Radiological Anatomy of the Abdomen and Pelvis Including Principles of FAST Scans Flashcards
How does an ultrasound work
Uses high frequency sound waves to obtain images from inside the body. The frequency is higher than the human auditory limit. Ultrasounds do not expose the patient to any ionizing radiation.
Discuss what different materials will look like in an ultrasound and give an example of each
- If material is sold particles are denser which reflect back the ultrasound waves, this shows up as white. - Bone
- If the material is fluid the ultrasound wives are transmitted, this shows up as black. - Full bladder
- Air is a strong reflector and you cannot see anything behind it - this is why we use gel.
List the 3 types of probes used in an ultrasound and what field of view they produce
- Linear array - Produces rectangular field of view
- Curvilinear array - produces wide sector field of view (for abdominal)
- Phased array - produces a sector field of view
What does echogenic mean and how would echogenic tissue appear in an ultrasound
- Echogenic tissue will appear brighter in an ultrasound as it is hyperechoic - can echo more of the soundwaves back to the transmitter so appears brighter. The capsule of a neonatal kidney is echogenic
What differences can you expect to see in an ultrasound of a neonatal kidney vs an adult kidney
- Renal pyramids do not appear as clearly in an adult kidney
- The cortex in a neonatal kidney is thinner.
- Corticomedullary differentiation would be clearer in a healthy adult but can be lost due to inflammation
- Renal pelvis is larger in an adult kidney
What is the hepatorenal fossa and what is its significance
- The kidney meets the liver here
- It forms the basis of a FAST scan as it is a sensitive area, if fluid is present here that can indicate visceral damage.
What does FAST in FAST scan stand for
- Focused Assessment of Sonography and Trauma
Why is the medulla of the kidney echogenic
- A little bit of fat sits in the medulla of the kidney to help open up the calyxes of the kidney.
- Shows good corticomedullary differentiation - cortex appears black and medulla more white.
What is a CT Urogram and what can you expect to see in it
- A patient is given contrast which travels in their body through the circulatory system, the image is then taken during the delayed phase which means enough time has passed for it to begin to drain through the kidneys. You would see other viscera such as the liver and spleen showing lower levels of contrast whereas the kidneys would show a lot of contrast. Specifically the calyxes. You can also clearly see the hepatorenal fossa.
What is hydronephrosis, what are the grades and how would each of these present on an ultrasound.
- A build up of fluid in the kidney due to the kidney not expelling urine as usual.
- Mild hydronephrosis - Fluid begins to accumulate in the kidney, patients may have drunken a lot of liquid at once or kidneys are beginning to struggle to filter out water.
- Moderate hydronephrosis - There is an obstruction within the kidney so fluid will backup into the kidney causing pelvicalyceal dilatation.
- Severe hydronephrosis - The presence of a large blockage causes a large backflow of fluid into the kidney causing structural distortion of the kidney causing the calyxes to push against the medulla, there is also blunting of the renal pyramids.
How would hydronephrosis appear on a CTKUB scan and what does CTKUB stand for
- You would be bale to clearly see the kidney with hydronephrosis being bigger than the other kidney as you get a full 3 dimensional image.
- Pelvicalyceal dilatation would be very clear.
- CTKUB stands for a CT scan of the Kidneys, Ureters and bladder. - It allows you to see calcium kidney stones which could be common in a patient with hydronephrosis(moderate hydronephrosis secondary to a renal stone)
