Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 399
the risk of occurrence, risk of recurrence, and a reasonable estimate of which therapeutic
approach is applicable. 593-607 Finally, a working knowledge of the proven and potential
familial and hereditary renal diseases in dogs (e.g., those affecting the Alaskan Malamute,
Alsatian, Basenji, Beagle, Bernese Mountain Dog, Bull Terrier, Cairn Terrier, Cavalier King
Charles Spaniel, Chinese Shar-Pei, Chow Chow, Cocker Spaniel, Doberman Pinscher,
Dutch Kookier, Foxhound [English], German Shepherd, Golden Retriever, Greyhound,
Keeshond, Lhasa Apso, Miniature Schnauzer, Newfoundland, Norwegian Elkhound, Old
English Sheepdog, Rhodesian Ridgeback, Rottweiler, Samoyed, Shetland Sheepdog, Shih
Tzu, Standard Poodle, Weimaraner, Wheaten Terrier [soft-coated] breeds) and the
Abyssinian cat is needed to establish whether the patient is at risk for such disease as well
as to establish a prognosis once the diagnosis is made. 608-680
U R I N A RY B L A D D E R
Normally, the bladder is a teardrop-shaped organ that is relatively firmly anchored by its
ligaments and the urethra to the caudal abdominal and pelvic areas. The size of the bladder
varies considerably because of its distensibility; however, normal bladders rarely extend
cranial to the umbilicus. Although diseases with identifiable survey radiographic findings
are uncommon, with the exception of radiopaque cystic calculi, there are several changes
in size, shape, density, or location that may be identified by contrast studies and correlated
with sets of differential diagnoses.
Density Changes. Changes in density may affect the wall or contents of the bladder. Most
cystic calculi are radiopaque, have irregular shapes, and are located in the “center” (most
dependent portion) of the bladder (Figs. 3-188 and 3-189). The density of the calculi
depends upon their size and their composition. The relative occurrence rates of the various
lower urinary tract calculi have been described.* Although the structure of a stone is
infrequently diagnostic as to its composition, there are some strongly suggestive shapes.
Calculi composed of silicates typically are shaped like children’s toy jacks. If the calculus is
relatively large (e.g., >10 mm in diameter), smooth, round or ovoid, and the same or less
opaque than the ilial wing and laminated, it is most likely composed of triple phosphates
(struvite), particularly if seen in a female dog. However, struvite stones may form into a
Fig. 3-188 A 4-year-old female
mixed breed dog with chronic hematuria
and stranguria. Survey radiographs
revealed a very large
laminated calcium density in the
bladder (black c). Diagnosis: Cystic
calculus (triple phosphate).
*References 594, 596, 599-602, 605, 607.