LETTER TO THE EDITOR
Year : 2014 | Volume
: 9 | Issue : 3 | Page : 180--181
Reply to the editor
Ali A. Hasan, Hoda A. Makhlouf
Department of Chest, Assiut University Hospital, Assiut University, Assiut, Egypt
Hoda A. Makhlouf
Department of Chest, Assiut University Hospital, Assiut University, Assiut
|How to cite this article:|
Hasan AA, Makhlouf HA. Reply to the editor.Ann Thorac Med 2014;9:180-181
|How to cite this URL:|
Hasan AA, Makhlouf HA. Reply to the editor. Ann Thorac Med [serial online] 2014 [cited 2020 Jul 6 ];9:180-181
Available from: http://www.thoracicmedicine.org/text.asp?2014/9/3/180/134078
Thank you for your interest in our article published in the Annals of Thoracic Medicine.
In our study, we did not count B-lines or assess the correlation between the number of lung comet [B-lines] and the extent and degree of pulmonary fibrosis detected by HRCT. We assessed the distance between each two adjacent B-lines and the findings of HRCT. For a given field, numerous B-lines showed a narrow distance between them compared with fewer lines. Also, we counted B-lines; only to diagnose a positive scan according to Volpicelli et al.  A positive region was defined by the presence of three or more B-lines in a longitudinal plane between two ribs (which counted easily) and in the evaluation of interstitial syndromes (including pulmonary fibrosis); two or more positive regions bilaterally suggested a positive exam. 
In this letter authors added other limitations; one of these limitations, was the lack of intra- and inter-observer analyses which is small, less than 5%.  Also, they have asked where we measured the distance between B-lines. The level of measuring the distance between B- lines by TUS may affect the results where the B-lines were narrow based and widens gradually towards the end of the screen. However, we tried to make the site of measuring was fixed just beneath the lung surface interface when the discrimination between 2 adjacent lines was obvious. This is the site of subpleural interstitial thickening that could be seen by transthoracic US.
The distances between each couple of two adjacent B-lines in millimeters are conceivably very approximate but this not against the use of Pearson's correlation test. Moreover, the mean distance between two adjacent B-lines and the median distance were closely related; and the data were normally distributed which means that Pearson's correlation test was appropriate.
We partially agree with the authors that we cannot rely exclusively on B-lines for the differential diagnosis of dyspnea in patients that can suffer from interstitial disease (acute or chronic), from lung congestion and other conditions. B-patterns are noticed in both acute and chronic conditions with ILD. ,, We included patients who already diagnosed as ILD based on clinical and HRCT findings. However, in this study, we did not evaluate the diagnostic accuracy of lung ultrasound in patients with ILD but assessed the usefulness of B-lines in evaluation of those patients and if they could play a complementary role in the diagnosis and monitoring of ILD patients, especially when HRCT cannot be done (In emergency room and in mechanically ventilated patients) and when avoiding unnecessary overload of radiation exposure is needed (as during pregnancy). However, sonographic signs other than B-lines are useful to differentiate the B-pattern of acute respiratory distress syndrome (ARDS), cardiogenic pulmonary edema and pulmonary fibrosis. 
One of the international evidence-based recommendations for point-of-care lung ultrasound is; in patients with diffuse parenchymal lung disease (pulmonary fibrosis), the distribution of B-lines correlates with computed tomography (CT) signs of fibrosis. (Strong: Level B). Another recommendations; in resource-limited settings, lung ultrasound should be considered as a particularly useful diagnostic modality in the evaluation of interstitial syndrome (strong: Level B) and use of sonography in diagnosis of interstitial syndrome is likely to improve the care of patients (strong: Level C). 
The clear-cut: "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 honeycombing" was confirmed by other authors. ,
We currently try to extend our work to detect optimal cutoff point by ROC curve analysis and to study the value of distance between B-lines, their number and other sonographic signs such as pleural line abnormalities (irregular, fragmented pleural line) and subpleural abnormalities (small echo-poor areas) in diagnosis and monitoring different types of interstitial lung diseases.
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