Exploring How Sonographers Approach High Uncertainty Cases: A Mixed Methods Study

Abstract

Introduction: Ultrasound of the pediatric appendix is a high-uncertainty diagnostic task in which visualization rates for a normal appendix are as low as 45–55%. Sonographers are the primary image acquisition professionals in this clinical context, and variability in their diagnostic decision-making has direct implications for patient outcomes. Using the theoretical framework of comfort with uncertainty, we explored how individual practitioners comfort with uncertainty informs cognitive reasoning and impacts patient diagnoses. Objective: To quantify the variability in sonographer diagnosis and interpretation of pediatric appendix ultrasound, identifying case-level and individual factors associated with diagnostic uncertainty, and explore sonographer perceptions of and strategies for navigating uncertainty in clinical practice. Methods: A mixed convergent explanatory sequential design study was conducted. Eighty-seven sonographers were recruited across Canada and completed a 40-case image survey developed using Decision-Aligned Response Modelling (DA-RM). Item Response Theory (IRT) quantified case difficulty and individual decision thresholds across visualization and diagnostic dimensions. Qualitative semi-structured interviews, informed by quantitative findings, explored sonographers' perceptions of uncertainty and were analyzed using Braun and Clarke's thematic analysis. Ethics approval was obtained through SickKids Hospital and Harvard Medical School. Results: Substantial inter-sonographer variability was identified. DA-RM mapped the full diagnostic spectrum, with theta values ranging from −2.28 to +1.84 logits for visualization and −1.68 to +2.02 logits for diagnosis. Cases with inherent diagnostic uncertainty ranged from -0.66 to + 1.12 logits. Sonographers’ individual decision biases ranged from -1.47 to 1.13, indicating their underlying sensitivity/specificity trade off. Three qualitative themes emerged: Uncontrollable Factors Create Uncertainty; Strategies to Navigate Uncertainty; and Creating Certainty in the Search. Discussion: Significant inter-sonographer variability in pediatric appendix ultrasound is not explained by experience or training level alone. DA-RM effectively characterized the full spectrum of diagnostic uncertainty, within cases and people. Qualitative findings revealed active cognitive strategies consistent with the adaptive learner, illustrating how uncertainty is managed in practice. Sonographers revealed that the body habitus of a patient has an impact on search satisficing. These findings highlight the need for targeted educational programmes cultivating uncertainty tolerance, metacognitive awareness, and adaptive decision-making in high-ambiguity sonographic settings.