Transcript Diagnostic Imag5 (2)

DLPMO
• Weight bearing
• Foot of interest
placed slightly
cranial
• Centered at middle
carpal joint
• Beam is 60
degrees lateral off
a straight dorsalpalmar
DMPLO
• Same as previous,
BUT, beam comes
from 60°
MEDIAL from a
straight DP
• Since beam comes
across the front of
the horse, have a
cooperative horse
Sedation if needed
A Review…
DORSAL
LATERAL
MEDIAL
PALMAR
CT or CAT Scan
• Computed tomography has just recently
become available for large animal patients.
• This equipment is very expensive and limited to
specialized facilities.
• Use is restricted in adult horses to the
examination of the head, cranial cervical spine
and distal limbs.
• Patient must be under anesthesia.
• Must be injected with radioisotope and is
absorbed by bony areas
• Used as a last resort in diagnosing.
CT scan of the horse’s nasal passages
This is the CT control room. The animal patient must be
anesthetized because you can not remain in the room with them.
There can be no motion or movement involved.
“By scanning foals as they mature, one is able to directly quantify the rate
of bone development in the distal limb. At this stage the foal must
be anesthetized for a short time so there is no movement artifact.”
MRI
• Magnetic Resonance Imaging; the area being
imaged is placed within a strong magnetic field
and stimulated by radio-frequency pulses.
These radio-frequency signals are collected
and analyzed by computers to form the image.
• Very, very costly and not widely available
• Anesthesia is required
• MRI tend to be superior to CT for soft tissue
imaging
• The head, cervical spinal cord and lower legs
can be imaged in an adult animal
• Precise and focal imaging tool that produces
images of all tissue types; bone, tendons,
ligaments, and fluid. Mainly utilized in equine
lameness.
Thermography
• Uses a heat camera to scan the body
surface temperature of the patient.
• Very popular because it is noninvasive, equipment is affordable and
portable.
• Primarily used to locate “hot spots”
which may indicate inflammation near
the body surface. Deeper locations
can not be detected, such as within
the thorax or abdomen.
Stifles: the right stifle shows a “hot spot”
over the medial femorotibial joint.
IR PROx Thermal Infrared Camera
Ultrasound
• Operates on high frequency sound
waves beyond our hearing.
• Uses sound waves to detect
differences in tissue density
• Generally superior to standard
radiographs for visualizing soft
tissues.
• Radiographs are superior for imaging
bony structures.
Common uses of Ultrasound
• Visualize kidneys and capable of ultrasound guided biopsy
• Lungs for pneumonia diagnosis and treatment
• GI for colics - small intestinal distension, large colon wall
thickness, peritoneal fluid, diagnosis of abcesses and
tumors
• Foals - GI disease, umbilical structures (diagnose umbilical
infections), ruptured bladder
• Liver - ultrasound guided biopsy
• Assist with lameness diagnosis, including the extent of
tendon and ligament damage
• Eyes
Common uses of Ultrasound cont…
• Monitor the mare's reproductive tract and
optimize the time for breeding
• The genital tract in stallions
• Early detection of pregnancy
• Early detection of problem pregnancies,
including fetal abnormalities
• Cardiovascular
• Ultrasound can be used to image the heart,
lungs, kidneys, liver, spleen, and intestines,
even during colic episodes.
Portable veterinary ultrasound
Brief Introduction to Ultrasound
• Transducer produces sound waves and
also receives reflected sound waves.
• Sound waves travel in a plane through
tissue.
• Sound waves are transmitted, absorbed or
reflected by tissues.
• Computer forms image – in shades of
gray.
• Bone appears white, fluids appear black
From: Zagzebski, JA; Essentials of Ultrasound
Physics, Mosby, © 1996
Musculoskeletal
Palmar distal extremity
Infected umbilicus
Reproduction
Uterine cysts
Echocardiography
Pericardial effusion
Abdomen
Liver - cholelithiasis
Thorax
Pleuropneumonia
Patient Preparation
Clip the area
Clean area
Coupling medium
alcohol
commercial gel
Imaging technique
Systematic organized approach – must be
familiar with normal
Scan from proximal to distal
Evaluate structures individually
Transducer perpendicular to structure
Limb should be weight bearing
Imaging Techniques
Label images - patient info, directions and
location
Two methods for location
1. Zones
2. Reference points
- cm distal to standard point
accessory carpal bone
point of hock
point of ergot
Transverse images
Palmar (skin surface)
Lateral
Medial
Dorsal
Rectal
ultrasound
examination of
a fetus
A 16-day
pregnancy,
visualized rectally
with a 5-mHz
probe.
Video..
Endoscopy
Endoscopy
• Endoscopes come in two basic
varieties; rigid and flexible.
• A thin tube that contains a fiberoptic
camera and a tool at the end
allowing samples to be taken from
various locations in the body. It is
passed through virtually any open
cavity on the body.
• Usually takes 2-3 people to operate
Control handpieces
Air/Water channel
Illumination lens
Instrument channel
Viewing lens
Illumination lens
Control handpiece and insertion
tube of the flexible endoscope.
Endoscope examination of the male urethra.
Notice how many people are involved.
Maintenance of the
Equipment
• You will be utilizing some if not all of
the previously mentioned
equipment.
• Take care of the equipment and it
will take care of you in the long run.
• Please follow ALL procedures in
your hospital/clinical pertaining
maintenance and trouble shooting
equipment.
• Follow ALL cleaning procedures as
The End