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An Urban Experience
than leiomyomas and breeding queens seem over- represented. When an adenocarcinoma is suspected, an FeLV test should be performed as well as a metastatic check-up. Some adenocarcinomas can be dif cult to diagnose, as they can mimic pyometra.
1.e. Vaginitis and foreign objects
Vaginitis can be observed on US with a perineal approach. Mostly vaginitis is observed in prepubescent animals. In an adult a foreign object, such as grass owns, should be excluded.
2. The ovaries
2.a. Cyst: ovarian and para-ovarian
Cysts are round, anechoic structures observed in the ovarian region and can vary in size. They can be para- ovarian. In this case, they are not associated with any reproductive disorder but their size could eventually become dramatic, causing mass effects on other organs and discomfort.
Ovarian cysts can be located in the cortex or the medulla. Only those located in the cortex can eventually secrete hormones and thus have an impact on the reproduction. Most of the time, the diagnostic of an ovarian cyst requires the combination of clinical  ndings, hormonal dosage and ultrasonographic detection of the cystic lesion in the cortex. There are 2 situations where the cyst can be con rmed with only ultrasound: if it’s larger than 5mm during the oestrus cycle or larger than 2mm in anoestrus.
2.b. Remnant ovarian syndrome
Ovarian tissue can be observed in sterilized females
at the usual localisation of the ovaries. It is highly recommended to perform the ultrasound when the queen has an oestrus behaviour. In addition, the uterus will show up enlarged with a layering of the endometrium and myometrium.
2.c. Neoplasia
Ovarian tumors are rare. They can be uni- or bilateral. Epithelial tumors are more frequent than germinal or stromal tumors. Their appearance on ultrasound is very variable.
1. Normal pregnancy
Ultrasonography is a non-invasive technique that allows an accurate diagnosis of pregnancy and allows serial evaluation of the developing embryo/foetus and extra- foetal structures. The early diagnostic can be done about 11 days after the  rst mating. At that time, for
an experimented radiologist, a 1,2 +/- 0,1mm small anechoic cavity can be observed in the lumen of the uterus (body or horns) which corresponds to the
embryonic vesicle. Due to high risk of resorption during that period, additional exams should be performed to con rm the persistence of the vesicle. The heartbeat can be observed between 15-17 days after the  rst mating. Other structures can be recognised at different times of the embryonic and foetal development.
Number of days after mating
Embryonic vesicle (1,2+/-0,1mm)
Heart beat
Hyperechoic liver
8 shape of the embryo
Detection of the stomach
Lung are hyperechoic to the liver
Eyes and kidneys are detected
Intestinal loops and layering
Table 1: Date of apparition of the most commonly used structures or organs (based on Zambelli et al 2002, Topie et al 2010.
In high risk pregnancies (previous dystocia, single kitten, pelvic fractures, old queens...), the apparition date of the various organs can be used as a landmark to estimate the gestation stage. Embryometry and foetometry
are other possibilities. Several formulas have been proposed over the last 20 years, but have been poorly tested in breeding cats, and recent studies pointed out insuf cient accuracy (about 50% at 2 days). This can be explained by the fact that several factors may in uence the parturition time, such as litter size, weight, age and breed. Therefore, the most recent articles about the subject propose to combine both methods to improve accuracy. Ultrasound close to the parturition is important to assess the viability of the foeti and to detect potential foetal distress (cardiac frequency less than 220bpm). It should be associated with foetometry and measurement of the progesterone (a drop can be observed).

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