AI Insight
This study evaluated agreement between six sonographers diagnosing schistosomiasis-related liver fibrosis using ultrasound in 3,302 participants in rural Uganda. Overall agreement on fibrosis patterns was 73%, with the most severe patterns showing poorest agreement (kappa values of 0.430 and 0.149 for patterns E and F). Video recordings showed essentially no inter-observer agreement, while still images demonstrated moderate to substantial agreement for most patterns, with 94% of readings within one severity level of the original diagnosis.
Why it matters
The findings suggest the current WHO Niamey protocol for classifying schistosomal liver fibrosis may need revision to reflect a continuous disease spectrum rather than discrete categories. Poor agreement on severe fibrosis patterns indicates that routine second readings are necessary to ensure patients with life-threatening disease receive appropriate medical care and prioritization.
Understand the Science
⚠️ Preprint – Noch nicht peer-reviewed
Dieser Artikel wurde noch nicht von unabhängigen Experten begutachtet. Die Ergebnisse sind vorläufig und sollten mit Vorsicht interpretiert werden.
Background: Schistosomiasis-related periportal fibrosis (PPF) diagnoses rely on point-of-care ultrasound imaging. Yet, the extent of agreement between sonographers, limitations of existing World Health Organization (WHO) protocols, and the applicability of ultrasound video remain poorly understood. Methods: In 2024, six sonographers performed ultrasound scans for 3302 participants aged 5-92 years within SchistoTrack, a community-based cohort in rural Uganda. We adapted and standardised the WHO Niamey protocol for the collection of curated ultrasound images of liver fibrosis patterns related to Schistosoma mansoni (ranging A-F) and liver ultrasound video sweeps. PPF was defined as patterns C-F. Images and videos were read for patterns of fibrosis by second sonographers who were blinded to field diagnoses. Second sonographers recorded their clinical confidence, the probe position and any ultrasound interference. Outcomes considered were simple agreement for individual patterns and agreement on whether any PPF pattern was present, using Cohen’s {kappa}. The influence of participant characteristics and image quality factors was evaluated against agreement outcomes. Results: Abnormal liver fibrosis patterns (B-F) were identified in 32.8% (1082/3302) of participants, and among these 2074 images were read by a second sonographer from 1040 participants. The percentage agreement was 73.0% (1515/2074) for broad pattern categories. Severe fibrosis patterns had the least agreement; E and F patterns had {kappa} = 0.430 and 0.149, respectively. The D pattern had the most agreement ({kappa} = 0.717). 94.0% of second sonographer readings were within one step of severity of the field diagnosis. Participant characteristics were not consistently associated with disagreement, though agreement clustered by the field sonographer. Clinical confidence, breathing/movement, fat interference and probe position were positively associated with disagreement. There was no agreement among the 1054 videos that were read by a second sonographer: {kappa} = 0.001 for PPF agreement and ranged 0-0.062 for individual patterns. Conclusion: We have presented the largest diagnostic study of inter-sonographer agreement for schistosomal liver fibrosis patterns. Disagreement between adjacent patterns of liver fibrosis may indicate that the WHO Niamey protocol should be updated to capture a continuous progression of liver fibrosis rather than distinct patterns. The greatest disagreement was among severe patterns, which supports routine second reading to ensure life-threatening cases are prioritised and appropriately triaged.