Transcript Lecture 3x - University of Agriculture Abeokuta

DIAGNOSTIC IMAGING A VALUABLE
TOOL IN VETERINARY PRACTICE
AJADI ADETOLA
COLLEGE OF VETERINARY MEDICINE
UNIVERSITY OF AGRICULTURE, ABEOKUTA, OGUN STATE.
AIMS
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To enable candidate extend and consolidate
clinical knowledge and skill gained at the
undergraduate level.
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To develop an in-depth understanding of the
application of veterinary diagnostic imaging in a
practice environment.
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To train candidate to develop practical skills in the
appropriate case selection for imaging studies.
EXPECTED OUTCOME
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Candidate will develop the ability to apply
diagnostic imaging techniques as part of the
overall investigation of a case.
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Candidate will develop the ability to determine
the appropriate techniques and views to use.
DEFINITIONS
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Diagnostic imaging: the use of radiant and non
radiant energy to obtain anatomical images of the
body for the purpose of diagnosis.
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Radiography: The use of radiant energy to obtain
latent images of body parts in photographic
emulsions.
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Ultrasonography: The use of high frequency
electromagnetic sound impulses to obtain real
time images of body parts.
DIAGNOSTIC IMAGING TECHNIQUES
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Radiography
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Computed tomography
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Ultrasonography
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Magnetic resonance imaging
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Radionuclide imaging
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Others.
RADIOGRAPHY
 Involved
the use of radiant energy.
 Depend
on the interaction of x-ray with matters.
 X-ray
cannot penetrate bone, limiting its use in the brain and
spinal cord.
 Good
for the thorax and abdomen.
 Visualization
 Contrast
depends on subject density and contrast.
agent can be administered to improve visualization.
RADIOGRAPHY
ULTRASONOGRAPHY
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Use of high frequency sound waves to obtain real time
images of body parts
Depends on the interaction of sound with matter.
It is non invasive.
Not limited by poor contrast.
Not impaired by fluid.
Can assess internal architecture.
Can allow for the evaluation of internal cardiac anatomy,
motion and function.
Can diagnose pregnancy; determine fetal sex, estimate
fetal size and expected date of delivery.
ULTRASONOGRAPHY
MAGNETIC RESONANCE IMAGING
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Depends on physical principles of nuclear magnetic resonance
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Does not depend on tissue density but on proton density, proton bulk
motion, diffusion magnetic susceptibility and chemical shift.
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It provides details image of soft tissue.
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Images can be enhanced by intravenous injection of paramagnetic
contrast medium, gadolinium.
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Diagnosis is based on lesion size, location and edema.
Very expensive and not available
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MAGNETIC RESONANCE IMAGING
COMPUTED TOMOGRAPHY
Involve the use radiant energy to create
attenuation map of patient.
 It allows one to obtain a cross-sectional image
slice of a subject, so that internal structural can be
visualized directly.
 X-ray attenuation is dependent on the energy of
the x-ray, election and physical density of the
material thickness of patient and effective atomic
number substance within the patient.
 Good for the brain, spinal cord, thorax and
abdomen.
 Useful when suspecting tumors of the brain, spinal
cords, lung or pancreases.
 Very expensive and not generally available
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COMPUTED TOMOGRAPHY
RADIONUCLIDE IMAGING
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Depends on the distribution of radio-pharmaceuticals in the body.
Technetium – 99m is the most commonly used radio
pharmaceuticals.
Planar imaging allows for region of interest analysis (ROI).
Dynamic flow studies assist in evaluating patient for possible portosystemic vessel anomalies, GFR determination, distal limb perfusion
and cardiac studies.
Single photon emission computed tomography (SPECT) allows for
dimensional image reconstruction thus improving anatomical
location of lesion.
Position emission tomography (PET) provides a functional
assessment of tumor metabolism.
Required hospitalization unit because of risk of radioisotopes.
Very expensive and not available.
RADIONUCLIDE IMAGING
OTHER IMAGING TECHNIQUES
Contrast techniques
 Digital radiography
 Positional radiography
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CONTRAST CYSTOGRAPHY
EXCRETORY UROGRAPHY
DIGITAL RADIOGRAPHY
CHART OF DIAGNOSIS
History
Physical Examination
tentative
*Prepare lost of
Differential Diagnosis
*Are you ready to treat?
Laboratory Examination
diagnosis
Tentative
Diagnosis
*Reduce or Increase
List of Differential
Diagnosis
*Are you ready to treat?
Imaging procedure
tentative
Diagnosis
*Reduce or Increase
List of Differential
Diagnosis
*Are you ready to treat?
Pathology
Treat.
Definitive
USES OF DIAGNOSTIC IMAGING
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Purchase examination
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Evaluation of trauma patient
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Evaluation of the cause of enlarged coelomic cavity
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Tumor diagnosis and tumor staging
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Management of fracture and other musculoskeletal
disorders
USES OF DIAGNOSTIC IMAGING
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Evaluation of the cause and location of site of hematuria
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Evaluation of the cause of urinary incontinency or continence.
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Evaluation of myelena, chronic diarrhoea and vomition.
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Evaluation of respiratory and/or cardiovascular disorders.
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Pregnancy diagnosis
Others
DIAGNOSTIC IMAGING IN PURCHASE EXAMINATION
To ensure that the animal to be purchased is
free of musculoskeletal problems.
 To ensure that clinically normal animal does
not have hereditary musculoskeletal disorders
 Hip dysplasia and Elbow dysplasia is a major
disease to screen for regularly in dogs
 Navicular disease is a disease to be screened
for in the horse.
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HIP DYSPLASIA
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Instability of the coxo- femoral joint caused by mal-development of
the femoral head and the acetabulum with resultant degenerative
osteoarthritic changes.
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Aetiology is hereditary- although the mode of inheritance is unknown.
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While heritability is estimated to range from 2-6% in other species, it
is about 46-61% in German shepherd.
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Overnutrition is one of the principal non- genetic factors that
influence the expression of canine hip dysplasia.
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Environmental factors such as type of housing, exercise e.t.c. also
influence the expression of canine hip dysplasia.
HIP DYSPLASIA
HIP DYSPLASIA
RADIOGRAPHIC EVALUATION OF THE HIP
HIP DYSPLASIA: EVALUATION
Penn Hip Distraction Projection
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It involves placing the dog in dorsal recumbency and the hip placed in
neutral position as if the dog is standing.
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The radiograph of the hip is obtained while the coxo-femoral joint is
compressed.
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A second radiograph is obtained when a distraction device is
positioned between the femurs.
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The two radiographs are evaluated to determine the laxity index (DI)
PENN-HIP DISTRACTION TECHNIQUE
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It is a valuable screening method for breeders before
litters are placed in homes
An accurate method for predicting dysplastic changes in
young animals from 6 months
Has greater heritability than the OFA method
It generates an index that can be used to predict
whether osteoarthritis will develop
It is a more sensitive method of identifying joint laxity
Requires special training to certify users
Require special equipment for hip distraction
Requires multiple radiographic projections
HIP DISTRACTION TECHNIQUE
HIP DISTRACTION TECHNIQUE
HIP DYSPLASIA: EVALUATION
Orthopedic foundation for animal (OFA) method
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It is the most popular screening program for coxofemoral
joint laxity
Requires only one radiograph i.e. the extended anteroposterior view
Has a large data base about coxofemoral phenotype
Inaccurate in young animals. The optimal time to radiograph
is 24- 36 months
Insensitive in identifying coxo-femoral joint laxity
The technique of extending femur camouflages signs of joint
laxity by spiral tension of the joint capsule
RADIOGRAPHIC EVALUATION OF THE HIP
HIP DYSPLASIA: FLUCKIGERS TECHNIQUE
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A variant of Penn Hip method in which Ortolani
maneuver is simulated with the dog in dorsal
recumbency’
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It discloses cranio-dorsal and lateral coxo-femoral joint
laxity defined by subluxation index (SI)
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It measures the functional laxity of the coxo-femoral
joint compared to the Penn Hip method which
measures the passive laxity
ELBOW DYSPLASIA
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Instability of the elbow joint characterized by intermittent
fore-limb lameness.
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It is generally a problem of the large breed of dogs e.g. Bull
Mastiff, Boerboel, Bernese mountain dog, Rottweiler, Great
Dane, and Alsatian.
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Osteochondritis dissecans of the medial humeral condyle
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Fragmented coronoid process
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Un-united anconeal process
ELBOW DYSPLASIA : EVALUATION
The following radiographic views should be
obtained:
 Flexed lateral
 Extended lateral
 Antero-posterior
 Latero-medial, cranio-caudal oblique
ELBOW DYSPLASIA: UAP
ELBOW DYSPLASIA: FCP
ELBOW DYSPLASIA: FCP
EVALUATION OF TRAUMA PATIENT
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Trauma in animal can result from road traffic accidents,
gun shot, fall or kick etc.
Trauma is often accompanied by varying degree of
musculoskeletal disorders and cardiopulmonary
compromise which may be very fatal.
There may be rib fracture, organ rupture, internal
bleeding, pulmonary contusion.
Radiographs of the skull, thoracic cavity and abdominal
cavity should be obtained and evaluated.
Two projections at right angle to each other is sufficient
in most cases.
THORACIC WALL TRAUMA
THORACIC WALL TRAUMA
ABDOMINAL WALL TRAUMA
ABDOMINAL WALL TRAUMA
ENLARGED COELOMIC CAVITY
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First rule out pregnancy in adult female animal
May be due to intra-abdominal mass, organ
displacement, anatomical obstructions or fluid
accumulation
Diagnostic imaging is performed to determine the
cause of abdominal enlargement and allow for biopsy
taken
Two vies at right should be obtained.
Ultrasonography is the preferred technique because it
allowed for simultaneous biopsy collection.
ENLARGED ABDOMINAL CAVITY
ENLARGED ABDOMINAL CAVITY
INTRA-ABDOMINAL MASS
INTRAPERITONEAL FLUID
TUMOR DIAGNOSIS AND TUMOR STAGING
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Tumors of internal organs are common causes of enlarged coelomic
cavities.
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Diagnostic imaging allows the location of the affected organ and for
biopsy taken.
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Technique adopted should depend on the size of the tumor and the
organ affected
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Radiography is good for recognition of pulmonary tumors and
skeletal tissue tumors.
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Ultrasonography is good for tumors of abdominal soft tissue and
allows simultaneous biopsy collection.
INTRA-ABDOMINAL MASS
INTRA-ABDOMINAL MASS
TUMOR STAGING
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The cytologic and or histologic type of all external
masses should first be determined before
removal.
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Both thoracic and abdominal radiographs and/or
ultrasound investigation should be part of the
protocol in the investigations of tumor metastasis.
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Common sites of tumor metastasis include the
lung, liver, spleen, abdominal lymph nodes.
Lumbar spine etc.
METASTATIC PULMONARY TUMOR
INTRA-ABDOMINAL TUMOR METASTASIS
FRACTURE MANAGEMENT: ROLE OF RADIOGRAPHY
Determine the location of fracture
 Determine the number of bones involved
 Determine the type fracture
 Determine the degree of soft tissue
involvement
 Evaluate the degree of bone reduction
 Evaluate the status of bone implants
 Assess the post reduction status of bone
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FEMORAL NECK FRACTURE
METAPHYSEAL FEMORAL FRACTURE
MULTIPLE BONE FRACTURE
POST REDUCTION RADIOGRAPH
OTHER MUSCULOSKELETAL DISEASES
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Metabolic bone disorders
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Neoplastic bone disorders
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Growth disorders
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Miscellaneous bone disorders
METABOLIC BONE DISEASE
NEOPLASTIC BONE DISEASE
MISCELLANEOUS BONE DISEASE
DISORDERS OF GROWTH
EVALUATION OF HEMATURIA
Frank blood in urine may be due to problem in
the kidney, bladder, urethra, vagina, penis or
vulva.
 Tumors of the reproductive tract and/or the
urinary tract are common causes of hematuria.
 Sonography, radiography and or contrast
studies can provide useful information to aid
diagnosis
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PER-CUTANEOUS ABDOMINAL ULTRASONOGRAPHY
PNEUMOCYSTOGRAPHY IN A DOG
EVALUATION OF DIARRHOEA, MYELENA OR VOMITION
Chronic diarrhoea with or without blood may be
associated with functional or anatomical
obstruction of the GIT.
 Persistent vomition may be due to esophageal
obstruction, gastric outlet obstruction or
intestinal obstruction
 Obstruction could be due to intraluminal, extraluminal or intramural masses.
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EVALUATION OF DIARRHOEA, MYELENA OR VOMITION
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GIT obstructions are best evaluated using survey
radiograph with or without contrast agents.
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Iodinated contrast agents should be used if perforation is
suspected.
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Positional radiography can be used to locate the site of
intraluminal obstruction.
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Ultrasonography is preferred when GIT masses is
suspected.
LATERAL THORACIC RADIOGRAPH: RADIOPAQUE
FOREIGN BODY
LATERAL ABDOMINAL RADIOGRAPH:
RADIOPAQUE FOREIGN BODY
PER-CUTANEOUS ABDOMINAL ULTRASOUND:
INTUSUSCEPTION
LATERAL ABDOMINAL RADIOGRAPH: INTRAMURAL GASTRIC MASS
EVALUATION OF RESPIRATORY AND/OR CARDIOVASCULAR
DISORDERS
Evaluate the location and pattern of pulmonary
disorders
 Evaluate the involvement of the cardiovascular
system in primary respiratory diseases.
 Determine the size of the (VHS) and of the
pulmonary vessels.
 Evaluate the cause of primary cardiovascular
disorder
 Determine the presence of secondary tumors in
the thoracic cavities.
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IMAGING OF THE CARDIOPULMONARY SYSTEM
Survey thoracic radiographs can give information
on heart size and pulmonary patterns.
 B- mode, M-mode, and Doppler echocardiography
can give functional data on the status of the heart
and explain the cause of arrhythmia.
 Radiographs should be obtained at maximum
inspiration using grid.
 Both left and right lateral radiographs, as well as
ventro-dorsal radiographs should be obtained.
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LATERAL RADIOGRAPH OF A GREAT DANE
VENTRO-DORSAL RADIOGRAPH OF A GREAT DANE
B-MODE ECHOCARDIOGRAPHY SHOWING LV
HYPERTROPHY
M-MODE ECHOCARDIOGRAPHY
OTHERS
Assist in monitoring patient progress.
 Assist in biopsy acquisition.
 Assist in pathologic examination.
 Medico-legal reasons.
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LATERAL THORACIC RADIOGRAPH FOLLOWING
TRAUMATIC PNEUMOTHORAX
POST OPERATIVE LATERAL THORACIC RADIOGRAPH FOLLOWING
TRAUMATIC PNEUMOTHORAX
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