Final Review Flashcards
What are the common disc protrusion sites?
T12-T13, T13-L1, C2-C3, C3-C4
Why is anesthesia recommended for spinal radiographs?
Prevents narrowing of the disc space with muscle spasms
In spinal radiographs, high ___ and low ___ create better contrast
high kVp, low mAs
Use of a ____ increases contrast for spinal radiographs
Grid
When positioning for a spinal radiograph, the vertebral column must always be _____ with the table top
parallel
When positioning for spinal radiographs, the disc spaces must be _____ with the table top
perpendicular
Common views for spinal radiographs
lateral and VD
Use of smaller cassettes and multiple views for spinal radiographs allow for what?
Perpendicular view of the disc spaces
Why are DV spinal views not as accurate?
Not parallel
Object-film distance distortion
How many views may be required for a full spinal study on a dog vs a cat?
Dog - 4-5 views
Cat - 1-2 views
What is the vertebral formula?
C7 T13 L7 S3 Cd20+ (tail)
Vertebral bone with no spinous process and two large lateral wings, articulate via synovial joints allowing greater movement
Atlas (C1)
Vertebral bone with large “blad-like” spinous process, peglike dense at cranial aspect forming atlantoaxial joint. No intervertebral disc between C1 and C2, articulates caudally with C3 via intervertebral disc
Axis (C2)
Vertebral bone with large transverse process (ventral lamina)
C6
What species has 18 pairs of ribs? (One breed does not)
Horses
Species with thoracic vertebrae that have tall spinous processes, large articular facets that form joints with the heads of the ribs
Dogs
In what species are rib heads cranial to respective vertebral body?
Cat
Where would you find the narrowest intervertebral disc space in a dog?
Between T10-T11
Which vertebra is the Anticlinal vertebra?
T11
What species have 4 fused vertebrae making up the sacrum?
pigs and sheep
What species have 5 fused vertebrae making up the sacrum?
Horses, cattle, goats and humans
Where should the beam be centered for a lateral view of the cervical spine?
C4
Where should the measurement be taken for a lateral view of the cervical spine?
C6
What should be included in the field of view for cervical spine XRays?
Base of skull to first few thoracic vertebrae
How should the patient be positioned for a flexed cervical spine radiograph?
Lateral recumbency with legs pulled caudally
Where should the beam be centered for a lateral thoracic spinal radiograph?
T7
How should limbs be positioned for a thoracic spine lateral view?
Moderately extended in opposite directions
What is the field of view for a thoracic spine lateral radiograph?
Last cervial to first lumbar vertebrae (shoulder joint to past the origin of the last rib)
Where should the beam be centered for a VD view of the thoracic spine?
Over caudal border of the scapula (T6)
How should the patient be positioned for a VD thoracic spine view?
Dorsal recumbency with legs pulled cranially
In a VD view of the thoracic spine how should the sternum be positioned?
Superimposed over the spine
What is the field of view for a lateral view of the lumbar spine?
T12 to the sacrum and include entire lumbar spine
What view visualizes the “nike swoosh”?
Lumbar spine - Transver spine superimposed at the origins
What is the field of view for lateral lumbosacral vertebrae?
L6 and entire pelvis
How should the patient be positioned for a VD view of the sacrum?
Dorsal recumbency with legs in normal position
How should the tube head be angled for a VD view of the sacrum?
30 degrees
What is the field of view for a VD view of the sacrum?
L6 and entire pelvis
How should the patient be positioned for a caudal spine radiograph?
Lateral recumbency with limbs in a natural position, tail extended caudally
What is the field of view for a caudal spine radiograph?
4-5 vertebrae on either side of area of interest or full tail
How should the cassette be placed for a caudal spine view?
Raise cassette with a foam pad to keep on same plane as the tail
What is measured if sinus cavities need to be radiographed?
Measure just rostral to the thickest part of the cranium to avoid overexposure
What are the views for a routine skull or survey study?
Lateral (affected side down), DV, or VD
Where is the measurement for a lateral skull view?
Over high point of zygomatic arch
Where is the beam centered for a DV view of the skull?
Lateral canthus of the eye
Where is the measurement taken for a DV view of the skull?
Over high point of the cranium
How should the patient be positioned for a DV view of the skull?
Sternal recumbency with head resting on cassette, sand bag on neck and front limbs relaxed or pulled caudally
What is the field of view for a DV view of the skull?
Include top of nose to base of skull
How should the patient be positioned for a VD view of the skull?
Dorsal recumbency, legs pulled caudally, sand bags on either side of the neck, nose parallel with cassette
Where should the beam be centered for a VD view of the skull?
Lateral canthus of the eye
Where should the measurement for a VD view of the skull be taken?
Lateral canthus of the eye
Where should the beam be centered for a rostrocaudal closed mouth view of the frontal sinuses (90 degree)
Through center of frontal sinuses and between the eyes
How should the patient be positioned for a rostrocaudal closed mouth view of frontal sinuses?
Dorsal recumbency with neck flexed, nose pointing upwards, legs pulled caudally alongside body
Where should the beam be centered for a rostrocaudal closed mouth view of the cranium (rostral 30 degree DCdVO)
Mid point between the eyes
Where is the measurement taken for a rostrocaudal closed mouth view of the cranium?
Area of frontal sinuses
How should the patient be positioned for a rostrocaudal closed mouth view of the cranium?
Dorsal recumbency with neck flexed, more flexion than frontal sinus view
What is the patient positioning for VD open mouth view of the nasal cavity?
Dorsal recumbency with maxilla taped to table, pull mandible open with tie or mouth wedge
Where should the beam be centered for VD open mouth view of nasal cavity?
Through the third upper premolar
What is measured for a VD open mouth view of the nasal cavity?
Upper jaw over the upper third premolar
How should the tube head be angled for a VD open mouth view of nasal cavity?
20-30 degrees rostrocaudally
What is the field of view for a VD open mouth view of nasal cavity?
entire maxilla to pharynx
What is the patient positioning for a tympanic bullae (rostral 10-30 VCdDO) Rostrocaudal open mouth view?
Dorsal recumbency with the neck flexed, nose pointed upward, legs pulled caudally. Pull maxilla cranially 10 degrees and mandible caudally 10 degrees
Where should the beam be centered for a rostrocaudal open mouth view of tympanic bullae?
Base of neck to commissure of lips
What is the field of view for a rostrocaudal open mouth view of tympanic bullae?
Entire pharyngeal region with bullae isolated
What is patient positioning for lateral oblique view of tympanic bullae?
Lateral recumbency with good side down, limbs pulled caudally, head rolled into natural position for oblique
What view is good for TMJ?
Lateral oblique view of tympanic bullae
What is patient positioning for VD oblique view of TMJ?
Lateral recumbency with affected side down, head rotated at 20 degrees with wedge, mouth may be open or closed
Soft tissues are difficult to identify on plain films due to lack of contrast. How can we better view these tissues?
Using contrast medium or performing ultrasound
What are two benefits of survey films?
Help determine proper exposure and eliminate need for contrast
What agents are used for positive contrast?
Barium or Iodine
Positive contrasts have ____ atomic numbers than tissue and bone
Higher
What contrast can safely be administered into a blood vessel?
Iodine
How should kVp be increased with positive contrast?
6-8 kVp
What agents are used for negative contrast?
Gasses with low specific gravity
Barium causes _____ when left free in abdominal cavity
Peritonitis
Why are iodine compounds not used in GI studies?
They aren’t thick enough to coat mucosa of the intestines
What is used in GI situations when perforations are suspected?
Iodine preparations
The higher the iodine concentration the more _______
contrast
Contrast preparation that is completely insolube therefore not diluted with alimentary secretions
Barium
What are BIPS?
Barium impregnated polyurethane spheres
Positive contrast agent that remains in spherical form, designed for transit time
BIPS
What is best used for negative contrast agents and why?
CO2 because it is rapidly absorbed
In a double contrast study which contrast should be administered first?
Negative contrast, to avoid air bubbles that mimic lesions
If necessary, what drug should be used to tranquilize patients in contrast studies?
Acepromazine
What drugs should be avoided when doing contrast studies?
Parasympathetic/anticholinergics
ie. Atropine and glycopyrolate
What circumstances contraindicate the use of contrast studies?
Fluid filled distended stomach or esophagus
Ruptured bowel
Dysphagic patients
Megaesophagus
Why are dysphagic patients or megaesophagus contraindicated for contrast studies?
Risk of aspiration
What is the ideal method for determining megaesophagus?
Esophagraphy