Background:Cystic fibrosis (CF) lung disease is usually monitored with chest X-ray(CXR), but lung ultrasound(LUS) is a non-irradiation method that shows abnormalities in many parenchymal lung diseases.
 
Aims and Objectives:To determine the role of LUS compared with CXR to monitor CF lung disease and to evaluate the correlation between LUS, CXR and pulmonary function tests(PFTs). 
 
Methods:This is a cross sectional study conducted between November 2022 and January 2023, aged 6-18 years. LUS was performed and scored by two pediatric pulmonologists during the routine outpatient visits of patients. Clinical and demographic characteristics, CXR findings, and PFTs results were recorded. CXR were scored with Chrispin-Norman score. LUS-CF scores were quantified as normal(0?1), mild(2?6), moderate(6?10), or severe(>10). LUS were correlated with clinical findings, CXR scores PFT.
 
Results:20 patients included to this study. The mean age was 12.6 ±3.05 years. 8 patients were using CFTR modulators. Median LUS score was 3.5(IQR:2.25-6.75), and median Chrispin-Norman score was 4(IQR:1.5-9) in patients using modulator. Median LUS score was 6.5(IQR:21.5-10.5), and median Chrispin-Norman score was 6(IQR:1-8) in patients without using modulator. There was no statistically significant difference between these groups(p>0.05).
LUS score had a very strong positive correlation with the Chrispin-Norman score(r=0.781, p<0.001). PFTs showed strong negative correlation with LUS score; FEV1(r= -0.756, p<0.001), FVC(r= -0.733, p<0.001), FEF-25-75(r= -0.766, p<0.001).
 
Conclusion:Our findings showed that LUS may be used instead of CXR for monitoring the lung disease in patients with CF.