Imaging of the urinary system Flashcards
The different types of radiography in urology are:
1.
2.
Plain (survey) radiography
Contrast radiography
In a lateral view of a normal radiograph of the abdomen, where do you centre the beam on?
Level of the caudal edge of the last rib, half way up from the ventral body wall
What are the four key points to collimate towards in a normal lateral radiograph of the abdomen?
Dorsal body wall dorsally
Greater trochanter caudally
Ventral body wall ventrally
Just caudal to the shoulder cranially
In a normal ventrodorsal view of the abdomen, where do you centre the beam?
In the midline at the level of the caudal edge of the last rib.
Need to go slightly more caudally in cats
In a normal ventrodorsal view of the abdomen, where do you collimate to?
The greater trochanter caually
Lateral body wall laterally
Caudal edge of the shoulder cranially
Why would you use a VD over a DV to look at the abdomen?
In a DV, the organs are more squashed up, whereas in a VD, the organs are separated out, so you can see the detail more easily.
Would you use a fast or slow screen when taking an abdominal radiograph?
Fast
Are the ureters normally seen on a plain (normal) radiograph?
No
The kidneys are around 2.5-2.5 times the length of L2 in a VD view, true or false?
True
In dogs, where is the right kidney approximately located?
T13-L1/2
In dogs, what structure is the right kidney in contact with cranially?
Caudate lobe of the liver, may not see this margin
In dogs, the left kidney is usually slightly more _____ and _____ than the right kidney.
Caudal
Ventral
Feline kidneys tend to be more _____ in shape and are more frequently _____ and more caudal than canine kidneys.
Oval
Superimposed
Why is the cranial pole of the right kidney often easier to see in cats than dogs?
It is separated from the caudate lobe of the liver by fat, making it easier to visualise.
Cats kidneys are normally 2-3 times the length of L2, true or false?
True
The bladder is usually found where in radiographs?
Caudo-ventral abdomen, midline on VD
Is the urethra usually visible on a radiograph in the normal animal?
No
When are contrast agents used?
When plain radiography gives insufficient organ detail.
What are the two different types of contrast agents commonly used?
Positive and negative
Positive contrast agents have a _____ atomic number, and are usually compounds containing _____ or iodine.
High
Barium
Negative contrast agents cause the structure on the radiograph to appear _____. Example of these are gases.
Radiolucent
Why do negative contrast agents appear radiolucent on radiographs?
They absorb virtually no radiation.
IVU (intravenous urography) uses _____ contrast media that provides both functional and anatomical information.
Positive
IVU is useful because you can follow the contrast through the entire urinary tract and can obtain specific information about each stage of the IVU, true or false?
True
What are the contraindications for using IVU?
Dehydration, hypovolaemia, severe renal failure, anuria
IVU can be performed conscious, true or false?
False, IVU requires GA.
Prior to an IVU, you would starve the animal for 24-36 hours, and would give the animal an enema, true or false?
True
You would perform an IVU straight away before any plain radiographs, true or fasle?
False, you would always perform a plain radiograph first
What are the different methods for administering the contrast used in an IVU?
High concentration with a low volume as a bolus into a peripheral vein
Low concentration with a high volume and be administered IV, but this is rarely used
One only radiograph is taken when performing an IVU, true or false?
No, multiple radiographs are taken to observe the passage of the contrast through the urinary tract
Dilated ureters are often cause for concern as they often related to _____ _____.
Ectopic ureters
A _____ _____ is where contrast is introduced to the vestibule and will drain into the urethra and bladder.
Retrograde vaginourethrogram
When performing a retrograde vaginourethrogram, you should be careful not to introduce too much contrast to the vagina, as this can cause the vagina to _____
Rupture
A _____ _____ is where contrast is introduced to the catheterised bladder.
Retrograde cystogram
Why is air a good contrast to use for a retrograde cystogram (pneumocystogram)?
Cheap, readily available, useful to identify the bladder (if intact) position and wall thickness
What are the downsides of using a pneumocystogram?
Poor mucosal detail, may miss small tears
Why would a positive contrast cystogram be good to use?
Used for suspected bladder rupture
What medium is used for a positive contrast cystogram?
Water-soluble iodine
What is a downside to using a positive contrast cystogram?
Expensive
What do you use when performing a double contrast cystogram?
Positive contrast and air
What are the indications of using a double contrast cystogram?
Good mucosal detail, contrast puddle is useful i.e. for identifying calculi
What types of contrast studies can be performed on the urethra?
Retrograde urethrography (males) Retrograse vaginourethrography (females)
The contrast medium can be injected with _____ _____ to keep the distension of the urethra with contrast long enough to take the radiograph as otherwise it very rapidly passes into the bladder.
Aqueous gel
What are the benefits of using US over radiography in urology?
Simple, safe (no risk of ionising radiation), cheap
US is superior to radiography when looking at soft tissue structures of the urinary tract, true or false?
True
What should the appearance of the cortex of the kidney be on US?
Evenly granular, hypoechoic to the liver in dogs but can be isoechoic, can be more echogenic (lighter) in cats
The medulla of the kidney is _____ to the cortex.
Hypoechoic
When looking at the cortex and medulla on US, you should look for good _____-_____ definiton.
Cortico-medullary
How is the pelvis recognised on US?
It should be echogenity due to the peripelvic fat present
You should be able to observe ____ layers of the bladder on US.
Three
What are the different layers of the bladder that you should be able to identify on US and how should they appear?
Inner mucosal interface (hyperechoic) Muscle layer (hypoechoic_) Outer serosal layer (hyperechoic)
What are the benefits of using CT in urology?
Superior soft tissue detail.
