Abdominal imaging

Question 1

List the indications for further investigation/diagnostic imaging of the abdomen

Answer 1

• Abdominal pain
• Weight loss/weight gain
• Diarrhoea, vomiting
• Not responding to other treatments
• Palpation of an obstruction

Question 2

List the advantages of abdominal ultrasonography

Answer 2

• can be performed standing or recumbent
• No need for sedation or anaesthesia
• Does not involve ionising radiation
• thickness of bowel can be imaged and measured
• Lymph nodes can be examined
• Intestinal motility can be assessed

Question 3

List the disadvantages of abdominal ultrasonography

Answer 3

• Gas can cause reverberation (comet tail artefacts) and shadowing
• patients need to be starved for min 12 hours before, preferably 24 hours before
• barium studies need to be done after ultrasound not before!

Question 4

List the 5 layers of the GIT wall and state their ultrasonographic appearance

Answer 4

• (Lumen - heterogenous, can appear very different)
• Mucosal surface: hyperechoic
• Mucosa: hypoechoic
• Submucosa: hyperechoic
• Muscularis: hypoechoic
• Serosa: hyperechoic

Question 5

Describe how you would carry out an ultrasound of the stomach and small intestine

Answer 5

• Sagittal plane, notch cranially
• Start just cuadal to xiphoid
• Move to LHS = fundus and body of stomach
• RHS = pylorus (reduced luminal size, pylorus seen as rounded mass of mixed echogenicity caudal to liver)
• Turn to transverse plane, fan transducer cranially and caudally to visualise limits of stomach
• Move caudally until loop of intestine appears
• Canvisualise longitudinal and transverse views (lines or rings)

Question 6

Describe how you would carry out an ultrasound of the large intestine

Answer 6

• ventral abdomen, caudal to stomach, just to left of midline can see descening colon
• Similar appeance to small intestine but larger diameter, slower contractions, more echogenic luminal contents, thinner wall

Question 7

Describe how you would carry out a ventrodorsal radiograph of the abdomen in the small animal

Answer 7

• Dorsal recumbency using trough
• Last rib centred under x-ray beam
• Edge of trough not inprimary beam
• Hindlimbs can beleft flexed, must not over lie abdomen
• Check for axial rotation
• Centring: midline of spine, level with caudal edge of last rib
• Collimation: caudall to femoral greater trochanter, should not include whole of abdomen to rib 7 cranially - include skin edges
• Exposure factors see chart on wall (if depth is over 10cm use grid and bucky tray)
• Label
• Artefacts (sandbags)
• Should be done in expiratory pause

Question 8

Describe how you would carry out a right lateral radiograph of the small animal abdomen

Answer 8

• Right lateral recumbency, abdomen under beam
• Foam wedge between hindlimbs so are parallel, extend caudally, tie (ensure quads not obscuring caudal abdomen)
• Secure neck with sandbac - split so dont strangle!
• Centring: level with caudal border of last rib, half way down abdomen
• Collimation/l caudal to femoral greater trochanters, should now include wholeof abdoomen to diaphragm (rib 7) cranially, dorsally spine, ventrally skin surface
• Exposure factors see wall chart, if over 10cm use grid and bucky tray
• Lavel
• Artefacts - sandbags