Gastrointestinal Imaging: Case-Based Illustrations

Russell Tucker, DVM, DACVR Washington State University College of Veterinary Medicine • Not normally visualized • Flaccid under general anesthesia • Fluid (reflux) in caudal thoracic esophagus Esophagus Contrast Exams

-positive (Barium solution & Barium paste)

-fluid, semi-soft & dry kibble mixtures Megaesophagus

“dorsal tracheal stripe” Esophagus motility evaluation 3 yr male chronic regurgitation

Large soft tissue at caudal esophagus 3 yr male Labrador Retriever chronic regurgitation

Large soft tissue at caudal esophagus Esophogram under Fluoroscopy

Barium liquid swallow passing by mass -no disruption of esopahgeal mucosa 3 yr male Labrador Retriever chronic regurgitation

Peri-esophageal cyst 3 yr male Labrador Retriever chronic regurgitation

Post-operative 2yr DSH w/ recurrent vomiting

Following prior Sx for suspected SI obstruction 2yr DSH w/ recurrent vomiting

Gastro-esophageal herniation

• • Small intestines – – – iIeum • Large bowel – cecum – ascending, transverse & descending colon fundus

pylorus

Intestinal Radiography Right Lateral Recumbent

• Fundus up – “non-dependent” F – air filled P • Pylorus down – “dependent” – fluid filled Left Lateral Recumbent

• Fundus down – “dependent” F – fluid filled

• Pylorus up P – “non-dependent” – air filled Normal gastric axis: parallels ribs – perpendicular spine Small intestines descending colon transverse ascending

Large intestines Normal Stomach

fundus

pylorus

Lateral projection Contrast Exams

Barium gastrogram mural (wall) lesion of greater curvature

= gastric mural tumor

Fasted for 12 hrs! “filling defect” Gastrointestinal Contrast Exams

-positive (BARIUM)

-negative (AIR)

-double contrast

= mucosal detail “Gastric distention” ~over eating ~chronic outflow obstruction Air Distention

~aerophagia Note: gas in SI “Gastric distention”

Normal position, but grossly food distended, = potential for torsion “Gastric Distention” normal position & increased size

= Air bubble on top of fluid filled stomach & air distended duodenum Gastric Distention normal position, but dilated

pylorus fundus

pylorus

fluid & air

~ chronic outflow obstruction GDV = gastric dilation

Right lateral projection usually diagnostic “double bubble” = compartmentalization GDV

Left lateral projection VD Gastric FB’s

opaque foreign materials = large rock in pylorus Double contrast (barium +air) gastrogram exam: intraluminal foreign body

a) rock b) metal c) plastic d) normal

??? Double contrast gastrogram intraluminal foreign body

Plastic bag Foreign Materials

monitor closely Gastric Foreign Bodies ???

Peptobismal tablets Small Intestines

Variable position within abdomen SI Size

Normal SI diameter in dogs: < 2-3x rib width < L2 veretbra body height

In cats < 12 mm in diameter Small Intestinal Obstruction Patterns:

“Mechanical ” “Functional ileus” Radiographic Signs of “Mechanical Obstruction”

• Varying degrees of SI distension • Proximal retention of air/ingesta • Hairpin turns of bowel loops • Layered “stacking” of SI loops • Signs of • Distention > 4 times the rib width or > 2 times height of L2 body “Mechanical Obstruction” “Mechanical Obstruction” Radiographic Signs of Functional Obstruction

• Usually uniform & generalized

• Bowel distension is usually mild

2-4 x rib width or 1-2 x L2

Little evidence of peristalsis “functional” ileus Functional Ileus generalized mild - moderate SI distention

Mechanical Ileus segmental moderate – marked SI distention Upper GI Barium Series

2-5 mls/kg via stomach tube (per os fails to achieve stomach filling) Multiple radiographs over time (times 0, 15, 30, 60, 120+ mins) to evaluate GI size, shape, contents & function Illustrative case: 1 yr old K9 vomiting & anorexia 1 week Illustrative case: 1 yr old K9 vomiting & anorexia for 1 week

Small intestinal filling defect causing partial obstruction

What is the cause??? a) Rock b) Tennis ball c) Ascarids d) Peach pit Small intestinal filling defect = peach pit with partial obstruction Upper GI: Sequence of Radiographs Survey films prior to barium administration • Immediate: • Rt & Lt lateral views • Ventrodorsal view • Dorsoventral view • 15 minutes: • Rt or Lt lateral view • Ventrodorsal or dorsoventral view • 30 minutes • 60 minutes • As needed to monitor transit to large bowel (~3 hrs) Barium Dose: 2-5 ml / kg required to obtain adequate distention & volume Adm: PO vs gastric tube Intestinal wall thickness requires intraluminal contrast (positive or negative) to properly evaluate = be cautious of evaluation wall thickness on non-contrast survey radiography exams Linear FB’s

“Accordion” or “Pleated” pattern Linear String FB

“Accordion” pattern 1 yr old DSH vomiting 3 days 1 yr old DSH vomiting 3 days 1 yr old DSH vomiting 3 days Mucosal defects

Pseudo-ulcers normal Infiltrative diseases along descending duodenum Large Bowel Contrast Evaluation of the Lower Intestinal Tract • Survey radiographs & complete clinical exam • Technique • Withhold food for 24 hours • Give cleansing enemas 6-12 hours prior • Sedation or anesthesia • Contrast • Liquid barium sulfate suspension • 10-20 ml/Kg Barium enema: use folley ballon cath in fill entire colon to cecum Large Bowel TC

AC

DC C

C TC AC DC

Colon diameter < length of L7 “megacolon”

Mechanical or Functional Etiology “Pneumocolon”

differentiate small vs large intestines “Pneumocolon” Differentiate large vs small intestines 60cc catheter tip syringe (K9 dose 1-3cc/kg air) Position in left lateral recumbency if PSS possible “Pneumocolon” Differentiate large vs small intestines 60cc catheter tip syringe (K9 dose 1-3cc/kg air) Position in left lateral recumbency if PSS possible Large Bowel Cecal-colic intussusception “” etiologies: = free abdominal air -penetrating injury -gas production -ruptured bowel -iatrogenic

Detection ~ volume of air “Horizontal beam” positional view: Kealy p. 34

free air

fundus fluid

Left lateral recumbent horizontal view Left lateral recumbent horizontal view Left lateral recumbent horizontal beam view: traps free air under right crus of diaphragm

free air

fundus fluid

Left lateral recumbent horizontal view Enough Already!