Ultrasound Evaluation of Lung Fields in Healthy Dogs: Scanning Technic and Aspects of Normality.
Background: The ultrasound exam has always played a secondary role in pulmonary imaging, with its applicability restricted in emergency care to screen for pleural and/or pericardial effusion, pneumothorax and pulmonary contusion. The recognition of different reverberating artifacts arising from the normal aerated lungs (A lines) and in the presence of lungs with interstitial and/or alveolar infiltrates (B lines) led to wider application of the technique in patients with respiratory syndrome. The objective of this study was to describe the ultrasound imaging methodology and the aspects of the pleura, pleural space and lung fields in healthy dogs.
Materials, Methods & Results: Twenty healthy dogs of different breeds and ages, males and females were evaluated in this study; good health status was confirmed by physical examination, electro and echocardiographic assessment, thoracic radiography and systemic arterial blood pressure measurements. Dogs were scanned by a single examiner experienced in diagnostic imaging and previously trained for 6 months in thoracic ultrasound image interpretation. A MyLab 40 with a microconvex multifrequency probe (5-8 MHz) was used in this study. Evaluation was performed in an orthopneic position (standing or sternal recumbecy) under manual containment. Ultrasound examinations were based on the VetBLUE (Veterinary Bedside Lung Ultrasound Exam) protocol. Lung fields were regionally scanned at the 2nd-3rd, 4-5th, 6-7th and 8-9th intercostal spaces in the right and left hemithorax. A subxiphoid window was added to screen for free fluid in the pleural space and/or pericardial sac. Pleural sliding and A lines, that are hyperechoic parallel equidistant lines arising from the visceral pleura-lung interface could be easily seen at all intercostal spaces in all dogs in this sample, with more difficult visualization at the 2nd-3rd intercostal space. B lines were observed in seven out of twenty dogs (35%). However, this artifact was limited to one intercostal space and a maximum of two lines were detected per field. B line artifacts were more commonly seen in the right hemithorax, at the level of the 8-9th intercostal space however without significant differences. In the subxiphoid window evaluation A lines were not detected.
Discussion: The observation of B lines in healthy dogs was previously described and as in our study there were no significant differences relative to B line observation relatively to the intercostal space neither between the right and the left hemithorax. B lines are generally associated with decreased pulmonary aeration in response to interstitial/alveolar infiltration, which generates reflections and comet tail artifacts. The low number of B lines observed in this study may be associated with larger veins or lymphatics vessels, focal interstitial thickening or microatelectasia. The high respiratory frequency does not interfere in the sonographic evaluation. The dyspnea presented for animals with acute respiratory syndromes can be aggravated in stress situations, such as the displacement to the radiology service and manipulation necessary to the radiographic projections. Regional scanning by some acoustic windows allows rapid assessment of the thorax, with significant contributions to decision making in emergency situations. However, ultrasonography does not eliminate the need for other imaging modalities such as radiography and computed tomography and should be seen as a screening tool for patients presenting with acute respiratory syndromes.
Agricola E., Bove T. & Oppizzi M. 2005. “Ultrasound Comet-Tail Images”: A Marker Of Pulmonary Edema . Chest. (127): 1690-1695.
Agricola E., Picano E., Opizzi M., Pisani M., Meris A., Fragasso G. & Margonato A. 2006. Assessment of Stress-induced Pulmonary Interstitial Edema by Chest Ultrasound During Exercise Echocardiography and its Correlation with Left Ventricular Function. Journal of the American Society of Echocardiography. 19(4): 457-463.
Arbelot C., Ferrari F., Bouhemad B. & Rouby J.J. 2008. Lung ultrasound in acute respiratory distress syndrome and acute lung injury. Current Opinion in Critical Care. 14 (1): 70-74.
Bouhemad B., Brisson H., Le-Guen M., Arbelot C., Lu Q. & Rouby J.J. 2011. Bedside ultrasound assessment of positive end-expiratory pressure-induced lung recruitment. American Journal of Respiratory and Critical Care Medicine. 183(3): 341-347.
Bouhemad B., Liu Z.H., Arbelot C., Zhang M., Ferrari F., Le-Guen M., Girard M., Lu Q. & Rouby J.J. 2010. Ultrasound assessment of antibiotic-induced pulmonary reaeration in ventilator-associated pneumonia. Critical Care Medicine. 38(1): 84-92.
Bushberg J.T., Seibert J.A., Leidholdt Jr. E.M. & Boone J.M. 2001. Ultrasound. In: The Essential Physics of Medical Imaging. 3rd edn. Philadelphia: Lippincott Williams & Wilkins, pp.500-576.
Copetti R., Soldati G. & Copetti P. 2008. Chest sonography: a useful tool to differentiate acute cardiogenic pulmonary edema from acute respiratory distress syndrome. Cardiovascular Ultrasound. (6): 16.
D´Anjou M.A. & Penninck D. 2015. Pratical physical concepts and artifacts. In: Penninck D. & D´Anjou M.A. (Eds). Atlas of Small Animal Ultrasonography. 2nd edn. Oxford: Wiley Blackwell, pp.1-18.
Jambrik Z., Monti S., Coppola V., Agricola E., Mottola G., Miniati M. & Picano E. 2004. Usefulness of ultrasound lung comets as a nonradiologic sign of extravascular lung water. American Journal of Cardiology. 93(10): 1265-1270.
Lichtenstein D.A. 2007. Ultrasound in the management of thoracic disease. Critical Care Medicine. 35(5): S250-S261.
Lichtenstein D.A., Lascols N., Mezière G. & Gepner A. 2004. Ultrasound diagnosis of alveolar consolidation in the critically ill. Intensive Care Medicine. 30(2): 276-281.
Lichtenstein D.A., Goldstein I., Mourgeon E., Cluzel P., Grenier P. & Rouby J.J. 2004. Comparative diagnostic performances of auscultation, chest radiography, and lung ultrasonography in acute respiratory distress syndrome. Anesthesiology. 100(1): 9-15.
Lichtenstein D.A., Meziere G., Biderman P., Gepner A. & Barre O. 1997. The comet-tail artefact: an ultrasound sign of alveolar-interstitial syndrome. American Journal of Respiratory and Critical Care Medicine. (156): 1640-1646.
Lisciandro G.R. 2014. The Vet BLUE lung scan. In: Lisciandro G.R. (Ed). Focused ultrasound techniques for the small animal practitioner. Oxford: Wiley Blackwell, pp.166-188.
Lisciandro G.R., Fosgate G.T. & Fulton R.M. 2014. Frequency and number of ultrasound lung rockets (b-lines) using a regionally based lung ultrasound examination named vet blue (veterinary bedside lung ultrasound exam) in dogs with radiographically normal lung findings. Veterinary Radiology and Ultrasound. 55(3): 315-322.
Rademacher N., Pariaut R., Pate J., Saelinger C., Kearney M.T. & Gaschen L. 2014. Transthoracic lung ultrasound in normal dogs and dogs with cardiogenic pulmonary edema: A pilot study. Veterinary Radiology and Ultrasound. 55(4): 447-452.
Silva F.R. 2007. Ultrassonografia torácica na contusão pulmonar. 90f. Porto Alegre, RS. Dissertação (Mestrado em Ciências Médicas) - Programa de Pós-graduação em Ciências Médicas, Universidade Federal do Rio Grande do Sul.
Soummer A., Perbet S., Brisson H., Arbelot C., Constantin J.M., Lu Q. & Rouby J.J. 2012. Ultrasound assessment of lung aeration loss during a successful weaning trial predicts postextubation distress. Critical Care Medicine. 40(7): 2064-2072.
Sperandeo M., Rotondo A., Guglielmi G., Catalano D., Feragalli B. & Trovato G.M. 2014. Transthoracic ultrasound in the assessment of pleural and pulmonary diseases: Use and limitations. Radiologia Medica. 119(10): 729-740.
Volpicelli G., Caramello V., Cardinale L., Mussa A., Bar F. & Francisco M.F. 2008. Bedside ultrasound of the lung for the monitoring of acute decompensated heart failure. American Journal of Emergency Medicine. 26(5): 585-591.
Volpicelli G., Mussa A., Garofalo G., Cardinale L., Casoli G., Perotto F., Fava C. & Francisco M. 2006. Bedside lung ultrasound in the assessment of alveolar-interstitial syndrome. American Journal of Emergency Medicine. 24(6): 689-696.
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