Transrectal ultrasonographic characterization of the accessory sex glands, pelvic urethra, and ureters in normal geldings.

Transrectal ultrasound of the internal urogenital tract may be used to aid in the diagnosis of reproductive tract and urinary tract pathology in both stallions and geldings. Abnormalities of the accessory sex glands of geldings are uncommon, although prostatic masses have recently been described in adult geldings presenting with dysuria, stranguria, and/or hematuria. The purpose of this study was to describe the normal ultrasonographic features and sizes of the accessory sex glands, caudal ureters, and pelvic urethra in clinically normal geldings. Eleven healthy geldings with no history of urogenital tract pathology were evaluated by a single observer experienced in ultrasound of the stallion accessory sex glands. The ultrasonographic appearance, relative anatomic relationships and sizes of the accessory sex glands, caudal ureters, and pelvic urethra were investigated using both rectal linear array and microconvex array transducers. Summary statistics including mean, standard error, confidence intervals, and range were calculated for each structure. There were no statistically significant differences in measurements between the left and right sides of paired structures or between measurements obtained with different transducers. Fluid was present in the seminal vesicles of 7 of 9 subjects. Midline cysts of the urethra as well as bulbourethral gland and prostatic cysts were identified. The normal reference ranges defined in this study will be useful in the clinical evaluation of geldings with suspected internal urogenital tract pathology.