Utilising ultrasonography to help in the visualisation of infection and disease is one invaluable function of an ultrasound scanner, and will serve as the topic for this article. A paper published by Ollivett TL et al., ‘Thoracic Ultrasonography and Bronchoalveolar Lavage Fluid Analysis in Holstein Calves with Subclinical Lung Lesions’, Nov-Dec 2015, 29(6):1728-34, J Vet Intern Med.  sought to address the issue of subclinical bovine respiratory disease (sBRD) in calves using ultrasonography as the method of examination. There were two main aims of this paper – to look at the suitability of using an ultrasound scanner to assess sBRD-linked lung lesions, and to examine the bronchoalveolar lavage fluid (BALF) and whether it could be used as an aid in diagnosing the presence of sBRD. It is worth noting that the findings reported in this study are thought to be novel.

The results revealed that ultrasound imaging was an appropriate method in revealing the presence of sBRD-linked lesions in the lung, being 94% sensitive and 100% specific. The results related to the examination of BALF were not as effective, although did allow the authors to determine a 'benchmark' of a particular cell type that will prove useful for future studies and analysis. Furthermore in cases where the lesions were detected, the aforementioned cell type was more likely to be at higher levels within the BALF.

The type of ultrasound scanner and probe used was also discussed in this paper, and may bear some relevance on the findings reported. In contrast to some previous studies, the researchers here used a linear rectal probe which by merit of its design was explained to be better for use on the thoracic region, where the ultrasound scanning was carried out. The restrictions of this study were also considered, and include a limitation of ultrasonography to assess certain parts of functional lung tissue whilst also preventing comparisons to be drawn between these results and the wider population of calves (only calves less than 12 weeks of age are able to be directly compared). The reasons for the latter include changes in the forelimbs of calves as they age, reducing the capability of ultrasound imaging.

Nevertheless, the take home message of this study reveals a use for veterinary ultrasound in the detection of bovine respiratory disease, and could be used in future cases for confirmation where lesions within the lung are suspected.