Abdominal radiography Flashcards
In abdo images: Fat creates
the radiographic background, thus you have poor details in thin animals. (serosal detail)
Detail is also lower in neonates/pediatric due to less abdominal fat and more free fluid in abdominal cavity = poor contrast!
Abdominal radiographs are indicated in the following types of patients:
– vomiting
– Abdominal pain
– Regurgitation
– Palpable mass
– Possibly foreign body
– Hematuria, melena
– Hernia
etc.
Preparation for abdominal radiographs.
● Fasting before study (ideally 12h, water available)
● Let the patient urinate/defecate before study
● Minimum 2 views: standard LAT + VD or DV
– VD preferable, because in DV internal organs more compressed = more distortions
● NB! Patients with breathing issues!
● Diaphragm and cranial part of pelvis must be seen in one view – NB! Large dogs tricky for this.
● Spine in one plane (use supportive pads if necessary), hind limbs stretched caudally.
● Ideal moment is expiratory pause – less motion artifact.
Interpretation of abdominal radiographs.
● Spine, caudal part of thorax, other structures outside abdomen – take a look!
● Large contrast organs – liver, kidneys, spleen, bladder etc.
● Visible parts of gastrointestinal tract.
● Do not forget the organs that normally are not visible – look for those too!
● Areas of unusual opaqueness.
Organs and structures that are normally visible in abdo radiographs.
● Stomach
● Duodenum
● Small intestine
● Caecum
● Colon
● Liver
● Spleen
● Prostata (in dogs, not in cats)
● Bladder
● Kidneys
● Peritoneum
● Diaphragm
● Pelvis
● Spine
● Sublumbar muscles
Organs and structures that are NOT normally visible in abdo radiographs.
● Adrenal glands
● Mesentery
● Mesenteric lymph nodes
● Pancreas
● Gall bladder
● Omentum
● Ovaries
● Uterus
● Ureters
● Abdominal aorta
● Blood vessels
Small amount of free fluid in abdominal cavity is
normal – not visible radiographically.
Ground-glass appearance – poor serosal detail with generalized fuzziness/mottled appearance, organs not clearly visualized can indicate: (2)
– Peritonitis
– Carcinomatosis (= the widespread dissemination of carcinoma in the body)
Factors decreasing contrast. (2)
emaciation
young age
Describe the right lateral abdominal view radiographically.
● RK – right kidney
● LK – left kidney
● D – duodenum
● PA – pylorus
● C – caecum
● CO – colon
● UB – urinary bladder
● SpT – spleen (tail)
Describe the left lateral abdominal view radiographically.
● RK – right kidney
● LK- left kidney
● PA – pylorus (stomach)
● D – duodenum
● CO – colon
● UB – urinary bladder
● C - caecum
Describe VD abdominal view radiographically.
● F – fundus of stomach
● SpH – head of spleen
● Pr - prostata
Right vs Left lateral view
Abdominal effusion
poor serosal detail due to pediatric patient
abdominal effusion
Ground-glass appearance = poor serosal detail with generalized fuzziness/mottled appearance, organs not clearly visualized can indicate e.g. peritonitis classically.
Describe Mass effect in the context of xray interpretation.
● A Mass/neoplastic change in one organ causes changes in location of other organs.
● Gives a hint for the location of the mass.
Describe the healthy liver in the context of xray interpretation.
● The triangular part between diaphragm, stomach and ventral abdominal wall.
● Homogenous usually
● Usually fits under costal arch
– Not a strict rule!
– In older dogs can be more caudally
– In young dogs the liver is proportionally bigger
– In deep chested breeds the liver seems to be smaller
● Appears larger on right lateral view – more room for lobes, can displace caudally.
● Cats have falciform fat pad that lifts the liver dorsally.
Describe the pathologic liver in the context of xray interpretation.
● Changes of shape and size – Larger is hepatomegaly.
● Extending markedly beyond costal arch + rounded edges – Unusually small = microhepatica.
● Mass changes
● Gall bladder pathologies
● Look for gastric axis and location of other organs!
● Rounded edges
(NB attached images are in health))
What is the Gastric axis?
Draw imaginary lines within grastric lumen: Normally should be perpendicular to spine or parallel to costal arch.
Only works for dogs.
e.g. liver masses will push gastric axis aside
trace the outline of the liver
Falciform fat
Normal liver in a Miniature schnautzer.
As you can see the liver reaches beyond the costal arch a little bit ventrally but thats okay and normal. Edges are nice and sharp.
normal liver despite reaching slightly past costal arch
filled stomach
spleen lower right
obvious hepatomegaly, reaches far beyond costal arch and edges are rounded not sharp.
gastric axis is altered.
mass effect, SI moved caudally.
gastric axis is extremely altered caudally
Hepatomegaaly + effusion
normal puppy with poor serosal detail. cartilaginous portion of ribs not visible.
microhepatica
Liver abscess (+ gas)
Calcification of liver (density is wrong, maybe a little small too)
lumen of stomach is not visible at all which is unusual (usually stomachs always have a little bit of gas inside)
left image: gallbladder marked with g, gas filled with a small mass dorsally
right image: gallbladder has high density content, stone.
Gastritis & Enteritis on abdo xray are
not visible
● Visible
– Gastric dilatation and volvulus (GDV)
– Ileus
– Foreign body
Describe the Stomach on abdo radiography.
e.g. right vs left lateral views
● The location of gastric axis mirrors the size of liver.
● Normally cranial to L4
● Left side lateral – pylorus filled with gas
● Right side lateral – pylorus filled with fluid→ ball-shaped. NB! Don’t rush to surgery!
Describe the positioning of the dog stomach on xray.
● Caudally to liver, cranially to transverse colon.
● Long axis perpendicular to spine or parallel to ribs.
● Pylorus is ventrally to fundus.
● VD/DV – Stomach perpendicular to spine, pylorus on right next to abdominal wall (U-shaped in some dogs).
Describe the positioning of the cat stomach on xray.
● Gastric axis is 30 degrees caudally or
perpendicular to spine.
● Most cats have falciform fat that lifts the liver and stomach dorsally.
● VD/DV – J-shaped stomach.
● Pylorus is superimposed to spine or is located next to it on right side.
Cat vs dog stomach on xray VD view.
dog = U shaped
cat = J shaped
Gastric axis in deep chested breeds.
Can look weird with deep chested dogs.
Gastric Axis may angle cranially and still be completely normal.
Describe gastric wall thickness evaluation radiographically.
● Difficult to evaluate gastric wall thickness radiographically – seems thicker if stomach filled with fluid (illusion).
– Contrast study
– Ultrasound is better for this eval.!
● Foreign body or just stomach content?
– NPO 12-24h + new study.
– Emptying may take ca 17h (dogs)
● How wise is it to do a new study after only 6h? Might not be long enough for the stomach to fully empty.
gastric Foreign body
gastric foreign body, cable in cat
gastric content (food)
Gastric dilatation and volvulus
● TWO different conditions!
● “Boxing glove” or “Double bubble” = classic volvulus.
“Double bubble means trouble!”
Dilatation without volvulus
● RL – gas in fundus (top pic)
● LL – gas in pylorus.
● Antrum located in normal position
rare case, full 360’C gastric torsion which makes it difficult to discern as a volvulus.
Describe the “Gravel sign” on xray.
refers to mineralization in some part of the GI tract
● caused by Chronic obstruction due to e.g.:
– Neoplasia
– Fibrosis
– Inflammation
– Hypertrophic pyloric stenosis
● Most commonly in pylorus (see density in image)
Describe the normal Small intestine on xray.
● Caudally to stomach, cranially to urinary bladder.
● Fasted animal: gas + content
– Dog: 1/3-2/3 gas
– Cat: markedly less gas
● Width can vary
– Less than double growth plate diameter in lumbar vertebra
– < double diameter of other small intestine parts
– < double diameter of 13. rib
– < 12mm (in cats)
● Dilated if radius is:
– > 4 x width of last rib
– > 1,6 x the height of the L5 vertebral body at its narrowest point
diaphragmatic hernia
hernia
Describe Linear foreign body on xray.
“String of pearls”-appearance aka plication.
– NB! In cats, this pattern may be normal in duodenum and proximal part of small intestine.
Describe ileus on xray.
● Dilatation of intestinal diameter, Gas/fluid will gather proximally to obstruction.
intestine can also fill with fluid and look like large sausages.
● Functional or mechanical
● In Chronic, you get the “gravel sign”
● NB! Caecum can look like ileus in right lateral view.
ileus
Volvulus of small intestine
mechanical ileus caused by foreign body
Describe Intussusception on xray.
● One intestinal segment telescopes into another part of intestine.
● Longer sausage-like part.
● Semilunar shadow, gas as background.
Describe normal Large intestine on xray.
● Caecum just right to midline, mostly gas in it, often comma shaped (see image).
– Do not confuse with gas-filled small intestine
– Can mimic ileus on LAT view
– cecum at L3 level
● In cats, the caecum is usually not visible.
● Shape, location and filling of the LI may vary.
● Colon width should be < L7 length.
● Radiographic finding usually nonspecific
– Ileus
– Intussusception
– Megacolon
normal anatomy
megacolon
e.g. older cats
Describe the normal Spleen on radiography.
● Long slender shape, cross-section triangular in dogs, more ovoid in cats.
● Variable size
– in Anesthesia may increase in size!
● Dorsal part “head” and ventral part “tail”.
● VD: triangular shadow on left side, next to abdominal wall (cat and dog).
● Lateral
– In cats, there may be triangular shadow dorsally between stomach and kidneys.
Middle part and tail usually not visible.
● If seen both VD and LAT, indicates possible splenomegaly.
– In dogs, seen along abdominal wall between liver and urinary bladder.
cat spleen
In cats’ lateral images, there may be triangular shadow dorsally between stomach and kidneys. Middle part and tail usually not visible.
VD: triangular shadow on left side, next to abdominal wall (cat and dog).
Describe normal Pancreas on xray.
● Normally not visible in dogs
● May be partially seen in overweight cats (left lobe) on VD view – caudally to fundus and medially or caudally to head of the spleen, cranially to left kidney.
● Important to know the localization
– Loss of peritoneal details
– Focal mineralization
– Mass effect
cat pancreas in overweight cat which makes it easier to see
pancreatitis in dog
mottled/ground glass in pancreas region in VD image
pancreatic mass in lateral image pushing other organs aside
Describe the Adrenal glands on xray.
Usually not visible
enlarged sublumbar lymph nodes (upper image)
mesenteric lymph nodes in lower image (+effusion, mass effect)
(when normal, they are not visible)
Describe the normal Kidneys and ureters on xray.
● Retroperitoneal organs
● Size, shape, opacity can be viewed.
● Retroperitoneal fat gives background
– Hard to view in Emaciated patient & retroperitoneal fluid makes it difficult to see stuff too.
– Superimposition with intestinal gas
● normal Size of kidneys (VD)
– Dog: 2,5-3,5 x L2
– Cat: 2,4-3,0 x L2 (1,9-2,6 x L2 older cats)
● Location
– Dog: right kidney more cranially, mostly same level with T12-L1. Left kidney more
caudally, mostly L1-L3.
– Cat: L1-L4, more ovoid shape.
● Ureters – normally not seen.
Renal Pathologies on xray
Size. Increased in:
● Hydronephrosis
● Neoplasia, inc lymphoma
● Cysts
● ARF
● Hypertrophy
● Acromegalia
● Abcess/hematoma
Size Decreased in:
● Smooth margin – hypoplasia, amyloidosis, CKD
● Irregular margin – CKD
● Calcifications
renal calcifications + ureter calcification too
abnormal kidney
hydronephrosis?
Ectopic kidneys that are way too caudal
(contrast agent in kidneys in image)
Describe the normal Urinary bladder and urethra on xray.
● Urinary bladder is very well seen
● Urethra not seen without contrast agent
bladder herniated out of abdo
urolithiasis in all images
some in urethra, some in bladder
overfilled bladder
Describe the normal uterus and ovaries on xary.
● Normally not visible
You can see the uterus when there’s contents:
● Pyometra
● Pregnancy
pyometra
dont confuse overfilled uterine horns with intestines
pyometra usually causes mass effect as well
Describe the normal Prostate on xray.
● Visible in dogs on Lateral, VD.
● Size variable
– e.g. larger in Scottish terriers
● Caudal edge may not be seen, sometimes dorsal edge not well seen either.
● May not be seen in Immature or sterilized patients.
● Not seen in cats
benign hyperplasia of the prostate causing stenosis of the colon
prostatic cyst
