Use of dual-phase contrast computed tomography for evaluation of the normal canine male genital tract

Computed tomographic features of canine prostatic carcinoma

Canine prostatic carcinoma (PC) has incompletely defined CT features. The purpose of this multicenter retrospective case series was to assess prostatic, regional, and distant findings of PC. Thirty dogs were enrolled. Consistent prostatic features included postcontrast heterogeneity with hypoattenuating, nonenhancing areas (30/30), capsular distortion (29/30), prostatic urethral effacement, displacement, or invasion (28/30), precontrast heterogeneity (27/30), and mineralization (24/30) which was always within or at the margin of the hypoattenuating areas. Consistent extraprostatic features included medial iliac lymph node enlargement (20/30), internal iliac lymph node enlargement (15/30), and periprostatic fat streaking or fluid (15/29). In a minority of dogs, there was lymph node mineralization, bladder trigone invasion, ureteral dilation, ductus deferens invasion, and bony changes consistent with hypertrophic osteopathy. Strongly suspected and potential bony metastases were noted infrequently (8/26), all in vertebrae regional to the prostate. In conclusion, these findings provide guidance on the expected CT features of canine PC.

Intra- and Inter-observer Variability of Computed Tomographic Measurements of the Prostate Gland in Neutered Dogs

The purpose of this study was to evaluate the intra- and inter-observer variability of computed tomographic measurements of linear prostate dimensions in neutered dogs without signs of prostatic disease, to determine potential associations between prostatic parameters and body weight or age and to provide reference ranges. Length, width and height of the prostate gland were measured in 62 neutered dogs with no signs of prostatic disease by three observers with different levels of training. Statistically significant positive associations were found between all prostatic parameters and body weight and between all prostatic parameters and age at castration, but not with age. Formulae allowing the calculation of the expected values for prostatic parameters based on body weight are provided [length = 15.3 + body weight (BW) × 0.3; height = 9.7 + BW × 0.16; width = 9.5 + BW × 0.2]. These may represent a useful tool for computed tomographic evaluation of the size of the prostate in neutered dogs. Subjective evaluations of the morphological appearance of the prostate gland are also provided.

Urodynamic and morphometric characteristics of the lower urogenital tract of male Beagle littermates from four months to two years of age

OBJECTIVE

To describe functional and anatomic changes of the lower urogenital tract of healthy male dogs during the sexually immature period and up to 2 years of age by urodynamic and morphometric assessment.

ANIMALS

6 sexually intact male Beagle littermates.

PROCEDURES

Dogs underwent electromyography-coupled urodynamic tests, CT-assisted retrograde urethrography, prostatic washes, and blood sampling monthly from 4 through 12 months of age and then at 3-month intervals. Urodynamic and morphometric variables and serum canine prostate-specific esterase concentrations were analyzed by statistical methods.

RESULTS

Integrated pressure of the urethra was significantly increased beginning at 8 months of age, compared with earlier time points. Urethral pressure peak amplitudes varied among anatomic regions. During bladder filling, few electromyographic signals were concurrent with urethral pressure peaks; these were most commonly detected in the penile portion of the urethra. Urethral length and prostate gland volume were significantly greater from 7 to 24 months of age than at younger ages. Urethral length was approximately 26 to 27 cm after 9 months, and prostate gland volume was approximately 11 to 12 cm³ after 11 months of age. Serum canine prostate-specific esterase concentrations correlated with prostate gland volume. Urinary bladder threshold volume was significantly increased at 6 months of age, compared with that at 4 months, with a maximum of 197.7 mL at 24 months.

CONCLUSIONS AND CLINICAL RELEVANCE

Urethral resistance was acquired at approximately 8 months of age, when growth of the lower urinary tract was incomplete. Electromyographic and integrated pressure measurement results and the distribution and amplitude of urethral pressure peaks highlighted the potential role of the prostate gland and possibly the bulbocavernosus muscles in control of continence.

ANATOMY, HISTOLOGY, AND DIAGNOSTIC IMAGING OF THE REPRODUCTIVE TRACT OF MALE AARDVARK ( ORYCTEROPUS AFER)

The reproductive tracts of three captive male aardvark ( Orycteropus afer) were evaluated to characterize the gross and histological anatomy, with correlations to ultrasonographic and computed tomographic imaging. Observations were made from a reproductive tract examined at necropsy, with subsequent evaluation of tissues histologically. Two living specimens were evaluated via ultrasonography with a 10-MHz linear transducer. One living animal was also evaluated via computed tomography. Prominent external scent glands were present at the base of the prepuce. Testicles were present internally at the level of the inguinal canal and capable of sliding into a subcutaneous position. Accessory sex glands consisted of seminal vesicles, prostate gland, and bulbourethral glands, with histological characteristics similar to other species. Ultrasonography was an effective tool for evaluation of internal and external reproductive structures, while the usefulness of computed tomography was limited in the evaluation of pelvic organs due to artifact from nearby bony structures. While a larger study population is desirable, this report provides an important comparative anatomical reference and will help improve the clinical management and care of this species.