Role of Lung Ultrasound in detection and assessment of severity of ILD in patients with Systemic sclerosis

ABSTRACT TITLE: Role of Lung Ultrasound in detection and assessment of severity of ILD in patients with Systemic sclerosis BACKGROUND: HRCT Thorax is gold standard for diagnosing ILD but has limitations because of cost and radiation exposure issues. Lung Ultrasound (LUS) has shown to be useful alternative for diagnosing ILD. AIM: To find out the diagnostic yield of Lung Ultrasound to detect ILD in patients with SSc-ILD. METHODS: All consecutive patients with Systemic sclerosis underwent HRCT, Pulmonary Function Test and Lung Ultrasound (LUS). LUS was done by chest physician who was blinded to the clinical, physiological, and radiological status of the patient. Presence of B-lines (number and sites)and broken pleura sign were recorded as sonographic features of ILD and correlated with the Warrick score in HRCT. RESULTS: A total of 117 patients (103 women) were included in the study. The number of B-lines detected on thoracic USG showed significant positive correlation with the Warrick score on HRCT (r=0.947;p<0.001). A significant relationship between presence of broken pleural sign in LUS and severity of Warrick score in HRCT was also found (p <0.001). With HRCT as the gold standard: the sensitivity, specificity, positive predicted value, and negative predicted value for LUS were found to be 100%, 98%, 98.9%, and 100% respectively. CONCLUSIONS: LUS is a good alternative to HRCT Thorax for early diagnosing of SSc-ILD. We propose LUS can be used as a screening tool for diagnosing lung interstitial involvement. It can also be used as a follow up tool to look for disease progression of ILD in patients with Systemic sclerosis.