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160 Cards in this Set
- Front
- Back
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patient preparation for abdominal radiographs
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withhold food for 12-24 hours
administer cleansing enemas ( at least 2-3 hours prior) encourage animal to empty bladder sedate animal if difficult to restrain or panting excessively |
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Normal lack of mesenteric fat in young animals may mimic...
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abdominal effusion
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technique settings for abdominal radiogrpahs
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use high contrast technique (low kVp and high mAs)
also use high contrast film, intensifying screens, and a grid to improve organ visualization |
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the gastric axis is...
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perpindicular to the spine or parallel to the ribs
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What are the standard abdominal radiography views for animals less than 300 lbs (dog, cat, foal, calf)
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left lateral and ventrodorsal
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why do we use abdominal compression?
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reduction in thickness results in a significant reduction of scatter radiation formation and improved film quality
adjacent structures (organs, masses) are separated from one another can aid in restraint of animal and motion artifact |
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When is a grid normally used
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when the thickness of the abdomen is greater than 10cm
measure the thickest portion of the abdomen |
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spleen
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relative size variable between cat and dog (larger)
lateral view: tail of spleen triangular shape w/ smooth sharp magins along ventral abdomen VD: head of the spleen is triangular and seen in left cranial abdomen just caudal and to left of the gastric fundus |
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what may you need to do to radiographic technique when using a compression band
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you may need to decrease kVp because you are decreasing the thickness of the structure
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kidneys
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normally located in cranial portion of the retroperitoneal space
uniform soft tissue opacity left kidney positioned caudal to right in the dog (more variable in cats) |
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abdominal organs are predominantly ___________ opacity
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soft tissue
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what are the borders for and entire abdomen radiograph
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cranial boundery= dome of diaphragm
caudal boundary = pelvic inlet ventral and lateral boundaries = abdominal wall dorsal boundary = spine |
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organs may appear more opaque when they are:
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thick, surrounded by air, or when there is summation with overlying structures
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urinary bladder
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highly variable size and location
in housebroken dogs may occupy up to 50% of the abdomen positioned more cranially in cats than dogs cranial and ventral margins usu. well visualized due to adjacent fat pads dorsal margin silhouettes w/ colon |
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presence of intra-abdominal fat...
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helps improve visualization of margins
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small intestines
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occupy the mid-abdomen in most normal dogs and cats
normally contains small volumes of gas and fluid |
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lack of fat (emaciated or young animals) results in:
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poor abdominal contrast and detail
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why do we use abdominal compression?
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reduction in thickness results in a significant reduction of scatter radiation formation and improved film quality
adjacent structures (organs, masses) are separated from one another can aid in restraint of animal and motion artifact |
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large intestine
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dog: often gas filled and located in right mid abdomen
cat: usu. not visible ascending colon in right mid abdomen transverse colon in cranial abdomen descending colon in the mid to caudal abdomen |
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what may you need to do to radiographic technique when using a compression band
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you may need to decrease kVp because you are decreasing the thickness of the structure
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abdominal wall
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can be seen as thing soft-tissue band due to contrasting density between muscles and fat in the fascial planes
visible only when the muscle planes are projected tangentially |
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abdominal organs are predominantly ___________ opacity
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soft tissue
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which abdominal structures are not normally seen?
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gall blader, pancreas, adrenal glands, ureters, prostate gland, ovaries, uterus, lymph nodes, and blood vessels
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organs may appear more opaque when they are:
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thick, surrounded by air, or when there is summation with overlying structures
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presence of intra-abdominal fat...
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helps improve visualization ofmargins
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fat deposits are most commonly found in...
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the falciform ligament
greater omentum mesentery retroperitoneal space |
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give _________ or __________ if needed to see stomach position more clearly
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air or barium
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Excretory urography
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radiographic study performed follwing intravenous injection of iodinated contrast medium
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_________, ___________, ___________ are sequentially opacified as contrast medium is excreted over time.
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kidney
ureters urinary bladder |
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What are the 3 phases of an excretory urography?
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Vascular phase
nephrogram phase pyelogram |
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Vascular phase
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opacification of arteries
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nephrogram phase
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-opacification of renal parenchyma
-contrast agent in renal tubules -opacity greatest early in study, then gradually diminishes |
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Pyelogram phase
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-opacification of collecting system: renal pelvis, diverticula, ureters
- less opaque early in study due to osmotic diuresis - more opaque later in study due to increased concentration of contrast agent over time |
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What are the synonyms for excretory urography?
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intravenous urography (IU, IVU)
excretory urography (EU) Intravenous pyelography (IVP) |
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indications for excretory urography
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evaluate renal and ureteral morph. (size, shape, position, margination)
eval renal and ureteral integrity (leakage - rupture, tear; filling defects - masses, calculi) eval relationship b/w kidneys and an abdom. mass evaluate ureteral function (limited) |
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contraindications for excretory urography
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-dehydration: acute tubular necrosis
-previous adverse reaction to iodinated contrast media -renal failure is not a contraindication but will degrade the quality of the study |
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contrast agents used for excretory urography
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all contain water-soluble organic iodine
-high density material rapidly cleared from circulation by renal excretion |
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how are contrast agents used for excretory urography cleared from circulation
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through renal excretion
-low protein binding -escreted almost entirely through glomerular filtration without tubular secretion |
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what are aternate excretion routes for contrast agents
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liver - gall bladder opacification
small bowel; bowel lumen opacification |
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EU contrast agents temporarily cause increased ______________________.
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renal tubular pressure
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Iothalamate diatrizoate
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ionic contrast media
inexpensive high osmolarity -----adverse reactions |
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Types of adverse reactions with ionic contrast media
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vomiting, urticaria (rash), anaphylactoid
CV collapse, Acute renal failure, Altered UA, Cellulitis |
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nonionic contrast agents
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more commonly used in humans
disadvantage: expensive, short shelf life advantage: iso-osmolar= lower risk of adverse reactions |
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what is the benefit to having an indwelling intravenous catheter: cephalic or jugular
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helps reduce risk of extravenous injection
might be needed if any adverse reactions to contrast |
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sequential abdominal radiograph times
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1-3 min: right lateral and VD views
10 min: right lateral and VD views 20 min: right lateral and VD views 40 min: right lateral and both VD oblique views |
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kidney shape and margination
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dog: more oblong
cat: more oval smooth rounded margins |
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Kidney size
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dog: 2.5 - 3.5 times the length of L2 vertebral body in VD view
neutered cat: 1.9 - 2.6 times L2 intact cat: 2.1 - 3.2 times L2 |
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Renal pelvis: size, shape, and margination
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best seen in pyelogram phase - 10 to 20 min.
<2mm thick in dog curvilinear or crescent shaped pelvic recesses or diverticuli - thin, fingerlike, outwardly radiating projections proximal ureter cone shaped smoothly marginated |
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location of the renal pelvis
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cranial retroperitoneal space
- T13 - L4 right more cranial than left in dogs may be ventrally displaced if large volume of retroperitoneal fat |
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ureteral contrast study
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best seen in the 20-40 min study
lateral oblique helps separate ureters and improve visualization of the trigone region |
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ureteral size, shape, margination
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some normal variation in shape and size due to peristalsis
maximum diameter usu. less than 2.5 mm in dogs should be smoothly marginated |
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ureteral location
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should extend from renal pelvis to trigone of urinary bladder
positioned in retroperitoneal space (varies w/ position of urinary bladder) |
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indications for cystography
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clinical suspicion of bladder disease
suspect bladder involved secondarily by adjacent disease size, shape, location, integrity of bladder |
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antegrade positive contrast cystography
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obtained by first performing and intravenous urogram
evaluate bladder at 30-40min post injection Adv: avoid passing urethral catheter (trauma); less likely to rupture bladder Dis: incomplete bladder distention, urine mixes with contrast |
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retrograde positive contrast cystography
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obtained by injecting positive contrast medium into the bladder by way of the urethra
adv: best study for suspected bladder rupture or herniation; also good for id'ing communication b/w |
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negative contrast cystography
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obtained by injecting air or gas into the bladder by way of the urethra
adv: inexpensive way to id relationship b/w bladder and adjacent structures dis: not very good for demo bladder rupture, air leakage hard to see relative to bowel gas |
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retrograde double contrast cystography
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obtained by injecting both iodinated contrast and air or gas into the urinary bladder by way of urethra
adv: best study for eval mural or intraluminal dz |
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radiographic technique adjustment for double contrast cystography
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reduce kVp settings from those used for survey radiographs
- at least 10% -allows for reduction in tissue density caused by air filled bladder |
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urethography
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gen. term referring to the radiographic eval of the urethra following intro of contrast media into the urethral lumen
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indications for urethrography
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clinical suspicion of urethral obstruction
localization of urethra relative to adjacent structures (prostate) determine cause of bloody urine (hematuria) |
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contraindications for urethrography
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none for positive contrast
negative contrast: communication b/w urethra and corpus cavernosum = increased risk of air embolism |
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Name the parts of the stomach
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What is the triangular radiopaque structure seen here?
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the orientation of the stomach based on the location of air in the stomach
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In a VD view the duodenum stays...
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right along the right abdominal wall
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canine small intestine diameter
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less than 1.6 times the height of L5 body
less than twice the rib width |
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feline small intestine diameter
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less than or equal to 12 mm
less than 2x the height of L4 body |
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wall thickness of the canine stomach
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between 3-5 mm (measure between rugal folds)
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wall thickness of the feline stomach
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2-3 mm (focal areas of thickening can be caused by lymphoma)
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What is the appearance of the stomach in sternal recumbency?
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air rises to fundus, fluid settles to body and pylorus
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What is the appearance of the stomach in dorsal recumbency?
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air rises primarily to body (+/- pyloric antrum) and fluid settles to fundus and distal pylorus
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What is the appearance of the stomach in right recumbency?
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air rises to fundus and body, and fluid settles to body and pylorus
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What is the appearance of the stomach in left recumbency?
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air rises to pylorus and fluid settles to fundus and body
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What is the position of this stomach?
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right lateral recumbent
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What is the position of the stomach?
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left lateral recumbent
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What is the position of the stomach in the picture?
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dorsoventral
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What is the position of the stomach in this picture?
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ventrodorsal
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GI contrast studies allow...
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enhanced visualization of GI structures beyond survey radiographic findings
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Barium powder as a contrast medium
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mix with water
tends to come out of suspension ***not the preferred agent |
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barium past as a contrast medium
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thick pasty suspension used for esophagrams
good coating of the mucosa persists longer than liquid barium |
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Barium liquid (commercially prepared) as a contrast medium
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premixed, flavored, sold in liquid form
used for upper and lower GI series can be used for esophagrams |
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Aqueous organic iodide preparations: ionic and non-ionic used as contrast media
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formulated for use in GI tract
used when perforation suspected not for routine use |
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An esophagram evaluates:
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size and location
mucosa motility foreign bodies mass lesions perforations |
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Barium paste/liquid for esophagrams
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use in routine esophagrams
good mucosal coating |
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Barium mixed with food used for esophagrams
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best for stricture diagnosis
poor mucosal coating |
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Aqueous organic iodide solution used for esophagrams
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use if suspected perforation
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Food Bolus Esophagram
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advantages: volume distension, stricture identification
disadvantage: poor mucosal coating, obscure lumen |
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organic iodide esophagram
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advantages: perforation
disadvantages: poor mucosal coating, poor distension, may pass across stricture, aspiration may cause pulmonary edema (ionic agents) |
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complications of an esophagram
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aspiration: barium, organic iodide solution (ionic)
barium inflammation: cervical, mediastinal, or soft pleural tissues if esophageal perforation present |
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Technique for Esophagram
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survey radiographs (always!)
administer dose (multiple swallows, 10-30 cc on hard palate or in buccal pouch, food: ad lib or force feed) fluoroscopy if available views: lateral, DV/VD, oblique as necessary |
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What is this U-shaped structure and is it considered normal?
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This is the esophagus. This can happen naturally and is most pronounced in brachycephalic dog
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What is the appearance of normal mucosa in an esophagram?
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striations: linear folds
margins: smooth cat: herringbone appearance in caudal 1/3 |
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Upper GI series
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time consuming and costly
replaced by ultrasound or endoscopy in many cases of GI disease |
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Preparation for an upper GI series
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fast 12-24 hours
enemas at least 2 hours prior avoid most sedatives b/c decrease GI motility (acepromazine-dog and ketamine/valium - cat have little effect on motility) |
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Dose for GI contrast study
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1 oz per 5 lbs body weight or 4-6cc/lb
- when dosing large dogs use the smaller end of the range, use the upper end of the range for smaller dogs -must distend stomach and bowel lumen |
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When using aqueous organic iodide solutions for upper GI contrast...
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use if perforation suspected
the contrast passage is more rapid so you need more rapid image sequencing hypertonic- can result in dehydration, dilution, and diarrhea **don't use ionated on fragile patients |
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Upper GI contrast complications
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infrequent:
aspiration Barium peritonitis |
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UGI series normal appearance
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mucosa: smooth, sharp, fimbriation
folds: rugae, linear folds outpouch: pseudoulcers wall thickness: variable |
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Lower GI series
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preparation - cleanse colon
survey rads: standard restraint: heavy anesthesia/sedation |
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technique for a lower GI series
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inflatable cuffed catheter
dose: dogs- 10-15 cc/lb; cats - 5-10 cc/lb; careful not to over-distend views: lateral and VD/oblique evacuate when complete |
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Pneumocolon
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distend colon with room air via catheter, tube, or syringe
help in determination of location of colon, intraluminal contents, mass lesions |
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what are the five layers present in the gastric and intestinal walls
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from outside to inside: serosa, muscularis, submucosa, mucosa, mucosal surface/lumen interface
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serosa
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thin hyperechoic layer
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muscularis
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thin hypoechoic layer
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submucosa
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thin hyperechoic layer
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mucosa
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prominent hypoechoic layer (the thickest layer)
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mucosal surface/lumen interface
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hyperechoic layer in the center of the bowel
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The upper airway includes:
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nasal cavity
paranasal sinuses larynx trachea |
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What is the most informative view for evaluation of the nasal cavities?
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open mouth ventrodorsal
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What are the common radiographic views for the nasal cavity?
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lateral
open mouth ventrodorsal rostrocaudal view of frontal sinuses |
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nasal conchae
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extend from canine teeth to level of 3rd premolars; visible as fine, semi-parallel lines
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ethmoid conchae
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continue caudally from 3rd premolars to cribiform plate; visible as fan-like delicate lines
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maxillary sinuses
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are inconsistently visible and are of minimal clinical significance in the dog and cat (unlike the horse)
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CT evaluation of the nasal cavity
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-much more sensitive for detection of nasal disease and determining extent/location of disease process
-necessary for radiation treatment planning |
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Larynx: Lateral view; head and neck slightly extended
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best for anatomical inspection
use lateral thorax tech. minus 10% of kVp value flexion may mimic retropharyngeal mass or caudal displacement of larynx |
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Epiglottis in dog/cat
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tip located at level of tympanic bula; base just caudal and dorsal to basihyoid bone
tip may be dorsal or ventral to soft palate, or may lie along pharyngeal floor during panting |
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soft palate (dog/cat)
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substantial soft tissue structure extending caudally from its junction with hard palate at level of last upper molar
separates oropharynx and nasopharynx tip of soft palate usu. contacts epiglottis |
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crichoid cartilage
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most caudal cartilage, triangular shaped
first to mineralize (mineralizes almost completely) lies ventral to cricopharyngeus muscle (cranial esoph. sphincter) |
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thyroid cartilage
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middle cartilage, less intense mineralization
may visualize rostral corner of cartilage |
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arytenoid cartilage
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extends rostrally from apex of thyroid cartilage
minimal mineralization (diff. to visu. in norm. animals) may visu. cuneiform and corniculate process of arytenoid cart. |
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basihyoid bone
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unpaired bone, easily visualized due to "end-on" location
lies cranial and ventral to epiglottis often mistaken (along w/ other hyoid bones) for bone foreign body (esp. on oblique views) |
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trachea
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lies roughly parallel to cervical vertebrae
descends ventrally towards heart, ending at carina |
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carina
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bifurcation of caudal thoracic trachea into right and left caudal mainstem bronchi
located at 5th or 6th intercostal space about 1/3 of the distance down the dorsoventral dimension of the thorax |
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redundant tracheal membrane
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trachealis muscle folds into lumen creating soft tissue opacity superimposed over dorsal half of trachea at thoracic inlet; rarely clinically significant
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mineralization of trachea and major bronchi
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common aging change, especially in chondrodystrophic breeds
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which portion of the pathologically collapsing trachea collapses most on expiration
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intrathoracic tracheal collapse
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which portion of the pathologically collapsing trachea collapses most on inspiration
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cervical tracheal collapse
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maxillary sinuses of the equine
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located lateral to nasal cavity
divided into rostral and caudal compartments which only communicate in mule and donkey infraorbial canal runs longitudinally through maxillary sinuses |
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rostral limit of rostral maxillary sinus
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located at 3rd cheek tooth (4th premolar)
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septum between rostral and caudal maxillary sinuses in the equine
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located above the 4th cheek tooth (1st molar)
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fluid in the sinus
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creates a fluid-air interface (abnormal radiographic finding)
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guttural pouch
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bilateral air-filled venral diverticuli of eustachian tube
divided into large medial and smaller lateral compartments which freely communicate ventral wall of gp is dorsal wall of nasopharynx |
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equine soft palate
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normally lies ventral to tip of epiglottis
divides pharynx into nasopharynx and oropharynx |
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techniques of thoracic radiology
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low contrast, long grey scale technique is best
high kVp, low mAs (resulting in shorrter time exposure and less motion artifact) |
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silhouette sign
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occurs when 2 objects are in close anatomic contact; radiographic borders of each object merge and are obliterated
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summation
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occurs when 2 objects are superimposed radiographically, but not in close anatomic contact; densities of 2 objects become additive, enhancing margins where they overlap
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radiographic views of the thorax
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at least 2 views at right angles to each other are essential
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lateral view
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named by side of animal closest to cassette
thorax centered on cassette, with x-ray beam centered just caudal to scapula front legs pulled forward to prevent superimposition of triceps over cranial thorax head and neck extended slightly |
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right lateral view of thorax
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the left and right crura of diaphragm are parallel w/ right crus more cranial (caudal vena cava can be seen entering r. crus)
heart appears more oval or egg shaped and more upright more overlap of right and left cranial lobar pulmonary vessels |
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left lateral view
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left crus of diaphragm displaced more cranially (assoc. with fundus of stomach)
left and right crus intersect at level of caudal vena cava heart appears more rounded with slight dorsal displacement of apex result. in a gap b/w cardiac apex and sternum cranial lobar pulmonary vessels more distinct and parallel |
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VD view
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animal positioned in dorsal recumbency
x-ray beam centered over caudal scapula three humps of diaphragm visible |
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on a left lateral the _________ artery, bronchi, and vein should be more magnified
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right b/c farther away from the cassette
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DV view of thorax
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best position for respiratory distress
diaphragm seen as a single hump caudal lung lobes appear narrower and taper caudally caudal lobar pulmonary vessels better visualized heart appears shorter in length (more accurate) |
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pulmonary lesion appearance in horizontal beam views of the thorax
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seen as smaller, sharper opacities when affected side of thoraax positioned opposite the cassette; lesions appear larger and less sharp when positioned opposite the cassette
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large animal thorax views
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at least 4 views needed to image entire thorax: cranioventral, craniodorsal, caudoventral, caudodorsal
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signs of inspiration (lateral view)
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extension of left cranial lung lobe of first rib; increased ventral angulation of trachea; flatter, more caudally located diaphragm; caudodorsal lung located caudal to T-12 in dogs or T-13 in cats; increased distance b/w heart and diaphragm
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signs of inspiration VD/DV view
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cardiac silhouette appears smaller; increased thoracic cavity width and length; dome of diaphragm caudal to T-8; caudolateral lung located caudal to T-10; decreased cardiodiaphragmatic contact
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general signs of expiration
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heart appears larger
lungs more radiopaque and smaller more overlap between heart and diaphragm |
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sternum
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eight sternebrae
manubrium: first xyphoid: last |
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structures contained within the mediastinum
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trachea, esophagus, heart, aorta, great vessels, thoracic lymph nodes, cranial and caudal vena cava, azygous vein, lymphatic ducts, thymus
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pulmonary vessels
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appear as well defined, opaque, small nodules when seen end on
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the cardiac silhouette is made up by:
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the heart, pericardium, pericardial and mediastinal fat, lymmph nodes, and structures at the hilus of the lung
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Required views for evaluating the heart
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two views at least, either VD or DV plus riht or left lateral are essential
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right lateral view of heart
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heart appears more oval and upright
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left lateral view of heart
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heart appears more rounded with slight dorsal displacement of apex
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ventrodorsal view of heart
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heart appears longer and narrower with apex to left of midline
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dorsoventral view of the heart
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heart appears shorter in length, apex more to the midline
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clock-face analogy for a VD/DV view of the heart
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11:00-1:00 -- ascending aorta
1:00 - 2:00 -- pulmonary trunk 2:00 - 3:00 left auricle 3:00 - 5-6:00 left ventricle 5-6:00 - 9:00 right ventricle 9:00 - 11:00 - right atrium |
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vertebral heart scale
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canine: 9.7 +/- 0.5 vertebral body lengths
feline: 7.5 +/- 0.3 vertebral body lengths |
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normal heart size can be affected by:
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respiratory cycle, pericardial and mediastinal fat, thoracic confirmation (breed), age (young larger relative to thoracic size), positioning for radiograph
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