Lapis ISSN 2398-2969

Radiology: chest (excl heart and lungs)

Contributor(s): Vetstream Ltd, Anna Meredith

Introduction

  • Radiography   Radiography: thorax  allows assessment of lung expansion and density and the thoracic wall.

Radiographic considerations 

  • The dorsoventral projection is often the most useful for identifying pathology involving the chest wall, and pleural and mediastinal spaces. 
  • The lateral projection is often used as a sole projection for thoracic radiography but this in fact provides poor detail of the dependent lung. 
  • Orthogonal views should be taken to locate the 3-dimensional position of a lesion. 
  • Oblique views may be required to highlight or skyline a lesion - particularly chest wall swellings where an oblique is useful to skyline the suspected lesion. 
  • The lung fields provide an inherent contrast within the thorax - a high KVp mAs should be used to maximize the range of densities available of pulmonary radiographs.
  • In rabbits it is essential to pull the forelimbs far forward to maximize visualization of the cranial thorax.
  • The scapulae are superimposed on the dorsal thorax in rabbits.

Use as short an exposure time as possible to minimize movement blur.

  • Rare earth screens, preferably fast screens, are required for medium to large dogs. 
  • Use of a grid will provide better images if the depth of tissue is >10 cm.

If the x-ray machine is low-powered it may not be possible to achieve a sufficiently short exposure time with a grid and image quality may have to be sacrificed. 

  • Exposure is normally made at the point of maximal inspiration to provide the most contrast within the thorax but this will depend on the lesion under examination.

Restraint 

  • Examination is normally performed under sedation or general anesthesia. 
  • Particular care is required with dyspneic animals.

Most dyspneic animals will lie quietly in sternal recumbency for a DV projection with minimal restraint and no sedation.

Stressful handling of dyspneic animals may result in fatal decompensation.

Indications

  • Dyspnea. 
  • Trauma. 
  • Evaluation of masses adjacent to the chest wall. 
  • Exophthalmos (impairment of vascular return to heart).
  • As part of minimum database in the investigation of many medical conditions, especially neoplasia, ascites.

Ultrasonography often more useful than radiography in the presence of pleural fluid.

Radiographic anatomy

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Interpretation

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Pitfalls

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Additional studies

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Further Reading

Publications

Refereed papers
  • Recent references fromPubMedpublished during the last 12 months.


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