Radiation Exposure of Patients and Interventional Radiologists during Prostatic Artery Embolization: A Prospective Single-Operator Study

Prostatic Artery Embolization: Lessons From 551 Procedures at a Single-Center

RATIONALE AND OBJECTIVES

This retrospective study evaluates the efficacy and safety of Prostatic Artery Embolization (PAE) for the treatment of benign prostatic hyperplasia (BPH) over five years at a single center, conducted by an experienced interventional radiologist.

MATERIALS AND METHODS

We analyzed 551 PAE interventions from January 2019 to July 2023. Key metrics included patient demographics, procedural details (radiation exposure, particle size), complication rates, pre- and post-interventional prostatic volume (PV), Prostate-specific Antigen (PSA) levels, International Prostate Symptom Score (IPSS), Quality of Life (QoL) scores and International Index of Erectile Function (IIEF) scores. We assessed data normality, performed group and paired sample comparisons, and evaluated correlations.

RESULTS

For 551 men, the average patient age was 68.81 ± 8.61 years undergoing bilateral embolization. The particle size predominantly used was 100-300 µm (n = 441). PAE lead to significant (p < .001) reduction of both PV (-9.67 ± 14.52 mL) and PSA level (-2,65 ± 1.56 ng/mL) between pre- and three months after PAE. Substantial improvement were observed for IPSS (-9 points) and QoL scores (-2 points), with stable IIEF scores. Only minor complications (n = 16) were reported, and no major complications were observed. Between the first PAE in 2019 and the routinely performed PAE in 2023 significant (p < .0001) reductions in fluoroscopy (-25.2%), and procedural times (-26.1%) were observed.

CONCLUSION

In conclusion, PAE is a safe and effective treatment for BPH, offering significant improvements in lower urinary tract symptoms (LUTS) and QoL while maintaining sexual function.

Multicenter Quantification of Radiation Exposure and Associated Risks for Prostatic Artery Embolization in 1476 Patients

Background Prostatic artery embolization (PAE) is a safe, minimally invasive angiographic procedure that effectively treats benign prostatic hyperplasia; however, PAE-related patient radiation exposure and associated risks are not completely understood. Purpose To quantify radiation dose and assess radiation-related adverse events in patients who underwent PAE at multiple centers. Materials and Methods This retrospective study included patients undergoing PAE for any indication performed by experienced operators at 10 high-volume international centers from January 2014 to May 2021. Patient characteristics, procedural and radiation dose data, and radiation-related adverse events were collected. Procedural radiation effective doses were calculated by multiplying kerma-area product values by an established conversion factor for abdominopelvic fluoroscopy-guided procedures. Relationships between cumulative air kerma (CAK) or effective dose and patient body mass index (BMI), fluoroscopy time, or radiation field area were assessed with linear regression. Differences in radiation dose stemming from radiopaque prostheses or fluoroscopy unit type were assessed using two-sample t tests and Wilcoxon rank sum tests. Results A total of 1476 patients (mean age, 69.9 years ± 9.0 [SD]) were included, of whom 1345 (91.1%) and 131 (8.9%) underwent the procedure with fixed interventional or mobile fluoroscopy units, respectively. Median procedure effective dose was 17.8 mSv for fixed interventional units and 12.3 mSv for mobile units. CAK and effective dose both correlated positively with BMI (R2 = 0.15 and 0.17; P < .001) and fluoroscopy time (R2 = 0.16 and 0.08; P < .001). No radiation-related 90-day adverse events were reported. Patients with radiopaque implants versus those without implants had higher median CAK (1452 mGy [range, 900-2685 mGy] vs 1177 mGy [range, 700-1959 mGy], respectively; P = .01). Median effective dose was lower for mobile than for fixed interventional systems (12.3 mSv [range, 8.5-22.0 mSv] vs 20.4 mSv [range, 13.8-30.6 mSv], respectively; P < .001). Conclusion Patients who underwent PAE performed with fixed interventional or mobile fluoroscopy units were exposed to a median effective radiation dose of 17.8 mSv or 12.3 mSv, respectively. No radiation-related adverse events at 90 days were reported. © RSNA, 2024 See also the editorial by Mahesh in this issue.

Initial Experience Using Digital Variance Angiography in Context of Prostatic Artery Embolization in Comparison with Digital Subtraction Angiography

RATIONALE AND OBJECTIVES

In previous clinical studies digital variance angiography (DVA) provided higher contrast-to-noise ratio (CNR) and better image quality in lower extremity angiography than digital subtraction angiography (DSA). Our aim was to investigate whether DVA has similar quality reserve in prostatic artery embolization (PAE). The secondary aim was to explore the potential advantages of the color-coded DVA (ccDVA) technology in PAE.

MATERIAL AND METHODS

This retrospective study evaluated 108 angiographic acquisitions from 30 patients (mean ± SD age 68.0 ± 8.9, range 41-87) undergoing PAE between May and October 2020. DSA and DVA images were generated from the same unsubtracted acquisition, and their CNR was calculated. Visual evaluation of DVA and DSA image quality was performed by four experienced interventional radiologists in a randomized, blinded manner. The diagnostic value of DSA and ccDVA images was also evaluated using clinically relevant criteria (visibility of small [< 2.5 mm] and large arteries [> 2.5 mm], feeding arteries and tissue blush) in a paired comparison. Data were analysed by the Wilcoxon signed rank test or the binomial test, the interrater agreement was determined by the Kendall W or Fleiss Kappa analysis.

RESULTS

DVA provided 4.11 times higher median CNR than DSA (IQR: 1.72). The visual score of DVA images (4.40 ± 0.05) was significantly higher than that of DSA (3.39 ± 0.07, p < 0.001). The Kendall W analysis showed moderate but significant agreement (WDVA = 0.38, WDSA = 0.53). The preference of ccDVA images was significantly higher in all criteria (63-89%) with an interrater agreement of 58-79%. The Fleiss Kappa range was 0.02-0.18, significant in all criteria except large vessels.

CONCLUSION

Our data show that DVA provides higher CNR and better image quality in PAE. This quality reserve might be used for dose management (reduction of radiation dose and contrast agent volume), and ccDVA technology has also a high potential to assist PAE interventions in the future.

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.

Radiation Exposure during Prostatic Artery Embolization: A Single Institution Review

ABSTRACT

Prostate artery embolization is a minimally invasive treatment for benign prostatic hyperplasia, and imaging is indispensable for the technical success of this procedure; however, imaging is a major source of radiation exposure for patients and healthcare providers. Radiation emission during prostate artery embolization procedures at a single institution was evaluated to determine radiation exposure with the goal to work toward minimizing exposure. All patients at a single institution that underwent outpatient unilateral/bilateral prostate artery embolization between 4 January 2019 and 16 November 2021 were retrospectively evaluated; data collected included body mass index, prostate volume, and indications for prostate artery embolization. Technical parameters recorded were air kerma, procedure time, fluoroscopy time, number of acquisitions, and intra-procedural imaging modalities. Fisher's t-test, ANOVA, and chi-square analyses were used as appropriate for statistical analysis (P < 0.05). Overall, 56 patients were included in the study. Body mass index (obesity; P = 0.0017) was a significant predictor of increased air kerma; prostate size and bilateral vs. unilateral prostate artery embolization were not significantly associated with increased air kerma despite the number of acquisitions being significantly different between bilateral and unilateral embolization (P = 0.0064). When evaluating radiation exposure during prostate artery embolization, increased body mass index significantly predicted increased air kerma. Contrary to the literature, the extent of embolization (bilateral vs. unilateral) was not associated with increased air kerma regardless of higher acquisitions and procedure time associated with bilateral prostate artery embolization. Increased radiation protection efforts should be considered for patients with higher body mass index to protect patients and practitioners.Health Phys. 124(0):000-000; 2023.

Use of the triple coaxial (triaxial) microcatheter system in superselective arterial embolisation for complex interventional cases: an initial experience with the system

LEARNING OBJECTIVE

To share our experience in utilising the triple coaxial (triaxial) system in superselective cannulation of arteries for complex embolisation procedures.

BACKGROUND

Percutaneous transcatheter selective embolisation is widely performed for a myriad of oncologic (e.g., trans-arterial chemo- or radio-embolisation) and non-oncologic (e.g., for embolisation of bleeding and benign conditions such as uterine fibroid and benign prostate hyperplasia) purposes. The cornerstone of such embolisation procedures is to achieve superselective cannulation of the arterial supply to the tumour/organ, preventing the complication of non-target embolisation. However, a multitude of factors, such as complex vascular anatomy, can pose challenges to achieving this goal.

CLINICAL FINDINGS/PROCEDURAL DETAILS

The triaxial system utilises two smaller microcatheters telescoped through each other over a microwire. We have adopted the triaxial system for specific cases due to its perceived superior torquability and trackability compared to the conventional coaxial system, in which superselective cannulation is anticipated to be challenging. The triaxial system is also favourable in situations where the inner microcatheter needs to be "sacrificed" after administering the embolics (e.g., after administering radioisotopes in radioembolisation, N-butyl cyanoacrylate [NBCA] glue or ethylene-vinyl alcohol copolymer [EvOH] Onyx). Through a case series with procedural details such as fluoroscopic time, contrast administered, etc., we hope to illustrate the utility and efficacy of the triaxial system as well as present pitfalls in its usage.

CONCLUSION

The triaxial system appears to be a valuable system for certain complex embolisation procedures and could be better suited than the conventional coaxial systems in these specific circumstances.

Anatomical variants in prostatic artery embolization in treatment of benign prostatic hyperplasia

Background

Benign prostatic hyperplasia (BPH) is the most prevalent benign tumor in aged men, and its prevalence is rising with age reaching 8% in the fourth decade of life and up to 90% in the ninth decade. PAE has long been considered as a safe and effective minimally invasive therapy option for individuals with moderate to severe lower urinary tract symptoms caused by prostatic hypertrophy. Because of the varying degrees of atherosclerosis seen in the elderly, PAE is generally a difficult treatment that necessitates a particular amount of knowledge of anatomy and a specific set of abilities. It is critical to emphasize anatomical information about PA that is required for a successful PAE, as well as radiation exposure factors that can be helpful in such a protracted treatment. This thesis provides a pictorial review of PA anatomy and prevalence of related anatomical variants, besides additional anatomical and radiation dosage concerns, and knows the important effect of the anastomosis on non-target embolization as in our study we included large number of cases (83 patients) to cover all types of variations and different types of anastomosis all were covered.

Results

A total of 83 patients (166 sides) were analyzed. Double arterial supply on the same side was noted in 1 patient (1.2%). In 3 patients (3.6%), only a unilateral PA was identified. PA origin frequencies were computed. Penile, rectal, vesical anastomoses, and anastomosis with the other side were identified with 7 (8.4%), 3 (3.6%), 2 (2.4%), and 8 (9.6%) of PAs, respectively. Mean skin radiation dose was 479 mGy.

Conclusions

When treating BPH with PAE, understanding PA anatomy is critical for achieving the best results. The anatomy of the PA is critical for preventing non-target embolization and is directly related to the correct identification of the anatomical pattern of the prostate arteries, and we should also take into account the presence of contralateral anastomoses; it is possible to achieve both prostate lobes through catheterization of the prostatic artery on only one side.

Prostate Artery Embolization in Patients above Eighty Years Old: Clinical Efficacy and Safety

Purpose Prostate artery embolization (PAE) has been established as an effective treatment option for benign prostate hyperplasia or hematuria of prostatic origin. We aim to confirm the effectiveness and safety of PAE in elderly patients aged ≥ 80 years old.

Materials and Methods Between January 2014 and August 2020, PAE was attempted on 54 elderly patients with lower urinary tract symptoms (LUTS) or prostatic hematuria who were unfit for surgical treatment or opted for PAE. Outcome parameters (International Prostate Symptom Score [IPSS], quality of life [QoL] score, International Index of Erectile Function score (IIEF), maximal urinary flow rate, postvoid residual, and prostate volume) were collected and analyzed at baseline, 6 months, 1, 2, and 3 years.

Results The mean patient age was 85.29 years (range: 80–98). Technical success was achieved in 50 patients (92.6%). Mean IPSS improved from 18 at baseline to 7.7, 8.5, 8.6, and 9.1 at 6 months, 1, 2, and 3 years. Mean QoL improved from 4.9 at baseline to 2.8, 1.7, and 1.5 at 6 months, 1, and 2 years. Mean prostate volume reduced from a baseline of 152.7 to 123.5 mL within 6 months and 120.5 mL after 7 months of PAE. Urinary catheter removal was successful in 13 out of 19 patients with urinary retention. PAE succeeded in stopping bleeding in 16 out of 17 patients with prostate-induced hematuria.

Conclusion PAE is a feasible low-risk treatment for LUTS with or without urinary retention or prostatic hematuria in elderly patients.

Potential of pre-interventional magnetic resonance angiography for optimization of workflow and clinical outcome of prostatic arterial embolization

PURPOSE

Impact of pre-interventional magnetic resonance angiography (MRA) on prostatic artery embolization (PAE) regarding workflow, radiation dose, and clinical outcome.

METHOD

Retrospective evaluation of 259 patients (mean age 68 ± 9, range 41-92) with benign prostatic hypertrophy (BPH) undergoing PAE between January 2017 and December 2020. MRA was performed in 137 cases. In 122 patients, no pre-interventional MRA was performed. Origin of the PA, volumetry of the prostatic gland and ADC values were evaluated. International Prostate Symptom Score (IPSS), Quality of Life (QoL) and International Index of Erectile Function (IIEF) were evaluated before and after PAE.

RESULTS

Origin of the PA was identified in all cases. Significant differences regarding volume reduction (-20 ± 13 ml with MRA vs -17 ± 9 ml without MRA) and ADC value reduction were found (-78 ± 111 10-6 mm2/s with MRA vs -45 ± 99 10-6 mm2/s without MRA). PAE workflow was modified in 16 patients due to MRA findings. Radiation dose (5518.54 ± 6677.97 µGym2 with MRA vs 23963.50 ± 19792.25 µGym2 without MRA) and fluoroscopy times (19.35 ± 9.01 min. with MRA vs 27.45 ± 12.54 min. without MRA) significantly differed. IPSS reduction improved (-11 ± 8 points with MRA vs -7 ± 9 points without MRA, p < 0.001), while QOL (-2 ± 1 points with MRA and -2 ± 2 points without MRA) and IIEF (+2 ± 10 points with MRA and +1 ± 11 points without MRA) showed no significant differences (p > 0.05).

CONCLUSIONS

Pre-interventional MRA facilitates improved workflow and patient safety of PAE while reducing radiation dose and intervention time.

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.

An Updated Meta-Analysis of the Efficacy and Safety of Prostatic Artery Embolization vs. Transurethral Resection of the Prostate in the Treatment of Benign Prostatic Hyperplasia

Background: Prostatic artery embolization (PAE) in the treatment of benign prostatic hyperplasia (BPH) has been introduced into clinical practice, but conclusive evidence of efficacy and safety has been lacking. Objective: To compare the efficacy and safety of prostatic artery embolization (PAE) vs. transurethral resection of prostate (TURP), we performed a meta-analysis of clinical trials. Methods: We searched randomized controlled trials (RCTs) from Pubmed, Embase, Wanfang, and CNKI from January 2000 to December 2020 and used RevMan 5.0 to analyze the data after five RCTs were included. Results: The reducing of prostate volume (PV) [Median mean (MD) 14.87; 95% confidence interval (CI) 7.52-22.22; P < 0.0001] and the increasing of maximum flow rate in free uroflowmetry (Qmax) (MD 3.73; 95% CI 0.19-7.27; P = 0.004) were more obvious in TURP than in PAE; however, the rate of lower sexual dysfunction [odds ratio (OR) 0.12; 95% CI 0.05-0.30; P < 0.00001] was lower in PAE compared with TURP. Meanwhile, no conspicuous difference in International Prostate Symptoms Score (IPSS) score (MD 1.42; 95% CI -0.92 to 3.75; P = 0.23), quality of life (Qol) score (MD 0.21; 95% CI -0.31 to 0.73; P = 0.43), post void residual (PVR) (MD 21.16; 95% CI -5.58 to 47.89; P = 0.12), prostate-specific antigen (PSA) (MD 0.56; 95% CI -0.15 to 1.27; P = 0.12), and complications (OR 0.90; 95% CI 0.20-4.05; P = 0.89) between PAE and TURP group was shown. Conclusion: PAE may replace TURP as an alternative treatment for Benign prostatic hyperplasia (BPH) patients who do not want to have surgery or with operational contraindications.

Center experience and other determinants of patient radiation exposure during prostatic artery embolization: a retrospective study in three Scandinavian centers

OBJECTIVES

To evaluate the effects of center experience and a variety of patient- and procedure-related factors on patient radiation exposure during prostatic artery embolization (PAE) in three Scandinavian centers with different PAE protocols and levels of experience. Understanding factors that influence radiation exposure is crucial in effective patient selection and procedural planning.

METHODS

Data were collected retrospectively for 352 consecutive PAE procedures from January 2015 to June 2020 at the three centers. Dose area product (DAP (Gy·cm²)) was selected as the primary outcome measure of radiation exposure. Multiple patient- and procedure-related explanatory variables were collected and correlated with the outcome variable. A multiple linear regression model was built to determine significant predictors of increased or decreased radiation exposure as reflected by DAP.

RESULTS

There was considerable variation in DAP between the centers. Intended unilateral PAE (p = 0.03) and each 10 additional patients treated (p = 0.02) were significant predictors of decreased DAP. Conversely, increased patient body mass index (BMI, p < 0.001), fluoroscopy time (p < 0.001), and number of digital subtraction angiography (DSA) acquisitions (p < 0.001) were significant predictors of increased DAP.

CONCLUSIONS

To minimize patient radiation exposure during PAE radiologists may, in collaboration with clinicians, consider unilateral embolization, pre-interventional CTA for procedure planning, using predominantly anteroposterior (AP) projections, and limiting the use of cone-beam CT (CBCT) and fluoroscopy.

KEY POINTS

• Growing center experience and intended unilateral embolization decrease patient radiation exposure during prostatic artery embolization. • Patient BMI, fluoroscopy time, and number of DSA acquisitions are associated with increased DAP during procedures. • Large variation in radiation exposure between the centers may reflect the use of CTA before and CBCT during the procedure.

MR angiography-planned prostatic artery embolization for benign prostatic hyperplasia: single-center retrospective study in 56 patients

PURPOSE

We aimed to evaluate the advantages of magnetic resonance angiography (MRA)-planned prostatic artery embolization (PAE) for benign prostatic hyperplasia (BPH).

METHODS

In this retrospective study, MRAs of 56 patients (mean age, 67.23±7.73 years; age range, 47-82 years) who underwent PAE between 2017 and 2018 were evaluated. For inclusion, full information about procedure time and radiation values must have been available. To identify prostatic artery (PA) origin, three-dimensional MRA reconstruction with maximum intensity projection was conducted in every patient. In total, 33 patients completed clinical and imaging follow-up and were included in clinical evaluation.

RESULTS

There were 131 PAs with a second PA in 19 pelvic sides. PA origin was correctly identified via MRA in 108 of 131 PAs (82.44%). In patients in which MRA allowed a PA analysis, a significant reduction of the fluoroscopy time (-27.0%, p = 0.028) and of the dose area product (-38.0%, p = 0.003) was detected versus those with no PA analysis prior to PAE. Intervention time was reduced by 13.2%, (p = 0.25). Mean fluoroscopy time was 30.1 min, mean dose area product 27,749 µGy•m2, and mean entrance dose 1553 mGy. Technical success was achieved in all 56 patients (100.0%); all patients were embolized on both pelvic sides. The evaluated data documented a significant reduction in IPSS (p < 0.001; mean 9.67 points).

CONCLUSION

MRA prior to PAE allowed the identification of PA in 82.44% of the cases. MRA-planned PAE is an effective treatment for patients with BPH.

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.

Prostatic Artery Embolization for Benign Prostatic Hyperplasia: Anatomical Aspects and Radiation Considerations from a Case Series of 210 Patients

Context Prostatic artery embolization (PAE) has been established as a safe and effective treatment option for symptomatic benign prostatic hyperplasia (BPH). Thorough knowledge of detailed prostatic artery (PA) anatomy is essential.

Aims The aim of this study was to provide a pictorial review of PA anatomy and prevalence of related anatomical variants, in addition to other anatomical and radiation dose considerations.

Settings and Design Case series and review of literature.

Materials and Methods We performed PAE for 210 patients from November 2015 to November 2020 under local anesthesia only. Anatomy, procedure duration, fluoroscopy time, radiation dose, technical success, and complications were analyzed.

Statistical Analysis Used Descriptive statistics were analyzed using Microsoft Excel software.

Results A total of 210 patients (420 sides) were analyzed. Double arterial supply on the same side was noted in 12 patients (5.7%). In 10 patients (4.7%), only a unilateral PA was identified. In two patients (0.9%), no PA could be identified. Frequencies of PA origins were calculated. Penile, rectal, and vesical anastomoses were identified with 79 (18.8%), 54 (12.9%), and 41 (9.8%) of PAs, respectively. Median skin radiation dose, procedure time, and fluoroscopy time were 505 mGy, 73 and 38 minutes, respectively. Complications occurred in nine patients (4.3%), none of them was major.

Conclusions Knowledge of PA anatomy is essential when treating BPH by PAE for optimum results. There is no enough evidence to support routine use of preoperative computed tomography angiography and intraoperative cone-beam computed tomography as means of improving safety or efficacy.

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.

Prostatic artery embolization performed in anteroposterior projections versus steep oblique projections: single centre retrospective comparative analysis

Background

To present and evaluate an approach for reduction of utilization of steep oblique angiographic projections during prostatic artery embolization (PAE).

Methods

Single-center, retrospective study of patients who underwent bilateral PAE (from October 2018 to November 2019) and in whom it was possible to embolize PA of at least one pelvic side utilizing anteroposterior projections only (AP-PAE group), with the following techniques: Identification of the origin of PA on anteroposterior angiographic views. Utilization of anatomic landmarks from the planning computed tomographic angiography. Distal advancement of the angiographic catheter or microcatheter in the anterior division of internal iliac artery. Gentle probing with microguidewire at the expected site of origin of the PA. The AP-PAE approach was initially applied to all PAE patients during the study period and when this approach failed, additional steep oblique projections were acquired; patients who underwent bilateral PAE, with both anteroposterior and oblique projections for both pelvic sides, formed the standard PAE (S-PAE) group. The AP-PAE group was compared with S-PAE group in terms of baseline clinical and anatomic features, technical/procedural aspects and outcomes.

Results

Forty-six patients (92 pelvic sides) were studied. AP-PAE was feasible in 12/46 patients (26.0%): unilateral AP-PAE in 9/46 patients (19.5%); bilateral AP-PAE in 3/46 patients (6.5%). AP-PAE group had larger prostates (p = 0.047) and larger PAs (p < 0.001). Body mass index (BMI) and other baseline features were comparable between the two groups (mean BMI, AP-PAE group: 27.9 ± 3.6, S-PAE group: 27.0 ± 3.5, p = 0.451). Mean fluoroscopy time and dose area product were lower in AP-PAE group (46.3 vs 57.9 min, p = 0.084 and 22,924.9 vs 35,800.4 μGy^.m², p = 0.018, respectively). Three months post PAE, comparable clinical success rates (11/12 vs 31/34, p = 0.959) and mean International Prostate Symptom Score reduction (60.2% vs 58.1%, p = 0.740) were observed for AP-PAE and for S-PAE group, respectively. No major complications were encountered.

Conclusion

AP-PAE is associated with significant reduction in radiation exposure and appears to be feasible, safe and effective, but it can be applied in a relatively small percentage of patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42155-021-00209-7.

Efficacy and safety of prostatic artery embolization for benign prostatic hyperplasia: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

To investigate the efficacy and safety of prostatic artery embolization (PAE) vs. transurethral resection of the prostate (TURP) in patients affected by benign prostatic hyperplasia (BPH). We also reviewed mean changes from baseline in PAE at selected follow-up points.

METHODS

PubMed, Web of Science, and Embase were searched up to May 1, 2020. Randomized controlled trials on PAE were collected according to specific inclusion and exclusion criteria. Meta-analyses were performed using RevMan 5.3, STATA 14, and GraphPad Prism 8. Pooled patient-reported scores and functional outcomes were calculated by using a fixed or random-effect model.

RESULTS

Eleven articles met our selection criteria and ten independent patient series were included in the final analysis. Pooled estimates suggested no significant difference between TURP and PAE for patient-reported outcomes including International Prostate Symptom Score (2.32 (- 0.44 to 5.09)) and quality of life (0.18 (- 0.41 to 0.77)) at 12 months. PAE was less effective regarding improvements in most functional outcomes such as maximum flow rate, prostate volume, and prostate-specific antigen. Moreover, PAE may be associated with relatively fewer complications, lower cost, and shorter hospitalization. After the PAE procedure, the overall weighted mean differences for all outcomes except sexual health scores were significantly improved from baseline during follow-up to 24 months.

CONCLUSION

PAE is non-inferior to TURP with regard to improving patient-reported outcomes, though most functional parameters undergo more changes after TURP than after PAE. Moreover, PAE can significantly continue to relieve symptoms for 24 months without causing serious complications.

KEY POINTS

• PAE is as effective as TURP in improving subjective symptom scores, with fewer complications and shorter hospitalization times. • PAE is inferior to TURP in the improvement of most functional outcomes. • Improvements due to PAE are durable during follow-up to 24 months.

Prostatic Artery Embolization: Equipment, Procedure Steps, and Overcoming Technical Challenges

In the last decade, prostatic artery embolization (PAE) established itself as a safe and effective treatment option for lower urinary tract symptoms (LUTS) attributed to benign prostate hyperplasia (BPH), with reproducible results across multiple centers and endorsement by important international societies. However, PAE is also known to be a technically demanding procedure. Accompanying the prevalence of benign prostate hyperplasia, the procedure is usually performed in older patients, in whom atherosclerosis and comorbidities are common features. Also, prostatic vascular anatomy is described to be complex and variable, and pelvic structures are deeply interconnected by anastomosis. Thus, PAE demands a deep familiarization with materials and devices, intraprocedure imaging techniques, microcatetherization skills and with the pelvic vascular anatomy. Especially in the beginning of the learning curve, the procedure can be time-consuming and related to high radiation exposure for both medical team and the patient. In this article, the main points of technical concern during PAE are described and discussed, such as the equipment needed, the effect of different embolic materials, patient's preparation for the procedure, arterial access sites, identifying and catheterizing the prostatic arteries, the embolization techniques, among others. Finally, the most frequent technical challenges are presented, and the possible strategies to overcome them are exemplified and discussed.

Prostatic artery embolization in patients with benign prostatic hyperplasia: perfusion cone-beam CT to evaluate planning and treatment response

This proof of concept is to evaluate the utility of perfusion cone-beam computed tomography (CT) in patients undergoing prostatic artery (PA) embolization (PAE) for benign prostatic hyperplasia (BPH) with moderate or severe-grade lower urinary tract symptoms (LUTS). PAE is a novel minimally invasive therapy and is both safe and effective procedure with low risks and high technical successes, making this procedure as the best alternative to surgery. A lot of technical changes would compromise clinical outcomes after procedure, including a variable prostate vascular anatomy, thin PA, and extensive atherosclerotic disease. The purpose of our study is to exploit the advantages of Perfusion Cone Beam Computed Tomography (CBCT) that could impact treatment and help interventional radiologists for treatment planning, diagnosis and for assessing the technical feasibility during PAE, mitigating the risk of nontarget embolization and suggesting clinical outcomes. Qualitative and quantitative clinical pre- and post-treatment values will be compared, to reach the best possible results.

Predictors of technical outcome for prostatic artery embolisation using pre-procedural CT angiography

OBJECTIVES

Predicting patients that will pose procedural technical challenges in prostate artery embolisation (PAE) remains difficult, with prolonged procedural times impacting on both patient dose and resource planning. Understanding the factors that influence these parameters as well as the likelihood of technical success is therefore important in effective patient selection and procedural planning.

METHODS

Data were collected retrospectively for 75 consecutive patients who underwent PAE. Multiple patient predictor variables available from planning computed tomography angiography (CTA) were identified and measured objectively. The vessel angles navigated during the procedure, prostate volume, prostate artery (PA) diameter, PA origin, aortic atheroma, iliac tortuosity and baseline demographics were correlated with outcome variables (fluoroscopy time, air kerma (AK), dose area product (DAP), the number of cone beam CTs (CBCTs)) performed and whether bilateral embolisation was possible (technical success). Data were analysed using linear regression, ANOVA, t tests and chi-squared tests.

RESULTS

Aortic atheroma severity significantly increased fluoroscopy time (p = 0.004), whilst air kerma (AK) was significantly greater in patients with smaller prostatic arteries (p = 0.009) and smaller pre-procedural prostate volumes (p = 0.038). Increased vascular tortuosity and prostatic artery origin were not shown to significantly affect fluoroscopy time or DAP. Smaller prostate artery size (p = 0.007) also increases the likelihood of either unilateral embolisation or technical failure.

CONCLUSIONS

Pre-operative prediction of technical outcome measures in PAE remains challenging. However, vascular calcification, prostatic artery diameter and prostate volume are likely to be important factors when considering the risk/benefits of PAE.

KEY POINTS

• Increased severity of atheroma and the presence of small prostate arteries increase fluoroscopy time and AK respectively during prostate artery embolisation. • Lower pre-procedural prostate volume increases the AK during procedures. • Smaller prostate artery size increases the likelihood of either unilateral embolisation or technical failure.

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.

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.

REDUCTION OF STAFF RADIATION DOSE IN PROSTATIC ARTERY EMBOLISATION

Prostatic artery embolisation (PAE) is used to treat patients with benign prostatic hyperplasia and with lower urinary obstructive tract symptoms. It is an interventional procedure which uses fluoroscopy equipment and can result in exposure to high doses of radiation in patients and staff. We aimed to demonstrate the reduction of radiation doses received by staff during PAE by implementing an optimised protocol called Radiation Exposure Curtailment for Embolisation (RECiFE). This protocol was implemented in cooperation with the medical team and technical team using Siemens Combined Applications to Reduce Exposure (CARE) protocol. The results showed approximately 83% reduction in the radiation doses received by the main physician during PAE. Thus, by adjusting the acquisition parameters of the angiographic equipment and implementing the RECiFE protocol, it is possible to optimise the PAE procedure and reduce the staff radiation dose.

ESTIMATION OF Hp(3) TO THE EYE LENS OF INTERVENTIONAL RADIOLOGISTS-RELATION BETWEEN THE EYE LENS DOSE AND RADIOLOGIST'S HEIGHT

The aim of the study was to estimate occupational radiation dose to the eye lens of radiologists and the dose reduction ratio of lead glasses during interventional radiology. Three interventional radiologists monitored Hp(3) using small-type optically stimulated luminescence dosemeters attached to the left inside and outside of the lead glasses with 0.07-mmPb [Hp(3)eye]. Hp(10) and Hp(0.07) were monitored, respectively, by attaching the personal dosemeter to the lead neck collar above the lead apron. The median Hp(3)eye with lead glasses and the median dose reduction ratio of lead glasses for the three radiologists were 8.02 mSv/y and 57.7%, respectively. The median Hp(3)eye without lead glasses [Hp(3)eye-w/o] for the three radiologists was 18.6 mSv/y, but Hp(3)eye-w/o for one of the radiologists was 24.1 mSv/y. Monitoring occupational radiation dose to the eye lens is important because interventional radiologists are at risk of exceeding the new dose limit.

RADIATION DOSES TO ANAESTHETISTS DURING PROSTATIC ARTERY EMBOLIZATION INTERVENTIONAL PROCEDURES

The objective of this study was to assess the radiation doses received by anaesthetists from prostatic artery embolization (PAE) procedures. Ten PAE procedures conducted in a reference hospital in the city of Recife, Brazil were investigated. Occupational dosimetry was performed using thermoluminescent dosemeters which were located next to the eyes, close to the thyroid (over the shielding), on the thorax (under the apron), on the wrist and on the feet of the physician's body. The results showed that the anaesthetist's feet received the highest doses followed by the eyes and the hands. In some complex PAE procedures the doses received by anaesthetists on the lens of the eyes and the effective dose were higher than those received by the main operator due to the anaesthetist's close position to the patient's table and the use of oblique projections. The personal dose equivalent Hp(3) per procedure for the anaesthetist's right eyebrow ranged from 20.2 μSv to 568.3 μSv. This result shows that anaesthetists assisting PAE procedures can exceeds the annual eye lens dose limit of 20 mSv recommended by the ICRP with only one procedure per week if radiation protection measures are not implemented during procedures.

Prostatic Artery Embolization-Anatomic Predictors of Technical Outcomes

PURPOSE

To determine if cone-beam CT and digital subtraction angiography analysis of pelvic arterial anatomy has predictive value for radiation exposure and technical success of prostatic artery embolization (PAE).

MATERIALS AND METHODS

This prospective, nonrandomized, single-center study included 104 consecutive patients with lower urinary tract symptoms secondary to benign prostatic hyperplasia. Cone-beam CT was performed in 160/208 (76.9%) hemipelves to determine prostatic artery (PA) origin. Classification of pelvic arterial tortuosity was possible in 73/104 (70.2%) patients. Learning curves of 2 interventionalists who performed 86.5% of PAEs were analyzed.

RESULTS

Tortuosity of pelvic arteries was classified as mild in 25 (34.2%) patients median age 64 years, moderate in 40 (54.8%) patients median age 69 years, and severe in 8 (11.0%) patients median age 70 years (mild vs moderate, P = .002; mild vs severe, P = .019); median fluoroscopy times were 24, 36, and 46 minutes (P = .008, P = .023); median contrast volumes were 105, 122.5, and 142 mL (P = .029, P = .064); and bilateral PAE rates were 84.0%, 77.5%, and 62.5% (P = .437), respectively. PA origin from superior vesical artery was most frequent (27.5%) and showed higher dose area product (median 402.4 vs 218 Gy ∙ cm², P = .033) and fluoroscopy time (median 42.5 vs 27 min, P = .01) compared with PA origin from obturator artery, which was least frequent. Interventionalist experience revealed significant impact on procedure times (median 159 vs 130 min, P = .006).

CONCLUSIONS

Tortuosity of pelvic arteries was more frequent in older patients and predicted worse technical outcomes of PAE. PA origin from obturator artery was associated with lower dose area product and fluoroscopy time, especially compared with PA origin from superior vesical artery. Interventionalist experience showed significant influence on technical outcome.

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.

Predictors of Prostatic Artery Embolization Technical Outcomes: Patient and Procedural Factors

PURPOSE

To identify technical factors that significantly change prostatic artery embolization (PAE) technical outcomes and to derive and test technical outcome predictive models.

MATERIALS AND METHODS

Retrospective analysis of PAEs performed by 2 operators (OPs) was performed: OP1, between April 2014 and May 2017 (n = 150); OP2, between February 2017 and December 2017 (n = 67). Multivariate analysis with mixed-effects modeling was used to test significance and derive predictive models. Mean difference was used to analyze prediction accuracy.

RESULTS

Moderate versus none subjective iliac tortuosity grade (SITG) and the presence of internal iliac atherosclerosis (PIIAA) versus none were associated with the following respective technical outcome increases: procedure time (PT): 43% (P < .01), 16% (P < .01); fluoroscopy time (FT): 47% (P < .01), 25% (P < .01); contrast volume (CV): 25.6 mL (P < .001), 13.7 mL (P = .01); and dose area product (DAP) 52% (P < .01), 20% (P = 0.03). Prostatic artery origin left obturator versus left superior vesical was associated with a 24% (P = .01) DAP decrease. For every 1 cc that prostate volume increased, CV decreased on average by 0.1 mL (P = .05). For every 1-cm decrease in patient height and 1-kg increase in weight, DAP increased on average by 0.02% (P < .01) for each. Unilateral versus bilateral versus 3-vessel embolization resulted in a 16.3-mL CV decrease on average for each additional vessel embolized (P = .03). The mean absolute differences between predicted and measured technical outcome values were: PT: 16 minutes, FT: 7 minutes, CV: 25 mL, and DAP: 44 Gy·cm².

CONCLUSIONS

In this study, higher SITGs and PIIAA most likely contributed to higher technical outcomes when controlling for the 2 OPs.

Prostatic Artery Embolization versus Standard Surgical Treatment for Lower Urinary Tract Symptoms Secondary to Benign Prostatic Hyperplasia: A Systematic Review and Meta-analysis

CONTEXT

Prostatic artery embolization (PAE) has been introduced into clinical practice for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH-LUTS) despite a lack of high-level evidence.

OBJECTIVE

To perform a systematic review and meta-analysis of clinical trials comparing efficacy and safety of PAE versus established surgical therapies.

EVIDENCE ACQUISITION

Medline, Embase, and York CRD were searched up to June 23, 2018. Only comparative studies were included. The risk of bias was assessed by the Cochrane Collaboration tool. Meta-analyses were performed using RevMan 5.3.

EVIDENCE SYNTHESIS

Five studies including 708 patients met the selection criteria. Risk of bias was rated high for most of the studies. Mean reduction in the International Prostate Symptom Score was lower after PAE compared with standard surgical therapies (mean difference 3.80 points [95% confidence interval: 2.77-4.83]; p<0.001). PAE was less efficient regarding improvements in all functional parameters assessed including maximum urinary flow, post void residual, and reduction of prostate volume. In contrast, patient-reported erectile function (International Index of Erectile Function 5) was better after PAE and significantly fewer adverse events occurred after PAE.

CONCLUSIONS

Moderately strong evidence confirms efficacy and safety of PAE in the treatment of BPH-LUTS in the short term. Significant advantages regarding safety and sexual function, but clear disadvantages regarding all other patient-reported and functional outcomes were found for PAE. Large-scale randomized controlled trials including longer follow-up periods are mandatory before PAE can be considered as a standard therapy and to define the ideal indication for PAE in the management of BPH-LUTS.

PATIENT SUMMARY

We reviewed the role of prostatic artery embolization (PAE) in the treatment of symptoms associated with benign overgrowth of the prostate. The results suggest that PAE is not as effective as established surgical therapies but has fewer side effects. Further research is required to determine whether PAE is the best treatment for certain types of patients. PAE should, therefore, not yet be considered a standard treatment.

Comparison of prostatic artery embolisation (PAE) versus transurethral resection of the prostate (TURP) for benign prostatic hyperplasia: randomised, open label, non-inferiority trial

OBJECTIVE

To compare prostatic artery embolisation (PAE) with transurethral resection of the prostate (TURP) in the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia in terms of patient reported and functional outcomes.

DESIGN

Randomised, open label, non-inferiority trial.

SETTING

Urology and radiology departments of a Swiss tertiary care centre.

PARTICIPANTS

103 patients aged ≥40 years with refractory lower urinary tract symptoms secondary to benign prostatic hyperplasia were randomised between 11 February 2014 and 24 May 2017; 48 and 51 patients reached the primary endpoint 12 weeks after PAE and TURP, respectively.

INTERVENTIONS

PAE performed with 250-400 μm microspheres under local anaesthesia versus monopolar TURP performed under spinal or general anaesthesia.

MAIN OUTCOMES AND MEASURES

Primary outcome was change in international prostate symptoms score (IPSS) from baseline to 12 weeks after surgery; a difference of less than 3 points between treatments was defined as non-inferiority for PAE and tested with a one sided t test. Secondary outcomes included further questionnaires, functional measures, magnetic resonance imaging findings, and adverse events; changes from baseline to 12 weeks were compared between treatments with two sided tests for superiority.

RESULTS

Mean reduction in IPSS from baseline to 12 weeks was -9.23 points after PAE and -10.77 points after TURP. Although the difference was less than 3 points (1.54 points in favour of TURP (95% confidence interval -1.45 to 4.52)), non-inferiority of PAE could not be shown (P=0.17). None of the patient reported secondary outcomes differed significantly between treatments when tested for superiority; IPSS also did not differ significantly (P=0.31). At 12 weeks, PAE was less effective than TURP regarding changes in maximum rate of urinary flow (5.19 v 15.34 mL/s; difference 10.15 (95% confidence interval -14.67 to -5.63); P<0.001), postvoid residual urine (-86.36 v -199.98 mL; 113.62 (39.25 to 187.98); P=0.003), prostate volume (-12.17 v -30.27 mL; 18.11 (10.11 to 26.10); P<0.001), and desobstructive effectiveness according to pressure flow studies (56% v 93% shift towards less obstructive category; P=0.003). Fewer adverse events occurred after PAE than after TURP (36 v 70 events; P=0.003).

CONCLUSIONS

The improvement in lower urinary tract symptoms secondary to benign prostatic hyperplasia seen 12 weeks after PAE is close to that after TURP. PAE is associated with fewer complications than TURP but has disadvantages regarding functional outcomes, which should be considered when selecting patients. Further comparative study findings, including longer follow-up, should be evaluated before PAE can be considered as a routine treatment.

TRIAL REGISTRATION

Clinicaltrials.gov NCT02054013.

Patient Radiation Exposure in Transradial versus Transfemoral Yttrium-90 Radioembolization: A Retrospective Propensity Score-Matched Analysis

PURPOSE

To compare differences in patient radiation exposure (PRE) during transarterial yttrium-90 (⁹⁰Y) radioembolization (TARE) between transradial access (TRA) and transfemoral access (TFA).

MATERIALS AND METHODS

A total of 810 consecutive first-time TARE procedures in patients from 2013 to 2017 were retrospectively reviewed. A propensity score-matching (PSM) analysis matched TRA and TFA groups on the basis of patient age, sex, weight, height, cancer type, ⁹⁰Y microsphere type, and number of previous procedures from the same and opposite approaches. Matched groups were then compared by PRE measures fluoroscopy time (FT), dose-area product (DAP), and cumulative air kerma (AK). Effect size for each PRE measure was calculated.

RESULTS

Before PSM, TRA and TFA groups differed significantly in mean age, weight, and number of previous procedures from the same and opposite approach (all P < .05). After PSM, each group consisted of 302 procedures (overall, n = 604) and no longer differed in any procedure performed before surgery measure. TRA did not differ from the matched TFA group regarding median FT (9.50 vs 9.40 minutes, P = .095), median DAP (67,066 vs 67,219 mGy·cm²; P = .19), or median AK (323.63 vs 248.46 mGy; P = .16). Effect sizes were 0.068, 0.054, and 0.110 for FT, DAP, and AK, respectively.

CONCLUSIONS

No statistical differences were found for PRE measures between the matched TRA and TFA approach groups. Furthermore, practical effect sizes were considered to be small for AK and less than small for FT and DAP, and therefore, any differences in PRE between the radial and femoral approaches for TARE are minor and unlikely to be noticeable in everyday clinical practice.

Prostatic artery embolization for benign prostatic obstruction: assessment of safety and efficacy

PURPOSE

Prostatic artery embolization (PAE) has seen a recent increase in interest as a treatment for men with benign prostatic obstruction (BPO). The appeal of this intervention lies in reported reduction in morbidity and its minimally invasive nature. The purpose of this review is to assess the safety and efficacy of PAE as a new treatment in BPO and explore risks surrounding its performance.

METHODS

A review of the literature was performed. Medical databases searched included PubMed, EMBASE, and Cochrane databases, limited to English, peer-reviewed articles. Search terms included prostatic artery embolization, lower urinary tracts symptoms, minimally invasive therapies, interventional radiology prostate, and benign prostatic hyperplasia. Articles were screened by two independent reviewers for content on development, methods, outcomes, and complications of PAE.

RESULTS

Suitability of patients to undergo PAE depends on review of patient history, pre-procedure visualisation of appropriate vascular anatomy and clinical parameters. Despite this selection of candidates favourable for procedural success, PAE is not without risk of complications, some of which can significantly affect patient quality of life.

CONCLUSIONS

Although initial findings show promise regarding safety and efficacy of PAE in improving symptom and quality-of-life scores, further investigation is required to establish durability of effect and the appropriate use of this experimental modality. There is currently limited robust evidence for the beneficial outcomes of PAE. Long-term follow-up studies will add to the evidence base to help further assess the feasibility of this procedure as an alternative to TURP.