Abdominal radiographs can be daunting, but here are six tips to help you get the most information from your studies and some tips on interpreting those images.
Have the patient prepared as best as possible, have them dry as wet hair shows up on x-rays and appropriately sedated, or anaesthetised if needed, to minimise the amount of radiation exposure to you and your staff.
2. Adjust according to depth
Adjust the settings based on the depth. The cranial abdomen is often wider and deeper than the caudal abdomen, so adjust the settings as appropriate. This will help make sure the areas of interest are appropriately exposed. Otherwise, the cranial abdomen is often underexposed, and the mid-abdominal region overexposed.
Take radiographs on expiration. This is the longest pause and will reduce motion artefact.
Routine abdominal studies vary, but at a minimum I perform two views – lateral and ventrodorsal (VD).
If I am assessing the gastrointestinal tract then I take three views: left and right lateral, and a VD view.
Why three views? Gas floats and fluid sinks, so the gas patterns change and provide valuable information. For example, on the right lateral view, gas moves into the fundus and fluid moves into the pylorus, so it looks like a soft tissue mass or foreign body.
If the patient is larger, I may take two or three images per view to make sure I image the entire abdomen. I make sure I image the entire abdomen from diaphragm to pelvis if the patient is large by dividing it into segments, cranial abdomen and caudal abdomen; sometimes cranial, mid-abdominal and caudal. This may mean standard two views turns into cranial and caudal VD and lateral views.
I often find there is too much to look at and it gets confusing with overlapping organs. I like to step back and look from a distance; sometimes, this gives me an overview of the image first.
Next, I use a systematic approach, starting with extra-abdominal structures and working inwards.
Then I assess the main organs – liver, spleen, kidneys, bladder and prostatic region and assess for a uterus. Once I have identified and assessed those, I look at the gastrointestinal tract (GIT).
This can be the most confusing part. I start with the stomach, assess size and position, then identify and track the colon from caecum to rectum. Once I’m happy I have identified the stomach and colon then everything else with gas in it is likely to be small intestinal.
If there is too much faeces, or if the gas is colonic, I administer a suppository enema to facilitate defecation. This can dramatically clear up a confusing x-ray and move gas.
If I am still concerned about an obstruction, but it is not obvious, I either transition to an ultrasound or repeat the abdominal study after a couple of hours of IV fluids and pain relief.
I find, once a patient is rehydrated, the GIT starts to move; gas and faeces shift, and things can look surprisingly different in a couple of hours. If it remains the same, or worsens, that also provides valuable information.
Don’t forget pyloric, high duodenal and partial obstructions that don’t give you the classic small intestinal dilation. The absence of a radiopaque foreign body or gas dilated small intestines do not rule out an obstruction.