Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 425
Fig. 3-227 A, A 12-year-old female mixed breed dog with
chronic stranguria. There was marked irregularity of the urethra
with multiple filling defects in both views. Differential
diagnoses include urethritis or urethral neoplasia. Diagnosis:
Chronic urethritis. B, An 11-year-old neutered female German
Shepherd with stranguria for 2 months. There was marked tortuosity
of the urethra with marked mucosal irregularity that
extended into the bladder. Differential diagnoses include urethral
neoplasia, inflammation, or periurethral fibrosis.
Diagnosis: Transitional cell carcinoma involving the bladder
and urethra.
A
B
Double-contrast techniques typically are thought of as useful for identification of
lower urinary tract filling defects, particularly calculi. However, by varying the concentration
of the contrast medium used, most oxalate urocystoliths can be differentiated
from most struvite urocystoliths. 437 By using a double-contrast solution with 80 mg
iodine per ml, most of the oxalate urocystoliths will become isoopaque (e.g., disappear)
within the contrast puddle. This can be useful for prediction of urocystolith mineral
type, but it can be a problem if a contrast medium solution is too dilute when used to
identify urocystoliths.
As ultrasonography becomes more popular, there is the difficult decision as to whether
ultrasonography or contrast radiography should be used for urinary bladder lesions,
whether intraluminal or intramural. Although there are currently no objective comparative
data on ultrasonography versus contrast cystography for bladder masses, there are data