Diagnosing pneumothorax through standardized bilateral ultrasound images comparison

Abstract

<b>Introduction:</b> Diagnosing pneumothorax (PTX) is often compared with a potentially poor prognosis, leading clinicians to find new ultrasound (US) signs to obtain a more confident diagnosis. <b>Aims and objectives:</b> To assess the diagnostic yield of a potential new US sign for PTX diagnosis. <b>Methods:</b> We designed a prospective case-control study; patients were evaluated with chest US in supine position, collecting a double-view image with two frames: one from the left lung and one from the right lung. An objective analysis, relying on an image-editing program, compared selected areas of 100-pixel width on both sides, whereas a subjective one included 10 different physicians, divided into 5 groups (4 blinded), answering whether the two sides differed by greyscale and/or horizontal artifacts. <b>Results:</b> 60 patients were enrolled (30 cases). The objective analysis showed a significant difference between the PTX side and the contralateral one, as opposed to the control group. We focused on the ROC curves with the higher area under curve (AUC). The combination of mean ratio (AUC 0.98), range ratio (AUC 0.89) and median ratio (AUC 0.95) resulted in a perfect curve (AUC=1.0). No significant differences were observed among the 5 different groups of physicians. <b>Conclusions:</b> Our results suggest this may be a potential new tool for diagnosing PTX; it could lead to new US software development, allowing physicians to obtain a much more confident diagnosis.