Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

22 Small Animal Radiolo g y and Ultrasono graphy
ultrasonographic abnormalities. Diagnoses should include all possible etiologies: toxic,
infectious, metabolic, nutritional, degenerative, neoplastic, iatrogenic, immune, idiopathic,
and developmental. The probable diagnosis usually is based on determining which of the
differential diagnoses can produce all of the radiographic or ultrasonographic abnormalities
observed. This probable diagnosis may be specific or general. An example of a specific
diagnosis might be a bone tumor (most likely osteosarcoma) in the case of an aggressive
but mixed (destructive and proliferative) lesion with a sunburst pattern in the distal radius
of a 9-year-old male Saint Bernard, or a renal cyst in the case of a focal anechoic area within
the kidney. A general diagnosis would be an enlarged kidney in a 5-year-old mixed breed
female dog, or increased echogenicity of the liver in a cat with hepatomegaly.
RECOMMENDATION FOR FURTHER DIAGNOSTIC MODALITIES
OR THERAPY
Once a radiographic or ultrasonographic diagnosis is reached, a program for confirmation of
the diagnosis or for treatment of the problem should be developed. This step is the result to
which the radiographic or ultrasonographic examination is properly oriented. One caveat of
the radiographic or the ultrasonographic diagnosis is that lesion appearance is neither cytologically
nor histologically specific. Further techniques that commonly are indicated include
additional diagnostic imaging procedures, hematologic or biochemical blood evaluations,
endoscopy, fine-needle aspiration, ultrasonographically guided fine-needle aspiration or core
tissue biopsy, or surgical exploration. Treatment plans might include pharmacologic therapies
(e.g., antibiotics for pneumonia) or surgical treatments (e.g., partial ligation of portosystemic
shunts). Another caveat of imaging diagnoses is that unless a wide array of possible differential
diagnoses are considered and an organized sequential plan to confirm or refute these is
developed, the appropriate test may not be run or the necessary further diagnostic modalities
might not be pursued. Therefore the formulation of a broad, but ranked, list of differential
diagnoses based on the combination of signalment (age, breed, gender), history, physical
examination findings, morphologic alterations observed via imaging, and any other available
information is a critical step in patient evaluation. In addition, it may be these differential possibilities
that justify the imaging modalities used and their sequence.
REFERENCES
1. Schnelle GB: Radiology in canine practice. The North American
Veterinarian, Evanston, Ill, 1945.
2. McGahan JP, Goldberg BB: Diagnostic ultrasound: a logical
approach. Lippincott–Raven, Philadelphia, 1998.
3. Miles KG: Basic principles and clinical applications of diagnostic
ultrasound. Comp Cont Educ Pract Vet 1989; 11:609.
4. Nyland GT, Mattoon J: Veterinary diagnostic ultrasonography. WB
Saunders, Philadelphia, 2001.
5. Kaplan PM, Murtaugh RJ, Ross JN: Ultrasound in emergency veterinary
medicine. Semin Vet Med Surg 1988; 3:245.
6. Curry TS, Dowdey JE, Murry RC: Christensen’s physics of diagnostic
radiology, ed 4. Lea & Febiger, Philadelphia, 1990.
7. Feeney DA, Fletcher TF, Hardy RM: Atlas of correlative imaging
anatomy of the normal dog: ultrasound and computed tomography.
WB Saunders, Philadelphia, 1991.
8. Herring DS, Bjornton G: Physics, facts, and artifacts of diagnostic
ultrasound. Vet Clin North Am 1985; 15:1107.
9. Kremkau FW: Diagnostic ultrasound: principles, instruments and
exercises, ed 5. WB Saunders, Philadelphia, 1998.
10. Barthez PY, Leveille R, Scrivani PV: Side lobes and grating lobes
artifacts in ultrasound imaging. Vet Radiol Ultrasound 1997;
38:387.
11. Douglass JP, Kermkau FW: The urinary bladder wall hypoechoic
pseudolesion. Vet Radiol Ultrasound 1993; 34:45.
12. Kirberger RM: Imaging artifacts in diagnostic ultrasound: a review.
Vet Radiol Ultrasound 1995; 36:297.
13. Lamb CR, Boswood A: Ultrasound corner—an artifact resulting
from propagation speed error. Vet Radiol Ultrasound 1995; 36:549.
14. Widmer WR, Kneller SK: Artifacts and technical errors presented as
part of the 1996 ACVR oral certification examination. Vet Radiol
1997; 38:156.
15. Miles KG: Basic principles and clinical applications of diagnostic
ultrasonography. Comp Cont Educ Pract Vet 1989; 11:609.
16. Carrig CB, Mostosky UV: The use of compression in abdominal radiography
of the dog and cat. Vet Radiol 1976; 17:57.
17. Zescov B, Petrociv B, Dragnovic B: Retropneumoperitoneal visualization
of abdominal organs in domestic animals. Vet Radiol 1976;
17:23.
18. Gomez JA, Lawson TL, Korobkin M, et al: Selective abdominal
angiography in the dog. Vet Radiol 1973; 14:72.
19. Farrow CS: Stress radiography. J Am Vet Med Assoc 1982; 181:777.
20. Barr F: Percutaneous biopsy of abdominal organs under ultrasound
guidance. J Small Anim Pract 1995; 36:105.
21. Crystal MA, Penninck DG, Matz ME, et al: Use of an ultrasoundguided
fine-needle aspiration biopsy and automated core biopsy for
the diagnosis of gastrointestinal diseases in small animals. Vet Radiol
Ultrasound 1993; 34:438.
22. Hager DA, Nyland TG, Fisher P: Ultrasound-guided biopsy of the
canine liver, kidney and prostate. Vet Radiol 1985; 26:82.
23. Lamb CR, Trower ND, Gregory SP: Ultrasound-guided catheter
biopsy of the lower urinary tract: technique and results in 12 dogs. J
Small Anim Pract 1996; 37:413.