1. health and fitness
2. disease

VPAT Regional Veterinary Congress 2014
How to interpret the radiographic pulmonary patterns
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
Introduction:
Four basic things had to be known regarding the description of the changes seen within the lung field.
Recognize that if there are multiple lesions or patterns, eatch must be reviewed systematically.
1) WHERE is the patology located? Not only should you describe specific lung lobes, but also the specific
region within the lung lobe that is involved (entire lobe, hilar, mid-zone or peripheral). You should ask yourself
is the lesion, focal, multi-focal or generalized.
2) The SEVERITY of the pulmonary abnormality should be described as mild, moderate or severe.
3) The POSITION of the cardiac silhouette relative to normal should be determined. The mediastinal shift
is critical to differentiate a consolidated from an atelectatic lung lobe. It becomes critical that you have a straight
DV or VD radiograph (sternebrae superimposed over vertebrae) in order to document a true mediastinal shift.
4) One needs to describe the pulmonary PATTERN or abnormality.
You should go through the first three step prior to tryingto sort out the pulmonary pattern. Most of the
time the patterns will be mixed and you have to determine whichpattern predominates. We recognize four
pulmonary patterns: ALVEOLAR, BRONCHIAL, INTERSTITIAL, VASCULAR.
ALVEOLAR PATTERN
In an alveolar pattern, the air that normally fills the alveoli, is replaced by fluid or displaced due to lung
lobe collapse in the case of atelectasis. The alveolar pattern has a numer of specific radiographic abnormalities
that will make diagnosis easier. The three classic roentgen abnormalities associated with the alveolar pulmonary
patten include: 1) presence of air broncograms, 2) presence of border effacement, 3) the presence of the lobar
sign.
Typically an alveolar pattern is going to be focal or multifocal, but rarely generalized (unless just prior to
death!)
A
B
C
Fig. 1A) Air bronchograms; 1B) Due to border effacement the right margin of the cardiac silhouette is not
defined; 1C) Lobar sign (S scaped line) that indicated that a lung lobe is less areated than the adiacent
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Fig. 2) Generalised Alveolar pattern in a severely dyspneic cat
The more you replace the air space, the more likely the dog or cat does not have gaseous exchange
which ultimately becomes incompatible with life.
The air bronchogram is the gold standard roentgen abnormality for the diagnosis of an alveolar lung
pattern. Unfortunatly, the air bronchogram is not always present in alveolar lung disease. A lung lobe with soft
tissue opacity is what we will see in these cases.
The distribution within the lung and the presence of secondary sign are most useful in refiningthe differential
diagnosis list.
1) Pneumonia. Bronchopneumonia typically has a ventral distribution., affecting the peripheral and mid
zone of the right middle, right cranial and left cranial lung lobe. The lesions begin at the periphery of the lung
lobes and extend to the hilus with increasing severity. Aspiration penumonia has the same distribution. Look
for evidence of esophageal dilation.
2) Edema. Classified as cardiogenic or non cardiogenic according to the cause. Cardiogenic edema is
secondary to left heard failure. Usually in the dog is symmetric with a marked peri-hylar distribution. In mitral
insufficiency with eccentric rigurgitation it can be asymmetric (mainly right sided for anatomically reasons), visible
in the DV view. In cat the distribution is more random and generalized with a more severe pattern located at
the accessory lobe area.
3) Atalectasis. It is the result of collapse of a lung lobe so that the affected area will be reduced in
expected size. A radiographic sign that may indicate volume loss is a mediastinal shift of the cardiac silhouette
toward the area of increased opacity.
4) Blood. Lung contusion or hemmorage may be due to either trauma or a coagulopathy. The distribution
is random and the distribution within the lung and the presence of secondary signs are most useful in refining
the differential diagnosis list.
5) Neoplasia. Rare presentation. If the distribution is atipical, the lobe volume is increased and the
ultrasound examination shows a mass inside the lung lobe, neoplasia should be considered.
BRONCHIAL PATTERN
A bronchial pattern occurs when the bronchial wall thickness is increased by cellular or fluid infiltration
or when air in the immediate peribronchial space has been replaced with cells or fluid. The peribronchial space
is actually a component of the interstitium, but a bronchial pattern is usually interpreted to mean that airway
disease is present. The increased radiographic opacity associated with the increased fluid content or cellularity
in or around the broncus results in increased conspicuity of the bronchial three. Radiologically, this manifests
as an increased number of ring shadows, created by an end-on relationship between the abnormal bronchus
and the primary x-ray beam, or an increased number of parallel lines, called tram lines by some, created by a
side-on relationship between the abnormal bronchus and the primary x-ray beam.
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Differential diagnosis of an increased bronchial pattern (too many rings and lines visible in the lung):
1) Bronchial mineralization (better visualisation of the bronchus due to thin hyperechoic wall), no clinical
meaning
2) Thickened soft tissue opacity wall (chronic bronchitis- allergic, parasitic)
3) Thickened peribronchial (edema, pulmunary infiltrate (eosinophilia), bronchopneumonia)
A
B
Fig. 3A) Mineralized bronchial walls: no clinical meaning. B) Thickened peribronchial tissue: typical of
chronic bronchitis
INTERSTITIAL PATTERN
Interstitial patterns come in two varieties, nodular and unstructured. Soft tissue nodules that vary in size
from 2 mm to 3 cm characterize a nodular interstitial pattern.
An unstructured interstitial pattern is present if the lung appears too light ans we can’t call it anything
else. The pattern is seen as a poorly defined, hazy increased opacity. It alters the appearance of the lung by
making small and medium sized vascular structures more difficult to see.
Differential diagnosis of generalized unstructured interstitial pattern:
1) Artifact. Underexposure, expiratory radiographs, obesity, conformation of the patient.
2) Geriatric fibrosis
3) Lymphoma
4) Interstital pneumonitis (often viral etiology)
5) Metabolic (uremia, pancreatitis, septicemia)
6) Disease in transition (edema, pneumonia, hemmorage…)
Differential diagnosis of nodular interstitial pattern:
a) Non cavitary, solitary nodule:
1) Thoracic wall artifact (tick, nipple…)
2) Pulmonary lung tumor (dog-caudal lung distribution)
3) Focal granuloma (foreign body, parasitic)
4) Fluid filled bulla (hematocele)
5) Hematoma
6) Abscess
7) Pulmonary cyst
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b) Non cavitary, multiple nodules
1) Pulmonary metastatic diseases
2) Micotic granulomas (miliary type, only in endemic geographic areas)
3) Lynphomatoid Granulomatosis (rare)
4) Eosinophilic Granulomatosis (rare)
Fig. 4) Increased generalized unstructured interstitial pattern in a dog with lymphoma
VASCULAR PATTERN
It is only because of normal aeration of the lung lobes that the normal pulmonary artery and vein can
be visualized. On the lateral radiograph, the cranial lobar artery is dorsal to the bronchus that in turn is dorsal
to the pulmonary vein. The triad of pulmonary artery, lobar bronchus andpulmonary vein extends from the ilar
region into the appopriate lung lobe. The pulmonary triad will progressively get smaller and divide into secondary
and tertiary branches in the mid zone and periphery of each lung lobe. On the right lateral radiograph, the right
and left cranial pulmonary triad will crossover each other close to their origin from the heart base region and
diverge away from each other as they extend into the periphery. On the left lateral radiograph, the pulmonary
triad of the left and right cranial lung lobe will parallel each other with the right cranial pulmonary triad being
ventral to the left and slightly larger than the left due to magnification.
Alterations in the size of the pulmonary veins and arteries result in increased or decreased overall lung
opacity. A hyperlucent lung can be the result of a small pulmonary vessels or absence of a normal vascular
pattern with in the lung field. Differential for a hyperlucent lung field include:
1) Hypovolemia
2) Shock
3) Addison
4) Severe pulmonic stenosis
5) Right to left shunts
Enlargement of the pulmonary artery, vein or both will cause an overall increase in pulmonary opacity.
This will cause an overall increase to the pulmonary opacity present that is not alveolar, bronchial or interstitial.
REFERENCES
Lang J, Wortman JA, Glickman LT, Biery DN, Rhodes WH: Sensitivity of radiographic detection of lung metastases
in the dog. Veterinary Radiology 1986. 27: 74-78.
Muhlbauer MC. Kneller SK. Radiography of the dog and cat. Wiley-Blackwell. 2013
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Interpreting radiography of the dyspneic dog and cat
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
Introduction:
Normal respiration is characterized by quiet, active inspiration followed by passive exspiration. Both phases
are smooth and symmetrical. The most common causes of dyspnea are airways obstruction and restrictive
respiratory pattern.
AIRWAY OBSTRUCTIONS
The airways obstruction can be at the level of upper airways or lower airways. Functionally are considered
upper airways the nasal cavity, pharynx, larynx and extrathoracic trachea. The lower airways are the intra-thoracic
trachea, the bronchi and the bronchiolis. Cat, not always followed the rules and can show radiographic signs of
upper airways diseases even if the obstruction is at the level of the trachea and the major bronchi.
Upper Airway Obstructions
The effect of upper airway obstruction correspond to the response observed on radiographs taken during
a Muller’s maneuver (inspiration against a closed glottis).
The alterations which should alert the reviewer to an upper airway obstruction on an inspiatory radiograph are:
1) an underaeration and small volume of the thorax
2) an high and well domed diaphragm
3) indrawing of intercostal muscles or the sternum (expecially in cats)
4) tracheal narrowing or collapse
The reduced lung volume is a partcularly importan discriminatory finding which strongly suggests upper
airway obstruction.
Fig. 1: Reduced lung volume in a dog affected by laringeal paralisis
Lower Airway Obstructions
The effect of lower airway obstruction corrispond to the response observed on radiographs taken during
a Valsavia maneuver (expiration against a closed glottis).
Lower airway obstruction usually affects primary the expiratory phase of respiration. The radiographic
changes which should alert the reviewer to a lower airway obstruction are:
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1) overaeration and increased volume of the lung and large residual lung volume at expiration
2) straight or even convex diaphragm
3) caudal position of the diaphragm with the lumbo-diaphragmatic angols at T13 to L1 in the dog and
L1 to L2 in the cat
4) pulmonary underperfusion, particularly in the middle and the peripheral zones.
The increased lung volume is a partcularly importan discriminatory finding which suggests lower airway
obstruction.
Fig. 2: Increased lung volume in a cat affected by lower airway obstruction
RESTRICTIVE PATTERNS
Changes of the lung, the chest wall and the pleural space can reduce the lung’s ability to expand normally.
Because many disorders can result in restrictive lung disease, it is advantageous to group them into four etiologic
categories, namely:
1) thoracic wall restrictions
2) intrathoracic non-pulmonary restrictions
3) intrathoracic pulmonary restrictions
4) abdominal restriction
Patients with a restrictive respiratorty pattern tend to have an increased respiratory rate with symmetric
inspiration and expiration.
REFERENCES
1) Muhlbauer MC, Kneller SK: Radiography of the dog and cat. Wiley-Blackwell. 2013
2) Suter PF, Lord PF: Thoracic Radiology. A text atlas of thoracic diseases of the dog and the cat. Wettswill,
Switzerland. 1984
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Use of radiology in coughing dogs and cats
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
Introduction
Dogs usually cough for tracheal collapse, bronchomalacia, broncopneumonia, cardiac diseases, bronchitis
and large lung mass.
Cats usually cough for bronchitis, mainly secondary to feline asthma and large lung mass.
Tracheal collapse
The trachea can be seen as a radiolucent tube extending from the caudal cervical region through the
toracic inlet, in a dorsal 2/3 position within the cranial thorax. The trachea terminates at the carina, which is the
bifurcation of the caudal thoraci trachea into the caudal mainstem bronchi. The normal trachea at the thoracic
inlet is between 15 and 20 % of the thoracic internal dimension as measured in a lateral radiograph. For bulldogs
and other brachycephalic breeds this measurement can approach 12% and still be considered normal. If a
clinical suspicion of tracheal disease exists, radiographs of the entire trachea should be obtained during inspiration
and expiration. Tracheal collapse is a common clinical entity in small and toy breed dogs. This is usually a
dynamic lesion that changes with the phase of respiration. On inspiration there is negative pressure within the
cervical portion of the trachea and it will collapse or narrow. On expiration, positive pressure within the thorax
causes narrowing of collapse of the intrathoracic trachea and in some cases the main stem bronchi. Apparent
uniform narrowing of the trachea may be seen in dogs due to hemorrhage caudes by intoxication by vitamin K
antagonist rodenticides. In these cases, the air shadow of the lumen will be much smaller than the outline of
the tracheal rings.
Bronchopneumonia
Bronchopneumonia is more common in dogs than in cats. Tipically has a ventral distribution, affecting
the peripheral and mid zones of the right middle, right cranial and left cranial lung lobes. The lesions begin at
the periphery of the lung lobes and extend to the hilus with increased severity. Complete alveolar opacification
of the righ middle lung lobe is a common findings. Aspiration pneumonia has a similar lobar distribution. Look
for evidence of esophageal dilatation and dysfunction that would support a diagnosisof aspiration pneumonia
Fig.1: An aged dog with a bronchopneumonia. Notice the air bronchogram and the alveolar patern superimposed
to the cardiac silhouette
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Cardiac diseases
Dogs can cought for cardiac diseases, cat usually don’t. Cardiogenic pulmonary edema results fro left
heard failure, mostly sedondady to mitral valve endocardiosis. Usually it begins in the hylar region of the caudal
lung lobes and extends to the periphery. Acutely decompensated endocardiosis can result in a focal, lobar,
severe alveolar pulmonary pattern in the right caudal lung lobe. Initially it may appear as an interstitial pattern
that coalesces to form an alveolar pattern. In dogs with dilated cardiomopathy, a more widespread is often seen
in overt cardiac failure. The edema may be distributed thoughout the lung with a perivascular random, patchy
distribution rather than hylar or discrete lobar distribution.
Recently Ferasin (2013) questioned if an increased left atrium that dorsally displaced the left main stem
bronchi, will be able to cause chough in dogs. From his work it appears clear that the dogs that are coughing
are the one with concomitant broncomalacia.
Bronchitis
Radiology is quite insensitive when diagnosis bronchial disease. Chronic bronchitis can result in central
and peripheral airway thickening. If the inflammation of the broncus is severe, it will spill over into adjacent
peribronchial interstitial structures. Chronic feline asthma is the most common cause of bronchitis in cats.
Chronic bronchial changes can over time, result in dilatation of the bronchi. If this dilatation is fixed (repetable
on multiple radiographs) then, the term bronchiectasis is used. Bronchiectasis has been shown to be more
prevalent in Cocker Spaniels. The bronchiectasis can be focal or generalised involving all bronchi. Dogs or cats
with chronic bronchial changes will usually benefit from a bronchoalveolar lavage.
Fig.2: Severe bronchitis in a young dog. Final diagnosis: lung word infestation
Large lung mass
A large focal, well distinct (because surrounded by air), soft tissue opacity can cause cough in dogs and
cats. A primary neoplasia is the first differential diagnosis, abscesses and granulomas are more rare causes. The
dorsal portion of the right caudal lung lobe is a common location for solitary lung masses.
REFERENCES
1) Ferasin L, Crews L, Biller DS, Lamb KE, Borgarelli M: Risk factors for coughing in dogs with naturally acquired
myxomatous mitral valve disease. J Vet Intern Med. Mar-Apr;27(2):286-92. 2013
2) Muhlbauer MC. Kneller SK. Radiography of the dog and cat. Wiley-Blackwell. 2013
3) Suter PF, Lord PF: Thoracic Radiology. A text atlas of thoracic diseases of the dog and the cat. Wettswill,
Switzerland. 1984
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Use of radiology in acute abdomen patients
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
Introduction
The concept of detail or inherent abdominal subject/object contrast is the basis for the radiographic
assessment and detection of focal or diffuse peritoneal or retroperitoneal disease. Peritonitis, organs rupture,
carcinomatosis, are all responsible for changement of the abdominal detail.
Abdominal detail
Detail within the peritoneum and retroperitoneal spaces is essential for evaluating the abdominal organs.
The quality of detail is determined by how much fat is present. This is assessed by looking for subcutaneous
fat, retroperitoneal fat and fat within the falciform ligament ventral to the liver. In normal body condition, the
complete outline of the left kidney and the caudal pole of the right kidney are visible in the dog. In cats both
kidneys should be clearly outlined. The serosal edges of the abdominal organs and the inner margin of the
muscle of the abdominal wall should be clearly visible in an animal in normal body condition. In animal with
no body fat, neither peritoneal, neither retroperitoneal organ can be discerned. This is normal in immature
patients and can also be seen in cachexia, due to severe and chronic illness. In cases where details is absent
due to cachexia the abdomen has a tucked appearance.
Fig.1: Lack of serosal details in a cachexis cat
Retroperitoneal fluid obliterates the outline of the kidneys. The degree to which the kidneys are obscured
depends upon the relative quantities of fluid and fat present. If a moderate or large volume of fluid is present,
the retroperitoneal space will be expanded causing ventral displacemente of the gastrointestinal tract. Possible
causes of increased fluid opacity in the retroperitoneum include hemmorhage, urine leakage, neoplasia and
infection.
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Fig.2: Severe reduction of retroperitoneal details due to a ruptured left adrenal mass
If there is a history of trauma, the possibility of hemorrhage or urine leakage from lacerated kidney or
ureter should be considered and can be confirmed or excluded by a limited excretory urogram. Retroperitoneal
gas enhances detail in the dorsal abdomen and structures such as the abdominal aorta and right kidney become
clearly visible. Pneumoretroperitoneum is usually the result of extension of a pneumomediastinum.
Peritoneal fluid accumulation results in a reduction of serosal imagin detail that may be confined to
specific part of the abdomen or generalized. The degree of loss of detail depends upon the relative quantities
of fluid and fat present. A small quantity of fluid in a normal or obese animal produces a mottled, wispy or
streaky appearance and blurred serosal edges. A large volume of fluid will produce a white out effect with no
serosal detail and usually a few gas filled loops of intestine floating in the mid abdomen. This may be distinguished
from cachexia by the shape of the abdomen and evaluating the retroperitoneal detail. Many types of fluid may
accumulate in the abdomen including trasudates, modified trasudates, exudates, blood, urine, chyle, bile and
neoplastic effusions. A small volume of fluid producing a mottled appearance either in part or all of the abdomen
is most commonly caused by peritonitis, hemorrhage or carcinomatosis.
Peritoneal gas is a grave finding unless there has been abdominal surgery within the last four weeks. Large
or moderate volumes of gas enhance the normal serosal detail. Normally invisible structures such as the caudal
surface of the diaphragmatic crura and cupola and the caudate lobe of the liver are visualized and the serosal
border detail of the intestinal tract becomes exquisite.
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Fig.3: Severe pneumoperitoneum, if so severe you should think to a perfored stomach
Smaller bubbles are more difficult to detect but can be distinguished by a number of features. These
bubbles may be seen at the periphery of the abdomen, away from the intestine. They may have distinct round
shapes, especially if there is fluid present or appear triangular as they outline the serosal edges of adiacent
intestinal loops. Possible causes of peritoneal gas include perforation of the gastrointestinal tract, rupture of an
abdominal abscess or penetrating trauma.
References:
1) Muhlbauer MC. Kneller SK. Radiography of the dog and cat. Wiley-Blackwell. 2013
2) Thrall DE: Textbook of Veterinary Diagnostic Radiology, Elsevier Saunders, Sixth edition, 2013
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Hints to help with gastrointestinal interpretation of radiographs
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
Stomach
The normal canine stomach lies transversely across the abdomen with the fundus left and dorsal, the
gastric body on the left of midline, the pyloric antrum being located to the right of midline. On a lateral radiograph,
the position of a normal pylorus is in the middle of the cranial abdomen. In puppies and cats the pylorus has
a different anatomic location. On the VD film the stomach resemble a J with the body and fundus on the left
of midline and the pyloric antrum and pylorus being located either on midline or just right of midline. Obtaining
VD and left and right lateral radiographs and sometime a DV film is recommended in case of suspected gastric
disease. These four different projections move gas and fluid within the lumen and will allow evaluation of much
of the inner mucosal margin. However stomach and intestinal wall thickness cannot be reliably assessed on
survey films and this is best done by a contrast procedure or ultrasound.
Gastric dilatation and volvulus is a life threatening condition of large and giant breed dog. If there is severe
dilatation, efforts should be directed to relieving this before radiographs are obtained. As these animals are
distressed and in shock the radiographic examination should be quick and minimally stressful. A single right
lateral recumbent film may be sufficient to establish a diagnosis. If stomach is in normal position, gas will be
present in the gastric fundus and body. If the stomach is rotated, the pylorus will be gas filled and located in
the dorsal abdomen. Dilatation of the esophagus and generalized splenomegaly are often noted. Gas within the
spleen, gastric wall or portal vasculature is indicative of necrosis, secondary gas producing infection and are
grave prognostic indicators.
Chronic partial obstruction of the gastric outflow caused progressively slower gastric emptying and results
in gastric dilation. In severe cases the dilated stomach may extend beyond the umbilicus. The stomach is usually
filled with fluid and a smaller quantity of gas. Accumulation of small mineral fragments, called the grsvel sign,
may be seen in the pyloric antrum due to sedimentation of the heavier, indigestible food particles.
The possibility of a gastric foreign body should be considered in animals with unresponsive vomiting and
no radiographic evidence of small intestinal obstruction. If a foreign body is suspected the examination should
include 4 projections.
Suspected gastric tumor are best evaluated by endoscopy and ultrasound, which allows assesment of
the liver and regional lymph nodes for metastasis.
Fig.1: Gas in the wall of a rotated stomach is an indicator of wall necrosis
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Small intestine
The normal small intestine fills the mid abdomen and forms multiple, smoothly flowing loops. Normal
feline small intestine contains little or no gas and measures no more than 12 mm from serosal to serosal surface.
Normal canine intestine contains a variable quantity of gas but should not be uniformly gas filled. The serosal
to serosal border should not exceed 1,6 times the height of the center of the fifth lumbar vertebral body.
Intestine should be dilated if exceeds these normal limits. The most common cause for an increased volume
of intestinal gas is aerophagia either due to dyspnea or stress but this will not cause abnormal dilation. When
evaluating radiographs one should be careful not to overlook fluid filled dilated loops that are much less
prominent than gas dilated segments.
One of the first decisions is to determine if a loop of intestine is part of the small intestine or colon.
Dilation of the small intestine is pathological and occurs due to a functional or mechanical ileus. The normal
colon is wider than small intestine and could be mistaken for dilated small intestine or vice versa. To resolve
this dilemma, a systematic approach is adopted. One should try to identify the entire colon. If the suspect loop
can be connected to another part of the colon then the question is answered. If the entire colon can be
accounted for and the abnormal segment is not connected to the colon, then by exclusion it must be small
intestine and is abnormal.
Large intestine
In most dogs, the caecum contains gas and is seen as a sigmoidal shadow in the right mid abdomen. The
colon usually contains enough gas or faeces that most of it can be identified. In cats, the caecum is usually not
seen. The presence of large amounts of gas in the colon is not unusual.
The absence of a normal gas shadow within the colon or caecumis is an important clue to the presence
of an ileocolic or caecocolic intussusception. If in doubt the question is quickly and simply resolved by performing
an abdominal ultrasound.
Costipation is overdiagnosed. The diagnosis should be made only if a large amount of well formed, opaque
faecal material is present filling and distending the colon.
Fig.2: Radiograph of a costipated cat
References:
1) Fischetti AJ, Saunders HM, Drobatz KJ: Pneumatosis in canine gastric dilatation-volvulus syndrome. Vet Radiol
Ultrasound. 2004 May-Jun;45(3):205-9.
2) Trevail T, Gunn-Moore D, Carrera I, Courcier E, Sullivan M: Radiographic diameter of the colon in normal and
constipated cats and in cats with megacolon. Vet Radiol Ultrasound. 2011 Sep-Oct;52(5):516-20.
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Use of radiographic contrast medium in urologic patients
Giliola Spattini
Med Vet, PhD, DECVDI
Clinica Veterinaria Castellarano, ITALY ([email protected])
IVP (Intra-venous pyelogram)
An IVP must not be performed in dehydrated, diabetic, or severely hypotense patients. Dehydration must
be corrected prior to performing this procedure.
1) Survey right lateral and VD projections of the abdomen should be made to determine technique
2) If the colon contains sufficient material to compromise the study a warm water enema should be
performed and the survey abdomen re-evaluated after 1 hour. Alternatively it is possible to perform
oblique views to avoid the superimposition of the colon and the left kidney
3) An intraveonous catheter should be placed for contrast injection, the largest possible. In large dogs
two catheter will be preferred for a quick contrast injections
4) Iodinated contrast: 880 mgI/Kg given as a rapid intravenous bolus. The dosage should be increase 10%
for patients with elevated BUN abd creatinine. Retching has been reported as an immediate side-effect
of rapid injection mainly in cats.
5) VD radiographs should be obtained at times 0, 20 seconds, 3 minute, 5 and 10 minutes
6) Lateral radiographs should be obtained at 3 minute, 5 and 10 minutes. The IVP is finished, when the
kidneys have lost all the contrast.
7) Negative contrast cystogram can be performed with a non compressive IVP to improve visualization of
ectopic ureters.
In the early phase of the study, there is commonly an overall increase in abdominal opacity due to the
vascular phase of the contrast injection.
Fig. 1: IVP time 0. The contrast is visualized in the arteries. Usually the best projection is the VD
Fig. 2: IVP time 20 seconds. Nefrographic phase: the contrast is in nefrons
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Table 1: visualization of the urinary system in IVP
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Fig. 3: IVP 3-5 minutes. Pielographic and uteters phase
Fig. 4: IVP 10 minutes. Most of the contrast medium is in the urinary bladder
Positive Constrast Cystography
This procedure is commonly performed to evaluate for a bladder leakage/rupture or anatomic abnormality. Only iodinated contrast media should be performed.
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1) Obtain survey right lateral and VD projections of the caudale abdomen/pelvis to determine technique
2) Sedation or light aneshtesia is usually necessary to perform cystography
3) Aseptically place urinary catheter into bladder
4) Withdraw as much urine as possible
5) Inject 3-5 ml (in the dog, 2 ml in the cat) of 2% lidocaine into the bladder to reduce straining caused
by bladder distention
6) Iodinated contrast dosage: 5 ml/kg (in dog, 2-5 ml in cat) iodinated contrast should be drawn up (in
dog, 25 ml total in the cat). The urinary ladder should be held during contrast infusion to prevent over
distention and rupture. Typical bladder hold 5-10 ml/kg however patologic change to the bladder, such
as fibrosis, may hold significantly less such as 1 ml/kg
7) Obtain right lateral, oblique and VD radiographs of the urinary bladder. If there is contrast leakage during
the study then more contrast should be added as needed to keep the bladder distendend
8) If a double contrast cystogram is to be performed following this study then withdraw as much contrast
as possible. Place patient in left lateral reumbency and re-inflate the urinary bladder with air. A starting
dosage of 5/ml/kg of air can be used however the bladder must be palpated during injection to prevent
over disention and rupture
Fig. 5: Positive contrast urethrography
Positive Contrast Urethrography
This procedure is used to evaluate the urethra for flaps, calculi, masses and tears. Iodinated contrast
must be used.
1) Heavy sedatio or light anestesia will facilitate this examination
2) Obtain two survey radiographs: a right neutral view and right lateral with the legs pulled forward centered
on the urethral region
3) Aseptically place a Foley catheter within the ost distal aspect of the urethra.
4) Iodinated contrast dosage: Cat 5 ml, Small dog 10 ml, Medium dog 20 ml, Large dog 30 ml
5) Inject 2 ml of 2% lidocaine into the urethra to reduce straining associated with this procedure
6) Inject approximately 50% of the contrast and obtain a lateral radiograph of the urethra within the leg
pulled forward. The radiograph should be obtained near the end of the injection or immediatelly after
finishing the injection
7) Inject the remaining contrast and obtein a second right lateral radiograph of the urethra. The second
radiograph is important for comparison to the first to fetermine if filling defects persist or represent
transient air bubbles.
REFERENCE
Wallack S: The handbook of Veterinary Contrast Radiography
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