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Diagnostic Imaging of the Gastrointestinal Tract
Plain Radiographs
Contrast Studies
Ultrasound
Plain Radiographs
Demonstrate distribution of fluid and gas within the tract
Plain Radiographs
In normal abdomen dependant on radiographic contrast
Plain Radiographs
Ascites significantly impairs diagnostic utility
Loss of serosal detail due to hydroperitoneum
Plain Radiographs
Cannot resolve soft tissue opacities as separate structures
Ultrasound
Resolves soft tissue opacities
Tumour within wall of small intestine
Ultrasound can see the wall lesion within the fluid filled loop of bowel,
plain radiographs cannot
Ultrasound
Cannot image through gas
Plain Radiographs and Ultrasound are complementary
Contrast Radiography
Allows visualization of the mucosal surface and indicates status of bowel
lumen
Contrast Radiography
Provides data regarding GI function
Esophagus
Megaesophagus
Esophageal Foreign Body
Megaesophagus
Retention of air or food material within the esophagus
Megaesophagus
Megaesophagus
Contrast study required only if do NOT see distended esophagus on
plain radiographs
Megaesophagus
Retention of barium within the esophagus
Normal Barium Swallow
Megaesophagus
Esophageal Foreign Body
Usually easy to identify
Good contrast with aerated lung
Esophageal Foreign body
Aspiration pneumonia is a common complication
Esophageal foreign body with aspiration pneumonia
Esophageal foreign body with aspiration pneumonia
Stomach
Gastric Dilation with Volvulus
GDV
Right lateral projection
Gastric Ileus
Gastric Ileus Normal Stomach
Normal Stomach
Foreign Bodies
Radiopaque Foreign Body
Semi radiopaque foreign body
Semi radiopaque foreign body
Hair Ball
Hair Ball
Hairball v Food Material?
Hairball has smooth margins and may not contact stomach wall
Do not disappear following fasting
Food material has irregular margins usually in contact with stomach wall
Disappears following fasting
Fibres e.g. carpet, socks are difficult to identify on plain radiographs and ultrasound and frequently require
contrast radiography
Double Contrast Gastrogram
Naso-gastric intubation
1-2 mls/kg undiluted barium
20ml/kg room air
Left lateral
Right lateral
Ventrodorsal
Dorsoventral
Normal Double Contrast Gastrogram
Carpet Foreign Body
Gastric Foreign Body
Gastric Foreign Body
Gastric Foreign Body
Gastric Tumours
Gastric Tumours
Uncommon
Filling defect on contrast study
May identify on ultrasound
May identify on ultrasound
But easily missed if stomach is gas filled
Gastric Tumour
Pyloric Dysfunction
Obstruction of pyloric outflow
Obstruction of pyloric outflow
Congenital
Obstruction of pyloric outflow
Congenital
Acquired
Neoplasia
Obstruction of pyloric outflow
Congenital
Acquired
Neoplasia
Fibrosis
Plain Radiographs
Enlarged Pylorus
Enlarged Pylorus
Enlarged Pylorus
Contrast Study
Hyperperistalsis
Hyperperistalsis
Hyperperistalsis
The hourglass appearance must be present on several radiographs
Narrowing of pyloric canal
Narrowing of pyloric canal
String or bird’s beak appearance
Narrowing of pyloric canal
Narrowing of pyloric canal
Narrowing of pyloric canal
Small Intestine
Obstruction is commonest abnormality identified
Foreign Body
Intussuception
Tumour
Foreign body most common
Complete obstruction
v
Partial obstruction
Normal width of small intestine
2-3 X width of a rib
Width of a vertebral body
Obstruction results in fluid or gas distension or a combination of both
Foreign body may be
Radiopaque
Semi-radiopaque
Radiolucent
Radiopaque small intestinal foreign body
Semi radiopaque small intestinal foreign body
Semi radiopaque small intestinal foreign body
Semi radiopaque small intestinal foreign body
Radiolucent small intestinal foreign body
Occasionally early enteritis, especially parvo virus infection will
present with intestinal distension
Parvo virus enteritis
Cases with clear plain radiographic evidence of obstruction require
surgery
They do not require an upper gastrointestinal series
The decision to perform an upper gastrointestinal study or a laparotomy
is influenced by experience in interpreting the plain radiographs
Clear evidence of rupture of the gastrointestinal tract is a
contraindication to an upper gastrointestinal series
Long standing cases of obstruction will also have hydroperitoneum
Pneumoperitoneum secondary to intestinal rupture
Pneumoperitoneum secondary to intestinal rupture
Fibres e.g. carpet or socks have a characteristic appearance on contrast
studies
Look for a linear or reticular fibre pattern
Sock foreign body
Sock foreign body
Linear Foreign Body
Contrast column has acute angles with contrast accumulation at the
angles
Linear Foreign Body
Linear Foreign Body
Linear Foreign Body
Partial obstruction of the small intestine
More challenging on plain radiographs
Partial obstruction of small intestine
Partial obstruction of small intestine
Partial obstruction of small intestine
Small Intestinal Tumours
Ultrasound most useful imaging modality
Normal small intestine
5 layers
Mucosal surface – white
Mucosa – black
Submucosa – white
Muscularis – black
Serosa – white
Normal small intestine
Normal small intestine
Normal single wall thickness
<5mm
Intestinal Tumour
Focal lesion
Intestinal tumour
Diffuse Thickening of Small Intestine
Gastro Intestinal Lymphoma
Inflammatory Bowel Disease
Gastro Intestinal Lymphoma
Tumours of colon
Uncommon
Normal colon
Tumour of the colon
Intussuception
Rarely diagnosed definitively on plain radiographs
Intussuception
Presents as non specific obstruction of small intestine
Ultrasound
Target appearance
Or
Too many layers
Intussuception
Requires a contrast study or ultrasound evaluation for
confirmation
Intussuception
Contrast Radiographs
Coiled spring appearance
Intussuception
Mega Colon