Diagnostic accuracy of lung ultrasound with elastography in predicting malignant origin of pleural effusions in an emergency department

Aims: Ultrasound is a valuable diagnostic tool in the diagnostic work-up of dyspnea and can identify even small pleural effusions. Incorporating Shear Wave Elastography (SWE) represents a possible tool in stratifying pleural effusions by risk of underlying malignancy. No previous studies have been conducted in an emergency department (ED), where it might have a clinical impact by hastening referral for diagnostic work-up of underlying malignancy. The aim of this study was to appraise the diagnostic accuracy of ultrasonographic findings associated with thoracic malignancy, as well as calculating optimal cut-off values for SWE in this regard. Methods: Patients with unilateral pleural effusion of unknown origin were included in the ED and subjected to a Focused Lung Ultrasound (FLUS) scan during their first 48 hours after admittance. Two index tests were applied: i) traditional 2D FLUS examination registering presence of diaphragmatic noduli, pleural thickenings and other findings associated with malignancy, and ii) a SWE examination of different Regions of Interest. Reference test was defined as subsequent diagnosis of malignant pleural effusion (MPE) in the three months following inclusion. Results: 39 patients were included. The 2D index test yielded a sensitivity of 28.57% (95%CI 3.67-70.96%) and a specificity of 90.62% (95%CI 74.98%-98.02%). The SWE max of intercostal space yielded a sensitivity of 100% (95%CI 47.82-100%) and a specificity of 59.09% (95%CI 36.35%-79.29%). Conclusion: FLUS with integrated SWE may aid in identifying MPE9s and improving referral to diagnostic work-up of underlying malignancy. Larger adequately powered studies are warranted.