Ultrasound of the Reproductive System: Male Dog

Ultrasonographic examination of male reproductive organs is commonly performed for andrologic evaluation of breeding dogs, localization of retained testicles, difficulties or abnormalities in urination or defecation, abdominal, scrotal, and penile pain or discomfort, caudal abdominal mass lesions, perineal hernia, clinical signs compatible with hormonal imbalances (hyperestrogenism), scrotal or penile trauma, and palpable scrotal abnormalities.
The dog is usually positioned in dorsal recumbency. A 5.0-MHz curvilinear transducer is appropriate in larger dogs but a 7.5- or 10-MHz transducer provides better detail and is recommended for most examinations. The prostate can be readily seen from a transabdominal approach and is located by following the bladder caudally to its terminus. Examination is performed in transverse and sagittal planes. In neutered dogs with an empty or intrapelvic bladder, ultrasonographic assessment of the prostate may identify only a small hypoechoic widening of the urethra ...