded to the status of cases and controls. Each subject was evaluated by
two operators. Primary and secondary outcome measures: inter-rater
agreement was measured through the Kappa statistics and the Intraclass
Correlation Coefficient. Results: The agreement was no higher than chance
for criterion 2-reflux in the deep cerebral veins (Kappa=-0.02) and 4-flow
not Doppler-detectable in one or both the internal jugular (IJVs) or
vertebral veins (VVs) (-0.09). It was substantially low for criterion
1-reflux in the IJVs and/or VVs (0.29), criterion 3-IJV stenosis or
malformations (0.23), and criterion 5-absence of IJV diameter increase
when passing from sitting to supine position (0.22). The Kappa value for
CCSVI as a whole was 0.20 (95% confidence limits=-0.01 - 0.42). Intraclass
Correlation Coefficients for the measure of cross-sectional area ranged
from 0.05 to 0.25. Inter-rater agreement was low for CCSVI experts (kappa=
0.24; -0.11 to 0.59), and non-experts (0.20; -0.33 to 0.73); neurologists
(0.21; -0.06 to 0.47) and non neurologists (0.18; -0.20 to 0.56); cases
(0.19; -0.14 to 0.52) and controls (0.21; -0.08 to 0.49). Zamboni-trained
neurosonographers ascertained CCSVI more frequently than non-trained.
Conclusions: Agreement was unsatisfactory for the diagnosis of CCSVI as a
whole, for each of its five criteria, and according to different
subgroups. Standardization of the method is urgently needed prior to its
further application in studies of patients with multiple sclerosis or
other neurological diseases.