Feasibility of intraoperative Doppler ultrasound for intersegmental plane identification in pulmonary segmentectomy: a retrospective preliminary validation study

Background: The intraoperative identification of intersegmental planes remains a technical challenge in pulmonary segmentectomy. Although indocyanine green (ICG) fluorescence imaging provides reliable visualization, its clinical adoption is limited by transient effects and high costs. This observational study aimed to evaluate the concordance between Doppler ultrasound and ICG fluorescence in the demarcation of intersegmental planes. Methods: In this retrospective cohort study, we analyzed 12 consecutive patients undergoing video-assisted thoracoscopic segmentectomy at The Fourth Affiliated Hospital of Soochow University (May 2020 to January 2021). Intraoperative Doppler ultrasound was applied to detect intersegmental planes via the assessment of the arterial blood flow differences, with subsequent ICG fluorescence imaging serving as the reference standard. All procedures were performed by senior thoracic surgeons with >10 years of experience in video-assisted thoracic surgery (VATS) segmentectomy. Doppler ultrasound was performed using preset vascular mode with optimized parameters (gain 15–20%, frequency 5.1 MHz, depth 0–1 cm). Inter- and intra-observer variability were not assessed, which represents a methodological limitation. Results: The cohort comprised 12 patients (8 males and 4 females; mean age 60.42±13.27 years). A close concordance was observed between the Doppler-identified intersegmental planes and the ICG fluorescence delineation across the majority of cases (11 out of 12, corresponding to a 91.7% concordance rate). Moreover, no procedural complications associated with either modality were noted. Conclusions: Doppler ultrasound demonstrated the potential to a potentially cost-saving and dye-free alternative to ICG fluorescence for intersegmental plane identification. However, these preliminary findings should be validated in larger prospective cohorts to address limitations of single-center design, small sample size, and operator-dependent ultrasound technique.