Extraglandular and intraglandular vascularization of canine prostate

Computed Tomographic Analysis of the Anatomical Characteristics of the Canine Prostatic Artery and Development of a Three-Dimensional Canine Prostate Cancer Model for Simulation of Prostatic Artery Embolization

The prognosis of prostate cancer in male dogs is considered poor to grave, and prostatic artery embolization (PAE) has been proposed as an alternative to traditional treatment options. This study analyzed the anatomical characteristics of the prostatic artery using computed tomographic (CT) angiography and developed a three-dimensional (3D)-printed prostate cancer model for PAE training. Computed tomographic images from 37 control dogs and 14 prostate cancer dogs were analyzed, with 102 pelvic sides classified into three types: the prostatic arteries originated from the internal pudendal artery in 100, an internal iliac artery in 1, and the umbilical artery in 1. Bodyweight was positively correlated with the diameters of the abdominal aorta and pelvic arteries in both groups. (p <.01). However, the normalized prostatic artery diameter was significantly larger for the prostate cancer group (p <.05). Computed tomography revealed local invasion of the bladder in 11 of the 14 dogs. Of 9 of the 11 dogs with confirmed bladder invasion, the caudal vesical, umbilical, and prostatic arteries were cancer-feeding in 9, 1, and 9, respectively. Based on the CT angiography images, a 3D-printed prostate cancer model was developed using a representative case that was close to the average value of each arterial blood vessel diameter. The model was used to simulate PAE, and successful embolization was confirmed using fluoroscopic guidance. Preprocedural CT angiography is useful for assessing the anatomical characteristics of the prostatic artery, and the 3D-printed prostate cancer model demonstrated the feasibility of PAE simulation.

Multispecies comparative prostate anatomy by imaging: Implications for experimental models of prostatic disease

BACKGROUND

There is an increasing interest in using preclinical models for development and assessment of medical devices and imaging techniques for prostatic disease care. Still, a comprehensive assessment of the prostate's radiological anatomy in primary preclinical models such as dogs, rabbits, and mice utilizing human anatomy as a reference point remains necessary with no optimal model for each purpose being clearly defined in the literature. Therefore, this study compares the anatomical characteristics of different animal models to the human prostatic gland from the imaging perspective.

METHODS

We imaged five Beagle laboratory dogs, five New Zealand White rabbits, and five mice, all sexually mature males, under Institutional Animal Care and Use Committee (IACUC) approval. Ultrasonography (US) was performed using the Vevo® F2 for mice (57 MHz probe). Rabbits and dogs were imaged using the Siemens® Acuson S3000 (17 MHz probe) and endocavitary (8 MHz) probes, respectively. Magnetic resonance imaging (MRI) was also conducted with a 7T scanner in mice and 3T scanner in rabbits and dogs.

RESULTS

Canine transrectal US emerged as the optimal method for US imaging, depicting a morphologically similar gland to humans but lacking echoic zonal differentiation. MRI findings in canines indicated a homogeneously structured gland similar to the human peripheral zone on T2-weighted images (T2W) and apparent diffusion coefficient (ADC). In rabbits, US imaging faced challenges due to the pubic symphysis, whereas MRI effectively visualized all structures with the prostate presenting a similar aspect to the human peripheral gland on T2W and ADC maps. Murine prostate assessment revealed poor visualization of the prostate glands in ultrasound due to its small size, while 7T MRI delineated the distinct prostates and its lobes, with the lateral and dorsal prostate resembling the peripheral zone and the anterior prostate the central zone of the human gland.

CONCLUSION

Dogs stand out as superior models for advanced preclinical studies in prostatic disease research. However, mice present as a good model for early stage studies and rabbits are a cost-effective alternative and serve as valuable tools in specific research domains when canine research is not feasible.

Yttrium-90 Radioembolization to the Prostate Gland: Proof of Concept in a Canine Model and Clinical Translation

PURPOSE

To investigate the feasibility, safety, and absorbed-dose distribution of prostatic artery radioembolization (RE) in a canine model.

MATERIALS AND METHODS

Fourteen male castrated beagles received dihydroandrosterone/estradiol to induce prostatic hyperplasia for the duration of the study. Each dog underwent fluoroscopic prostatic artery catheterization. Yttrium-90 (⁹⁰Y) microspheres (TheraSphere; Boston Scientific, Marlborough, Massachusetts) were delivered to 1 prostatic hemigland (dose escalation from 60 to 200 Gy), with the contralateral side serving as a control. Assessments for adverse events were performed throughout the follow-up (Common Terminology Criteria for Adverse Events v5.0). Positron emission tomography/magnetic resonance (MR) imaging provided a confirmation after the delivery of absorbed-dose distribution. MR imaging was performed before and 3, 20, and 40 days after RE. Tissue harvest of the prostate, rectum, bladder, urethra, penis, and neurovascular bundles was performed 60 days after RE.

RESULTS

All the animals successfully underwent RE. Positron emission tomography/MR imaging demonstrated localization to and good coverage of only the treated hemigland. No adverse events occurred. The MR imaging showed a significant dose-dependent decrease in the treated hemigland size at 40 days (25%-60%, P < .001). No extraprostatic radiographic changes were observed. Necropsy demonstrated no gross rectal, urethral, penile, or bladder changes. Histology revealed RE-induced changes in the treated prostatic tissues of the highest dose group, with gland atrophy and focal necrosis. No extraprostatic RE-related histologic findings were observed.

CONCLUSIONS

Prostate ⁹⁰Y RE is safe and feasible in a canine model and leads to focal dose-dependent changes in the gland without inducing unwanted extraprostatic effects. These results suggest that an investigation of nonoperative prostate cancer is warranted.

Endocrine, prostatic vascular, and proapoptotic changes in dogs with benign prostatic hyperplasia treated medically or surgically

Benign prostatic hyperplasia (BPH) is a disorder related to hormone imbalance, local angiogenesis, and prostate growth, which can be treated surgically (orchiectomy) or medically (most commonly with finasteride). However, finasteride therapy is not completely established in dogs regarding local action and posology. This study aimed to evaluate the effect of different doses of finasteride and orchiectomy on hormonal profile, prostate apoptosis, blood flow, and biometry in dogs with BPH. Dogs were assigned to the following groups: untreated, 0.1 mg, 0.2 mg, and 0.5 mg/kg/d of finasteride and orchiectomy. All dogs were assessed monthly: day 0 (before treatment), day 30, and day 60 and subjected to prostate B-mode and Doppler ultrasonography and hormonal analysis (testosterone and dihydrotestosterone). After 60 d, prostatic biopsy was performed for histology and immunohistochemical evaluation for apoptosis (caspase-3). On day 60, percentage reduction of prostatic volume was greater in orchiectomized dogs than that in finasteride groups, which, conversely, was greater than untreated dogs. On day 60, 0.2-mg finasteride, 0.5-mg finasteride, and orchiectomy groups had higher prostatic blood flow than 0.1-mg finasteride and untreated groups. In addition, both 0.5-mg finasteride and orchiectomy groups had an increase in prostate artery resistance. Orchiectomy significantly decreased androgen concentrations at 30 d onward, differing from the remaining groups. The orchiectomy group had lower caspase-3 immunostaining, however, not different from untreated and 0.5-mg finasteride. In conclusion, 0.5 mg/kg finasteride promoted more effective prostate apoptosis and hemodynamic effects among medical treatments, whereas orchiectomy caused prostate atrophy and sharp endocrine changes in dogs with BPH.

Reproductive and endocrinological effects of Benign Prostatic Hyperplasia and finasteride therapy in dogs

Benign prostatic hyperplasia (BPH) is one of the most important reproductive disorders in aging dogs. Therapeutic measures include orchiectomy and pharmacological treatment, leading to reduction of prostate volume and clinical signs. One of the most common drugs used in BPH treatment is finasteride, but data regarding its possible side effects are scarce. Thus, the aim of this study was to evaluate the effects of BPH and short-term (2 months) finasteride therapy on clinical, endocrinological, and reproductive parameters in dogs. Dogs were allocated into four experimental groups: Non-affected (n = 5), BPH (n = 5), Non-Affected-Finasteride (n = 5) and BPH-Finasteride (n = 5) groups. Dogs were evaluated monthly during 2 months by a complete breeding soundness examination, B-mode ultrasound and Doppler ultrasonography of the testicular artery, hormonal profile (testosterone, estrogen and dihydrotestosterone) and oxidative profile of the prostatic fluid. After 2 months, dogs were gonadectomized and testicles were subjected to histologic analysis. Finasteride treatment reduced dihydrotestosterone concentrations, without negative influence on semen quality and also reverted testicular hemodynamics changes of BPH. On the other hand, BPH was accompanied by significant changes in testosterone and estrogen concentrations and semen quality, mainly related to sperm kinetics alterations. In conclusion, BPH dogs have important hormonal and sperm alterations, however, short-term finasteride treatment (2 months) was able to reduce overall effects of BPH, thus representing a method of therapy for BPH treatment.

Perfusion change in benign prostatic hyperplasia before and after castration in a canine model: Contrast enhanced ultrasonography and CT perfusion study

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.

Prostatic hyperplasia: Vascularization, hemodynamic and hormonal analysis of dogs treated with finasteride or orchiectomy

As a consequence of a hormonal imbalance, Prostatic Hyperplasia (PH) is characterized by increased prostate volume, along with higher local angiogenesis and vascularization. Orchiectomy is the common treatment for dogs, however it is not an option for breeding animals. Thus, finasteride arises as the drug of choice for stud dogs. Therefore, the aim of this study was to evaluate the effects of orchiectomy or finasteride therapies on hormonal and vascular dynamics of PH dogs. Fifteen dogs, aged 6–13 years were assigned to: Untreated Group (dogs diagnosed with PH—n = 5), Finasteride treated group (PH dogs treated with finasteride—n = 5) and Orchiectomy treated group (PH dogs submitted to orchiectomy–n = 5). Evaluations were performed in a monthly interval (first day of treatment; after 30 and 60 days). Doppler ultrasonography was performed to measure prostatic volume, vascularization and hemodynamic profile of prostatic artery. Dihydrotestosterone, estrogen and testosterone concentrations were measured. At day 60, prostatic biopsy was performed for histological, immunohistochemical and qPCR analysis for VEGF-A expression. At day 60, vascularization score was higher in untreated compared to treated groups (finasteride and orchiectomy). Furthermore, VEGF-A expression was lower in the Orchiectomy Treated Group, but VEGF-A was immunohistochemically lower in both treated groups (finasteride and orchiectomy) compared to the Untreated Group. The efficiency of finasteride treatment in reducing clinical signs, prostate volume and vascularization appears to be similar to orchiectomy. In conclusion, both PH medical and surgical therapy lead to reduction in prostate dimension and VEGF-A expression and, consequently, lower local vascularization. However, orchiectomy promotes marked hormonal changes, which ultimately lead to prostate atrophy.

The relationship of embolic particle size to patient outcomes in prostate artery embolisation for benign prostatic hyperplasia: a systematic review and meta-regression

AIM

To explore the relationship of embolic particle size used in prostate artery embolisation (PAE) to patient outcomes.

MATERIALS AND METHODS

A systematic review of PubMed, EMBASE, and the Cochrane database was undertaken to identify all existing studies using PAE for benign prostatic hyperplasia (BPH). Inclusion criteria included prospective studies reporting baseline and 12-month International Prostate Symptom Score (IPSS) and particle size. Exclusion criteria were overlapping studies, commentaries, abstracts, and letters. Data extraction from eligible studies included the size of embolic particle, particle material, and baseline and 12-month values for the following patient outcomes: IPSS, IPSS quality of life, urinary flow rate (Q-max), prostate volume, prostate specific antigen, and post-void residual volume. A meta-regression analysis was then undertaken to examine the relationship of particle size to patient outcome measures.

RESULTS

Six studies with a total of 687 patients were identified. Meta-regression analysis demonstrated particle size as a statistically significant (p<0.001) moderator of 12-month IPSS change following PAE. No statistically significant relationships were identified with other patient outcome measures.

CONCLUSION

Smaller embolic particle size is associated with a greater reduction in IPSS following PAE.

Ejaculation effect on blood testosterone and prostatic pulsed-wave Doppler ultrasound in dogs

Local vessels ultrasonography evaluates prostatic physio-pathologic states. Testosterone promotes tissue and vascular growth. Knowing variables on prostatic vasculature is crucial to correctly apply Pulsed-Wave exam. The study aims to assess how ejaculation and blood testosterone affect Pulsed-Wave indexes. Serial blood testosterone dosages and Pulsed-Wave exams were performed in 20 dogs, immediately before (T0) and after (T1) ejaculation and 6 hr later (T2). Arteria prostatica cranialis, Arteriola capsularis, Arteriola trabecularis and Arteriola parenchimalis were evaluated and mean Pulsatility and Resistivity Index, Systolic-Peak, End-Diastolic and Mean Velocity calculated. Data were grouped by time and vessel (ANOVA, p ≤ 0.05). At T1, Resistivity Index significantly lowered in A. prostatica cranialis, A. trabecularis and A. parenchimalis but grew in A. capsularis; Pulsatility Index had the same pattern, but not significant in A. parenchimalis; Systolic Peak Velocity, End-Diastolic Velocity, Mean Velocity significantly rose in A. capsularis and A. trabecularis. No indexes differed at T0 and T2. Testosterone did not differ at T0 (10.93 ± 7.05 ng/ml), T1 (12.71 ± 7.29) and T2 (10.54 ± 6.63). Results stated the risen prostatic vascular flow postejaculation, affecting Pulsed-Wave. Due to semi-rigid capsule, impairing vasodilation of other vessels, only A. capsularis indexes increased. Intimal cushions of A. prostatica cranialis kept velocities fixed; A. capsularis and A. trabecularis lack of intimal cushions, thus velocities grew. In A. parenchimalis, precapillary sphincters opening allows increased flow redistribution in vasodilated parenchymal bed, keeping velocities fixed. As testosterone, not affected by ejaculation, did not peak, vascular changes are not due to testosterone itself. These physiological effects of ejaculation suggest proper sexual rest before Pulsed-Wave exam planned to explore suspected prostatic neovascularization.

Canine prostate models in preclinical studies of minimally invasive interventions: part I, canine prostate anatomy and prostate cancer models

The high prevalence of prostate cancer (PCa) in elderly men and technical advances in early detection of localized PCa have led to continued efforts to develop new therapeutic options of minimally invasive nature in current urologic oncology community. Increasing newly emerging therapies are undergoing preclinical tests on the technical feasibility, efficacy and safety in animal experiments. The dog is an ideal large animal because of its similar anatomy to human and the capability allowing the use of the same medical devices applied in future clinical trials. Awareness of the local anatomy, microvascular structure, and histological features of the prostate in dogs is essential to experimental design and performance of the tested procedures and techniques. Although dogs with spontaneous PCa may be used in preclinical investigation, the low incidence and pathological features limit its utility. Alternatively, canine orthotopic PCa models have a great potential in preclinical research for this purpose. The goal of this review is to provide detailed anatomic and histological information of the canine prostate, outline the pathological and clinical characteristics of spontaneous PCa in dogs and discuss the current status of canine orthotopic PCa models.

Prostatic Arterial Embolization with Small Sized Particles for the Treatment of Lower Urinary Tract Symptoms Due to Large Benign Prostatic Hyperplasia: Preliminary Results

Background:

The clinical failure after prostatic artery embolization (PAE) with conventional particles was relatively high, in treatment for lower urinary tract symptoms (LUTS) due to benign prostatic hyperplasia (BPH). We reported the results of PAE with combined polyvinyl alcohol particles 50 μm and 100 μm in size as a primary treatment in 24 patients with severe LUTS secondary to large BPH.

Methods:

From July 2012 to June 2014, we performed PAE in 24 patients (65–85 years, mean 74.5 years) with severe LUTS due to large BPH (≥80 cm³) and refractory to medical therapy. Embolization was performed using combination of 50 μm and 100 μm in particles size. Clinical follow-up was performed using the International Prostate Symptom Score (IPSS), quality of life (QoL), peak urinary flow (Q_max), postvoid residual (PVR) volume, the International Index of Erectile Function (IIEF), prostatic specific antigen (PSA), and prostatic volume measured by magnetic resonance imaging at 1, 3, 6, and every 6-month thereafter. Technical success was defined when PAE was completed in at least one pelvic side. Clinical success was defined as the improvement of both symptoms and QoL. A Student's t-test for paired samples was used.

Results:

PAE was technically successful in 22 patients (92%). Bilateral PAE was performed in 19 (86%) patients and unilateral in 3 (14%) patients. Follow-up data were available for 22 patients observed for mean of 14 months. The clinical improvement at 1, 3, 6, and 12-month was 91%, 91%, 88%, and 83%, respectively. At 6-month follow-up, the mean IPSS, QoL, PVR, and Q_max were from 27 to 8 (P = 0.001), from 4.5 to 2.0 (P = 0.002), from 140.0 ml to 55.0 ml (P = 0.002), and from 6.0 ml/s to 13.0 ml/s (P = 0.001), respectively. The mean prostate volume decreased from 110 cm³ to 67.0 cm³ (mean reduction of 39.1%; P = 0.001). The PSA and IIEF improvements after PAE did not differ from pre-PAE significantly. No major adverse events were noted.

Conclusions:

The combination of 50 μm and 100 μm particles for PAE is a safe and effective treatment method for patients with severe LUTS due to large BPH, which further improves the clinical results of PAE.

Prostatic arterial embolization for the treatment of lower urinary tract symptoms as a result of large benign prostatic hyperplasia: A prospective single-center investigation

OBJECTIVE

To evaluate the effectiveness and safety of prostatic arterial embolization as a primary treatment for patients with lower urinary tract symptoms as a result of large benign prostatic hyperplasia.

METHODS

A total of 64 patients with prostates >80 mL were included in the study. Prostatic arterial embolization was carried out using a combination of 50-µm and 100-µm particles. Clinical follow up was carried out using the International Prostate Symptom Score, quality of life, peak urinary flow, postvoid residual volume, International Index of Erectile Function Short Form, prostate-specific antigen, and prostatic volume at 1, 3, 6 and every 6 months thereafter.

RESULTS

Prostatic arterial embolization was technically successful in 60 of 64 patients (93.8%). Follow-up data were available for 60 patients with a mean of 18 months. A clinical improvement, defined as reduction of International Prostate Symptom Score and increase of peak urinary flow, at 1 month, 3 months, 6 months, 12 months and 24 months, was achieved in 95.0%, 95.0%, 93.3%, 92.6% and 90.5%, respectively. A total of 42 patients had completed the follow up at 24 months after prostatic arterial embolization. There was an improvement in terms of mean International Prostate Symptom Score (pre-prostatic arterial embolization vs post-prostatic arterial embolization 27.0 vs 8.0; P < 0.01), mean quality of life (5.5 vs 2.0; P < 0.01), mean peak urinary flow (7.0 vs 13.0; P < 0.01), mean postvoid residual volume (130 vs 45.0; P < 0.05) and prostatic volume (121.0 vs 71.5, reduction of 40.9%; P < 0.01) were significantly different with respect to baseline.

CONCLUSION

Prostatic arterial embolization seems to be a safe and effective treatment method for patients with lower urinary tract symptoms as a result of large benign prostatic hyperplasia, and it might play an important role for patients in whom medical therapy has failed, who are not candidates for surgical treatment.

Prostatic arterial embolization for the treatment of lower urinary tract symptoms due to large (>80 mL) benign prostatic hyperplasia: results of midterm follow-up from Chinese population

BACKGROUND

Currently, large prostate size (>80 mL) of benign prostatic hyperplasia (BPH) still pose technical challenges for surgical treatment. This prospective study was designed to explore the safety and efficacy of prostatic arterial embolization (PAE) as an alternative treatment for patients with lower urinary tract symptoms (LUTS) due to largeBPH.

METHODS

A total of 117 patients with prostates >80 mL were included in the study; all were failure of medical treatment and unsuited for surgery. PAE was performed using combination of 50-μm and 100-μm particles in size, under local anaesthesia by a unilateral femoral approach. Clinical follow-up was performed using the international prostate symptoms score (IPSS), quality of life (QoL), peak urinary flow (Qmax), post-void residual volume (PVR), international index of erectile function short form (IIEF-5), prostatic specific antigen (PSA) and prostatic volume (PV) measured by magnetic resonance (MR) imaging, at 1, 3, 6 and every 6 months thereafter.

RESULTS

The prostatic artery origins in this study population were different from previously published results. PAE was technically successful in 109 of 117 patients (93.2%). Follow-up data were available for the 105 patients with a mean follow-up of 24 months. The clinical improvements in IPSS, QoL, Qmax, PVR, and PV at 1, 3, 6, 12, and 24 months was 94.3%, 94.3%, 93.3%, 92.6%, and 91.7%, respectively. The mean IPSS (pre-PAE vs post-PAE 26.0 vs 9.0; P < .0.01), the mean QoL (5.0 vs 3.0; P < 0.01), the mean Qmax (8.5 vs 14.5; P < 0.01), the mean PVR (125.0 vs 40.0; P < 0.01), and PV (118.0 vs 69.0, with a mean reduction of 41.5%; P < 0.01 ) at 24-month after PAE were significantly different with respect to baseline. The mean IIEF-5 was not statistically different from baseline. No major complications were noted.

CONCLUSIONS

PAE is a safe and effective treatment method for patients with LUTS due to large volume BPH. PAE may play an important role in patients in whom medical therapy has failed, who are not candidates for open surgery or TURP or refuse any surgical treatment.

Effect of pulsed electromagnetic field therapy on prostate volume and vascularity in the treatment of benign prostatic hyperplasia: a pilot study in a canine model

BACKGROUND

Benign prostatic hyperplasia (BPH) is a result of urogenital aging. Recent studies suggest that an age-related impairment of the blood supply to the lower urinary tract plays a role in the development of BPH and thus may be a contributing factor in the pathogenesis of BPH. The canine prostate is a model for understanding abnormal growth of the human prostate gland. We studied the efficacy of pulsed electromagnetic field therapy (PEMF) in dogs to modify prostate blood flow and evaluated its effect on BPH.

METHODS

PEMF (5 min, twice a day for 3 weeks) was performed on 20 dogs affected by BPH. Prostatic volume, Doppler assessment by ultrasonography, libido, semen quality, testosterone levels, and seminal plasma volume, composition and pH were evaluated before and after treatment.

RESULTS

The 3 weeks of PEMF produced a significant reduction in prostatic volume (average 57%) without any interference with semen quality, testosterone levels or libido. Doppler parameters showed a reduction of peripheral resistances and a progressive reduction throughout the trial of the systolic peak velocity, end-diastolic velocity, mean velocity, mean, and peak gradient of the blood flow in the dorsal branch of the prostatic artery. The pulsatility index and the resistance index did not vary significantly over time.

CONCLUSIONS

The efficacy of PEMF on BPH in dogs, with no side effects, suggests the suitability of this treatment in humans and supports the hypothesis that impairment of blood supply to the lower urinary tract may be a causative factor in the development of BPH.

Embolization therapy for benign prostatic hyperplasia: influence of embolization particle size on gland perfusion

PURPOSE

To assess the influence of embolic size on the therapy response of prostatic arterial embolization (PAE) based on perfusional changes seen on dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Twelve beagles underwent PAE, four dogs with each particle size: A: 100-300 μm; B: 300-500 μm; and C: 500-700 μm. Prior to and 1 month after the embolization all dogs underwent prostate DCE MRI.

RESULTS

After embolization, time to maximal perfusion intensity for prostate parenchyma increased in B (188 vs. 135 sec, P = 0.023) and C (200 vs. 120 sec, P = 0.001), while it did not change for A (139 vs. 124 sec, P = 0.39). The maximal relative intensity increased after embolization in C (3.84 vs. 2.38, P < 0.001), while it did not change for A (2.50 vs. 2.44, P = 0.36) and B (3.23 vs. 2.9, P = 0.21). The extent of visualized intraprostatic urethral wall increased after embolization in B compared with A and C, 239.5 ± 138.1% vs. 56.1 ± 34.3, P = 0.04. Enhancement changes correlated with prostate volume changes: prostate volumes in A decreased less as compared with B and C (77 ± 34% vs. 56 ± 14%), P = 0.02.

CONCLUSION

The enhancement and morphological data are useful to monitor response to therapy after embolization. Embolization with 300-500 and 500-700 μm particle may provide better results than with 100-300 μm particles in a canine model.