Vet360 Vol 4 Issue 3 June 2017 Vet360 - Page 23

ADVERTORIAL quire accurate information about thickness of the soft tissue. MRI will always be better for precise imaging of the brain, as its possible see much more subtle tu- mours, and to better visualise inflammatory chang- es. This said, a well performed CT head, done with and without contrast agent can be very helpful if MRI is not an option. Thorax Whilst thoracic radiographs are a quick and easy way to visualise inside the thorax, a CT scan can provide so much more information. Especially as one weakness of all radiographs is that they are try- ing to visualise a 3D structure on a 2D image. This can cause major issues with superimposition, espe- cially leading to the risk of pathology being hidden by the heart. CT: Canine Abdomen If you are looking for secondary tumours the sensi- tivity of CT compared to a plain thoracic radiograph is so much better- down to close to 1mm com- pared to 1cm. When looking at any thoracic pathology, from pneumonia through to deciding whether an object is a tumour, node or cyst, CT is would allow for greater diagnostic interpretation of your image. For assessment of multiple thoracic fractures, CT is amazing as you can see where every piece of bone is, in direct relationship to all the organs- but you need to consider if the animal is stable enough for a CT at this point, as unlike humans you cannot just ask for breath holds, so a GA is needed for high quality thoracic CT scans. Abdomen For accurate staging of abdominal masses CT is truly unique in the image quality definition, and by watch- ing how a mass uptakes contrast agent you can often work out the type of mass - helping you decide if sur- gery is an option. Contrast will also allow you to accu- rately work out what other organs have been invaded. Tumours react differently to contrast agent, and you can get a good idea about vascularity, which can be vital to know prior to surgery. The sensitivity of CT to pick up additional tumours is helpful in staging. When looking at a prostate mass you can see accurately whether it has invaded neighbouring tissues. As with thoracic scanning, you most likely need a GA to get the best CT abdomen images, as you need to be able to control the patient’s respiration, and an ul- trasound may be the better option at this point if the patient is not in a stable condition. Contrast Agent Contrast agent is very useful for CT scanning, as it can tell you so much about the type of mass that you are looking at. It is important to use the correct dose- which is nor- mally 2mls per kg (but can vary, so always read the dosage advice). If you are planning to use contrast you MUST do a pre-contrast scan, as without this you can- not check for uptake. CT: Thorax If you are using a conventional CT scanner and you are looking for arterial and venous phased imaging, you will need to use a Contrast Injector pump, as it’s not physically possible to inject the contrast manually as fast as is required. If you are not looking to show arterial phase, you can manage without a pump, but its hard work! Issue 03 | JUNE 2017 | 23