Canis ISSN: 2398-2942
Radiology: cardiac examination
Contributor(s): Fraser McConnell, Jordi Lopez-Alvarez
- Radiology plays an important part in the diagnosis and management of cardiac disease. It allows assessment of the pulmonary vasculature and lungs which is not possible with echocardiology.
- Radiology also plays an important role in the differentiation of cardiac and respiratory cough.
Follow the diagnostic tree for the Radiographic Detection of Canine Cardiomegaly Radiographic Detection of Canine Cardiomegaly.
- For the investigation of cardiac disease a right lateral projection and dorsoventral (DV) projection should be taken.
- Careful positioning is important, particularly to prevent rotation of the thorax which can lead to a false impression of mild left atrial enlargement.
This effect is most marked in deep chested dogs, eg Doberman pinscher.
- The heart has a complex shape and even small degrees of rotation can make assessment of chamber size unreliable, particularly on the DV projection.
- Care must be taken to ensure that the stress of radiography will not cause further decompensation in animals with congestive heart failure.
- Oxygen supplementation via a face mask may help ease the patient's respiratory distress improving the quality of the radiographs.
- A DV projection can usually be taken without sedation in dyspneic animals.
- The lateral projection can then be taken after the patient's condition has been stabilized.
- In most cases, however, it is safer to give a low dose of sedation Sedation / sedative protocols if required than to struggle with a dyspneic animal.
- The intramuscular or intravenous combination of butorphanol Butorphanol and acepromazine Acepromazine maleate ) are generally used in cardiac patients.
Alpha 2 agonists should be avoided.
- A high kV low mA technique should be used to reduce contrast within the thorax and allow exposure times to be kept as short as possible.
- Movement blur Radiography: film faults is one of the most common problems in thoracic radiography, particularly in dyspneic patients.
- This can be minimized by using a high kV, dispensing with a grid and using a fast film/screen Radiography: X-ray film combination.
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- Recent references from VetMed Resource and PubMed.
- Gugjoo M B, Mozammel Hoque, Saxena A C, Zama M M S, Amarpal (2013) Vertebral scale system to measure heart size in dogs in thoracic radiographs. Advances in Animal and Veterinary Sciences 1 (1), 1-4.
- Sleeper M M & Buchanan J W (2001)Vertebral scale system to measure heart size in growing puppies. JAVMA219(1), 57-59.
- Lamb C R, Wikeley H, Boswood A & Pfeiffer D U (2001)Use of breed-specific ranges for the vertebral heart scale as an aid to the radiographic diagnosis of cardiac disease in dogs. Vet Rec148, 707-711.
- Buchanan J W & Bucheler J (1995)Vertebral scale system to measure canine heart size on radiographs. JAVMA206(2), 194-199.