1. Ultrasound of the Reproductive System Stacy Fielding

2. Technique 7.5-10mHz transducers Dorsal recumbency is routine
5 mHz in mid to late term pregnancy, pyometra, ovarian tumors
Dorsal recumbency is routine
Larger animals standing
Full bladder enhances visualization of uterus
Acoustic window

3. Ovaries Near caudal pole of kidney 1.5cm x 0.7cm x 0.5cm
Homogenous parenchyma
Cortex and medulla
Hard to differentiate
Cortex contains follicles

4. Ovaries-cont’d Anestrus/early proestrus Diestrus
Small, oval to bean shaped
Homogenous echogenicity (like renal cortex)
Follicles anechoic, become larger as ovulation approaches
Diestrus
CL/CH has multifocal anechoic to hyperechoic areas

5. Ovarian Structures

6. Ovaries Cystic Ovaries Ovarian Neoplasia Anechoic Thin walls
Acoustic enhancement
Solitary/multiple
Unilateral/bilateral
May see associated pyometra or hydrometra
Ovarian Neoplasia
Several kinds
Mostly unilateral
Smooth or irregular margins
Variable appearance
MET CHECK!

7. Normal Uterus Location: between urinary bladder and descending colon
Various sizes
Uterine horns: 10-14cm x cm
Uterine body: 1.4-3cm x 3cm
Cervix: 1.5-2cm x 0.8cm
Solid, homogenous, relatively hypoechoic
May have thin hyperechoic border
Cannot differentiate layers

8. Normal Uterus-cont’d Uterine horns not easily identified Cervix
Lost in mesenteric fat and small bowel echoes
Cervix
Hyperechoic, linear

9. Pyometra U/S is modality of choice for Dx
Enlarged uterus & uterine horns
Luminal contents
Homogenous, anechoic
Echogenic, “swirling”
May see varying wall thickness
Endometrium may contain anechoic foci
Ddx: hydrometra, mucometra
Monitor response to therapy

10. Uterine Neoplasia Adenomas Leiomyomas Leiomyosarcomas
Isoechoic to surrounding tissue, may project into the lumen

11. Pregnancy Diagnosis 21-35 days after breeding
Remember conception can occur several days afterward
May be difficult to count fetuses
Radiography recommended late in gestation, following mineralization
Earliest change = enlarging uterus
Non-specific
Gestational sac (blastocyst)
First confirmatory sign
Anechoic, several mm diameter
Thin, hyperechoic wall
17-20 d

12. 18 day pregnancy

13. Pregnancy-cont’d Embryo: 23-25 d Yolk sac: 25-28 d
Oblong, echogenic, several mm
Yolk sac: d
U-shaped echogenic structure
Extends across gestational sac
Zonary placenta: 27-30d
Thin hyperechoic layer surrounding gestational sac

14. Fetal Viability Cardiac activity Fetal movement Fetal resorption
Day post LH surge
Fluttering echoes
Fetal movement
Day 35
Fetal resorption
before day 25
Embryonic fluid becomes hypoechoic
Echogenic particles
Abortion
After day 35
Sonographic appearance disappears

15. Organogenesis (From Nyland & Mattoon)
Fetal Structure
Days Post LH Surge
Fetal orientation 28
Limb buds 35
Skeleton
33-39
Stomach, bladder
35-39
Lungs
38-42
Kidneys, eyes
39-47
Cardiac chambers 40
Intestines
57-63

16. Prostate Caudal to bladder, at level of trigone
Ventral to rectum
Normal appearance varies
Age
Neuter status
Young to middle age intact male:
homogenous, moderate echogenicity
Smooth margins, hyperechoic rim
Prostatic urethra
Hypoechoic to anechoic round structure on midline

17. Prostate Diseases Benign Prostatic Hyperplasia Prostatitis
Older intact dogs
Symmetrical enlargement
May be up to 4 times normal
Variable echogenicity and texture
Prostatitis
Acute or chronic
Symmetrical or asymmetrical
Heterogenous appearance
May see hypoechoic areas (cyst or abscess)
Mineralization, fibrosis

18. Prostate Diseases Neoplasia Cysts Paraprostatic Cysts
Older neutered dogs
Enlarged
Irregular shape
Texture varies
Hyperechoic foci with acoustic shadowing = mineralization
May see cyst-like lesions
Examine surrounding structures!
Cysts
Developmental or congenital
Anechoic contents
Thin hyperechoic wall
Vary in size and #
Paraprostatic Cysts
Muellerian duct remnant or extension of lobe
Anechoic, fluid filled
May see swirlies
Variable wall thickness
May see compartments

19. Prostatic Cyst

20. Testes Homogenous texture Parietal and visceral tunics:
hyperechoic
Mediastinum testis:
Echogenic linear structure on midline
Tail of the epididymis
Nearly anechoic
Coarse echotexture

21. Testicular Neoplasia Interstitial, Sertoli cell, seminoma
May all appear the same
Mixed appearance on U/S
Hemorrhage
Necrosis
May obliterate mediastinum testis +/- epididymis

22. Testes-cont’d Retained testes Orchitis Small size
Caudal to kidneys to inguinal canal
Difficult to see on U/S
Orchitis
Patchy, hypoechoic parenchyma
Hyperechoic if chronic
Epididymal enlargement
Abscesses
Irregular shaped
Hypoechoic contents
May look like neoplasia!