Special Procedures in Veterinary
Radiology--Urogenital
Travis C. Saveraid, DVM, DACVR
Assistant Clinical Professor
College of Veterinary Medicine –
University of Minnesota
Roentgen Signs
• Margin
• Shape
• Opacity
• Number
• Size
• Location
1
Urogenital Contrast Procedures
• Intravenous Pyelogram (IVP); a.k.a.
Intravenous Urogram (IVU), Excretory
Urogram (EU)
• Cystography (positive, negative, double)
• Urethrography (retrograde, normograde)
• Vaginography
IVP
IVP-indications
• Identification / characterization of
kidneys and ureters
• Ectopic ureters
• Suspected renal or
ureteral calculi
• Identification of enhancement voids in
renal parenchyma
• Rough estimate of renal function
2
IVP-indications
• Abnormal renal size/shape on survey
radiographs or palpation
• Inability to identify kidney(s) on palpation
or radiographs
• Identify filling defects in renal pelvis /
ureters
• Hematuria without lower urinary tract signs
• Suspected ureter rupture
IVP-indications
• Incontinence
• Assess involvement of kidney/ureter in
adjacent disease processes (e.g. neoplasia in
bladder trigone)
• Suspected pyelonephritis
3
Diverticulum
Renal Pelvis
Ureter
IVP-contraindications
•
•
•
•
DEHYDRATION
Allergy to Iodine
Heart failure
Renal failure/azotemia are NOT
contraindications but will affect the
quality of the study
4
IVP-complications
• Vomiting
• Hemodynamic effects (hypotension,
hypervolemia)
• Contrast medium induced renal failure
• Allergic reaction to contrast (hives,
anaphylaxis)
• Non-diagnostic study
IVP-materials
• Enema materials
• Contrast agent— iodinated (ionic fine
for most patients, consider using nonionic for azotemic or critical patients
• IV catheter – typically cephalic vein
IVP-materials
• Compression band? - Vetrap
• Fluoroscopy unit – if available
• Crash kit
– Fluids
– Endotracheal tube
– Drugs (epinephrine, steroids, antihistamines,
dopamine)
5
IVP-preparations
• Fast 12-24 Hours, enemas as needed
to clear colon
• Survey radiographs to establish
technique, assess preparation, and
check for changes since last
radiographs
• Sedation or anesthesia can be helpful in
some patients
Non-prepared
abdomen.
Prepared Abdomen
6
Collect Urine for Urinanalysis
before IVP
• Most contrast will increase urine specific
gravity for up to 24 hours following IVP
• Some contrast medium inhibits growth of
urinary pathogens
• If urine not collected before IVP, collect
urine at least 24 hours after procedure.
IVP-procedure
• Details vary from reference to reference and
radiologist to radiologist
• Basic principles
– Adequate dose for opacification of tract
– Adequate timing to assess functional questions
– Adequate views to assess anatomic questions
(e.g. obliques for ureter termination)
IVP-procedure
• Typical dose 800-900 mg I/kg body weight
– Most ionic agents are 350-400 mg I/ml, so 1
ml/lb (Omnipaque is 240 mg I/ml)
– Maximum volume 90ml
– Dose may be increased 1.5 to 2 X for azotemic
patients to compensate for poor uptake
– Inject as a bolus through catheter
– Helps to warm contrast (less viscous)
7
IVP-procedure
• Ventrodorsal view at time 0
• VD and lateral views at 5, 10, 20 and 40
minutes
• Oblique lateral views (or fluoro) at 5
minutes to assess termination of distal
ureters
IVP-options
• Compression band is referred to in some
references
– Tight bandage around caudal abdomen
– Increases distension of pelvis and proximal
ureters
– Yields little additional information and carries
small risk
• Concurrent negative
cystogram
– Urethral catheter
placed, bladder
distended with gas
(room air o.k. in most
situations, NO2 or CO2
in cases of hematuria)
– Provides improved
contrast with the
ureters as they enter
the trigone
– Helpful for suspected
ectopic ureters
IVP-options
8
IVP-options
• “Paddle” views
– Radiolucent paddle (e.g. wooden spoon) gently
applied to abdomen during exposure to displace
organs
– Particularly useful to displace intestines away
from kidneys and bladder
– Less useful in large, blocky patients
– May need to decrease technique (thinner)
Bladder Stones?
Yes – Look closely!
9
IVP-normal findings
• Three phases
– Angiogram phase: all blood vessels opacify,
very brief (usually miss it), not too relevant in
our patients
– Nephrogram phase: kidneys are actively
concentrating iodine, persists to some degree
throughout study. Early phase cortex brighter
than medulla, later enhancement is uniform
– Pyelogram phase: pelvis and ureters enhance
Survey
Angiography phase to early
Nephrogram phase
IVP-normal findings
• Uniform, symmetric renal enhancement
• Opacity of kidneys fades over time
• Size (on VD view)
– Dog: 2.5-3.5 x L2
– Cat: 2.4(1.9?)-3.0 x L2
• Shape elongated, may be flattened on lateral
view (cats slightly rounded)
10
IVP-normal findings
• Without abdominal compression, renal
pelvis and pelvic recesses approximately
2mm or less
• Pelvis and recesses sharply marginated
• Proximal ureter generally less than 2.5 mm
• Visibility of ureters is variable due to
peristalsis
IVP-normal
IVP-normal
11
IVP-normal findings
• Ureters course medially on VD, dorsally on
lateral from renal pelvis
• Ureters often superimposed on spine on
VD, each other on lateral
• Ureters terminate at trigone dorsally, with a
hook
• Bladder gradually fills with contrast
IVP-normal findings
IVP-abnormal findings
• Enhancement timing
–
–
–
–
–
–
–
Never
Poor, fading
Poor, persistent
Poor, increasing
Fair-good, fading (normal)
Fair-good, persistent
Fair-good, increasing
12
IVP-no enhancement
• Renal absence (agenesis, excision)
• No blood flow (infarcted, transected,
ligated, avulsed)
• Nonfunctional (may get vascular blush)
• Contrast dose too low, too slow or wrong
place (extravascular, connectors popped
loose)
Unilateral
enhancement
13
IVP-Poor, fading
• Any cause of polyuric
renal failure
• Contrast dose too low
or too slow
IVP-poor, persistent
• Chronic glomerular
dysfunction
• Non-specific
generalized renal
disease
IVP-poor, increasing
• Acute obstruction
• Hypotension
• Ischemia
14
IVP-good,
persistent
• Acute tubular necrosis
• Contrast mediuminduced renal failure
• Hypotension postcontrast
IVP-good, increasing
• Hypotension post
contrast
• Acute obstruction
• Contrast mediuminduced renal failure
IVP-abnormal findings
• Enhancement pattern
–
–
–
–
Uniform (normal)
Focally non-uniform
Multifocally non-uniform
Absent
15
IVP-focal
• NAG (neoplasia,
abscess, granuloma)
• Cyst
• Infarct
IVP-focal
IVP-multifocal
• NAGs (including FIP)
• Polycystic
• Infarcts (including
pyelonephritis)
• Chronic generalized
disease
16
IVP-abnormal findings
• Size
– Too small
– Too large
• Shape
– Too round (usually also large)
– Irregular
• Margin
– Irregular
– Fuzzy
IVP-normal size, irregular
• NAG with atrophy of
more normal tissue
• Chronic infarcts
• Chronic inflammation
• PKD
• Remember you don’t
know how big they
were to begin with…
IVP-small, smooth
• Hypoplasia
• Glomerulonephritis
• Amyloidosis
17
IVP-small,
irregular
• “End-stage” renal
disease
• Dysplasia
IVP-large, smooth
• Hydronephrosis
• Infiltrate (neoplasia,
amyloid)
• Inflammation
• Hypertrophy
• Perinephric pseudocysts
• Subcapsular fluid or
infiltrate
IVP-large, smooth
18
IVP-large, smooth
IVP-large,
irregular
• NAG
• Hematoma
• Perirenal
pseudocyst
• Polycystic Kidney
Disease (PKD)
IVP-fuzzy margin
• Perinephric edema
• Perinephric
hemorrhage
• Urine leak
19
IVP-abnormal findings
• Number
– Too few
– Too many
• Location
– Formed in wrong location?
– Herniated?
– Displaced?
IVP-number
• Too few—see “non
opacification”
• Too many—transplant
(hopefully in history),
supernumery kidneys (a.k.a.
renal duplication) has been
reported, RARE
– If the extra kidney-shaped
thing on surveys doesn’t
enhance, probably not a
kidney
IVP-location
• Anomalous location not uncommon,
particularly left
• Kidney herniations are uncommon, can be
body wall, diaphragm
• Being displaced by an adjacent mass is most
common
20
IVP-abnormal findings
• Pelvis abnormal size
– Large
• Shape/Margin
– Irregular
– Rounded
• Opacity
– Filling defects
IVP-pelvis enlarged
• Pyelectasia, mild
– Physiologic
– Pre-hydronephrosis
• Hydronephrosis
– Obstructive
– Pyelonephritis
– Space-occupying
lesion
IVP-pelvis irregular, rounded
• “Marginal” filling
defects (next slide)
• Pyelonephritis
• Neoplasia
21
IVP-pelvic
filling defects
• NAG
• Calculi (more detail
in cysto. section)
• Blood clots
IVP-abnormal findings
• Ureter size
– Large
– Small
• Shape/Margin/opacity
– Dilation
– Irregularity
– Filling defects
• Location
22
IVP-ureter large, small
• Large=hydroureter
– Obstructive
– Ureteritis
• Small=stricture
Ureteral
Obstruction
IVP-ureter stricture
23
IVP-ureter irregular
• Ureteritis
• Infiltration
– Most commonly from
bladder neoplasia
IVP-ureter
filling defects
• Calculi
• Blood clots
• Bubbles
IVP-ureter filling defects
24
IVP-ureter location
• Ectopic ureter common cause of incontinence
–
–
–
–
–
–
–
Urethra
Vagina
Uterus
Vulva
Colon
“tunneling”
Females >>> Males
IVP-ureter location
• Hydroureter is common, but not invariable
• Pyelonephritis is often concurrent
• Other anomalies may be present
(ureterocele, pelvic bladder, etc)
• Often difficult to capture
– Gas in bladder, “paddle” views, obliques,
fluoro can help
IVP – Ectopic
Ureter
25
IVP-ectopic ureter
IVP-ectopic ureter
IVP-ectopic ureter
26
IVP-ureter rupture
• Should be considered with any
retroperitoneal fluid/loss of detail
• Can be difficult to “capture”, particularly if
tear is small and renal function is poor
IVP-ureter rupture
IVP Alternatives-ultrasound
• Advantages: Provides better anatomic and
vascular information. Allows for acquiring
samples (FNA or biopsy of renal
parenchyma, pyelocentesis). Can combine
with radiography (pyelography).
• Disadvantages: Not as widely available. No
functional information. More operator and
equipment dependent. Findings often nonspecific and may be misleading.
27
Ultrasound
IVP Alternatives-scintigraphy
• Advantages: Provides detailed functional
information (global and each kidney)
• Disadvantages: Not widely available.
Makes patient radioactive. Limited
anatomic information.
• Advantages: Detailed
cross sectional anatomy
(no superimposition)
• Disadvantages: Not
widely available,
expensive. Greater
radiation dose. Less
temporal information.
Requires heavier
sedation or general
anesthesia
IVP AlternativesCT scan
28
Cystography
Cystography-indications
• To determine the following for the urinary
bladder:
–
–
–
–
–
Location
Shape
Contents
Integrity
Wall thickness and texture
Cystography-indications
•
•
•
•
Hematuria with lower urinary tract signs
Palpable abnormality (e.g. crepitus)
Recurrent urinary tract infections
Lower urinary tract signs without evidence
of infection on urinalysis
29
Cystography-indications
• Abnormalities on survey radiographs
–
–
–
–
Opacity
Shape
Size
“Number”
• As an aid in surgical planning for known
abnormality
Cystography-indications
• To investigate other mass effects and
diseases in the area of the bladder
• To investigate causes of urinary
incontinence or retention
• Suspected rupture
Cystography-contraindications
• Really are none other than, perhaps,
previous allergic response to iodine
• Some known or suspected conditions may
alter the protocol
30
Cystography-complications
•
•
•
•
•
Bladder rupture
Fatal gas embolus
Hematuria
Splitting of mucosa
Vesicoureteral reflux (risk of inducing
pyelonephritis if cystitis present)
• Infection
Cystography-materials
• Urinary catheter (Foley if possible,
stopcock, lube
• Positive contrast material (ionic iodine,
NOT BARIUM)
• Negative contrast material (gas; room air
o.k., but risk of fatal air embolism, CO2 or
NO2 safer)
• Sedation?
Cystography-materials
31
Cystography-preparations
• Fast and enemas as for IVP
• Survey radiographs
• Sedation
• Urinary catheter placed and urine drained
Cystography-procedure
From: Manual of Veterinary
Echocardiography; June A. Boon
Cystography-procedure
• Urinary bladder distended with gas until palpably
full (not taut)
• Draw up 10cc/kg and palpate constantly while
infusing, also check for back pressure on the
syringe
• After bladder distended with gas, instill a small
“puddle” of full-strength positive contrast (1-5cc
total, depending on size of the bladder; can always
put more in!)
32
Cystography-procedure
• Have less bubbles when inject air first
• Roll patient 360° to coat mucosa with
positive contrast
• Take right AND left lateral views, VD (or
two obliques off of VD)
Cystography-options
• Can instill local anesthetic solution first to
decrease spasticity
• Can use only gas (negative cystography) or
only iodine (positive cystography) rather
than “double contrast”
– Negative-not very helpful
– Positive-use dilute agent (25%), often precedes
urethrography, arguably better for diverticuli
Cystography-normal findings
• Bladder should be oval with a caudal taper
toward trigone (cats more spherical,
especially males)
• Mucosal surface should be smooth
• Wall should be approximately 1 mm thick
and uniform
• No filling defects in puddle
33
Cystography-normal findings
• Distended bladder should be entirely within
the abdomen
• Minimal contrast may reflux into the ureters
and even the renal pelvis
• No contrast material should leak into the
peritoneum or retroperitoneum
Cystography-normal
Cystography - Normal
34
Cystography - Normal
Cystography-normal
Cystography-abnormal findings
• Mobile filling defects
–
–
–
–
Air bubbles
Stones
Blood clots
Foreign bodies
• Immobile filling defects
– Attached stones/clots/foreign bodies
– Masses
35
Cystography-stones
Cystography-stones
Cystography-stones
• Opaque stones (On SURVEYS-all lucent with
positive contrast)
– Oxalate
– Silica
– Phosphate (less opaque than above)
• Lucent stones
– Cystine
– Urate
• Algorithm exists on CVM website
36
Cystography-air bubbles
• Most common artifact in lower urinary tract
procedures
• Mimic stones
• Differentiating features
– Round unless in direct contact with another bubble
(side flattens)
– Change with time and position (move, dissipate,
coalesce with others)
– At margins of puddle (remember that “down” is the
MIDDLE of the puddle)
Cystography-air bubbles
Cystography-blood clots
• Typically very irregular, inhomogeneous
opacity, poorly marginated, and mobile
• Organized, adherent clots are dead ringers
for masses
• Lavage may break up clot, also should
dissipate with time (hours to days)
37
Cystography-abnormal findings
•
•
•
•
•
Wall abnormally thick
Wall irregular without distinct mass
Outpouching of wall
Leakage of contrast material
Dissection of contrast material into wall
Cystography-wall thickness
•
•
•
•
Neoplasia
Inflammation
Hemorrhage
Edema
Cystography – Wall Thickness
38
Cystography – Wall Dissection
Cystography-outpouching wall
• Urachal diverticulum
common congenital
– May predispose to
UTI
• Can see eventration
with trauma
(basketball with torn
cover)
Cystography-leakage
39
Cystography-leakage
Bladder Rupture
Cystography-abnormal findings
• Intrapelvic (“pelvic”) bladder
• Bladder displaced into hernia
• Bladder displaced by other structures
40
Cystography-displacement
Cystography-displacement
Cystography-displacement
41
Cystography Alternativesultrasound
• Advantages: Fast, non-invasive, may allow
sampling, can potentially find smaller
abnormalities
• Disadvantages: May miss “big picture”
lesions, operator dependent, expensive
equipment
Bladder Ultrasound
Cystography Alternativescystoscopy
• Advantages: allows direct visualization and
sampling of lesions
• Disadvantages: expensive, time consuming,
operator dependent, patient size dependent,
may not be able to see whole bladder
42
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