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Today’s Veterinary Practice November/December 201462
ImagIng EssEnTIals Peer reviewed
radiography of reptile patients
is routinely used for evalu-
ation of traumatic injuries
and the gastrointestinal and
reproductive tracts.
A reptile radiography study typically
includes lateral and dorsoventral views.
Additional collimated views of areas of
interest are obtained in specific species.
For example, in turtles and tortoises, a
craniocaudal view is added to complete
the study.
Unlike dogs or cats, whole-body radio-
graphs are taken of reptiles in order to
visualize the entire coelomic cavity. In
addition, horizontal beam radiographs
of reptiles other than snakes (turtles
and tortoises) are important for visu-
alization of the dorsal coelomic struc-
tures (lungs).
Imaging Essentials provides comprehensive
information on small animal radiography
techniques, and the series has addressed
the majority of anatomic areas in canine
and feline patients, including the head and
spine, thorax and abdomen, and the limbs
and joints. avian radiography was most
recently covered in our september/October
2014 issue. access these articles through
our online Article Library, available at
tvpjournal.com.
Danielle Mauragis, CVT, and
Clifford R. Berry, DVM, Diplomate ACVR
University of Florida
rePtile radiograPhy
November/December 2014 Today’s Veterinary Practice 63
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POSITIONING
Anesthesia/Sedation
The reptile patient can undergo radiography awake, but general
anesthesia is sometimes required to ensure good-quality posi-
tioning. Conscious turtles and tortoises have the ability to hold
their extremities and head within or close to their shells. In the
instance of fracture, sedation or anesthesia may be needed to
relax the neck or extremity and isolate it, avoiding superimposi-
tion with the shell, for complete evaluation.
Restraint Techniques
For whole-body studies, conscious turtles or tortoises can some-
times be restrained by taping the limbs to or inside the shell
(Figure 1):
1. Tape a figure-8 pattern with 2-inch porous tape over the tho-
racic and pelvic limbs.
2. Start with the carapace or plastron and tape over a thoracic
limb, followed by the opposite pelvic limb, then back to the
same thoracic limb.
3. Cross over the shell to the contralateral pelvic limb and then
the contralateral thoracic limb, and continue in a figure 8 pat-
tern for at least a second time.
To tape the head inside the carapace, place a piece of 2-inch
porous tape from the carapace down over the head and secure
B
A
Figure 2. Tortoise placed in radiolucent tub
for a laterally positioned, horizontal-beam
radiograph (A) and corresponding radiograph
(B). Snake positioned in a tube for either
lateral or dorsoventral radiographs (C).
C
Figure 1. Figure-8 taping of a tortoise; cranial
view.
to the plastron.
To prevent the patient from moving
forward:
• Place a sponge anchored with a sandbag
in front of the nose of a lizard, turtle, or
tortoise
• Place a chelonian in a radiolucent plastic
tub (Figure 2).
•Use a similar tub for a snake in order to
keep the entire snake spread out for a
dorsoventral projection; a tube can be
used to keep the snake straight for lat-
eral or dorsoventral projections.
Projections
Due to the nature of the coelomic cavity,
use horizontal-beam or cross-table projec-
tions, if possible, for the lateral and cranio-
caudal projections of turtles and tortoises.
In other reptile species, vertical-beam dor-
soventral projections are also acceptable.
RADIOGRAPHIC EXPOSURE
Technique and exposure depend on the
size of reptile.
•Use an abdominal technique due to the
variable opacities of the coelomic cavity.
•A grid is recommended for patients with
depth greater than:
» 10 cm (film/screen)
» 15 cm (digital radiography).
•Measure each projection and use appro-
priate technique as indicated by the
technique chart.
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Today’s Veterinary Practice November/December 201464 tvpjournal.com
• If using a horizontal-beam method, remem-
ber to adjust technique when not using the
grid: decrease the mAs by 1/3 if the original
technique was set with an 8:1 grid.
DORSOVENTRAL PROJECTION
1. Place the patient in ventral (sternal) recum-
bency directly on the:
» Cassette for a tabletop technique
» X-ray table for a film tray technique.
2. Ensure collimation includes the entire
shell or body of the reptile—the skull and
extremities in addition to the coelomic cav-
ity (Figure 3).
B
A
Figure 3. Tortoise positioned in sternal recum-
bency for dorsoventral projection (A) and cor-
responding radiograph (B). Presence of metal
plates and screws are result of shell fracture
repair after the tortoise was hit by a car.
Figure 4. Tortoise elevated off the x-ray table for horizontal-beam
lateral projection (A) and corresponding radiograph (B).
LATERAL PROJECTION
Positioning
Place the patient in right lateral recumbency; however, in
the instance of trauma or pathologic abnormality, place
the affected side closest to the cassette.
Horizontal-Beam or Cross-Table Technique
(Figure 4)
If possible, use a horizontal-beam or cross-table for the
lateral projection.
1. Rotate the x-ray tube head 90° toward the patient.
2. Place the cassette or detector on the right side of the
patient—or the affected side—and secure it in place
with a cassette holder or sandbag.
3. Elevate the patient off the x-ray table, which places the
patient as close to the middle of the cassette or detector
as possible, by using radiolucent sponges, positioning
troughs, or boxes.
4. Center the x-ray beam at midbody of the patient and
ensure collimation includes the entire shell or body.
A
B
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Tabletop or Film Tray Technique
(Figure 5)
If a horizontal beam is not available:
1. Place the patient in lateral recum-
bency directly on the:
» Cassette for a tabletop technique
» X-ray table for a film tray tech-
nique.
2. Prop turtles and tortoises in lat-
eral recumbency by using a posi-
tioning trough or sponges.
3. Ensure collimation includes the
entire shell or body of the reptile.
CRANIOCAUDAL PROJECTION
(TURTLES/TORTOISES)
The craniocaudal projection of the
turtle or tortoise is used to visual-
ize the left and right sides of the
lungs.
Horizontal-Beam or Cross-Table
Technique (Figure 6)
If possible, use a horizontal-beam or
cross-table for this projection.
1. Rotate the x-ray tube head 90°
toward the patient.
2. Place the cassette or detector
behind the patient and secure it
in place with a cassette holder or
sandbag.
3. Elevate the patient off the x-ray
table, which places the patient as
close to the middle of the cassette
or detector as possible, by using
radiolucent sponges, positioning
troughs, or boxes.
4. Center the x-ray beam in front of
the patient’s head—the patient
will be looking at the collimator.
5. Ensure collimation includes the
left and right sides of the shell.
The left and right hemisphere
should appear equal, with the
spine superimposed.
Tabletop or Film Tray Technique
(Figure 7, page 66)
If a horizontal beam is not available:
1. Place the patient in a cranial to
caudal direction directly on the:
» Cassette for a tabletop technique
» X-ray table for a film tray tech-
nique.
2. Ensure collimation includes the
entire shell or body of the turtle/
tortoise.
Figure 6. Horizontal-beam craniocaudal radiograph of tortoise;
comparison of the radiographs in Figures 6 and 7 (page 66)
demonstrates that horizontal-beam imaging clearly depicts the
lungs without superimposition of the coelomic contents.
Figure 5. Tortoise placed in positioning trough for vertical-
beam lateral projection (A) and corresponding radiograph (B);
this approach is used if horizontal-beam radiographs cannot
be obtained. Comparison of the radiographs in Figures 4 and 5
demonstrates that horizontal-beam imaging clearly depicts the
lungs without superimposition of the coelomic contents.
B
A
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Today’s Veterinary Practice November/December 201466 tvpjournal.com
Suggested Reading
han CM, hurd Cd. Practical Diagnostic Imaging for the
Veterinary Technician, 3rd ed. Philadelphia: elsevier, 2004.
lavin lM. Radiography in Veterinary Technology, 5th ed.
Philadelphia: elsevier, 2013.
thrall de (ed). Textbook of Veterinary Radiology, 6th ed.
Philadelphia: Saunders elsevier, 2012.
A
Figure 7. Tortoise placed in positioning trough
for vertical-beam craniocaudal projection (A) and
corresponding radiograph (B); this approach can
be used if horizontal-beam radiographs cannot be
obtained.
B
Figure 8.
Dorsoventral
cranial
radiograph
of a monitor
lizard: Two
projections
are required
to image the
entire body
of this lizard.
In some
snakes,
more than 2
radiographs
are required,
with the
patient
in lateral
recumbency.
Danielle Mauragis, CVT, is a
radiology technician at University of
Florida College of Veterinary Medicine
where she teaches diagnostic imag-
ing. She coauthored the handbook of
radiographic Positioning for veterinary
technicians and received the Florida
Veterinary Medical Association’s 2011 Certified
Veterinary Technician of the Year Award.
Clifford R. Berry, DVM, Diplomate
ACVR, is a professor in diagnostic
imaging at University of Florida College
of Veterinary Medicine. His research
interests include cross-sectional imag-
ing of the thorax, nuclear medicine,
and biomedical applications of imag-
ing. He received his DVM from University of Florida
and completed a radiology residency at University of
California–Davis.
IMAGE QUALITY
For quality control of any diagnostic image, follow a
simple 3-step approach:
1. Use the appropriate technique (appropriate expo-
sure and development factors).
2. Obtain the entire anatomic region of interest in the
image. In larger reptiles, sequential cranial to caudal
radiographs with the patient in lateral or sternal
recumbency ensures complete evaluation.
3. Make sure the anatomic region is positioned appro-
priately with regard to centering, alignment, and
symmetry. Symmetry, especially for musculoskeletal
structures, is key to proper evaluation because it
assists the interpreter, especially with regard to ana-
tomic differences between species.
For the coelomic cavity, all projections—dorso-
ventral, lateral, and craniocaudal (turtle/tortoise)—
should include as much of the patient as possible. For
other lizards or snakes, the tail or other portions of
the coelom will need to be radiographed separately
(Figure 8). n
November/December 2014 Today’s Veterinary Practice 67tvpjournal.com
PRaCTICal TECHnIQUEs |
•Treat the incision with cold pack therapy, 10 minutes
Q 6 H, for 2 to 3 treatments.
Care & Follow-Up
Patients are typically kept in the hospital overnight and
discharged the day after surgery. Postoperative activity is
limited to strict crate rest for 8 weeks after surgery. Post-
surgery recheck examinations are performed at 2, 6, and
12 weeks.
IN SUMMARY
Patellar luxation can cause clinically significant hindlimb
lameness in cats. Patients with persistent lameness attribut-
able to patellar luxation should be considered candidates
for surgical therapy.
Surgical treatment of patellar luxation is typically a mul-
tistep process. The exact techniques required vary from
patient to patient. The final decision about which surgical
techniques to use in a particular patient is based on intra-
operative assessment of patellar tracking in the trochlear
groove.
Use of sound decision making and intraoperative atten-
tion to detail lead to consistently successful surgical cor-
rection of feline patellar luxation. n
References
1. Smith gK, langenbach a, green Pa, et al. evaluation of the association
between medial patellar luxation and hip dysplasia in cats. JAVMA 1999;
215(1):40-45.
2. Scott hw, Mclaughlin r. Feline Orthopedics. london: Manson Publishing
ltd, 2007, pp 218-222.
3. Johnson Me. Feline patellar luxation: a retrospective case study. JAAHA
1986; 22:835-838.
4. loughin Ca, Kerwin SC, hosgood g, et al. Clinical signs and results of
treatment in cats with patellar luxation: 42 cases (1992-2002). JAVMA
2006; 228(9):1370-1375.
5. Putnam rw. Master’s thesis: Patellar luxation in the dog. ontario, Canada:
University of guelph, 1968.
6. Singleton wB. the surgical correction of stifle deformities in the dog. J
Small Anim Pract 1969; 10(2):59-69.
7. Kowaleski MP, Boudrieau rJ, Pozzi a. Stifle joint. in tobias KM, Johnston
Sa (eds): Veterinary Surgery: Small Animal. St. louis: elsevier, 2012, pp
906-998.
8. Piermattei dl, Johnson Ka. An Atlas of Surgical Approaches to the Bones
and Joints of the Dog and Cat, 4th ed. Philadelphia: elsevier Saunders,
2004, pp 342-349.
9. talcott Kw, goring rl, de haan JJ. rectangular recession trochleoplasty
for treatment of patellar luxation in dogs and cats. Vet Compar Orthop
Traumatol 2000; 13:39-43.
10. Piermattei dl, Flo gl, deCamp Ce. Handbook of Small Animal
Orthopedics and Fracture Repair, 4th ed. St. louis: Saunders, 2006, pp
562-632.
Caleb Hudson, DVM, MS, Diplomate
ACVS, is a surgeon at Gulf Coast
Veterinary Specialists in Houston, Texas.
His special interests include total joint
replacement and minimally invasive
surgery. Dr. Hudson received his
DVM from University of Missouri, and
completed a rotating internship in small animal medicine
and surgery, residency in small animal surgery, and MS
in veterinary science from University of Florida.
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(Practical Techniques: Surgery continued from page 37)
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