31 - Radiology Flashcards
What do I need to know
- Identify organs
- Which imaging is best for which organs
- Which imaging best diagnoses some diseases
Air colour in x ray plain film
Black
CT
- 300 x the radiation of x ray
- better contrast of organs
- expensive
What is contrast determined by in x ray?
Different densities
Bones white
Tissue grey (not well contrast/defined unless surrounded by fat which is darker)
Air is grey
intraperitoneal and retroperitoneal
iP -liver and GB spleen gut tail of pancreas first part of doudenum
RP - kidneys
most of pancreas
adrenal glands
duodenum (2/3/4th part)
3 pathologies you will see in liver
trauma
cancer/metastases
cirrhosis
Gallbladder pathologies
Gallstones
cancer
Symptoms of liver and GB
- RUQ pain/epigastric (appropriate pain)
- jaundice (late)
- abnormal LFTs
Investigations for GB and liver
- Ultrasound
Where duodenal ulcer pain
Middle epigastric
What colour are vessels in US
BLACK
Helps define structures
How does a fatty liver appear on CT
White and speckly
Hepatic steatosis
Fat lobules reflect more sound waves
Ecogenic (whiter)
Target lesions in liver?
Hypoechoic rims (less reflection of echoes)
Metastases
Could come in with LFT or screening
What does hep c result in the liver looking like
chronic hep resulting the shrunken livers
Hep C curable today
Yes but increased risk to hepatocellular carcinoma
Ecogenic nodule in liver?
Do CT scan
Shows enhancement pattern that is characteristic of benign
Can you get all of the pancreas on one CT scan
No because of the angle it is on; inferior, lateral, posterior
Are all gall stones radio opaque
No more are not radio opaque than are
What colour is the GB in US
Black as is filled with fluid
Gallstone in US
white
dense
shadow as can’t penetrate
What are you likely to see in cholecystitis
Thickened wall of GB
Gallstones
Fluid outside of gb
Probe on GB will hurt
How thick should wall of gb be
3mm
Can CT be used to see stones
Not great
Can be pretty good
Preference to do US first
When would you use CT instead of US for gallstones
If you thought a stone was in the CBD or pancreatic duct because US isn’t as good as CT to see pancreas
CT or US for GB/cholecystitis
US
can’t put CT and ask if patient has pain
See stones better
See GB well
What is better at seeing the pancreas
CT not US
LI/splenic flexure on CT
Bubbly poo
Solid and gas provides natural contrast
If swallows contrast can see some extra contrast
SI on CT
Fluidfilled fulls gut
Spleen problems
Trauma
Cancer/lymphoma
Portal hypertension - splenomegaly
Does spleen cause pain
Not usually
Trauma will bleed
How does 2 layers of blood present
1 darker than the other in series (fresher)
Can leak into peritoneum
What mode of imaging do you use in a trauma setting
CT
Time consuming
Problems in stomach
Cancer and ulcers (ulcers more painful)
SI problems
Obstruction
Crohns (inflamed)
Cancer
Ischaemic
Colon problems
cancer
infection
appendicitis
IBD (inflam)
Cancer more common is Sior LI
LI
What are the 2 ways to get free air
- Trauma
- Gut perforation (i.e. ulceration)
Use to roll patients. Now upright chest xray
Imaging if suspect free air
Ct
Especially if trauma
Symptoms of stomach
Pain
Weight loss
Haematemesis (vomiting)
Imaging stomach
- abdominal plain film is limited
- UGI/barium or endoscopy (if gastroenterologist vs hospital)
> don’t do in ED. Uncommon. Not first line of investigation for most GI problems - CT if trauma/severe pain/speeds transit/could be any cause/
Imaging SI
- plain film first (looking for obstruction)
- CT if severe
- maybe US if dont know
Symptoms SI
- bloating pain (obstruction)
- haematesis (bleeding/ulcer)
- vomiting (obstruction)
SI bowel obstruction
- could be caused by cancer
- causes vomiting and bloating
- dilated in plain film
How to identify SI bowel obstruction (x ray)
- > 3cm dilated
- valvulae conniventes transverse entire SI
- inner abdomen vs picture frame
- less gas/black in LI (solid stool)
SI obstruction on CT
- LI is peripheral and bubbly/natural constrast
- SI valvulae conniventes
- location centre
- and filled with fluid not bubbly/poo
CT SI obstruction
- dilated and filled with fluid
Pain to direct us to appendicitis and what modality to use
Right iliac fossa (starting in epigastric)
X ray USELESS
What to use for appendix
- if young try use US (can say is painful)
- older CT
What does appendix look like on CT
- Right hand side
- small dilated tube
How does Crohns/IBD look like?
- inflamed thickened SI
- increased enhancement as inflemmed
- stranding in surrounding fat
- crohns can cause fistula, perforation, obstruction and dilated downstream
LI symptoms
- melaena
- change in bowel habit
- PR bleeding
LI imaging
- x ray
- CT if present in hospital
- endoscopy if present at private
Faecal loading
- full of stool in LI
- bit of dilation
Colon cancer?
‘apple core’ + change in bowel habits
Colon cancer in Ct
- concentric thickening of colon wall (CANCER)
- stranding into fat
What do you often do for ascites
US so can put in needle so don’t burst
Relation of pancreas duo and SMA
SMA behind pancreas and infront of duo (DONT get confused)
Will see 3/4 parts of the duodenum behind SMA at a lower level to the pancreas
What goes wrong in the pancreas
Pancreatitis
Cancer
Trauma
Diabetes
Features of chronic pancreatitis
Calcification
Dilation of duct (scarring)
Irregular side branching
Recurrent acute pain
Features of acute pancreatitis
PAIN
Serum lipase and amylase
Imaging then often unnecessary
Why will you ask for CT for pancreas
- US doesnt show well
- look for complications of pancreatitis;
ischaemic pancreas (hardely see pancreas)
pseudocysts
gallstones
stranding into fat (early pancreatitis)
