Inter-examiner variability of Transcranial Doppler procedure and reports: A multicenter survey

Objective. To assess the clinical use of Transcranial Doppler (TCD) and the reproducibility of TCD reports. Methods. A multicenter survey involving 45 Italian laboratories (the Italian Transcranial Doppler Group - ITDG) was carried out by investigating the examination procedure, the parameters and normative data, and the interpretation criteria applied to reach diagnostic conclusions. The inter-examiner agreement on 10 TCD reports was computed using Kappa statistics. Results. Investigators consider both qualitative (flow direction, signal detectability) and quantitative measurements (mean flow velocity and pulsatility index values), applying their own normative criteria reference which may differ slightly between centers. TCD reports appear to be highly reproducible when based upon the interpretation of qualitative data (Kappa index. 0.95-1.00), whereas a moderate agreement is obtained when considering alterations in quantitative parameters (Kappa: 0.44-0.81). Conclusions. The application of the same criteria in different laboratories may facilitate the standardization of TCD examinations and support the reproducibility of clinical reports based on TCD parameters.