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82 Cards in this Set
- Front
- Back
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What effect does gastric distention have on the abdomen?
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obscures visualization of adjacent structures and creates a mass effect
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How do you prevent gastric distention in abdominal radiographs?
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withhold food for 12-24 hours and produce cleansing enemas 2-3 hours prior to procedure
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What does a full urinary bladder do for an abdominal radiograph?
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mimics a mass and displaces adjacent structures
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How do you empty a urinary bladder prior to radiographs?
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walk outside, catheterize, or express bladder
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What are the diagnostic quality factors when preparing an abdominal radiograph?
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(1) patient prep
(2) technique settings (3) positioning |
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Since the abdomen is a low contrast area, how do you maximize contrast resolution in the image?
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-low kVp, high mAs
-use a grid (esp. if thicker than 10 cm) |
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What are standard views for the abdomen?
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left lateral and VD for animals less than 300 lbs
(right lateral and DV are also helpful in determining gas patterns) |
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What are the boundaries for an abdominal radiograph?
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-CRANIAL: dome of diaphram (xiphoid sternebra)
-CAUDAL: pelvic inlet (pubic bone and greater trochanter) - Venteral and Lateral boundaries: abdominal wall |
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How would you adjust the kVp setting to visualize pelvic structures?
(pelvic radiographs are often needed to visualize urethra, rectum or prostate) |
-use 10% higher kVp
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How would you minimize thickness and motion?
-displace bowel loops? |
-compression band (may need to decrease kVp in this case)
-paddle |
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Where are normal fat deposits founds?
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retroperitoneal space and falciform ligament (may mimic intra-abdominal masses), greater omentum and mesentary
-fat helps improve visualization of margins |
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Lack of fat in the abdomen results in what?
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-poor abdominal contrast and detail - may mimic abdominal effusion
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Where may sublumbar muscles be viewed?
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-in lateral view if retroperitoneal fat for contrast
cats and rabbits can be seen in VD because they have large muscles |
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Which surfaces of the diaphragm are visible?
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-cranial surface is visible due to differential density interface of lungs
-caudal surface is silhouetted with cranial surface of the liver and not normally visible |
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How do you differentiate left from right crus?
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left - associated with gastric fundus (often visible because it contains air)
right - associated with the caudal vena cava |
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Is variation of liver position normal in older dogs and deep chested dogs? How and why?
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liver is normally contained in the costal arch, but in older dogs, the liver may extend caudal to the costal arch due to laxity of ligaments
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Where is the axis of the stomach located?
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parallel to the ribs and perpendicular to the spine
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What does the right caudate lobe of the liver silhouette with? what about the rest of the liver?
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-right lobe silhouettes with right kidney
-most of caudal liver silhouettes with liver |
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How is the liver BEST visualized?
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ventrally - because of fat associated with the falciform ligament (esp. prominent in cats
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What does the caudoventral angle of the liver look like?
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-distinct, acute angle, and lies at the level of the costal arch (margins are smooth and sharply marginated)
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What is a bad view to see the liver?
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VD view - it gradually tapers and is superimposed on the stomach
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In the VD view in the dog, where is the pylorus located?
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to the right (right, cranial abdominal quadrant, about half way to the midline and right abdominal wall)
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In the VD view in the cat, what is the shape of the stomach and where is the pylorus?
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-gastric axis is J shaped with the pylorus at or near the mid line
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What are the positions of the spleen?
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-head in the left cranial dorsal abdomen (seen in VD view as a triangle just below the stomach)
-body in the mid-ventral abdomen -tail in the right midventral abdomen (see in lateral view as a triangular shape) -sometimes positioned longitudinally parallel to the left lateral wall |
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What do the dorsal margins of the bladder silhouette with?
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the colon
-bladder is more cranial in cat |
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Which direction may the SM bowel be displaced in fat animals or if the colon is distended?
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to the right
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What structure of the large intestine is often filled with gas and is in the right abdomen?
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cecum - mimics a dilated small bowel loop
(NOT visible in the cat) |
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What abdominal structures are not seen in an abdominal radiograph?
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1 - gall bladder
2- pancreas 3 - adrenals 4- ureters 5 -prostate 6 -ovaries and uterus 7 - lymph nodes 8 - blood vessels |
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What is an excretory urography?
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-IV injection of contrast medium (iodinated) with sequential opacification of urinary tract over time (kidneys, ureters, and bladder)
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What are the 3 phases of an excretory urography?
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(1) Vascular phase
(2) Nephrogram phase (3) Pyelogram |
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What consists of the nephrogram phase?
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-opacification of the renal parenchyma
-contrast agent in renal tubules -greatest in early part of study |
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What consists of they pyelogram?
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-opacification of the collecting system (renal pelvis, diverticula, ureters)
-less opaque early in the study - needs time to concentrate |
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What are the indications used in an excretory urogram?
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1 - morphology
2 - integrity 3 - location 4 - ureteral function = * RENAL function is limited |
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When renal and ureteral evaluation is done, how is integrity evaluated?
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-leakage
-filling defects --> masses or calculi |
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When ureteral function is evaluated, what is looked at?
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-patency
-motility |
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What are contraindication for excretory urography?
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-dehydration --> can cause acute tubular necrosis
-previous adverse reaction -renal failure is NOT a contraindication, BUT will degrade quality of study |
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What are characteristics of the EU contrast media?
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-water-soluble organic iodide that is high density
-rapidly cleared from body by renal excretion (passive GF without tubular secretion) - low protein binding |
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What can EU contrast media cause in kidney?
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temporary cause increased renal tubular pressure
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Where may you see other excretion routes for EU contrast media?
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-liver (opacification of gall bladder)
-SM bowel |
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What is a disadvantage to used (ionic) contrast media?
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adverse reactions due to high osmolality
Adverse reactions include: vomiting, rash, anaphylactoid, CV collapse (rare), acute renal failure, cellulitis, altered urine analysis |
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Why don't we normally use non-ionic contrast media in vet med?
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expensive, short shelf life
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What is the most important component of proper technique?
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preparation
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What are the components of patient prep in a EU?
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1 - rehydration
2 - 24 hour fast, water ad lib 3 - cleansing enema at least 2 hours prior to radiography (one night before and one in AM) - if given under 2 hours, will have gas obstruction 4 - indwelling IV catheter 5 - sedation (anesthesia if really needed, giant breed or ectopic ureter) |
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How do you inject the contrast medium for an EU?
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-bolus IV injection (dose 800mg I/kg)
-fast as possible -sternal if awake |
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What is the sequence of radiographs for a EU?
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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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When is a good time to use compression?
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-if the renal pelvis is not visible in the 10 minute films
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What are cons to using an abdominal band?
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-displacement of viscera may obscure kidneys, may cause apparent dilation of ureters/pelvis, may alter GFR
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What is the size of the kidney in the dog?
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- 2.5-3.5 times the length of L2 vertebral body in VD view
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What is the shape of the kidney in dogs and cats?
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dog - oblong
cat - round/oval |
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What is the size of a kidney in a cat?
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- 2.1-3.2 times L2 in a intact cat (larger)
- 1.9-2.6 times L2 in a neutered cat |
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What phase is the renal pelvis best seen?
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pyelogram 10-20 minutes
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What is the appearance of a renal pelvis?
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-less than 2 mm in a dog
-C-shaped -finger-like processes -(proximal ureter is cone-shaped) |
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Where are the kidneys located?
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-between T13 and L4 in the cranial retroperitoneal space
-right is more cranial in dogs |
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What could abnormally change the opacity of the kidney?
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-gas-filled bowel loop (superimposed)
-enlarged mammary gland (superimposed) -may appear more opaque if surrounded by large amounts of retroperitoneal fat |
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What factors affect degree of opacification during a EU?
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1 - renal blood flow
2 - Glomerular Filtration of contrast media 3 - tubular reabsorption of water 4 - dose and dose rate |
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What does the end-on view of a deep cicumflex iliac bifurcation look like?
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mimics a calculus
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Are ureters normally seen on a survey film?
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no due to silhouette
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When are ureters best seen in post-contrast films?
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20-40 minutes (lateral oblique views help separate the ureters and improve visualization of the trigone area)
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Why may there be some difference in size and shape of ureters?
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peristalsis - it is transient
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What is the max diameter of ureters in a dog usually?
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2.5 mm in dog - smooth and marginated
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Where are ureters located?
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extend from renal pelvis to trigone of urinary bladder
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What is a cystography?
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a radiographic evaluation of the bladder (to visualize internal structures) following intraluminal administration of positive or negative contrast media
-performed following IV urography or performed following retrograde injection of media |
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What are the indications to perform a cystography?
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1 - clinical evidence of bladder disease
2 - adjacent disease 3 - size, shape, location, integrity of wall |
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What are possible complications to cystography?
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1 - bladder rupture
2 - subserosal leakage - inflammation of mucosa 3 - air embolism via venous system (RARE) - to avoid place in left lateral recumbancy to keep air in right ventrical and away from pulmonary artery as you inject air |
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How is an antegrade positve contrast cystography done?
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-obtained first be performing an intravenous urogram and evaluate bladder at 30-40 minutes post contrast
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What are advantages and disadvantages to performing a antegrade positive contrast cystography?
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Advantages: avoid passing a urethral catheter and less likely to rupture bladder
Disadvantages: incomplete bladder distension and urine mixes with contrast media |
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What is a retrograde positive contrast cystography and how is it performed?
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-obtained by injecting positive contrast medium into the bladder by way of the urethra
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What are the advantages to a retrograde positive contrast study?
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-BEST way for suspected bladder rupture detection
-good for ID of communication between bladder and adjacent structures |
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What are the basic steps for preparing and completing a retrograde cystography?
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1 - fasting (24 hours) and enema (2 hours prior)
2 - survey rads first 3 - sedate (males) anesthetize (females) 4 - pre-fill catheter with sterile water 5 - catheterize and withdraw urine 6 - lidocaine 7 - dilute positive contrast agent with 2 parts sterile water 8 - slowly inject while palpating 9 - take lateral and VD views and remove contrast after finished |
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Where is the bladder neck in dogs?
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within or immediately cranial to the pubis (bladder is more cranial in cats)
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What is the disadvantage to a negative contrast cystography?
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not very good for demonstrating bladder rupture, air leakage hard to see relative to bowel gas
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What is a negative contrast cystogram good for?
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good for locating bladder when displacement suspected because iit s inexpensive and easy
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What is a double contrast cystography?
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-injecting BOTH iodinated contrast and air into the urinary bladder via the urethra
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What is the best method for determining mural or intraluminal diseases?
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double contrast cystography
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How do you performa double contrast cystography?
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-inject positive contrast media first (retrograde) then slowly inject negative contrast medium while palpating the bladder
-reduce the kVp setting by 10% or will overexpose -take contrast out after complete |
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What is the thickness of the urinary bladder?
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thin - thickness indicated disease (should be smooth and regular)
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What is a urethrography.
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radiographic evaluation of the urethra following introduction of contrast media into the urethral lumen (used to describe positive contrast studies because negative are not done for the urethra)
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What is a urethrography used for?
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-suspected obstruction of urethra or leakage
-location of urethra relative to adjacent structures - determine cause of bloody urine |
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In a male dog, how many survey radiographs do you take before the procedure for a urethrography?
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-one VD view
-2 laterals - one with legs in neutral position, the second with hindlimbs flexed forward to profile penile urethra without superimposition (best for seeing calculis in penile urethra |
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What are the steps to a urethrography in a male dog?
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1 - survey radiograph (including flexed leg)
2 - pre-fill catheter with contrast media and attach catheter to syringe containing remaining media (10-30 cc) 3- catheterize distal portion of urethra 4 - inject 1/2 dose and expose lateral radiograph during last 2-3 cc 5- reposition dog for VD view and inject remainder contrast media and expose as above |
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Where would you inflate the balloon catheter in a male dog undergoing a urethrography?
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middle of os penis
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Where would you place the catheter bulb in a female dog during a urethrography?
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just inside urethral orifice (less dose of contrast media needed (4-12 cc)
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