Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization

Clinical question
Is baseline ultrasound elastography predictive of prostate artery embolization efficacy?

Take away point
Baseline prostatic elastic modulus and shear wave velocity measurements each predict efficacy of prostate artery embolization at 1 year.

Reference
de Assis A.M., Moreira A.M., Carnevale F.C., Marcelino A.S.Z., Antunes A.A., Srougi M., and Cerri G.G. Role of Ultrasound Elastography in Patient Selection for Prostatic Artery Embolization. J Vasc Interv Radiol. 2021 Oct; 32 (10): 1410-1416.

Click here for abstract

Study design
Prospective, observational, descriptive, single-center cohort study.

Funding Source
No reported funding

Setting
Academic setting. University of Sao Paulo Medical School, Sao Paulo, Brazil.

Figure

Figure Scatter plots showing a moderate positive correlation between baseline SWV and 12-month IPSS (R = 0.68, P = .002) (a) and EM and 12-month IPSS (R = 0.62, P = .007) (b). EM = elastic modulus, IPSS = International Prostate Symptom Score (IPSS < 8, optimal; IPSS ≥ 8, suboptimal), SWV = shear wave velocity.

Summary

Ultrasound elastography (US-E) has recently been described as a novel tool to evaluate prostate artery embolization (PAE) outcomes with anatomical and functional assessments in patients with benign prostatic hyperplasia (BPH). US-E demonstrated that PAE not only treats bladder outlet obstruction (BOO) by reducing prostate volume, but also by improving the α-adrenergic mediated effect on prostatic muscular tonus, which addresses the dynamic component of BOO. While recent US-E research gave interesting insights on PAE mechanism of action, research on the prognostic role of US-E is lacking.

The authors performed a prospective, observational, descriptive, single-center cohort study involving 20 consecutive patients. Inclusion criteria were lower urinary tract symptoms LUTS) attributed to BPH for at least 6 months refractory to standard medical treatment (α-1 adrenergic receptor antagonist with or without 5-α reductase inhibitor), international prostate symptom score (IPSS) ≥ 8, and prostate volume ≥ 40 cm3 and ≤ 200 cm3. Exclusion criteria were biopsy-confirmed cancer, active urinary infection, presence of urinary retention requiring use of Foley urinary catheter, serum creatinine ≥ 2 mg/dL, and previous pelvic surgery or radiotherapy. From February 2018 to October 2019, 20 patients met inclusion criteria but 2 did not return for follow up and 1 refused to complete evaluation therefore the remaining 17 entered statistical analysis.

Primary endpoints were prostatic elastic modulus (EM) and shear wave velocity (SWV) assessed with US-E up to 30 days before and at 23–37 days after PAE. Patients on α-1 adrenergic antagonist were maintained until after the second US-E evaluation, after which the medication was permanently withdrawn. Secondary endpoints included IPSS questionnaire, IPSS-Quality of Life (QoL) item, and peak urinary flow rate (Qmax) assessed using uroflowmetry, among others. All ultrasound examinations were performed transrectally with an 11C3 endocavity probe (Toshiba Medical Systems Corporation, Otawara, Japan) on a Toshiba Aplio i800 (Toshiba Medical Systems Corporation) utilizing 2-dimensional sound wave elastography (SWE) via acoustic structure quantification and dynamic energy generation via acoustic radiation force impulse that generated multifocal stress and enabled EM and SWV measurement by building colored elastographic maps. This meant the exams did not depend on tissue compression by the operator during examinations. EM and SWV values were obtained from maps including the transitional zone of both lobes of the prostate simultaneously in at least 2 axial slices at the middle third of the prostate. All examinations were performed by the same radiologist (A.S.Z.M.).

Pearson product-moment correlation tests were used to assess association of IPSS at 1 year with baseline EM and SWV. Receiver operating characteristic (ROC) curves were used to determine predictive cutoff values of baseline EM and SWV. PAE efficacy at 1 year was considered optimal at IPSS < 8, QoL < 2, or Qmax ≥ 12 mL/s, respectively. Area under ROC curves were obtained at 95% confidence interval and statistical significance was defined as bicaudal type I error (p) < 0.05.

16 of the 17 patients (94.1%) underwent bilateral PAE. Catheterization was technically unsuccessful in the remaining 1 patient (5.9%) due to atherosclerosis. EM was moderately positively correlated with IPSS at 1 year (R = 0.62) and SWV was slightly more positively correlated with IPSS at 1 year (R =0.68), with both correlations being statistically significant (p = 0.007 and p = 0.002, respectively). SWV was also slightly positively correlated with QoL at 1 year but without statistical significance (p = 0.09, R = 0.41). Baseline EM ≥ 50.14 kPa predicted suboptimal IPSS with 84.6% specificity, suboptimal QoL with 68.8% specificity, and suboptimal Qmax with 80.0% specificity; and baseline SWV ≥ 5.9 m/s predicted suboptimal IPSS with 100% specificity, suboptimal QoL with 81.3% specificity, and suboptimal Qmax with 90.0% specificity. Results consistently demonstrated inferior PAE outcomes for patients with very low initial prostate elasticity, with potential to predict patient suitability for PAE using the possible prognostic cutoff values of EM < 50.14 kPa and/or SWV < 5.9 m/s.

Commentary

This study (1) further described PAE’s effect on prostate elasticity as measured via EM and SWV, and (2) explored the prognostic value of US-E in categorizing patients as good candidates for PAE by assessing IPSS, QoL, and Qmax at 1 year. A notable advantage to this study was the use of ultrasound that utilized dynamic energy generation via acoustic radiation force impulse, which meant ultrasound exams were not operator dependent. 

Possible limitations include the fact that all ultrasounds were read by the same radiologist, who is one of the authors and no indication of blinding was described, and the sample size of 17. 

This research further supports the hypothesis that PAE’s efficacy is based, at least partially, on prostate elasticity, which is a dynamic component to BOO. The results suggest a potential prognostic role for US-E in patient stratification for PAE. Additional future study, perhaps multi-center and/or with blinding, can be helpful in continuing to explore these initial promising results.

Additional Reading:

Video presentation on the history and development of shear wave elastography: https://www.spiedigitallibrary.org/conference-proceedings-of-spie/11242/112420B/Shear-wave-elastography--from-ultrasound-to-optics/10.1117/12.2540509.full?SSO=1

Review on acoustic radiation force impulse imaging: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3337770/

Post Author
Zayn Mohamed, JD
MS-4 Doctor of Medicine Candidate,
University of South Florida Morsani College of Medicine

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Modified Microcoil for Preoperative Localization of Solitary Pulmonary Nodules: A Prospective, Single-Arm, Multicenter Clinical Study

Clinical Question:
What is the efficacy and safety of the modified microcoil device for use in precise preoperative localization of solitary pulmonary nodules (SPNs) prior to video-assisted thorascopic surgery (VATS)?

Take Away Point:
Image-guided percutaneous placement of the modified microcoil device can facilitate efficient thorascopic resection of SPNs.

Reference:
Modified Microcoil for Preoperative Localization of Solitary Pulmonary Nodules: A Prospective, Single-arm, Multicenter Clinical Study. Zhang, Zhiyuan, et al. Journal of Vascular and Interventional Radiology. 2021; 32: 1470-1477. doi.org/10.1016/j.jvir.2021.06.026.

Click here for abstract

Study Design:
Prospective, single-arm, multicenter clinical study.

Funding Source:
Beijing Municipal Science & Technology Commission, Capital Funds for Health Improvement and Research, and Beijing Municipal Administration of Hospitals Clinical Medicine Development of Special Funding Support.

Setting:
Three (3) Institutions; (1) Beijing Friendship Hospital, Capital Medical University, China. (2) The First Affiliated Hospital of Bengbu Medical College, Bengbu, China. (3) Nantong Tumor Hospital, Nantong, China.

Summary:

Video-assisted thorascopic surgery (VATS) is a minimally invasive option for malignant lung tumor removal. However, a large percentage of solitary pulmonary nodules (SPNs) are not localized or palpated during VATS, particularly non-solid/semisolid nodules, of which up to 78% have been reported to contain malignancy. Localization of SPNs prior to surgery can significantly improve VATS success rate. Several techniques are currently utilized to localize pulmonary lesions before excision, including both liquid markers and solid metallic markers/hooks.


A new modified microcoil device (designed in collaboration with Cherish Medical Device; Jiangsu, China) was prospectively evaluated as a method to enhance preoperative SPN coil localization. The device (Figure 1) involves partial insertion of the microcoil within the lung parenchyma, with its tail placed above the visceral pleura (Figure 2).


The prospective, multi-center study included 96 consecutive patients (96 PMNs) from 3 medical centers who underwent CT-guided SPN localization. Inclusion criteria included patients aged 18-75 years with peripheral lung nodules (diameter ≤ 2cm). Patients were excluded if they were deemed unsuitable secondary to clinical limitations, severe systemic disease, organ failure, or coagulation disorders.

Primary outcomes were measured as both technical and clinical success. (1) Technical success was defined as microcoil deployment within 10 mm of lesion edge and (2) Clinical success was defined as successful microcoil positioning with visual confirmation during VATS, lack of microcoil dislodgement or displacement, and maintained coil integrity during excision. Secondary outcomes were safety, including complications during deployment and any adverse device-related events.

Technical success rate was 100% and clinical success rate was 96.9% (95% CI, 91%-99%); all 96 nodules were successfully resected during VATS. Microcoil dislodgement occurred in 3 patients, likely due to nodule proximity to the visceral pleura. The complication rate was 1% with  asymptomatic pneumothorax not requiring intervention (minor complication) incurred in 1 patient and no major complications otherwise. All nodules were resected. No major complications or cancer recurrences were observed 90 days following excision.

Commentary:

The authors conclude that the new modified microcoil device is safe and effective for SPN localization prior to VATS, with a reported localization success rate of 96.9% and SPN resection rate of 100%, without the need for fluoroscopy.

Specifically, the authors highlight features of the microcoil device including a helical tail to clearly mark the pleural surface without the need for fluoroscopy, a push rod with marking scale allowing rapid and accurate deployment, and microcoils of various lengths to compensate for SPN location variability.

Techniques for pulmonary nodule needle localizations have been previously described and typically involve wire-localization with the modified hook needle technique (e.g. Kopans, Hawkins) and/or methylene blue staining. However these techniques could only be utilized in the immediate pre-procedural setting. This device allowed for much more flexibility in the timing of surgical excision (e.g. following-day VATS) while maintaining a very low complication rate.

The reported results illustrating the safety and effectiveness of the new modified microcoil device are promising. However, the study was not without its limitations. Learning curve was not evaluated. Only patients with solitary lung nodule were included in the study. And most importantly, there was no comparison group and therefore the comparative benefits of this device and its associated technique could not be evaluated. Large-scale, randomized clinical trials are needed to determine whether the modified microcoil has advantages over other devices such as conventional microcoils and hook wires

Additional Ref:
Thistlethwaite, P. A., Gower, J. R., Hernandez, M., Zhang, Y., Picel, A. C., & Roberts, A. C. (2018). Needle localization of small pulmonary nodules: Lessons learned. The Journal of Thoracic and Cardiovascular Surgery, 155(5), 2140–2147. https://doi.org/10.1016/j.jtcvs.2018.01.007

Post Author:
Noam Kupfer, MD (PGY-3)
Vascular & Interventional Radiology (Integrated) Residency, Class of 2025
Rush University Medical Center

David M. Tabriz, MD
Assistant Professor - Vascular & Interventional Radiology
Program Director - Vascular & Interventional Radiology (Integrated) Residency
Program Director - Vascular & Interventional Radiology (Independent) Residency
Rush University Medical Center
@DrDaveTabriz

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Percutaneous MR Imaging-Guided Laser Ablation and Cryoablation for the Treatment of Pediatric and Adult Symptomatic Peripheral Soft Tissue Vascular Anomalies

Clinical question
Is magnetic resonance (MR) imaging-guided laser ablation, cryoablation safe and effective in treating symptomatic soft tissue vascular anomalies (VAs) in the trunk and extremities?

Take-away point
MR imaging-guided laser ablation and cryoablation are both safe and effective in treating symptomatic soft tissue VAs in the trunk and extremities.

Reference
Augustine MR, Thompson SM, Powell GM, et al. Percutaneous MR imaging-guided laser ablation and cryoablation for the treatment of pediatric and adult symptomatic peripheral soft tissue vascular anomalies. Journal of Vascular and Interventional Radiology. 2021;32(10):1417-1424.

Click here for abstract

Study design
Retrospective cohort study

Funding source
Self-funded or unfunded

Setting
Single institution, Mayo Clinic Rochester, MN

Figure

Figure 1. Magnetic resonance (MR) imaging-guided laser ablation in an 8-year-old female patient with persistent pain from a right lateral thigh intramuscular slow flow venous malformation after multiple prior percutaneous sclerotherapy treatments. (a) The T2-weighted preablation MR image showed a hyperintense intramuscular slow flow venous malformation in the right lateral thigh (yellow arrow). (b) Intraprocedural T2-weighted MR imaging showed the laser fiber (yellow arrow) traversing the venous malformation. The venous malformation was ablated with multiple pullback activations of the laser fiber. After ablation, (c) the T2-weighted and (d) T1-weighted gadolinium-enhanced images showed a decreased T2 signal and enhancement throughout the venous malformation (yellow arrows).

Summary

Soft tissue vascular anomalies (VAs), also referred to as vascular tumors, can result in significant symptomatology whether benign or malignant, simple or combined. These symptoms can be localized, such as pain and cosmetic issues, as well as systemic and life-threatening such as high-output heart failure or consumptive coagulopathy. These masses have classically been treated with surgical resection, percutaneous sclerotherapy, or transarterial embolization depending on characteristics such as size, location, proximity to critical structures, and flow. These modalities often have variable success, requiring multiple treatments to attain remission. Percutaneous ablation procedures, including radiofrequency (RF), cryoablation, and laser ablation, have been demonstrated to be safe and effective in treating the more refractory VAs. However, the most-commonly employed imaging modalities, ultrasound and computed tomography (CT), are limited in their abilities to visualize vascular lesions. Magnetic resonance (MR) imaging is a promising alternative given its unmatched ability in delineating soft-tissue boundaries and its demonstrated ability to effectively monitor treatment response in VAs.

In this retrospective case series, patients with symptomatic VAs treated with MR-guided laser ablation or cryoablation over an approximately 6-year period were analyzed. Patients were included if they had persistently and locally symptomatic VAs after previous first-line therapies, were not offered further first-line therapies, and had lesions in locations that were deemed safe for ablation procedures. All patients underwent pre-procedural MRI and had their pain assessed on the visual analog scale (VAS). Post-procedurally, patients followed up 6-12 months later to have their pain reassessed. This was done via VAS, and patients were classified as either having complete, partial, or no resolution of symptoms. Post-ablation MRI was only obtained if patients had residual symptoms, which occurred in 17 patients. Pre- and post-ablation MR images were compared in terms of maximum VA diameter of the T2 hyperintense portion, semiquantitative percentage enhancement of the total VA at baseline, and the percentage decrease in the T2 signal and enhancement at follow-up. Major and minor complications were also analyzed.

30 patients with 34 VAs treated over 60 sessions were included in this study. The VAs were located in the thorax (n = 3), abdomen/pelvis (n = 2), upper arm (n = 5), forearm (n = 1), hand (n = 1), thigh/hip (n = 12), and lower leg (n = 10). 31 VAs in 27 of the patients caused moderate to severe pain and 3 VAs in 3 patients caused swelling/mass effect, prompting treatment. Mean baseline pain score in painful VAs was 6.4 ± 1.6. 9 patients were taking analgesics to manage this pain, including 2 taking narcotics, 2 taking both narcotic and non-narcotic medications, and 4 patients taking neuromodulatory medications. All 34 VAs were classified as low-flow malformations. Of the 60 ablation procedures, 49 were done with laser, 10 with cryoablation, and 1 with both. The median number of ablations per VA was 1.5 (1-7). 27 ablations utilized both US and MR guidance while 33 used MR alone. Laser ablation was the default modality choice while cryoablation was used in cases in cases with nearby critical structures. 18 sessions resulted in same-day discharge, 36 resulted in overnight observation, and 6 were admitted for greater than 24 hours. All 6 admissions were for post-ablation pain control. Only 23 patients with 27 VAs had adequate follow-up data. At a mean of 12.2 months ± 10.1 (0.4-29.3), 19 (95%) of patients treated for pain and 2 (67%) of patients treated for swelling/mass effect reported partial or complete resolution of symptoms. Mean pain score was 1.6 ± 1.8 (0-5) with a mean reduction of 5.7 ± 1.0 (p < 0.001). 17 patients underwent post-ablation MRI. 15 of these were with contrast. Reduction in maximum size from baseline was 2.3 cm ± 2.7 (p = 0.004). 13 patients experienced >50% decrease VA T2 signal while 11 patients experienced >50% decrease in VA contrast enhancement. No major complications were noted. 10 minor complications occurred in 9 (30%) of the patients. These included post-ablation hematoma (n = 3), transient paresthesia (n = 4), transient weakness (n = 2), and nontarget thermal injury (n = 1).

Commentary

This study builds off of smaller studies of its kind and reports promising outcomes in a larger patient population. MR imaging-guided laser and cryoablation are shown to be safe and effective modalities for treating symptomatic peripheral VAs, both as initial and subsequent therapy for persistent lesions. MR guidance specifically helps to visualize and treat VAs that were not conspicuous on US or CT imaging. Patients suffering from painful lesions in particular experienced significant decreases or resolution in pain post-procedurally. All complications were minor and were treated with minimal observation or short-term hospitalization. 

This study has several limitations, including its retrospective nature, difficulty in accurately measuring VA dimensions post-ablation, and lack of consistent pre-procedure workup and post-procedure follow-up. Also, the use of subjective pain scores is subjective and highly variable. Lastly, the included number of patients/ablations was inadequate to allow detailed assessment of the differences between cryo-ablation versus laser ablation, nor location-specific VA response. Future studies would benefit from symptom reporting standardization, prospective randomized design, and larger patient population.

Post Author
Jared Edwards, MD
General Medical Officer
Medical Readiness Division
Naval Surface Forces Pacific, San Diego, CA
@JaredRayEdwards

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Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

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

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

Take-away point
Prostate Y90 RE is safe and feasible in a canine model, with focal dose-dependent prostate changes, without unwanted extraprostatic effects.

Reference
Mouli SK, et al. Yttrium-90 Radioembolization to the Prostate Gland: Proof of Concept in a Canine Model and Clinical Translation. J Vasc Interv Radiol. 2021 Aug;32(8):1103-1112.e12.

Study Design
Preclinical animal study

Funding Source
Research grants from Boston Scientific provided to Northwestern University Department of Radiology, Section of Interventional Radiology.

Setting
Single-center.

Summary

Prostate cancer is the most common non-cutaneous cancer in men. Currently, nonoperative candidates are managed with brachytherapy (BT) or external-beam radiotherapy (EBRT), however biochemical recurrence and radiation induced toxicity to adjacent structures range from 10% to 60%. Prostatic artery (PA) embolization already has an established safety and efficacy profile for the treatment of lower urinary tract symptoms secondary to benign prostatic hyperplasia (BPH). However, both bland and chemoembolization for prostate cancer have not shown efficacious outcomes in small studies. Y90 radioembolization has proven efficacy and safety as HCC locoregional therapy and may be replicated for prostate cancer treatment.

14 castrated canines were assigned to Y90 treatment groups: low (60-70Gy), medium (80-120Gy), and high dose (150-200Gy). Doses were delivered to 1 hemi-gland of each subject. After 60 days, gross pathologic and histologic analysis of the prostate, bladder, penis, rectum, urethra, and the left and right neurovascular bundles was performed.

Y90 administration was technically successful in all subjects, with dose delivered to target hemigland without significant non-target exposure by imaging. Serial MRI follow up demonstrated hemigland volume significantly and progressively decreased with noticeable signal changes on T2 weighted, ADC map, and DCE (dynamic contrast enhanced imaging) sequences. The high-dose group demonstrated higher volume loss (60%) compared to the low-dose group.

Gross pathological examination demonstrated radiation-induced glandular changes in a dose-dependent fashion, with the high-dose group demonstrating increased degeneration, inflammation, and atrophy of the prostatic gland sand glandular epithelial metaplasia. The majority of the contralateral control hemiglands were histologically unremarkable. No adverse events were noted on clinical, pathologic, or histologic analysis including: cavitary necrosis, hemorrhage, urinary retention, incontinence, hematuria, diarrhea, or rectal bleeding. No significant radioactivity was detected in the animals’ urine and feces during follow up. No gross pathological or histological abnormalities were seen in the surrounding tissues upon necropsy including perianal inflammation or necrosis, urethral strictures, radiation cystitis or proctitis. In 1 high-dose subject, there were isolated microspheres in the periprostatic tissues (bladder, rectum, neurovascular bundle) but no evidence of tissue damage. Particularly, the neurovascular bundle (NVB) appears to be relatively spared in radioembolization.

Commentary

The authors noted that EBRT or brachytherapy have better homogeneity, but at the expense of more normal tissue exposure. The beta particle penetration of Y90 has limited range which provides more accurate locoregional target tissue coverage with limited risk to surrounding structures. Even with high theoretical absorbed doses delivered to the treated prostate hemigland (155–502 Gy), the most conservative QUANTEC limits were not exceeded for surrounding organs.

Some drawbacks noted during this study were that each animal served as its own control with the contralateral untreated prostate hemigland, which may have received some inadvertent dose due to intraprostatic collaterals. Furthermore, compared to similar canine models for prostate bland embolization, the volume changes with radioembolization in this study were not as profound and were dose dependent. However, the level of atrophy was still greater than those seen following EBRT in preclinical and clinical studies. The author also noted a few limitations of the study, namely (1) a canine prostatic hyperplasia model was used and (2) microdosimetry provided a range of dose distributions from ideal to conservative due to limitations gland segmentation on micro-CT.

This study proves the technical success of Y90 prostate radioembolization in a canine hyperplasia model, demonstrating pathologic and histologic evidence of significant dose-dependent glandular atrophy without evidence of radiation induced side effects. Perhaps most notably, neurovascular bundle sparring is an attractive opportunity if similar treatment effects can be proven. This is a very promising first step and we look forward to the ensuing clinical safety and efficacy trials.

Post Author
Vaishak Amblee, MD
Rush University Medical Center
Integrated Vascular & Interventional Radiology Residency, Class of 2023

David M. Tabriz, MD
Program Director, Vascular & Interventional Radiology (Integrated)Program Director, Vascular & Interventional Radiology (Independent)
Rush University Medical Center
@DrDaveTabriz

Edited and formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

Combined Transarterial Embolization and Percutaneous Sclerotherapy as Treatment for Refractory and Nonresectable Aneurysmal Bone Cysts

Clinical question
To evaluate the use of combined transarterial embolization (TAE) and percutaneous sclerotherapy in the treatment of nonresectable and refractory aneurysmal bone cysts (ABCs).

 
Take away point
Combined TAE and percutaneous sclerotherapy is a minimally invasive, safe, and effective procedure that can be used to treat nonresectable ABCs and to significantly improve patients’ quality of life.

Reference
Masthoff M, Gerwing M, Schneider KN, et al. Combined Transarterial Embolization and Percutaneous Sclerotherapy as Treatment for Refractory and Nonresectable Aneurysmal Bone Cysts. J Vasc Interv Radiol. 2021;32(10):1425-1434.e2. doi:10.1016/j.jvir.2021.07.008

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Study design
Retrospective, single-center, observational study that included patients with refractory and nonresectable ABCs treated with combined TAE and percutaneous sclerotherapy. Decision to treat with combined selective TAE and percutaneous sclerotherapy was made by an interdisciplinary board.

Funding Source
No reported funding.

Setting
Academic setting. University Hospital Münster, Münster, Germany; University Hospital Essen, Essan, Germany; University Hospital Ludwig Maximilian University of Munich, Munich, Germany.

Figure



Flow scheme of the treatment algorithm for combined transarterial embolization and percutaneous sclerotherapy for refractory and nonresectable ABCs.

(a) and (b) Representative images of transarterial embolization of an aneurysmal bone cyst (ABC) of the left clavicle. Angiography showed arterial hypervascularization of an ABC (a, black arrowheads) with arterial feeding vessels from the axillary artery. Superselective embolization of the feeding vessels led to the complete embolization of the ABC, while the axillary artery was successfully spared. (c) Representative fluoroscopic imaging of percutaneous sclerotherapy after transarterial embolization followed by administration of the sclerosing agent via the percutaneous bone access needle (white asterisk). (d) Baseline T2 axial magnetic resonance (MR) imaging showed the typical appearance of an ABC (white arrowhead) with T2 hyperintense, partially blood-filled cysts. (e) Follow-up T2 axial MR imaging scan after treatment showed a heavily reduced number and size of cysts (white arrowhead) with complete mineralization of the ABC. (f) Baseline radiograph showed the typical osteolytic, multicystic appearance of an ABC of the left clavicle. (g) Follow-up radiograph showed complete mineralization of the ABC after combined transarterial embolization and percutaneous sclerotherapy.

Summary

ABCs are rare osseous lesions that tend to occur in people under the age of 20. Symptoms may include pain, swelling, neurologic symptoms due to local nerve compression, movement restriction, or pathologic fractures. The goal of ABC therapy is to eradicate neoplastic tissue and enable remineralization. The mainstay treatment has been complete intralesional curettage or excision and filling. Alternatives including TAE, percutaneous sclerotherapy, or denosumab therapy have also been used.

The authors preformed a retrospective review of 16 consecutive patients who were treated with combined TAE and percutaneous sclerotherapy for refractory and nonresectable ABCs. Median age of the patients was 17 years. Only 1 of the patients had a history of pathologic fracture at the initial presentation. Seven of the patients had not undergone any previous therapies for ABC, one had a prior curettage, and none had undergone any systemic therapies. Data collected by the investigators included radiographic and magnetic resonance (MR) imaging, in addition to quality-of-life assessments which were performed prior to the first and at least 4 weeks after the final intervention. The median follow-up was 27.3 months. Two radiologists who were blinded to the interventions independently assessed the imaging data for several variables: number of intralesional cysts, size of the largest cyst, occurrence of pathologic fractures, grade of intralesional mineralization (using a 5-point Likert scale), and grade of lesion fluid-fluid levels (using a 4-point Likert scale established in the literature). TAE and percutaneous sclerotherapy treatment sessions were performed sequentially. TAE was used to achieve complete arterial devascularization and percutaneous sclerotherapy followed TAE until either ABC necrosis was achieved (using diminished lesional contrast enhancement as a marker) or clinical symptom relief was attained.

The interventional procedures were performed under general anesthesia. Feeding vessels of the ABCs were embolized using EVOH (Onyx Liquid Embolic System). During the same session, multiple percutaneous accesses into a majority of the ABC cavities were achieved under fluoroscopic guidance. Sclerotherapy was performed by injecting DiscoGel, which contained gelified 96% ethyl alcohol, cellulose derivative product, and tungsten and polidocanol. The investigators used 2 standardized outcome parameters, the Musculoskeletal Tumor Society (MSTS) score and the 36-Item Short Form Survey (SF-36), to assess clinical outcome and quality of life. For both these parameters, higher scores represent a higher quality of life.

Clinical Outcome – Imaging Data

Overall, a mean of 1.6 ± 0.7 TAEs and 3.2 ± 1.7 percutaneous sclerotherapies were performed with a technical success rate of 100%. Complete or subtotal, defined as >90% of arterial feeding vessels, was achieved in all patients. No adverse events were reported during the procedures and no procedure-associated long-term adverse events were observed at follow-up. Follow-up imaging scans showed a decreased number of intralesional cysts in 15/16 patients and a decreased cyst size in 14/16 patients. ABC lesion mineralization significantly increased while the fluid-fluid levels of the ABCs significantly decreased (P < .0001). All 9 patients who received contrast-enhanced follow-up MR imaging showed either complete (1) or partial response (8) to treatment. There was also a significant reduction in mean contrast-enhanced lesion size following therapy (P = .0003). There was no pathologic fracture development during the follow-up period and no patient had ABC recurrence after the initial treatment response. One patient became a surgical candidate after intervention led to ABC downstaging, and one patient was switched to denosumab therapy after showing prolonged partial response.

Clinical Outcome – Quality of Life

Both scoring systems, the MSTS score and the SF-36 survey, showed significantly improved quality of life scores. The MSTS score increased to 28.8 ± 1.8 from a baseline of 14.1 ± 8.6 (P < .0001). Similarly, the SF-36 physical functioning score improved from 44.3 ± 32.3 to 93 ± 13.5 (P <.0001) while the SF-36 score for role limitations due to physical health improved from 23.3 ± 40.6 to 93.3 ± 25.8 (P < .0001). Only 1 patient did not demonstrate significant improvement in both SF-36 categories. The SF-36 also assesses the effects of physical disease on mental health; all mental health-associated categories demonstrated significant improvement (P < .001). Social functioning (P = .0004), pain (P < .0001), and outlook on future health (P < .0001) all significantly improved. Overall, the MSTS and SF-36 scores demonstrated a clinical success rate of 93.8% in improved quality of life.

Commentary

The authors of this study demonstrated the efficacy and safety of combined TAE and percutaneous sclerotherapy for the treatment of refractory and nonresectable ABCs. The similar success rate of this minimally-invasive intervention to primary surgery may warrant further investigation into using combined TAE and percutaneous sclerotherapy in new contexts; either as primary treatment in resectable ABCs or to downstage lesions to facilitate future surgery. Additionally, the lack of ABC recurrence during the median follow up of 27.3 months demonstrates the superior durability of this method compared to other treatment strategies. There are several limitations to this study, including but not limited to its retrospective nature, the lack of control group, heterogenous distribution of ABC lesions, lack of standardized response criteria for bone lesions, and failure to perform contrast-enhanced follow-up MR imaging on each patient. In spite of these limitations, this study is important because adds credence to the idea that the pathogenesis of ABCs stems from dysplastic vessels and neoplastic cell proliferation. Current treatment options for ABCs tend to favor a surgical approach; however, applying the treatment strategies in this study to a wider range of ABC patients, initially in a prospective trial setting for clinical validation, may improve overall clinical outcomes.

Post Author
Kaelan Chan
Medical Student, MS4
University of Cincinnati College of Medicine

Edited and Formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University

PÉRDIDA DE SANGRE PERIOPERATORIA EN PACIENTES CON EMBOLIZACION PREVIA DE LAS ARTERIAS PROSTATICAS BILATERALES, SOMETIDOS A PROSTATECTOMÍA SIMPLE: ANALISIS DE PAREAMIENTO POR PUNTAJE DE PROPENSIÓN

Pregunta clinica
¿Es la embolización bilateral de las arterias prostáticas (EBAP) segura y eficaz para reducir la pérdida de sangre intraoperatoria durante la prostatectomía simple?

Mensaje principal
La embolización bilateral de las arterias prostáticas preoperatoria reduce de forma segura y eficaz el sangrado intraoperatorio y el tiempo quirúrgico.

Reference

Sare A, Kothari P, Cieslak JA, et al. Perioperative blood loss after preoperative prostatic artery embolization in patients undergoing simple prostatectomy: a propensity score‒matched study. Journal of Vascular and Interventional Radiology. 2021; 32(8):1113-1118.

Click here for abstract

RESUMEN

Proposito

Evaluar la pérdida de sangre perioperatoria después de la embolización bilateral de las arterias prostáticas (EBAP) antes de la cirugía en pacientes sometidos a prostatectomía simple.

Métodos
Se hizó una revisión retrospectiva de las historias clínicas identificando 63 pacientes (edad promedio, 65.3 ± 8.0 años) con hipertrofia prostática benigna y síntomas graves del tracto urinario inferior, que se sometieron a prostatectomía desde septiembre de 2014 a diciembre de 2019. Dieciocho pacientes (28.5%) fueron sometidos a EBAP antes de la cirugía. Se obtuvieron datos demográficos, resultados de laboratorio, información del procedimiento operatorio, detalles del curso hospitalario e informes de patología. Se realizó un análisis de pareamiento por puntaje de propensión 2: 1 para comparar la pérdida de sangre intraoperatoria en los pacientes que se sometieron a prostatectomía simple, con la pérdida de sangre intraoperatoria en aquellos que se sometieron a EBAP antes de la cirugía.

Resultados
Dieciséis (89%) de 18 pacientes fueron sometidos a EBAP antes de la cirugía. Treinta y dos pacientes que se sometieron a prostatectomía sin embolización antes de la cirugía fueron seleccionados para el análisis de pareamiento por puntaje de propensión 2: 1 basado en la edad, raza, tipo de cirugía, tamaño de la glándula prostática y comorbilidades. La pérdida de sangre estimada (PSE) promedio para la prostatectomía simple fue de 545 ± 380 ml (promedio ± desviación estándar). Hubo una reducción estadísticamente significativa en la PSE en los pacientes que se sometieron a EBAP (303 ± 227 ml, p <0.01). El tiempo operatorio también se redujo significativamente en los pacientes que se sometieron a EBAP antes de la cirugía (p <0,05). Los pacientes que se sometieron a EBAP no presentaron complicaciones relacionadas con el procedimiento.

Conclusiones
La EBAP antes de la cirugía parece ser segura y puede ser eficaz para reducir el sangrado perioperatorio y el tiempo operatorio.

Resumen

La hiperplasia prostática benigna (HPB) es una causa común de síntomas del tracto urinario inferior, afecto a la mayoría de los hombres mayores de 60 años y a más del 80% de los hombres mayores de 70 años. El tratamiento de primera línea ha implicado históricamente modificaciones en el estilo de vida y uso de farmacoterapias con inhibidores de la 5 α-reductasa, bloqueadores α, e inhibidores de la fosfodiesterasa; recomendándose la cirugía si estas medidas no proporcionan un alivio adecuado. Las opciones quirúrgicas incluyen resección transuretral de la próstata (RTUP) y prostatectomía simple abierta, con tasas de complicaciones que aumentan a medida que aumenta el tamaño de la próstata. La complicación más común es el sangrado que requiere transfusión, y se ha demostrado que ocurre en 11.9% de los pacientes sometidos a prostatectomia simple abierta, que generalmente se realiza en pacientes con próstatas grandes. Se ha demostrado que la embolización preoperatoria es un método seguro y eficaz para reducir la pérdida estimada de sangre, las transfusiones y la duración de la estancia hospitalaria (EH) durante la resección de una variedad de tumores hipervasculares, pero aún no se ha evaluado en pacientes sometidos a prostatectomía.

En esta serie retrospectiva de casos, se analizaron 63 pacientes con hipertrofia prostática y con síntomas obstructivos del tracto urinario bajo (SOTUB). Todos los pacientes tenían próstatas con peso mayor de 80 gramos y posteriormente se sometieron a prostatectomía. Los pacientes se sometieron a EBAP o no embolización antes del procedimiento. Se excluyeron los pacientes sometidos a EAP unilateral. Los datos recopilados incluyeron la información demográfica, las comorbilidades, el volumen prostático preoperatorio (obtenido con ultrasonido transrectal), tipo de prostatectomía, detalles técnicos de la EBAP, laboratorios hematológicos pre y postoperatorios, PSE, tiempo operatorio, transfusiones y la duración del postoperatorio con irrigación continúa de la vejiga (ICV). En los pacientes sometidos a embolización se practicó una EBAP utilizando microesferas de hidrogel de 250 μm hasta el cese del flujo anterógrado, seguido de una inyección de gelfoam. Dentro de las 2 semanas posteriores a la EBAP los pacientes se sometieron a una prostatectomía robótica o a una prostatectomía abierta suprapúbica.

En este estudio se analizaron 60 pacientes, 16 pacientes sometidos a EBAP y 44 pacientes que no se embolizaron. De los 44 pacientes no embolizados, se incluyeron 32 para el pareamiento por puntaje de propensión en relación 2:1. En el grupo de embolización, 11 pacientes se sometieron a prostatectomía robótica, mientras que 5 se sometieron a prostatectomía suprapúbica abierta; en comparación con 10 y 22 pacientes respectivamente en el grupo sin embolización. Las características demográficas y basales entre los grupos no fueron significativamente diferentes. La mediana de tiempo entre EBAP y prostatectomía fue de 6 días (4-18 días). La PES promedio fue de 303 ± 219.7 ml en el grupo de EBAP en comparación con 545 ± 380 ml en el grupo no embolizado (p < 0.01). El tiempo operatorio promedio en el grupo de EBAP fue de 140.5 ± 35.4 minutos frente a 180.5 ± 56.6 minutos en el grupo no embolizado (p < 0.01). La disminución en la hemoglobina durante la cirugía fue de 2.16 g/dl en el grupo de EBAP y de 3.50 g/dl en el grupo sin embolización (p = 0.020). El 6% de los pacientes del grupo EBAP se sometieron a transfusión en comparación con el 19% en el grupo sin embolización, pero con una promedia de 0.19 unidades por paciente en el grupo EBAP versus 0.44 en el grupo sin embolización, que no fue significativamente diferente (p = 0.334). La EH no difirió significativamente entre los grupos y no se produjeron complicaciones mayores o menores.

Comentario

La Asociacion Americana de Urologia recomienda la cirugía como estándar en atención de la HPB; sin embargo, las próstatas grandes pueden ser difíciles de tratar y tienen tasas más altas de complicaciones hemorrágicas. La embolización de las arterias prostáticas ha demostrado que es segura y eficaz para el tratamiento de la hematuria relacionada con la próstata y los SOTUB. Este estudio demostró una disminución en la pérdida de sangre operatoria y en el tiempo promedio operatorio en pacientes sometidos a EBAP preoperatoria antes de prostatectomía para próstatas grandes (> 80 g). Sin embargo, no demostró una reducción estadísticamente significativa en la EH o en el uso de transfusiones. La falta de diferencia en las transfusiones puede deberse al tamaño reducido de la muestra en combinación con variabilidad en los umbrales de transfusión entre los urólogos. El único estudio previo similar a este, y que se menciona en este estudio, encontró una disminución en la EH y pérdida de sangre intraoperatoria, pero solo se usó como referencia la variación en los laboratorio hematológicos y no evaluó las PES. Esto sugiere que la falta de La diferencia significativa en la EH en este estudio puede deberse al tamaño de la muestra. Esta es una reconocida limitación del estudio además de su naturaleza retrospectiva. Un desafío en La estandarización propuesta por los autores es el intervalo de tiempo relativamente grande entre EBAP y prostatectomía, que puede haber resultado en diferencias en el desarrollo de circulación colateral antes de la cirugía, lo que resulta en diferencias clínicamente significativas en la pérdida de sangre. Las futuras investigaciones deben centrarse en ensayos aleatorizados que incluyan múltiples centros con gran volumen de procedimientos y en investigaciones sobre el tiempo en el desarrollo de la generación de circulación colateral en la próstata.

Autor del comentario
Jared Edwards, MD
Oficial Medico General
Division de Preparación Médica
Fuerza Navales de Superficie del Pacifico. San Diego, CA
@JaredRayEdwards

Translated by Pilar Bayano Molano, MD
Associate Professor Interventional Radiology
UT Southwestern Medical Center

Formatted by @NingchengLi

Interventional Radiology Resident

Dotter Institute, Oregon Health and Science University