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

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

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

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Virtual Injection Software Reduces Radiation Exposure and Procedural Time of Prostatic Artery Embolization Performed with Cone-Beam CT

PURPOSE

To evaluate the impact of virtual injection software (VIS) use during cone-beam computed tomography (CT)-guided prostatic artery embolization (PAE) on both patient radiation exposure and procedural time.

MATERIALS AND METHODS

This institutional review board (IRB)-approved comparative retrospective study analyzed the treatment at a single institution of 131 consecutive patients from January 2020 to May 2022. Cone-beam CT was used with (Group 1, 77/131; 58.8%) or without VIS (Group 2, 54/131, 41.2%). Radiation exposure (number of digital subtraction angiography [DSA] procedures), dose area product (DAP), total air kerma (AK), peak skin dose (PSD), fluoroscopy time (FT), and procedure time (PT) were recorded. The influences of age, body mass index, radial access, and use of VIS were assessed.

RESULTS

In bivariate analysis, VIS use (Group 1) showed reduction in the number of DSA procedures (8.6 ± 3.7 vs 16.8 ± 4.3; P < .001), DAP (110.4 Gy·cm2 ± 46.8 vs 140.5 Gy·cm2 ± 61; P < .01), AK (642 mGy ± 451 vs 1,150 mGy ± 637; P = .01), PSD (358 mGy ± 251 vs 860 mGy ± 510; P = .001), FT (35.6 minutes ± 15.4 vs 46.6 minutes ± 20; P = .001), and PT (94.6 minutes ± 41.3 vs 115.2 minutes ± 39.6, P = .005) compared to those in Group 2. In multivariate analysis, AK, PSD, FT, and PT reductions were associated with VIS use (P < .001, P < .001, P = .001, and P = .006, respectively).

CONCLUSIONS

The use of VIS during PAE performed under cone-beam CT guidance led to significant reduction in patient radiation exposure and procedural time.

Angiographic Imaging of Prostatic Artery Origin in a Greek Population and Correlation With Technical and Clinical Aspects of Prostatic Artery Embolization

Background This study aimed, first, to angiographically investigate and analyze prostatic artery (PA) origin in a Greek male population with benign prostatic hyperplasia (BPH) treated with prostatic artery embolization (PAE) and, second, to correlate prostatic arterial anatomy with technical and clinical aspects of PAE. Methodology This was a retrospective study of BPH patients who underwent PAE in a single tertiary center in Greece from June 2019 to July 2022. For the first part of the study, PA was imaged with computed tomography angiography (CTA) before PAE and with digital subtraction angiography (DSA) during PAE in all patients. A widely accepted system for the classification of PA origin was applied. Type I, a common origin of PA and superior vesical artery (SVA) from the anterior division of internal iliac artery (IIA). Type II, PA originating from the anterior division of IIA, separate from, and inferior to SVA. Type III, the origin of PA from the obturator artery. Type IV, the origin of PA from the internal pudendal artery. Type V, rarer origins of PA. For the second part of the study, a subgroup of patients from the first part (treated with the same PAE protocol and free of vascular pathology that could have interfered with the technical success of PAE) was selected. In this subgroup, differences in PA origin were correlated with technical aspects (feasibility of catheterization of PA, fluoroscopy time (FT), dose area product (DAP)) and clinical outcomes of PAE. Results After the exclusion of four patients, 159 patients were included in the first part of the study. From a total of 355 PAs, 110 (31%) were compatible with type I, 58 (16.3%) type II, 45 (12.7%) type III, 110 (31%) type IV, and 32 (9%) type V. PA origin from an accessory internal pudendal artery was the most common among the rare origins of type V. Regarding the second part of the study (a subgroup of 101 patients selected to facilitate comparisons between the different types of PA origin), type I was associated with significantly more incidences of failed or difficult catheterization of the PA compared to all other types combined (27/64 vs. 18/138, p < 0.001). Types III, IV, and V showed a relatively low degree of technical difficulty. Patients with type I PA origin of at least one pelvic side (subgroup (I), n = 48) had significantly longer FT and DAP compared to the rest (subgroup (O), n = 53). Clinical success rates of PAE were slightly lower for the subgroup (I), although the difference was not statistically significant (75.8% vs. 83.8% at 18 months post-PAE, p = 0.137). No major complications were observed. Conclusions This is the first study of PA origin in Greece. It was demonstrated that types I and IV of PA origin were the most common and had the same prevalence. Type I showed significantly higher technical difficulty compared to the others, but had no significant impact on the clinical outcomes of PAE.

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

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

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

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

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

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.

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.