Radiology of the Acute Abdomen

Question 1

What is the acute abdomen?

Answer 1

Sudden, severe abdominal pain caused by something

• burst
• blocked
• inflamed
• loss of blood supply

Question 2

What kinds of imaging can be done?

Answer 2

Plain films
US
CT

Question 3

What are the four main densities on plain abdominal film?

Answer 3

Gas - black
Fat - dark grey
Muscle, bowel wall, solid organ and blood vessel - light grey
Bone - white

Question 4

Which organs should it be possible to see on a plain abdominal X-Ray?

Answer 4

Kidneys
Liver
Bladder
Small bowel
Large bowel 
Spleen
Stomach

Question 5

Can you see gallstones on X-Ray?

Answer 5

Sometimes (20% of of gallstones are calcified)

Question 6

The edges of which muscle can be seen on X-Ray?

Answer 6

Psoas

- from the transverse processes of the lumbar vertebrae to combine with the iliacus muscle

Question 7

What is a poreclain gallbladder?

Answer 7

Calcification of the gallbladder, believed to be brought on by excessive gallstones
- as the gallbladder is calcified, the stones are not normally visiable

Question 8

Why can some of the bowel be seen on X-Ray?

Answer 8

Gas shadows

- if the whole bowel can be seen, this is pathological

Question 9

What is Chilaiditi’s syndrome and how is it diagnosed?

Answer 9

A condition where a portion of the bowel is located between the liver and the diaphragm

• can obstruct the small bowel
• appears as gas where there isn’t usually on X-Ray

Question 10

How can an inguinal hernia be suspected on X-Ray?

Answer 10

There is a loop of bowel seen below the level of the inguinal ligament

Question 11

What is biliary gas an indicatory of?

Answer 11

Biliary stent in situ
Previous surgery
ERCP

Question 12

Is imaging useful for identify inflammation?

Answer 12

Abdominal X-Ray
- useful for colitis
- non-specific in other inflammatory conditions
Ultrasound
- cholecystitis (and appendicitis if they are young and slim)
CT is the first choice in every other inflammatory condition

Question 13

What are the identifying features of colitis on abdominal X-Ray?

Answer 13

Thumbprinting
- thickening of the wall of the colon
- thickening of the haustral folds leads to thumbprinting
Mucosal islands
- dark patches along the bowel 
 Toxic megacolon
- extremely dilated colon

Question 14

Which imaging modalities are best for identifying a perforation?

Answer 14

Chest X-Ray 
- sensitive for free gas
Abdominal X-Ray
- less sensitive (very subtle)
CT to confirm and look for cause

Question 15

What signs of obstruction are abdominal X-Rays good at identifying?

Answer 15

Small and/or large bowel dilation
How much gas is in the colon
If there is any gas in the rectum
If there are any complications
- ischaemia 
- perforation

Question 16

How can small bowel obstruction on X-Ray be identified?

Answer 16

Centrally located multiple dilated loops of gas filled bowel

Valvulae conniventes confirm it’s small bowel

Question 17

What is a caecal volvulus?

Answer 17

Caecum isn’t reteroperitoneal, and therefore is mobile (susceptible to twisting or folding)

Question 18

How can a caecal volvulus be identified on X-Ray?

Answer 18

Grossly dilated and is no longer in the anatomical position

Caecal embryo sign

Question 19

What imaging modalities are used to test for ischaemia?

Answer 19

Abdominal X-Ray is non-specific
- positive signs means advance ischaemia
CT is first choice

Question 20

What is pneumoperitoneum?

Answer 20

Gas within the peritoneal cavity, but outside of the bowel lumen
- usually due to peforation