Small Animal Radiology and Ultrasound: A Diagnostic Atlas and Text

Chapter Three The Abd omen 437
Fig. 3-246 A 3-year-old neutered
female mixed breed dog had a vaginal
discharge. The longitudinal
sonogram revealed a slightly thickened
uterine stump (longer arrows)
that ended in a mixed echogenicity
mass (short arrows). Diagnosis:
Uterine stump granuloma.
In cats, fetal heart rates remain stable during pregnancy and average 228 beats per
minute (bpm). In dogs, fetal heart rates increase during pregnancy from an average of 214
bpm initially to an average of 238 bpm by day 40. The heart rate slows slightly around the
time of parturition. 842 By means of fetal head diameter (HD) measured across the calvarium,
body diameter (BD) at the level of the liver, gestational sac diameter (GSD), or crown
rump length (CRL) measurements, ultrasonography can be used to assess gestational age
(GA) in queens and bitches. The formulas used include 7,838,843 :
Bitches:
Queens:
GA less than 40 days
GA (+/− 3 days) = (6 × GSD) + 20
GA (+/− 3 days) = (3 × CRL) + 27
GA greater than 40 days
GA (+/− 3 days) = (15 × HD) + 20
GA (+/− 3 days) = (7 × BD) + 29
GA (+/− 3 days) = (6 × HD) + (3 × BD) + 30
GA greater than 40 days
GA (+/− 2 days) = (25 × HD) + 3
GA (+/− 2 days) = (11 × BD) + 21
The canine uterus is incompletely involuted by ultrasonography until up to 15 weeks postpartum.
837 However, because of its seasonally polyestrous reproductive cycle, the feline
uterus can be sonographically involuted by 24 days postpartum. 800
Variability in the appearance of the uterus is observed. In the first 1 to 4 days postpartum,
the uterus is large and its contents are heteroechoic. Placentation sites may be visible as ovoid
heteroechoic areas. Both hypoechoic and hyperechoic uterine contents are visible, and the
uterine wall is thick. As uterine involution progresses, the wall becomes thinner and placentation
sites become more uniform and less distinguishable from the rest of the uterine wall. 390
PROSTATE
The prostate is normally a bilobed ovoid or round, tissue-dense structure with a
smooth, regular margin, located almost partially or entirely within the pelvic canal. A