Can high-frequency transthoracic sonography play a competitive role with high-resolution computed tomography in the assessment of dyspnea?

Background
Transthoracic ultrasound (TUS) can potentially give important complementary information in particular conditions like bedside rapid diagnostic evaluation of dyspneic patients who commonly present to emergency (ER) units.


Objective
Assessing the significance and diagnostic utility of B-lines and pleural line abnormalities detected on TUS among patients presented to the ER unit for the assessment of dyspnea against high-resolution computed tomography findings.


Patients and methods
A prospective observational study including 240 consecutive patients was conducted. TUS was done for patients presenting to the ER for the assessment of dyspnea. B-lines and the pleural line were evaluated by a linear and convex transducers. Sonographic findings were reported against high-resolution computed tomography findings, which was considered the gold standard.


Results
Slightly rough, fringed, irregular, interrupted, wavy, coexistence of more than one abnormal type of pleural line were detected in 30.8%, 35.4%, 19.2%, 17.9%, and 30% of cases, respectively. Warrick score classified patients with interstitial lung disease to mild (44.6%), moderate (36.3%), and severe (19.2%). Diffusing capacity for carbon monoxide (DLCO% predicted) and total lung capacity (TLC% predicted) predicted showed negative correlation with Warrick score (r=−0.66, r=−0.48 respectively, P≤0.001 for both) and positive correlation with distance between B lines (r=0.31 and 0.30 respectively, P≤0.001 for both). Warrick score at a cutoff more than 7 showed 96.3% sensitivity and 64.3% specificity. Distance between B lines at cutoff more than 3 mm had 100% sensitivity and 40.4% specificity. Cutoff more than 3 for B lines number/scan showed 92.6% sensitivity and 31% specificity. Pleural thickness at cutoff more than 2 mm showed 100% sensitivity and 34% specificity. Abolished lung sliding showed 96.3% sensitivity and 50% specificity.


Conclusion
TUS is an important tool for the diagnosis and assessment of pulmonary disorders. B-lines number and distance, pleural line abnormalities, lung sliding, and pleural thickness added diagnostic value for the ER assessment of dyspneic patients.