Abdominal Radiology Flashcards
what are normal guidelines for dog liver (3)
1) extends just caudally to the costal arch
2) comes to a point
3) >2 intercostal spaces
what are normal guidelines for a cat liver (2)
1) does not extend beyond costal arch
2) comes to a point
what is the normal orientation of the gastric axis… what does a cranial shift and a caudal shift tell you
normally roughly parallel with the ribs; cranial shift = microhepatia; caudal shift = hepatomegaly
where is the only attachment of the spleen
the gastrosplenic ligament that connects the dorsal extremity of the spleen to the stomach
where is the spleen located
left
the _______ extremity of the spleen is fixed whereas the _______ extremity of the spleen varies widely in the dog
dorsal; ventral
what part of the spleen do you usually not see on the lateral view in the cat
ventral extremity (unlike dogs where we can normally see this)
what are indicators of splenomegaly (3)
1) very obvious, large spleen
2) margins rounded
3) can occur secondary to GDV, so may see concurrent signs of GDV
what are signs of splenic torsion (3)
1) splenomegaly
2) displacement caudally and dorsally
3) may see emphysema
which kidney is more cranial
R more cranial than L (R is right on time, L lags behind…)
to properly assess the size of the kidneys, the patient should be in what orientation and why
VD; kidneys fall beside the spine so we can properly compare kidney size to vertebrae
what are the guidelines for kidney size in the dog
2.5-3.5x length of L2 on VD
what are the guidelines for the kidney in the cat (2)
2-3x length of L2 on VD; may see central fat opacity
how should the margins of the kidney appear
smooth and uniform
______ (nephroliths) occur in the renal ______, whereas ________________ occurs in the renal __________
calculi; pelvis; dystrophic mineralization; parenchyma
T/F you can differentiate calculi from dystrophic mineralization using RADs but not U/S
F; cannot differentiate with either of these imaging modalities
what are the normal guidelines for the ureters in the dog and cat
they track through fat in the retroperitoneal space; you will not see normal ureters unless performing an excretory urogram
when evaluating the ureters, what should you take caution of
the deep circumflex iliac a branches off the aorta at a 90 degree angle and can mimic a ureteral calculi
what are the guidelines for the bladder in the dog
1) size varies
2) pear-shaped to ellipsoid
3) cranial to brim of pelvis, but may be intra-pelvic when empty
what are the guidelines for the bladder in the cat
1) size varies
2) ellipsoid
3) always intra-abdominal, typically 2-3 cm cranial to pubis
what types of lower urinary calculi will not appear on radiographs and what is the exception
“Dont C U”
Dried solidified blood
Cystine
Urate
Exception: mixed composition stone containing calcium oxalate will be seen
what are the guidelines for the urethra (2)
1) will not see normally unless performing a urethrocystogram or vaginourethrocystogram
2) intra-pelvic always wider than intra-penile in males
how do urethral calculi appear on radiographs performed with contrast medium
as filling defects
what are the guidelines for the prostate
1) will not normally see
2) located in cranial portion of pelvic cavity
what are the guidelines for an abnormal prostate
1) enlarged
2) displaces bladder cranially and rectum dorsally
3) may see mineralization or gas
On evaluation of a radiograph of a male that was castrated at a young age, you notice a mass in the caudal-ventral abdomen, caudal to the bladder and cranial to the pelvis. The mass has mineralization. The bladder has been displaced cranially and the rectum displaced dorsally.
What is the diagnosis?
prostatic neoplasia
1) dog castrated at young age
2) enlarged prostate
3) mineralized prostate
at what stage of pregnancy do you notice fetal mineralization in the:
dog
cat
dog: 45 d
cat: 36 d
what are the guidelines for the normal uterus
typically not visible; if gravid, not evident until larger than the bowel
what are the guidelines for the normal ovaries
typically not visible, enlarged by neoplasia
what are diagnostic indicators of a pyometra
1) soft tissue/fluid opacity that takes a tubular shape
2) bowel displaced cranially, dorsally and centrally
3) enlarged uterine body located between the colon and bladder
how do we typically image the testes
using ultrasound, not radiographs
what is the best approach to identify the parts of the GI tract
1) identify the stomach
2) identify the colon and cecum
3) all remaining tubular organs are small intestine
can perform a pneumocolonogram if needed to help improve visualization of the colon
what is the typical location of the stomach
within the costal arch, but can vary
if you suspect a GDV in a patient, what is the most important view to take and how would a GDV appear in this view
take RIGHT LATERAL; appears like Popeye’s arm/Smurf hat
when assessing the stomach, it is important to correlate ________ with __________
opacity; history (ex. dog hasn’t eaten or drank in 2 days but the stomach contains fluid and soft tissue… abnormal)
if you suspect a gastric outflow obstruction in the pyloric region of the stomach, what is the most important view to take
LEFT LATERAL
when evaluating for FB, it is important to take how many views and why
take 3! redistributes gas and fluid to help visualize the FB
what are normal SI guidelines in the dog
<1.6x the central height of L5
what are normal SI guidelines in the cat
<2x the end plate height of L2
what do normal intestines look like
smooth contours with focal narrowing of peristalsis and commonly gas opacity
you should never rely on RADs to determine _____________, with the exception being
intestinal thickness; exception is when markedly thick and lumen is non-uniformly distended
what is a good view to determine if there is a small intestinal FB
left lateral
compare and contrast the cecum of the dog to the cecum of the cat (3 for each)
Dog: semicircular; compartmentalized; normally gas opacity
Cat: cone; non-compartmentalized; rarely gas opacity
what are normal guidelines for the colon in the dog
< length of L7
what are normal guidelines for the colon in the cat
< 1.3x length of L5; >1.5x indicates megacolon
what abdominal organs can normally be seen on radiographs
1) liver +/- gallbladder
2) spleen
3) kidney
4) stomach
5) SI
6) cecum
7) LI
8) bladder
what abdominal organs cannot normally be seen on radiographs
1) pancreas
2) uterus
3) ovaries
4) mesentery/omentum
5) lymph nodes
6) ureters
7) urethra
8) adrenal gland
how many zones do we split the lateral view in the dog and cat into
5
how many zones do we split the ventral view in the dog and cat into
4
lateral zone 1 contains:
- stomach
- liver
- dorsal spleen
- adrenal glands
lateral zone 2 contains
- liver
- gallbladder
- descending duodenum
- pancreas
- ventral spleen
lateral zone 3 contains
- SI
- cecum
- colon
- kidneys
- adrenal glands
- spleen
- uterus
- ovaries
- mesentery
- mesenteric LN
lateral zone 4 contains
- colon
- lumbar LN (medial iliac LN)
lateral zone 5 contains
- bladder
- prostate
- uterus
VD zone 1 contains
- pancreas
- liver +/- gallbladder
- duodenum
- R kidney
- R adrenal
VD zone 2 contains
- stomach
- liver
- dorsal spleen
- pancreas
- L adrenal
VD zone 3 contains
- spleen
- SI
- LI
- L kidney
- cecum
- R kidney
- L adrenal
- pancreas
- uterus
- ovaries
- LNs
VD zone 4 contains
- bladder
- prostate
- uterus
- medial iliac LN
the opacity of abdominal masses may be (4):
- soft tissue
- gas
- mineral
- fluid
what is serosal contrast
the ability to see serosal surfaces of abdominal viscera
pneumoperitoneum (increases/decreases) serosal contrast whereas peritoneal effusion (increases/decreases) serosal contrast
increases; decreases
what causes an artificial decrease in serosal contrast (3)
1) young animal
2) underexposed image
3) reduced fat
thinner patients require (more/less) effusion to lose serosal detail
less
what are 3 reasons why young animals have an artifactual decrease in serosal contrast
1) they tend to have a small amount of peritoneal effusion
2) more brown fat (soft tissue opacity)
3) reduced fat in general
what are 3 indicators of peritoneal effusion
1) distended abdomen (sometimes)
2) loss of serosal contrast (ranges from moderate to complete)
3) gas still present in stomach/SI/colon but you can no longer see the walls
Fluid FALLS
how would you distinguish moderate from marked peritoneal effusion
moderate: focal/partial loss of serosal contrast
severe: complete loss of serosal contrast
what are the causes of pneumoperitoneum (4)
1) can occur post-operatively
2) rupture of a gas-filled abdominal organ
3) penetration of body wall
4) gas-producing bacteria present
what are signs of pneumoperitoneum (3)
1) increased serosal contrast
2) gas penetrating the liver lobes
3) obvious stomach wall
Gas RISES
what space makes up the retroperitoneum
the space ventral to the vertebrae and dorsal to the peritoneum that connects with the mediastinum and extends from the diaphragm to the perineum
what structures are contained within the retroperitoneum (4)
1) kidneys
2) ureters
3) adrenal glands
4) medial iliac LN
what are 4 things to look for to diagnose a retroperitoneal pathology
1) irregular structures OR you can see all other abdominal organs except kidneys
2) wispy pattern of fat and fluid in the retroperitoneal space
3) hammock hugging the kidneys
4) patterns of lines in the retroperitoneal space that silhouette with kidneys
