First Trimester Point of Care Ultrasound: Imaging Features and Review Behaviors Associated With Diagnostic Accuracy.

OBJECTIVES

We aimed to identify the most diagnostically challenging features in first-trimester point-of-care ultrasound (FT-POCUS) images. We also sought to determine the physician image review behaviors associated with increased diagnostic accuracy.

METHODS

We conducted a multicenter prospective cross-sectional study in a convenience sample of emergency physicians in the United States and Canada. The web-based intervention included 400 FT-POCUS cases acquired via the transabdominal or transvaginal approach. Participants reviewed FT-POCUS cases to identify pregnancy-related imaging findings. We captured clickstream-level data with each case encounter, including the correctness of a participant's response and physician image review behaviors.

RESULTS

We enrolled 317 participants, who collectively generated 16,295 case interpretations. The most diagnostically challenging imaging findings included eccentrically located gestational sac and endometrial collection/heterogeneous uterine material (p < 0.001 for all comparisons). Participants who reported "definite" certainty, as opposed to "probable," demonstrated a significantly higher odds of getting the diagnosis of intrauterine pregnancy (IUP) present or absent correct (OR = 4.48; 95% CI 4.00, 5.01) and a lower odds of time spent reviewing cases (OR = 0.46; 95% CI 0.40, 0.51). Those who reviewed a higher proportion of available views per case were more likely to accurately identify a fetal heartbeat (OR = 1.51; 95% 1.34, 1.69), multiple IUPs (OR = 1.33; 95% CI 1.10, 1.61), and adnexal structures (OR = 1.11; 95% CI 1.04, 1.17), but less likely to correctly identify an IUP (OR = 0.93; 95% CI 0.88, 0.99) and endometrial fluid collection/heterogeneous uterine material (OR = 0.96; 95% CI 0.92, 0.99).

CONCLUSIONS

Emergency physicians interpreting FT-POCUS images encountered specific diagnostic challenges that may increase risks to patient safety. We found that higher diagnostic confidence correlated with greater diagnostic accuracy and efficiency. Reviewing a larger proportion of available images improved diagnostic accuracy for some findings, but not for others.