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Chapter 8

MEDRADSC 2Z03 Chapter Notes - Chapter 8: Gallstone, Sonographer, Superficial Vein


Department
Medical Radiation Sciences
Course Code
MEDRADSC 2Z03
Professor
Dawn Danko
Chapter
8

Page:
of 5
Ultrasound – Abdomen
Abdominal Preparation
History
Before the scan, a relevant history will be taken. Questions asked include:
When did you last eat? This is to check that the patient has fasted appropriately for the
scan.
Have you had any abdominal surgery? This is to find out whether the sonographer should
expect altered anatomy, such as a missing gall bladder!
What pain/symptoms are you having? Are there particular types of food that bring on the
pain? This is particularly relevant with gall stones, where patients experience pain after a
fatty meal due to the contraction of the gall bladder.
Preparation
For abdominal ultrasound, the patient must fast for at least 6 hours (although this
varies slightly from site to site).
This is to ensure the patient's stomach, containing food or gas, will not be
superimposed over the organs to be scanned, and also to ensure the gall bladder is
appropriately distended.
The gall bladder is a reservoir for bile.
When a person eats fatty food, the gall bladder contracts, squeezing bile out into
the gut to help digest the fat.
In a fasting state, the gall bladder fills with bile, this allows the sonographer to
image it clearly.
Figure 5 shows a hypoechoic gall bladder. Figure (a) is in a fasted state, between
the measuring callipers.
The gall bladder is well distended. Figure (b) is 60 minutes after eating a fatty
meal.
The gall bladder is much smaller, and the wall appears much thicker.
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Figure 5: (a) Fasting gall bladder, (b) Gall bladder after fatty meal
Abdominal Images
Transducer
A curved 1 – 6 MHz transducer is used.
Organs demonstrated
Structures examined during an abdominal ultrasound include the pancreas, gall
bladder, common bile duct (CBD – which connects the gall bladder to the gut, and
where small stones can become lodged), liver, both kidneys, spleen and
abdominal aorta.
Below in figure 6 are two images of a hyperechoic structure in the gall bladder.
This is a very good example of how we can use posterior shadowing to help in our
diagnosis.
Figure (a) shows a hyperechoic structure and strong posterior shadowing behind
it. This is the classic appearance of a gall stone.
Figure (b) again shows a hyperechoic structure but no posterior shadowing –
sound is being transmitted all the way through this structure.
Therefore, this is a gall bladder soft tissue polyp and not a gall stone.
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Figure 6 (a) Gall bladder containing a gall stone (b) Gall bladder containing a polyp
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