Transthoracic ultrasonographic features of typical high-resolution computed tomography signs of interstitial lung diseases

Abstract

Objective: To investigate the accuracy of bedside transthoracic lung ultrasonography (TLU) in different typical high resolution computed tomography (HRCT) signs of interstitial lung diseases (ILDs). Methods: Fifty patients first diagnosed with ILDs were enrolled from January 2016 to December 2018. There were 21 males and 29 females. The mean age was (56±14) years(rang 42-73 years). TLU was performed in inspiration for the characters of A-lines and B-lines as well as pleural at anterior, lateral and dorsal chest walls, respectively. HRCT was selected at three levels according to the upper, middle, and lower lung fields. The range of each level needing to be evaluated corresponded to the TLU scanning field one by one, and recording the signs of HRCT. Early change of ILDs was definite as the HRCT score was no more than 1 and no honeycomb was present. The correlation between A-lines, B-lines, pleural abnormal and HRCT signs was evaluted. Spearman's correlation coefficient was used to evaluate the relationship between B-lines and HRCT score. Results: The sensitivity and specificity of A-lines for HRCT normality were 83.9% and 84.9%, respectively. Coincidence rate was 84.6%. The sensitivity and specificity of B-lines for HRCT abnormality were 84.9% and 83.9%, respectively. Coincidence rate was 84.6%. Interlobular septal thickening shadow had fewer B-lines and narrower interval than other HRCT signs, while the other HRCT signs had no differences in B-lines. And the sensitivity and specificity of B-lines for detection the early change of HRCT in ILDs were 89.5% and 89.2%, respectively. Coincidence rate was 89.3%. A positive correlation was found between the number of B-lines and HRCT scores (R=0.827, P<0.001), and the width of B-lines and HRCT score (R=0.951, P<0.001). Meanwhile, a negative correlation was found between the interval of B-lines and HRCT score (R=-0.831, P<0.001). The sensitivity and specificity of TLU for HRCT pleural abnormality were 100.0% and 90.0%, respectively. Coincidence rate was 93.6%. Conclusions: TLU showed high sensitivity and specificity in finding interstitial changes of the lung. It gives a new view on the diagnostic possibilities of ILDs and may be used to evaluate the severity and the therapeutic effect of treatment. However, TLU could not differentiate HRCT signs of ILDs.