B-lines: Transthoracic chest ultrasound signs useful in assessment of interstitial lung diseases

ABSTRACT

This prospective study was conducted to evaluate the value of sonographic B-lines [previously called ''comet tail artifacts''], which are long, vertical, well-defined, hyperechoic, dynamic lines originating from the pleural line in assessment of interstitial lung diseases [ILD] and compare them with the findings of chest high-resolution computed tomography [HRCT] and pulmonary function tests [PFTs]. Sixty-one patients with ILD underwent transthoracic lung ultrasound for assessment of the presence of B-lines and the distance between them. These findings were compared with that of chest HRCT [ground glass, reticular, nodular or honey combing] and PFT as forced vital capacity [FVC], total lung capacity [TLC], diffusion capacity for carbon monoxide [DLCO] and partial arterial oxygen pressure [PaO[2]]. All patients had diffuse bilateral B-lines. The distance between each of the two adjacent B lines correlated with the severity of the disease on chest HRCT where B3 [the distance was 3 mm] correlated with ground glass opacity and B7 [the distance was 7 mm] correlated with extensive fibrosis and honey combing. Also, the distance between B-lines inversely correlated with FVC [r = -0.848, P < 0.001], TLC [r = -0.664, P < 0.001], DLCO [r = -0.817, P < 0.001] and PaO2 [r = -0.902, P < 0.001]. B-lines that are lung Ultrasound signs seem to be useful in the assessment of ILD.