Lung Ultrasound for Imaging of B-Lines in Dogs and Cats—A Prospective Study Investigating Agreement between Three Types of Transducers and the Accuracy in Diagnosing Cardiogenic Pulmonary Edema, Pneumonia and Lung Neoplasia

Abstract

Transthoracic heart and lung ultrasound (LUS) was performed in 200 dogs and cats with dyspnea to evaluate the agreement between the results obtained using three types of transducers (microconvex, linear, and phased array) and to determine the accuracy of LUS in discriminating between three conditions commonly causing dyspnea in companion animals: cardiogenic pulmonary edema (CPE), pneumonia, and lung neoplasm. The agreement beyond chance was assessed using the weighted Cohen’s kappa coefficient (κw). The highest values of κw (>0.9) were observed for the pair of microconvex and linear transducers. To quantify B-lines the lung ultrasound score (LUSscore) was developed as a sum of points describing the occurrence of B-lines for each of 8 standardized thoracic locations. The accuracy of LUSscore was determined using the area under ROC curve (AUROC). In dogs AUROC of LUSscore was 75.9% (CI 95%: 65.0% to 86.8%) for distinguishing between lung neoplasms and the two other causes of dyspnea. In cats AUROC of LUSscore was 83.6% (CI 95%: 75.2% to 92.0%) for distinguishing between CPE and the two other causes of dyspnea. The study shows that results obtained with microconvex and linear transducers are highly consistent and these two transducers can be used interchangeably. Moreover, the LUSscore may help identify dogs with lung neoplasms and cats with CPE, however its diagnostic accuracy is only fair to moderate.

Lung ultrasound score in dogs and cats: A reliability study

“…In small animal veterinary medicine, many different scores have been described previously. Some studies have focused on counting B‐lines without examining the entire thoracic surface 7‐11 . Others referred to lung regions or quadrants or intercostal spaces, with a more extended analysis of the entire pleural surface 12,13,15 .…”

“…Pleural effusion: fluid collection in the pleural space, which could be anechoic, hypoechoic, flocculated, finely corpuscular, or anechoic with isolated fibrin branching. 6 In small animal veterinary medicine, different B-line scoring systems have been developed, [7][8][9][10][11][12] sometimes including the description of tissuelike patterns. 13,14 Such scoring systems have been used to assess the severity of specific diseases, with higher sensitivity and agreement of LUS, compared to computed tomography of the chest, than chest radiographs.…”

Investigation of the relationship between pulmonary lesions based on lung ultrasound and respiratory clinical signs in foals with suspected pulmonary rhodococcosis

“…Finally, we consider it difficult to agree with treating only foals presenting both clinical signs and very severe pulmonary lesions, as indicated in one paper 6 , since fever and dyspnoea may be of serious concern, especially in very young foals. Although highly sensitive, LUS also has some limitations in diagnosing pulmonary pathology, and it can visualize abnormalities located close to the pleural surface but not in the pulmonary parenchyma; thus, certain lesions might sometimes be omitted 10,14,29 . Additional diagnostic modalities, such as thoracic radiographs and computed tomography, can also be considered in more complex cases.…”

“…Based on our clinical experience, foals were suspected of R. equi pneumonia if they demonstrated at least one of the following clinical signs (henceforth referred to as respiratory clinical signs): (i) fever > 39.5 °C provided that other apparent potential causes of fever were ruled out; (ii) dyspnoea defined as a respiratory rate > 30 breaths per minute accompanied by a noticeable increase in the respiratory effort; and (iii) marked murmurs or crackles on thoracic auscultation 13 . The decision to include fever as a diagnostic criterion for R. equi pneumonia was based on the endemic status of the farms and previously documented association of pyrexia with R. equi pneumonia in foals at a certain age 7,11,14 .…”

“…LUS examination was performed using a portable ultrasound scanner (4Vet Slim, Dramiński, Gietrzwałd, Poland) with a linear 8-10 MHz transducer (Dramiński, Gietrzwałd, Poland), the type of transducer most suited to the evaluation of pleura and superficial pulmonary lesions 14 . www.nature.com/scientificreports/ During the examination, foals were restrained by stable personnel.…”