Objectives: The aim of this study was to assess inter‑ and intra‑observer agreement of detection and grading of oedema measured by vascular physicians using ultrasonography.
Method: In this observational study, three investigators read 113 videos of ultrasonography of the medial lower leg of 77 patients using a 15-18 MHz linear probe and reported whether oedema was present or not and, if present, to what extent. The videos were selected by the coordinator and sent every two months for a period of six months to the three investigators. Intra‑ and interobserver agreements were calculated using the Fleiss Kappa coefficient, reported with their 95% confidence interval and interpreted using the Landis and Koch values.
Results: Inter-observer agreement as to whether oedema was present or not was 0.88 (0.77-0.98), 0.96 (0.89-1.0) and 0.91 (0.80-1.0) for the first, second and third readings, respectively. The concordance was considered to be "excellent." Inter-observer agreement as to the severity of oedema was 0.52 (0.38-0.65), 0.53 (0.39-0.66) and 0.61 (0.47-0.75) for the first, second and third readings, respectively. The concordance was "moderate". Intra-observer reliability for the diagnosis of oedema was only 0.89 (0.70-1.0), 0.93 (0.75-1.0) and 0.92 (0.74-1.0) for the first, second and third reader, respectively, which was "excellent".
Conclusions: The inter-observer agreement interpreting ultrasound videos using standard probes was excellent. Only moderate agreement in grading the severity of the edema using our arbitrary criteria was shown.
Keywords: Oedema; diagnosis; ultrasounds.