Abdominal imaging Flashcards Preview

Phase 3B Radiology > Abdominal imaging > Flashcards

Flashcards in Abdominal imaging Deck (17)
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1
Q

AXR basics.

a) 2 types
b) Adequate exposure

A

a) AP erect and AP supine

b) Diaphragm to pelvis

2
Q

AXR interpretation: systematic approach.

- BBC

A
  • Bowels and other organs
  • Bones
  • Calcifications and stones
3
Q

Abdominal XR.

a) Ureteric stones - appearance
b) Main differential? - distinguishing features

A

a) Calcium oxalate (80%) - radiopaque, elongated, craggy edges
b) Phleboliths - calcified deposits in veins - rounder and smoother than ureteric stones

4
Q

Abdominal XR.

- Small bowel obstruction vs LBO

A
  • SBO - more central, valvulae conniventes (beaded appearance - traverse entire width of bowel)
  • LBO - more peripheral, haustra (only partly traverse the width of bowel), larger
5
Q

Abdominal XR.

a) Appearance of faeces
b) In constipated patient, what may you see?

A

a) Mottled appearance - due to gas trapped within the solid faeces. Often visible in the colon
b) Impacted solid faeces in the rectum/ colon

6
Q

Volvulus.

a) Define
b) 2 most common (in adults) and their classic appearance on AXR
c) Type in infants

A

a) Volvulus is a twisting of the bowel on its mesentery

b) - Sigmoid volvulus: ‘coffee bean’ appearance
- Caecal volvulus: foetal appearance

c) - Midgut malrotation - presents with bilious vomiting. Requires Ladd’s procedure

7
Q

Bowel obstruction.

a) Threshold widths for the SI, LI and caecum
b) Dilatation above how many cm is a high risk for imminent rupture?
c) Gas in the rectum - significance?

A

a) 3cm - small intestine
6cm - Large intestine
9cm - caecum

b) 10 cm

c) In the context of bowel obstruction…
- If there is gas in the rectum, there is only a partial obstruction
- If no gas is seen in the rectum, the obstruction is complete

8
Q

Bowel obstruction.

a) 4 cardinal clinical features of bowel obstruction
b) Management

A

a) Absolute constipation
Abdominal pain
Abdominal distension
Vomiting

b) - CT or AXR to diagnose obstruction (CT better than XR for seeing where the obstruction is)
- May do CXR to assess for perforation (pneumoperitoneum)
- Drip (IV fluids) and suck (NG tube)
- Avoid AKI (dehydration common due to loss of fluid via vomiting/ NG losses, and also due to lack of water reabsorption in the colon)

9
Q

Perforated viscus.

a) If worried about bowel perforation, what radiograph should be ordered?
b) What is the differential for pneumoperitoneum

A

Erect CXR
- look for pneumoperitoneum (air under the diaphragm)

b) Chilaiditi sign
- bowel below diaphragam (haustra visible)
- due to chronic constipation and faecal impaction - give an enema

10
Q

IBD features on AXR.

A
  • Thumb-printing – mucosal thickening of the haustra due to inflammation and oedema causing them to appear like thumb prints projecting into the lumen
  • Lead-pipe (featureless) colon – loss of normal haustral markings secondary to chronic colitis
  • Toxic megacolon – colonic dilatation without obstruction associated with colitis
11
Q

Gallbladder on AXR.

- possible findings

A
  • Gallstones (if calcified)

- Post-cholecystectomy clips

12
Q

Bones visible on AXR

A
  • Ribs
  • Vertebrae: Lumbar, Sacrum, Coccyx
  • Pelvis
  • Proximal femurs
13
Q

Calcifications visible on AXR (and other visible paraphernalia)

A
  • Calcified gallstones in the RUQ
  • Renal stones/staghorn calculi
  • Pancreatic calcification
  • Vascular calcification (eg. phleboliths)
  • Costochondral calcification
  • Contrast (eg. following a barium meal)
  • Surgical clips (eg. post-cholecystectomy)
  • Ureteric stents
  • Naval jewellery artefact over the approximate location of the umbilicus
14
Q

Ureteric stones on AXR.

a) Where do they commonly lodge? (3)
b) If not visible on XR, gold standard is…?

A

a) - Uretopelvic junction (UPJ)
- Pelvic brim
- Vesico-ureteric junction (at level of ischial spines)

b) Non-contrast CT KUB

15
Q

Phleboliths vs. ureteric calculi

A

Phleboliths - rounder and more homogenous

16
Q

Reporting an AXR.

  • Type of film
  • Patient details and DOB
  • Relevant admission details
  • Any previous films for comparison
  • Exposure and quality
  • Bowel width
  • Bony pathology
  • Calcification/ other
  • Summary

Example for normal AXR of Jayne Lister, DOB 11/04/1970

A
  • “This is a supine AP abdominal radiograph of Jayne Lister, date of birth 11/4/1970.
  • She was admitted with… (?bowel obstruction)
  • The film is of good quality with appropriate exposure.
  • No prior imaging is available for comparison.
  • Both the small and large bowel appear within normal limits.
  • Other abdominal viscera appear normal within the limits of this projection.
  • No obvious bony pathology is identified.
  • No abnormal calcification is seen.
  • In summary this is a normal plain radiograph of the abdomen.”
17
Q

Apple core sign

a) what is it?
b) seen using which modality?

A

a) Sign of colorectal cancer constricting the lumen of the bowel to produce an apple core appearance; may be associated with bowel obstruction
b) Barium enema