Radiation Exposure During Prostatic Artery Embolisation: A Systematic Review and Calculation of Associated Risks

[Minimally-Invasive Surgical Techniques (MIST): Shedding Light on the Mist]

As life expectancy increases and there is growing demand for BPH treatments, innovative technologies have been developed, allowing for swift recovery, symptom relief, low complication rates, and the possibility of performing procedures on an outpatient basis, often under local anaesthesia. This review aims to describe the outcomes of newly developed minimally-invasive surgical therapies (MIST) for BPH treatment in terms of functional voiding parameters and sexual function. These therapies are categorized into primarily ablative (Aquablation [Aquabeam]), non-ablative (Prostatic Urethral Lift (PUL, Urolift), temporary implantable devices [iTind]), and secondarily ablative procedures (convective water vapor ablation, Rezum, Prostate Artery Embolization [PAE]). All MIST technologies have advanced the medical care of patients with BPH while preserving ejaculation. However, there is a shortage of long-term data specifically addressing re-intervention rates and the preservation of functional voiding parameters. Although there is promising data from regulatory trials and randomized studies, all MIST therapies are potentially associated with severe complications. Patients considering such methods must be thoroughly informed about their inferiority compared with established transurethral procedures like TUR-P and enucleation.

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.

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.

One-year outcomes after prostate artery embolization versus laser enucleation: A network meta-analysis

Background

Although holmium laser enucleation (HoLEP) is considered a size-independent procedure for treatment of an enlarged prostate, prostate artery embolization (PAE) is emerging as an alternative modality to treat moderate and large benign prostatic hyperplasia. This study aims to compare the early post-operative and short-term efficacy of PAE and HoLEP.

Methods

PubMed, Cochrane Library and EMBASE databases were searched. Network meta-analysis was performed following PRISMA-N-guidelines. Post-operative parameters analysed include international prostate symptom score (IPSS), quality of life (QOL), post-void residual urine (PVR), maximal uroflow rate (Qmax) and serious adverse events (SAE). Random effects model calculated weighted mean differences (WMD). If 95%CI crossed the line of no effect (WMD = 0), evidence indicated no statistically significant difference between treatments compared.

Results

Qualitative and quantitative syntheses included 20 and 18 studies with 1991 and 1606 patients, respectively. At 3 months, there was no statistically significant difference between PAE and HoLEP in IPSS score improvement [WMD: -2.21: 95%CI: (-10.20, 5.78), favouring PAE], QoL score improvement [WMD: -0.22:95%CI: (-1.75, 1.32), favouring PAE] and PVR improvement [WMD: 26.97: 95%CI: (-59.53, 113.48), favouring HoLEP]. However, PAE was found inferior to HoLEP for Qmax improvement [WMD: 8.47, 95%CI: (2.89, 14.05), favouring HoLEP]. At 1-year follow-up, there was no statistically significant was found between PAE and HoLEP for IPSS score improvement [WMD:6.03, 95%CI: (-1.30, 13.35)], QoL score improvement [WMD: 0.03, 95%CI: (-1.19, 1.25)], PVR improvement [WMD:4.11, 95%CI: (-32.31, 40.53)] and Qmax improvement [WMD:2.60, 95%CI: (-2.20, 7.41)] with all differences favouring HoLEP. PAE was superior to HoLEP for SAE [PAE vs. HoLEP-OR: 0.68, 95%CI: (0.25, 1.37)].

Conclusion

HoLEP was superior to PAE at 3 months for Qmax improvement. There was no significant difference in IPSS, QoL, PVR and Qmax improvement at 1 year between PAE and HoLEP. PAE was also associated with lesser SAE compared to HoLEP. Studies on the long-term outcome of PAE are needed to establish the durability of early outcomes after PAE.

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.

Prostatic Artery Embolisation: Do We Still Need It and for Whom?

Prostatic artery embolisation (PAE) is now endorsed by international evidence-based guidelines as a treatment for lower urinary tract symptoms presumed secondary to benign prostatic obstruction (LUTS/BPO) for selected patients. PAE is a truly minimally invasive technique, with proven efficacy and safety demonstrated for the short- to mid-term. As it has a unique treatment approach (endovascular instead of transurethral), its profile and ideal application differ clearly from other treatments for LUTS/BPO, which must be considered for patient selection. This mini review examines the role of PAE in the treatment of LUTS/BPO on the basis of current evidence. PATIENT SUMMARY: For properly selected patients, prostatic artery embolisation (PAE), in which arteries feeding the prostate are blocked in a nonsurgical procedure, is one of the treatment options for obstruction of urine outflow caused by benign enlargement of the prostate. This article examines the role of PAE according to the evidence available in the literature.

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.

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.

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: 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.

Prostatic Artery Embolisation Versus Transurethral Resection of the Prostate for Benign Prostatic Hyperplasia: 2-yr Outcomes of a Randomised, Open-label, Single-centre Trial

BACKGROUND

Prostatic artery embolisation (PAE) for the treatment of lower urinary tract symptoms secondary to benign prostatic obstruction (LUTS/BPO) still remains under investigation.

OBJECTIVE

To compare the efficacy and safety of PAE and transurethral resection of the prostate (TURP) in the treatment of LUTS/BPO at 2 yr of follow-up.

DESIGN, SETTING, AND PARTICIPANTS

A randomised, open-label trial was conducted. There were 103 participants aged ≥40 yr with refractory LUTS/BPO.

INTERVENTION

PAE versus TURP.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

International Prostate Symptoms Score (IPSS) and other questionnaires, functional measures, prostate volume, and adverse events were evaluated. Changes from baseline to 2 yr were tested for differences between the two interventions with standard two-sided tests.

RESULTS AND LIMITATIONS

The mean reduction in IPSS after 2 yr was 9.21 points after PAE and 12.09 points after TURP (difference of 2.88 [95% confidence interval 0.04-5.72]; p =  0.047). Superiority of TURP was also found for most other patient-reported outcomes except for erectile function. PAE was less effective than TURP regarding the improvement of maximum urinary flow rate (3.9 vs 10.23 ml/s, difference of -6.33 [-10.12 to -2.54]; p <  0.001), reduction of postvoid residual urine (62.1 vs 204.0 ml; 141.91 [43.31-240.51]; p =  0.005), and reduction of prostate volume (10.66 vs 30.20 ml; 19.54 [7.70-31.38]; p =  0.005). Adverse events were less frequent after PAE than after TURP (total occurrence n = 43 vs 78, p =  0.005), but the distribution among severity classes was similar. Ten patients (21%) who initially underwent PAE required TURP within 2 yr due to unsatisfying clinical outcomes, which prevented further assessment of their outcomes and, therefore, represents a limitation of the study.

CONCLUSIONS

Inferior improvements in LUTS/BPO and a relevant re-treatment rate are found 2 yr after PAE compared with TURP. PAE is associated with fewer complications than TURP. The disadvantages of PAE regarding functional outcomes should be considered for patient selection and counselling.

PATIENT SUMMARY

Prostatic artery embolisation is safe and effective. However, compared with transurethral resection of the prostate, its disadvantages regarding subjective and objective outcomes should be considered for individual treatment choices.

Reasons to consider prostatic artery embolization

PURPOSE

Prostatic artery embolization (PAE) has emerged as a truly minimally invasive treatment option for patients with lower urinary tract symptoms presumed secondary to benign prostatic obstruction (LUTS/BPO) over the last few years and is now supported by evidence-based international guidelines. Here, we provide an overview on the profile of PAE based on the most relevant and recent literature.

METHODS

A comprehensive review of literature on PAE was conducted on PubMed-Medline. The most relevant literature was summarized narratively.

RESULTS

While there is still a lack of long-term data, efficacy and safety data have been published for the short to mid-term. As with any minimally invasive technique, relief of bladder outlet obstruction is less pronounced after PAE compared to more invasive resective techniques. This is likely to be associated with higher re-intervention rates during the longer term. However, due to its beneficial safety profile, PAE represents an interesting option for many patients and could fill a niche between pharmacotherapy and formal surgical intervention. Given its unique treatment approach, i.e. endovascular instead of transurethral, PAE has a clearly different profile compared to other minimally invasive treatments. Performance with local anesthesia with possible continuation of anticoagulant drugs and no upper prostate size limit are the most important advantages of PAE.

CONCLUSION

PAE represents a valuable supplement in the treatment armamentarium of LUTS/BPH if patients are selected appropriately.

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.

[A (new) revolution in the treatment of benign prostatic hyperplasia? Aqua-ablation and prostate embolization]

Surgical treatment of benign prostatic obstruction (BPO) is one of the most common procedures in urology. Numerous alternative methods have been developed in recent years to overcome the potential limitations of transurethral resection of the prostate (TURP) while providing comparable effectiveness and less morbidity. In a randomized study with a currently available follow-up of 3 years, the Aquabeam® system has shown comparable functional results with a lower rate of adverse events compared to TURP. Sufficient functional results were also found in a cohort study in patients with prostate volumes up to 150 ml. However, the rate of transfusions raises the question of optimal coagulation. Further cohort studies with short-term follow-up confirmed the results of the randomized studies. Prostate artery embolization (PAE) has been compared to TURP in several randomized trials. In randomized studies, the reduction of BPO-associated symptoms after PAE is only slightly inferior to that after TURP. In contrast, the improvement of functional parameters after embolization is inferior to that after TURP. This is primarily due to the inferior desobstruction. In addition, long-term results from randomized studies are lacking, so that no final assessment has yet been possible with regard to the durability of the desobstruction. In summary, both Aquabeam® and PAE are potential alternatives to standard methods, which-in case of adequate patient selection-can supplement the operative armamentarium in the wider concept of an individualized therapy of BPO.