Comparative Analysis of Cone-Beam CT Angiogram and Conventional CT Angiogram for Prostatic Artery Identification Prior to Embolization

Benefits and advances of Cone Beam CT use in prostatic artery embolization: review of the literature and pictorial essay

Prostatic artery embolization (PAE) has proven to be an efficacious treatment for urinary symptoms of benign prostatic hyperplasia. PAE is performed in a complex and challenging anatomical field which may pose difficulties from procedural standpoint. Cone beam computed tomography (CBCT) has been proposed as an invaluable tool during the PAE procedure. A review of different techniques and advancements, as well as demonstration of CBCT benefits via a pictorial overview of the salient examples is lacking. The techniques of CBCT are discussed herein and the virtual injection technology as an advancement in CBCT is discussed. To show the merits of CBCT in PAE, a pictorial overview of various clinical scenarios is presented where CBCT can be crucial in decision making. These scenarios are aimed at showing different benefits including identification of the origin of the prostatic artery and avoiding non-target embolization. Other benefits may include ensuring complete embolization of entire prostate gland as angiographic appearance alone can be inconclusive if it mimics a severely thickened bladder wall or ensuring adequate embolization of the median lobe to provide relief from "ball-valve" effect. Further examples include verification of embolization of the entire prostate when rare variants or multiple (> 2) arterial feeders are present.

PAE planning: Radiation exposure and image quality of CT and CBCT

PURPOSE

To determine accurate organ doses, effective doses, and image quality of computed tomography (CT) compared with cone beam CT (CBCT) for correct identification of prostatic arteries.

METHOD

A dual-energy CT scanner and a flat-panel angiography system were used. Dose measurements (gallbladder (g), intestine (i), bladder (b), prostate (p), testes (t), active bone marrow of pelvis (bmp) and femura (bmf)) were performed using an anthropomorphic phantom with 65 thermoluminescent dosimeters in the pelvis and abdomen region. For the calculation of the contrast-to-noise ratio (CNR) of the pelvic arteries, a patient whose weight and height were almost identical to those of the phantom was selected for each examination type.

RESULTS

The effective dose of CT was 2.7 mSv and that of CBCT was 21.8 mSv. Phantom organ doses were lower for CT than for CBCT in all organs except the testes (g: 1.2 mGy vs. 3.3 mGy, i: 5.8 mGy vs. 23.9 mGy, b: 6.9 mGy vs. 19.4 mGy, p: 6.4 mGy vs. 13.2 mGy, t: 4.7 mGy vs. 2.4 mGy, bmp: 5.1 mGy vs. 18.2 mGy, bmf: 3.3 mGy vs. 6.6 mGy). For human pelvic arteries, the CNR of CT was better than that of CBCT, with the exception of one prostate artery that showed stenosis on CT. Evaluation by experienced radiologists also confirmed the better detectability of prostate arteries on CT examination.

CONCLUSIONS

In our study preprocedural CT had lower organ doses and better image quality comparedd with CBCT and should be considered for the correct identification of prostatic arteries.

Prostatic Arterial Embolization for Treatment of Lower Urinary Tract Symptoms Associated with Benign Prostatic Enlargement

PURPOSE OF REVIEW

Prostatic artery embolization (PAE) is an emerging minimally invasive technique for lower urinary tract symptom reduction from benign prostatic hypertrophy (BPH). While the technique is becoming increasingly popular with patients and interventional radiologists, most urologists remain skeptical of the PAE's long-term efficacy and comparative success to the gold standard transurethral resection of the prostate.

RECENT FINDINGS

PAE has been found in multiple meta-analyses to perform similarly to the gold standard transurethral resection of the prostate (TURP) with regard to patient-driven measures like IPSS and IPSS-QoL, while also performing favorably in objective measurements including Qmax and PVR out to at least 12 months post intervention. Furthermore, PAE has a demonstrated shorter hospital length of stay and fewer adverse events when compared to TURP. PAE provides patients with an alternative to transurethral options for the management of LUTS in the setting of bladder outlet obstruction. While long-term evidence demonstrating the durability of PAE is still forthcoming, the procedure has been demonstrated to be safe according to multiple meta-analyses. Patients deserve to be counseled on PAE as an alternative to surgery and made aware that while the overall treatment effect may not be as robust or durable, the procedure carries a favorable adverse event profile that is attractive to patients wishing to avoid a trans-urethral approach.

Contrast-enhanced magnetic resonance angiography in the identification of prostatic arterial anatomy in patients with benign prostatic hyperplasia: prospective comparison with digital subtraction angiography

AIM

To evaluate the utility of contrast-enhanced magnetic resonance angiography (CE-MRA) for identifying prostatic artery (PA) anatomy in patients with benign prostatic hyperplasia (BPH) before PA embolisation (PAE), using digital subtraction angiography (DSA) as the reference standard.

MATERIALS AND METHODS

A total of 176 patients underwent pelvic CE-MRA at 3 T. DSA was performed within the following 7 days. Two interventional radiologists compared the CE-MRA findings with DSA findings to assess the anatomy of the PAs. The rates of correct identification of the origins and collaterals of the PAs by CE-MRA were calculated. The utility for predicting the optimal X-ray tube angle obliquity for visualising the origins of the PAs by CE-MRA was evaluated. An exact McNemar's test was used to compare the detection rates of the PAs and the collaterals with DSA versus CE-MRA. A two-sided p-value of <0.05 was considered statistically significant.

RESULTS

Of the 376 PAs identified by DSA, CE-MRA correctly identified the origins of 369 vessels (98.1%), with a 1.9% false-negative rate and no false-positive results. Of the 57 total collaterals identified by DSA, CE-MRA identified 50 vessels correctly (87.7%), with a 12.3% false-negative rate and no false-positive results. No significant differences were observed between CE-MRA and DSA in the identification of the PA origins (p=0.824) and the collaterals (p=0.327). The optimal degree for an oblique projection to visualise the origins of the PAs could be predicted accurately (100%) by pre-procedural CE-MRA.

CONCLUSION

CE-MRA before PAE can reliably predict the PA anatomy and facilitate procedural planning.

Controversies in Prostate Artery Embolization: Future Best Practice

Prevalence of lower urinary tract symptoms secondary to benign prostatic hyperplasia is correlated with age. Men seeking treatment options with a low side effect profile often turn to prostate artery embolization (PAE). PAE continues to be refined with advanced tools and optimized techniques. Nonetheless, there exist controversies in terms of best practices for the management of lower urinary track symptoms (LUTS) with PAE. These controversies are essential for medical progress. Herein we suggest best practices moving forward based on currently available data. Given extensive safety data, we recommend PAE be considered alongside medical management and as a precursor to surgery. Given demonstrated efficacy across gland sizes, PAE can be performed in a single session, ideally in a hybrid angio-CT suite, without preoperative cross-sectional imaging. PAE should be initially performed with 300- to 500-μm size particles, and instead consider exploring other particles and sizes for repeat PAE. Finally, PAE can also be considered as first-line option for recurrent disease given the efficacy and excellent safety profile. This article is not meant to purport a dogma, but rather to serve as a guide to the experienced practitioner in challenging his or her own biases when performing PAE.

Updates on Preprocedural Evaluation and Patient Selection for Prostatic Artery Embolization

Prostatic artery embolization (PAE) is a safe and effective treatment for benign prostatic hyperplasia. Patient evaluation is a critical and important part of this growing practice. History taking should include symptoms score evaluations for lower urinary tract symptoms, erectile function, and prostatitis symptoms score. The objective evaluations commonly include measurement of prostate specific antigen, postvoid residual volume, and uroflowmetry as well as urodynamic studies in selective patients. Imaging evaluation may include computed tomography angiography or magnetic resonance angiography, elucidating prostate volume, prostate gland morphology, vasculature, and prostate cancer. With evolving knowledge on PAE, we aim to discuss patient evaluation and selection based on updated evidence and discuss specific scenarios.

Cone Beam CT with Automatic vessel Detection Software versus Conventional 2D Fluoroscopy with Overlay for Prostate Artery Embolization: A Comparison of Prostatic Artery Catheterization Time and Radiation Exposure

Purpose To evaluate the effect of cone-beam computed tomography (CT) with automatic vessel detection software on prostate artery catheterization and fluoroscopy time in prostate artery embolization (PAE).

Methods Fifty patients undergoing PAE for BPH were enrolled in this prospective study. Twenty-five PAEs were performed using automatic vessel detection software with syngo embolization guidance (study) and were compared with 25 PAEs performed using conventional two-dimensional (2D) fluoroscopy with overlay (control). PAE was performed using 300–500 μm trisacryl gelatin spherical particles. The primary outcome parameters were prostatic artery catheterization time and fluoroscopy time.

Results Bilateral PAE was achieved in 24/25 cases in both groups. The median right and left prostatic artery catheterization times were similar between the two groups, (p = 0.473 and p = 0.659, respectively). The median fluoroscopy time (28.0 and 42.0 minutes, p = 0.046) and total procedure time (70.0 and 118.0 minutes, p < 0.001) were shorter in the study group. The median total dose area product (DAP) was not significantly different. However, the median CBCT DAP (11406 vs. 6248, p < 0.001) was higher in the study group, while median fluoroscopy DAP (7371 vs. 8426, p < .049) was higher in the control group. Median digital subtraction angiography (DSA), CBCT, and fluoroscopy DAP accounted for 27%, 45%, and 29% of the total DAP in the study group and 32%, 29%, and 39% in the control group (p < 0.001), respectively. All complications were Clavien–Dindo Grade 1.

Conclusion Although CBCT with automatic vessel detection software had no significant effect on time-to-prostatic artery catheterization and total radiation exposure, it reduced the fluoroscopy time and procedure time.

Single-Center Retrospective Comparative Study Evaluating the Benefit of Computed Tomography Angiography Prior to Prostatic Artery Embolization

PURPOSE

To explore whether a computed tomography angiography (CTA) of the pelvis prior to prostatic artery embolization (PAE) is a beneficial preprocedural planning tool regarding the technical success.

MATERIALS AND METHODS

Eighty patients with lower urinary tract symptoms treated with PAE were analyzed retrospectively. Forty of these patients received a CTA of the pelvis prior to the procedure (Group A) and were compared to 40 patients who were treated with PAE without prior CT imaging (Group B). Technical success rate, rate of complications, fluoroscopy time (FT), and mean dose area product (DAP) were assessed and compared. All operators performed at least 50 PAE prior to this study. When needed, cone-beam CT (CBCT) was available during intervention.

RESULTS

Mean age was 68.43 ± 8.30 years in Group A and 70.42 ± 7.11 years in Group B (p = 0.252). Mean body mass index was 26.78 ± 3.73 in Group A and 26.85 ± 3.5 in Group B (p = 0.319). Overall technical success was 96.3%. Bilateral PAE was achieved in 60 patients (75.0%) while unilateral PAE was performed in 17 patients (21.3%). Technical failure (no embolization) occurred in two patients of Group A and one patient of Group B. No statistical significance was seen between groups for technical success rate (p = 1.0). Mean DAP was 10,164 × cm² ± 3944 cGy × cm² in Group A and 10,039 × cm² ± 3761 cGy × cm² in Group B (p = 0.885). Mean FT was 49.27 ± 22.97 min in Group A and 44.32 ± 17.82 min in Group B (p = 0.285). No intervention-related complications during PAE were reported.

CONCLUSION

With experienced interventionalists and CBCT available during PAE, preprocedural CTA has no additional benefit for technical outcome.

Prostatic Artery Embolization for Benign Prostatic Hyperplasia—A Primer for Interventional Radiologists

Male patients over 50 years with lower urinary tract symptoms (LUTS) and benign prostatic hyperplasia (BPH) are potential candidates for prostatic artery embolization (PAE). PAE is not a perfect fit for all BPH patients. Careful pre- and postpostprocedural evaluation/consultation with correct selection of patients should be tailored on an individual basis. Evaluated parameters include the following: LUTS severity quantification with validated questionnaires as the international prostate symptom score (IPSS) and quality of life (QoL), erectile and ejaculatory evaluation with validated questionnaires, blood tests including full blood count, coagulation profile, renal function and total/free prostate-specific antigen (PSA), prostate volume measured by multiparametric magnetic resonance (mpMR) of the prostate and/or transrectal ultrasound, uroflowmetry measuring the peak urinary flowrate (Qmax), and postvoid residual urine (PVR). Correct arterial anatomy identification with either computed tomography (CT) angiography, MR angiography, or intraprocedural cone-beam CT (CBCT) are suggested for a confident procedure and avoiding potential complications. The minimally invasive nature of PAE with a faster recovery, preserving the sexual function, and comparable results to standard prostatic surgery make the procedure an attractive choice for many male patients suffering with this condition. Patients should be informed about the potential for higher retreatment rates and shorter duration of treatment effect when compared with standard prostatic surgery. In this comprehensive review, we provide an updated toolbox for all interventional radiologists interested in the PAE practice for patients with BPH. We explain how to evaluate patients during consultation before and after PAE, describe the preprocedural imaging required, explain the technique, and narrate how to optimize outcomes. Finally, we review the level of evidence of PAE for BPH.

A retrospective anatomical study of the cerebral dural venous sinus outflow pathways utilizing three-dimensional rotational venography

OBJECTIVE:

Proper blood flow is essential for the maintenance of homeostasis for the human cerebrum. The dural venous sinuses comprise the dominant cerebral venous outflow path. Understanding the spatial configuration of the dural venous sinuses can provide valuable insight into several pathological conditions. Previously, only two-dimensional or cadaveric data have been used to understand cerebral outflow. For the first time, we applied three-dimensional rotational venography (3D-RV) to study and provide detailed quantitative morphological measurements of the terminal cerebral venous sinus system in several pathological states.

SUBJECTS AND METHODS:

Patients who underwent a 3D-RV procedure were identified by reviewing our local institution's endovascular database. Patients with high-quality angiographic images were selected. Eighteen patients were included (37.1 ± 3.8 years). Sinuses were divided into four segments, starting at the torcula and ending at the internal jugular vein. Segment length, 3D displacement, and cross-sectional area were measured.

RESULTS:

The transverse sinus (60.2 mm) was the longest segment, followed by the sigmoid sinus (55.1 mm). Cross-sectional areas were smallest at the middle of the transverse sinus (21.3 mm²) but increased at the sigmoid sinus (33.5 mm²) and at the jugular bulb (49.7 mm²). The only variation in displacements of venous flow was at the sigmoid-jugular junction, where 55% of cases had lateral displacements versus 45% medial, and 78% superior versus 22% inferior.

CONCLUSIONS:

We describe the terminal venous sinus system of patients with a variety of diagnoses, detailing segment length, cross-sectional area, and 3D path.

Prostatic Artery Embolization: Indications, Preparation, Techniques, Imaging Evaluation, Reporting, and Complications

Benign prostatic hyperplasia (BPH) is a noncancerous growth of the transitional zone of the prostate, which surrounds the prostatic urethra. Consequently, it can cause lower urinary tract symptoms (LUTS) and bladder outlet obstruction symptoms that may substantially reduce a patient's quality of life. Several treatments are available for BPH, including medications such as α-blockers and 5α-reductase inhibitors and surgical options including transurethral resection of the prostate and prostatectomy. Recently, prostatic artery embolization (PAE) has emerged as a minimally invasive treatment option for selected men with BPH and moderate to severe LUTS. Adequate pre- and postprocedural evaluations with clinical examinations and questionnaires, laboratory tests, and urodynamic and imaging examinations (particularly US, MRI, and CT) are of key importance to achieve successful treatment. Considering that the use of PAE has been increasing in tertiary hospital facilities, radiologists and interventional radiologists should be aware of the main technical concepts of PAE and the key features to address in imaging reports in pre- and postprocedural settings. An invited commentary by Lopera is available online. Online supplemental material is available for this article. ^©RSNA, 2021.

Advanced image guidance for prostatic artery embolization - a multicenter technical note

BACKGROUND

Prostatic artery embolization (PAE) is associated with patients' quality of life improvements and limited side effects compared to surgery. However, this procedure remains technically challenging due to complex vasculature, anatomical variations and small arteries, inducing long procedure times and high radiation exposure levels both to patients and medical staff. Moreover, the risk of non-target embolization can lead to relevant complications. In this context, advanced imaging can constitute a solid ally to address these challenges and deliver good clinical outcomes at acceptable radiation levels.

MAIN TEXT

This technical note aims to share the consolidated experience of four institutions detailing their optimized workflow using advanced image guidance, discussing variants, and sharing their best practices to reach a consensus standardized imaging workflow for PAE procedure, as well as pre and post-operative imaging.

CONCLUSIONS

This technical note puts forth a consensus optimized imaging workflow and best practices, with the hope of helping drive adoption of the procedure, deliver good clinical outcomes, and minimize radiation dose levels and contrast media injections while making PAE procedures shorter and safer.

Limiting radiation exposure during prostatic arteries embolization: influence of patient characteristics, anatomical conditions, and technical factors

OBJECTIVE

To assess the influence of patient characteristics, anatomical conditions, and technical factors on radiation exposure during prostatic arteries embolization (PAE) performed for benign prostatic hyperplasia.

MATERIALS AND METHODS

Patient characteristics (age, body mass index (BMI)), anatomical conditions (number of prostatic arteries, anastomosis), and technical factors (use of cone beam computed tomography (CBCT), large display monitor (LDM), and magnification) were recorded as well as total air kerma (AK), dose area product (DAP), fluoroscopy time (FT), and number of acquisitions (NAcq). Associations between potential dose-influencing factors and AK using univariate analysis and a multiple linear regression model were assessed.

RESULTS

Forty-one consecutive men (68 ± 8 years, min-max: 40-76) were included. LDM and CBCT decreased the use of small field of view with 13.9 and 3.8% respectively, both p < 0.001. The use of a LDM significantly reduced AK (1006.6 ± 471.7 vs. 1412 ± 754.6 mGy, p = 0.02), DAP (119.4 ± 64.4 vs. 167.9 ± 99.2, p = 0.04), FT (40.4 ± 11.5 vs. 53.6 ± 25.5 min, p = 0.01), and NAcq (16.3 ± 6.3 vs. 18.2 ± 7, p = 0.04). In multivariate analysis, AK reduction was associated with lower patient BMI (β = 0.359, p = 0.002), shorter FT (β = 0.664, p < 0.001) and CBCT use (β = - 0.223, p = 0.03), and decreased NAcq (β = 0.229, p = 0.04).

CONCLUSION

LDM and CBCT are important technical dose-related factors to help reduce radiation exposure during PAE, and should be considered in standard practice.

KEY POINTS

• The use of large display monitor (LDM) and cone beam computed tomography (CBCT) both decreased the need for magnification during prostatic arteries embolization (PAE). • The use of LDM reduces radiation exposure during PAE. • Total air kerma is associated with patient's body mass index, fluoroscopy time, CBCT, and the number of acquisitions.

Prostatic Artery Embolization: Influence of Cone-Beam Computed Tomography on Radiation Exposure, Procedure Time, and Contrast Media Use

Purpose

To evaluate the effect of cone-beam computed tomography (CBCT) on radiation exposure, procedure time, and contrast media (CM) use in prostatic artery embolization (PAE).

Materials and Methods

Seventy-eight patients were enrolled in this retrospective, single-center study. All patients received PAE without (group A; n = 39) or with (group B; n = 39) CBCT. Total dose-area product (DAP_total; Gycm²), total entrance skin dose (ESD_total; mGy), and total effective dose (ED_total; mSv) were primary outcomes. Number of digital subtraction angiography (DSA) series, CM use, fluoroscopy time, and procedure time were secondary outcomes. PAE in group A was performed by a single radiologist with 15 years experience, PAE in group B was conducted by four radiologists with 4 to 6 years experience.

Results

For groups A vs. B, respectively, median (IQR): DAP_total 236.94 (186.7) vs. 281.20 (214.47) Gycm²(p = 0.345); ED_total 25.82 (20.35) vs. 39.84 (23.75) mSv (p =  < 0.001); ESD_total 2833 (2278) vs. 2563 (3040) mGy(p = 0.818); number of DSA series 25 (15) vs. 23 (10)(p = 0.164); CM use 65 (30) vs. 114 (40) mL(p =  < 0.001); fluoroscopy time 23 (20) vs. 28 (25) min(p = 0.265), and procedure time 70 (40) vs.120 (40) min(p =  < 0.001). Bilateral PAE was achieved in 33/39 (84.6%) group A and 32/39 (82.05%) group B(p = 0.761), all other patients received unilateral PAE. There were no significant differences between clinical parameters and origins of the prostatic arteries (PA) (p = 0.206–1.00).

Conclusion

Operators with extensive expertise on PAE may not benefit from addition of CBCT to DSA runs, whereas for operators with less expertise, CBCT when used alongside with DSA runs increased the overall radiation exposure.

Improving Cone-Beam CT Angiography for Prostatic Artery Embolization: Is a Low-Dose Protocol Equivalent to the Standard?

PURPOSE

To compare the utility of low-dose versus standard cone-beam computed tomography (CT) angiography protocols in identifying nontarget embolization (NTE) during prostatic artery embolization (PAE).

MATERIALS AND METHODS

A prospective, single-center, Phase-1 study (NCT02592473) was conducted for lower urinary tract symptoms in benign prostatic hyperplasia. Prostate volume, international prostate symptom score (IPSS), quality of life score (QoL), International Index of Erectile Function (IIEF), peak flow rate, UCLA Prostate Cancer Index (UCLA-PCI), and postvoid residual were recorded at baseline and 1, 3, 6, 12, and 24-months after PAE. Six-second (standard protocol, n = 29) or 5-second (low-dose protocol n = 45) rotations were made. Images were selected and matched in pairs by areas of NTE and compared by readers using a binomial generalized estimating equation model. Procedural outcomes were analyzed using a linear mixed model.

RESULTS

Seventy-four cone-beam CT angiographies were performed in 21 patients. IPSS and QoL scores significantly improved (P <.05). There was no change in UCLA-PCI or IIEF scores. Dose area product of the low- and standard-dose protocol were 37,340.82 mGy·cm² ± 104.66 and 62,645.66 mGy·cm² ± 12,711.48, respectively, representing a dose reduction of 40.4%. A total of 120 comparisons showed no preference between the 2 protocols (P =.24). Observers identified 76 and 69 instances of NTE in the standard- and low-dose protocols, respectively (P =.125).

CONCLUSIONS

Low-dose cone-beam CT angiography achieved equivalent clinical utility in identifying NTE during PAE, with the advantage of a lower radiation dose.

Current Debates Regarding Optimal Patient Evaluation and Procedural Technique for Prostatic Artery Embolization

There are active debates surrounding patient evaluation and procedural techniques of prostate artery embolization. This review evaluates the available evidence on the value of urodynamics, the effect of prostate gland size, the benefits of pre- and intraprocedural cross-sectional imaging, the utility of a balloon-occlusion microcatheter, the differences among embolic particle sizes and types, and the merits of radial versus femoral arterial access.

Semi-automatic prostatic artery detection using cone-beam CT during prostatic arterial embolization

BACKGROUND

Due to the broad variability of the prostatic artery (PA), its origin, small calibers, and tortuous courses, prostatic arterial embolization (PAE) is challenging, time-consuming, and results in high radiation doses.

PURPOSE

To evaluate the accuracy of PA detection using cone-beam computed tomography (CBCT) performed from the aortic bifurcation in combination with a semi-automatic detection software in comparison to oblique view digital subtraction angiography (DSA) with internal iliac artery (IIA) injection.

MATERIAL AND METHODS

Twenty-two consecutive patients were included in this retrospective, IRB-approved study between July and December 2017. CBCT from the aorta and 30° oblique-view DSA from both IIAs were obtained for PA detection. Results of suggested PAs from the semi-automatic vessel detection software after CBCT and IIA DSA were compared. Moreover, dose area product (DAP) was recorded. Statistical analysis included Spearman's correlation, Mann-Whitney U test, and the Wilcoxon test considering P<0.05 as significant.

RESULTS

PA type was classified significantly better with CBCT compared to DSA (P=0.047). In IIA DSA, PAs could not be identified in 18% on the left and in 17% on the right side. CBCT detected all PAs, although truncation occurred in 59% because of the limited field of view. Mean DAP of the whole procedure was 257,161.32±127,909.36 mGy*cm². Mean DAPs were for a single DSA 14,502.51±9,437.67 mGy*cm² and for one CBCT 15,589.23±2,722.49 mGy*cm². A mean of 14.82 DSAs and only one CBCT were performed. CBCT accounted for 6% and DSA for 84% of the entire DAP of the procedure.

CONCLUSION

CBCT with semi-automatic feeding vessel detection software detects PAs more accurately than IIA DSA and may reduce radiation dose.

Prostatic Artery Embolization for the Treatment of Lower Urinary Tract Symptoms Due to Benign Prostatic Hyperplasia: 10 Years' Experience

Background Long-term experience with prostatic artery embolization (PAE) for benign prostatic hyperplasia remains limited. Purpose To evaluate the efficacy, safety, and long-term results of PAE for benign prostatic hyperplasia. Materials and Methods This retrospective single-center study was conducted from June 2008 to June 2018 in patients with moderate to severe benign prostatic hyperplasia-related symptoms. International Prostate Symptom Score (IPSS), quality-of-life score, maximum urinary flow rate, postvoid residual volume, prostate-specific antigen (PSA), and prostate volume were assessed. PAE was performed with 100-500-μm embolic microspheres. Mixed-model analysis of variance and Kaplan-Meyer method was accessed, as appropriate. Results A total of 317 consecutive men (mean age ± standard deviation, 65 years ± 8) were treated. Follow-up ranged from 3 months to 96 months (mean, 27 months). Bilateral and unilateral PAE was performed in 298 (94%) and 19 (6%) men, respectively. Early clinical failure occurred in six (1.9%) and symptom recurrence in 72 (23%) men at a median follow-up of 72 months. Mean maximum improvement was as follows: IPSS, 16 points ± 7; quality-of-life score, 4 points ± 1; prostatic volume reduction, 39 cm³ ± 39 (39% ± 29); maximum urinary flow rate, 6 mL/sec ± 10 (155% ± 293); and postvoid residual volume, 70 mL ± 121 (48% ± 81) (P < .05 for all). Unilateral PAE was associated with higher recurrence (42% vs 21%; P = .04). Baseline PSA was inversely related with recurrence (hazard ratio, 0.9 per nanograms per milliliter of PSA; 95% confidence interval [CI], 0.8, 0.9; P < .001). Embolization with combined particle sizes (100-500 μm) did not relate to symptom recurrence (hazard ratio, 0.4; 95% CI: 0.2, 1.1 for 100-500-μm group vs 300-500-μm group and hazard ratio, 0.4; 95% CI: 0.1, 1.5 for 100-500-μm group vs 100-300-μm group; P = .19).None of the patients presented with urinary incontinence or erectile dysfunction. Conclusion Prostatic artery embolization was a safe and effective procedure for benign prostatic hyperplasia with good long-term results for lower urinary tract symptoms. © RSNA, 2020 Online supplemental material is available for this article.

Influence of Interventionists' Experience on Radiation Exposure of Patients Who Underwent Prostate Artery Embolization: 4-Year Results from a Retrospective, Single-Center Study

PURPOSE

To assess radiation exposure in men undergoing prostate artery embolization (PAE) for the treatment for symptomatic, benign prostatic hyperplasia depending on growing experience of interventional radiologists over a 4-year period.

METHODS

A total of 250 consecutive patients underwent PAE at a single center. Data on radiation exposure [dose area product (DAP), effective dose (ED), entrance skin dose (ESD), and fluoroscopy time (FT)] were retrospectively evaluated. Primary outcomes of interest were patient radiation exposure in five consecutive groups of 50 patients each and Pearson correlation with the number of patients treated.

RESULTS

Median DAP, ED, and ESD during prostate artery embolization were significantly higher in the first compared to the second 50 patients (56 298 µGym² vs. 24 709 µGym², p < 0.001, 146.4 mSv vs. 64.2 mSv, p < 0.001, and 5.1 Gy vs. 2.4 Gy, p < 0.001, respectively). The following consecutive groups did not differ significantly from the respective preceding group in terms of DAP, ED, and ESD. Number of digital subtraction angiography series, FT, and procedure time decreased with increasing operator experience (Pearson's r = - 0.240, p < 0.001, r = - 0.269, p < 0.001, and r = - 0.504, p < 0.001, respectively). Bilateral prostate artery embolization was associated with less ESD and shorter FT than unilateral embolization (median 2.5 vs. 3.5 Gy, p = 0.02, and 26 min vs. 42 min, p < 0.001, respectively).

CONCLUSION

Exposure to radiation in men who underwent PAE decreased with growing operator experience and decreasing complexity of procedures.

Modern imaging and image-guided treatments of the prostate gland: MR and ablation for cancer and prostatic artery embolization for benign prostatic hyperplasia

Multiparametric MRI (mpMRI) has proven to be an essential tool for diagnosis, post-treatment follow-up, aggressiveness assessment, and active surveillance of prostate cancer. Currently, this imaging technique is part of the daily practice in many oncological centres. This manuscript aims to review the use of mpMRI in the set of prostatic diseases, either malignant or benign: mpMRI to detect and stage prostate cancer is discussed, as well as its use for active surveillance. Image-guided ablation techniques for prostate cancer are also reviewed. The need to establish minimum acceptable technical parameters for prostate mpMRI, standardize reports, uniform terminology for describing imaging findings, and develop assessment categories that differentiate levels of suspicion for clinically significant prostate cancer led to the development of the Prostate Imaging Reporting and Data System that is reviewed. Special focus will also be given on the most up-to-date evidence of prostatic artery embolization (PAE) for symptomatic benign prostatic hyperplasia (BPH). Management of patients with BPH, technical aspects of PAE, expected outcomes and level of evidence are reviewed with the most recent literature. PAE is a challenging technique that requires dedicated anatomical knowledge and comprehensive embolization skills. PAE has been shown to be an effective minimally-invasive treatment option for symptomatic BPH patients, that can be viewed between medical therapy and surgery. PAE may be a good option for symptomatic BPH patients that do not want to be operated and can obviate the need for prostatic surgery in up to 80% of treated patients.

Radiation Dose in Prostatic Artery Embolization Using Cone-Beam CT and 3D Roadmap Software

PURPOSE

To evaluate the radiation dose in patients undergoing prostatic artery embolization (PAE) using cone-beam CT and 3-dimensional (3D) guidance software.

MATERIALS AND METHODS

In this single-center retrospective study, 100 patients with benign prostatic hyperplasia (mean prostate volume, 83.6 mL ± 44.2; 69.4 ± 9.6 years of age; body mass index, 26.5 ± 4.2) were treated using PAE between October 2016 and April 2018. Informed consent was obtained from all participants included in the study. All patients received at least 1 intraprocedural cone-beam CT per side for evaluation of the vessel anatomy and software rendering of 3D guidance for catheter guidance. Digital subtraction angiography (DSA) was performed in the distal branches only. The total dose area product (DAP), along with the DAP attributed to fluoroscopy, DSA, and cone-beam CT, were assessed.

RESULTS

Bilateral embolization was achieved in 83 patients (83%). The average total DAP was 134.4 Gy ⋅ cm² ± 69.5 (range, 44.7-410.9 Gy ⋅ cm²). Fluoroscopy, DSA, and cone-beam CT accounted for 35.5 Gy ⋅ cm² ± 21.3 (range, 8.6-148.6 Gy ⋅ cm²) or 26.4% (percentage of total DAP), 58.2 Gy ⋅ cm² ± 48.3 (range, 10.3-309.3 Gy ⋅ cm²) or 43.3%, and 40.7 Gy ⋅ cm² ± 14.5 (range, 15.9-86.3 Gy ⋅ cm²) or 30.3%, respectively. Average procedure time was 89.4 ± 27.0 minutes, and the average fluoroscopy time was 30.9 ± 12.2 minutes.

CONCLUSIONS

Intraprocedural cone-beam CT in combination with 3D guidance software allows for identification and catheterization of the prostatic artery in PAE. Furthermore, the results of this trial indicate that this study protocol may lead to a low overall radiation dose.

Prostatic Artery Embolization for Benign Prostatic Hyperplasia: Patient Evaluation, Anatomy, and Technique for Successful Treatment

Symptomatic benign prostatic hyperplasia is a common condition in the aging population that results in bothersome lower urinary tract symptoms and decreased quality of life. Patients often are treated with medication and offered surgery for persistent symptoms. Transurethral resection of the prostate is considered the traditional standard of care, but several minimally invasive surgical treatments also are offered. Prostatic artery embolization (PAE) is emerging as an effective treatment option with few reported adverse effects, minimal blood loss, and infrequent overnight hospitalization. The procedure is offered to patients with moderate to severe lower urinary tract symptoms and depressed urinary flow due to bladder outlet obstruction. Proper patient selection and meticulous embolization are critical to optimize results. To perform PAE safely and avoid nontarget embolization, interventional radiologists must have a detailed understanding of the pelvic arterial anatomy. Although the prostatic arteries often arise from the internal pudendal arteries, several anatomic variants and pelvic anastomoses are encountered. Prospective cohort studies, small randomized controlled trials, and meta-analyses have shown improved symptoms after treatment, with serious adverse effects occurring rarely. This article reviews the basic principles of PAE that must be understood to develop a thriving PAE practice. These principles include patient evaluation, review of surgical therapies, details of pelvic arterial anatomy, basic principles of embolization, and an overview of published results. Online supplemental material is available for this article. ^©RSNA, 2019.

Computed Tomography for 4-Dimensional Angiography and Perfusion Imaging of the Prostate for Embolization Planning of Benign Prostatic Hyperplasia

OBJECTIVES

The aim of this study was to evaluate the feasibility of a computed tomography (CT) protocol enabling the visualization of the prostatic artery (PA) before prostatic artery embolization (PAE) in benign prostatic hyperplasia, which provides quantitative perfusion information of the prostate gland.

MATERIALS AND METHODS

In this institutional review board-approved study, 22 consecutive patients (mean age, 67 ± 7 years) who were planned to undergo PAE underwent a dynamic CT scan of the pelvis (scan range, 22.4 cm; cycle time, 1.5 seconds; scan time, 44 seconds; 25 scan cycles; 70 kVp; 100 mAs) after the administration of 70 mL of iodinated contrast media (flow rate, 6 mL/s; 10 seconds' delay). Image postprocessing consisted of a spatiotemporal, frequency-depending multiband filtering technique with noise reduction, motion correction, resulting in (1) time-resolved, temporal maximum intensity projection (MIP) images from fusion of multiple arterial time points; (2) 4-dimensional (4D) CT angiography images after bone and calcium plaque removal; and (3) parametric perfusion maps of the prostate. Intraprocedural cone-beam CT was performed with a microcatheter in the PA. In both modalities, the contrast-to-noise ratio of the right internal iliac artery or the PA was calculated, respectively. Visibility of the PA was scored using a Likert scale (score 1 = not seen, to score 4 = intraprostatic PA branches seen). Quantitative perfusion analysis of the dynamic pelvic CT included calculation of the blood flow, blood volume, mean transit time, and flow extraction product.

RESULTS

The average volume CT dose index and dose length product of CT was 35.7 ± 6.8 mGy and 737.4 ± 146.3 mGy·cm, respectively. Contrast-to-noise ratio of the pelvic vessels on temporal MIP images and cone-beam CT were 45 ± 19 and 69 ± 27, respectively (P < 0.01). The mean visibility score of the PA was 3.6 ± 0.6 for 4D-CT angiography and 3.97 ± 0.2 for cone-beam CT (P < 0.001). The PA was visualized in 100% of 4D-CT angiography examinations, with one PA being visible only proximally. Prostate CT perfusion analysis showed blood flow, blood volume, mean transit time, and flow extraction product values of 27.9 ± 12.5 mL/100 mL/min, 2.0 ± 0.8 mL/100 mL, 4.5 ± 0.5 second, and 12.6 ± 5.4 mL/100 mL/min, respectively, for the whole prostate gland. About half the patients showed a pronounced difference between the lobes.

CONCLUSIONS

We introduced a CT protocol for PAE planning providing excellent visualization of the PA on temporal MIP images and 4D-CT angiography at a reasonable dose and low contrast volume. In addition, quantitative perfusion information is available, which might be useful for outcome prediction after embolization.