Hormonal and vascular changes affecting the canine prostate after castration were investigated to identify the effects of hormones and perfusion on the development of benign prostatic hyperplasia (BPH). Concentrations of serum testosterone and estrogen and intraprostatic dihydrotestosterone (DHT) were compared between 5 normal dogs, 6 dogs with mild BPH, and 6 dogs with marked BPH. In addition, prostatic perfusion using contrast-enhanced ultrasonography (CEUS) and CT perfusion (CTP), as well as CT volumes of the prostates were compared. The changes in these values following castration were assessed in 6 dogs with marked BPH. CEUS revealed significantly slower prostatic arterial inflow and relatively faster venous outflow in BPH versus normal prostate. Permeability and blood volume were not significantly different between the groups via CTP. Intraprostatic DHT level was higher in BPH than in normal prostate and decreased significantly following castration, which was accompanied by a rapid decrease in prostatic volume. On CEUS, arterial inflow to the prostate significantly decreased following castration. Blood volume within the prostate decreased significantly by day 60 following castration. Permeability increased significantly during the early phase after castration; however, by day 60 post-castration, all perfusion parameters decreased significantly. Perfusion changes including venous parameters measured by CEUS and blood volume changes measured by CTP, however, did not support the backflow theory postulating that BPH is induced by vascular changes from congested testes. The major etiology for the development of BPH is attributed to be increased levels of DHT rather than vascular changes.

中文翻译：

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犬模型阉割前后良性前列腺增生的灌注变化：对比增强超声和 CT 灌注研究

研究了影响阉割后犬前列腺的激素和血管变化，以确定激素和灌注对良性前列腺增生 (BPH) 发展的影响。比较了 5 只正常犬、6 只轻度 BPH 犬和 6 只显着 BPH 犬的血清睾酮和雌激素以及前列腺内双氢睾酮 (DHT) 的浓度。此外，还比较了使用对比增强超声 (CEUS) 和 CT 灌注 (CTP) 的前列腺灌注，以及前列腺的 CT 体积。在 6 只具有显着 BPH 的狗中评估了阉割后这些值的变化。CEUS 显示 BPH 与正常前列腺相比，前列腺动脉流入显着减慢，静脉流出相对较快。通过 CTP，各组之间的渗透性和血容量没有显着差异。BPH 中前列腺内 DHT 水平高于正常前列腺，去势后显着下降，伴随着前列腺体积的迅速减少。在 CEUS 上，去势后前列腺的动脉流入显着减少。到阉割后第 60 天，前列腺内的血容量显着下降。去势后早期渗透率显着增加；然而，到阉割后第 60 天，所有灌注参数都显着下降。然而，灌注变化，包括由 CEUS 测量的静脉参数和由 CTP 测量的血容量变化，不支持回流理论，假设 BPH 是由充血的睾丸血管变化引起的。