Initial Results of Image-Guided Percutaneous Ablation as Second-Line Treatment for Symptomatic Vascular Anomalies

Magnetic Resonance Imaging-Guided Cryoablation of Prostate Cancer Lymph Node Metastasis

PURPOSE

To evaluate the safety and effectiveness of magnetic resonance (MR) imaging-guided cryoablation of prostate cancer metastatic lymph nodes (LNs).

MATERIALS AND METHODS

Fifty-two patients with prostate cancer who underwent MR imaging-guided LN ablation from September 2013 to June 2022 were retrospectively reviewed. Of these, 6 patients were excluded because adequate ablation margins (3-5 mm) could not be achieved secondary to adjacent structures. The remaining 46 patients (mean age, 70 years [SD ± 7]) underwent 55 MR imaging-guided cryoablation procedures of metastatic LNs (25 in the pelvic sidewall, 20 within the pelvic region, and 10 in the abdomen) with procedural intent of complete ablation. Locoregional tumor control (ie, technical success in the target LN) was evaluated on initial follow-up positron emission tomography (PET) scans at a mean of 4 months (SD ± 2). Preablation and postablation prostate-specific antigen (PSA) levels were recorded. Imaging follow-up continued until a median of 27.5 months (range: 3-108 months).

RESULTS

Ninety-five percent (52/55) of treated LNs demonstrated no considerable activity on PET scans at initial follow-up at 4 months (SD ± 2). PSA decreased to an undetectable level of <0.1 ng/mL after cryoablation in 14 of 46 (30.4%) patients with corresponding lack of activity in 13 of 46 (28.2%) patients on continued PET imaging follow-up. Only 6 of 55 (10.9%) patients had transient adverse events, which all resolved with no long-term sequalae.

CONCLUSIONS

MR imaging-guided percutaneous cryoablation of metastatic LNs is a safe and technically effective technique for treating metastatic prostate cancer in LNs.

Magnetic resonance - guided treatment of low-flow vascular malformations and the technologies to potentiate adoption

Vascular malformations are congenital, non-neoplastic lesions that arise secondary to defects in angiogenesis. Vascular malformations are divided into high-flow (arteriovenous malformation) and low-flow (venous malformations and lymphatic malformations). Magnetic resonance imaging (MRI) is the standard for pre-and post-intervention assessments, while ultrasound (US), X-ray fluoroscopy and computed tomography (CT) are used for intra-procedural guidance. Sclerotherapy, an image-guided therapy that involves the injection of a sclerosant directly into the malformation, is typically the first-line therapy for treating low-flow vascular malformations. Sclerotherapy induces endothelial damage and necrosis/fibrosis with eventual involution of the malformation. Image-guided thermal therapies involve freezing or heating target tissue to induce cell death and necrosis. MRI is an alternative for intra-procedural guidance and monitoring during the treatment of vascular malformations. MR can provide dynamic, multiplanar imaging that delineates surrounding critical structures such as nerves and vasculature. Multiple studies have demonstrated that MR-guided treatment of vascular malformations is safe and effective. This review will detail (1) the use of MR for the classification and diagnosis of vascular malformations, (2) the current literature surrounding MR-guided treatment of vascular malformations, (3) a series of cases of MR-guided sclerotherapy and thermal ablation for the treatment of vascular malformations, and (4) a discussion of technologies that may potentiate interventional MRI adoption including high intensity focused ultrasound and guided laser ablation.

Resolution of Pain after Percutaneous Image-Guided Cryoablation of Extraperitoneal Endometriosis

PURPOSE

To retrospectively evaluate the relief of pain after percutaneous image-guided cryoablation of symptomatic extraperitoneal endometriosis (EE).

MATERIAL AND METHODS

From 2017 to 2022, cryoablation of EE was performed at a single institution on a total of 47 lesions in 42 consecutive patients (median age, 37 years; interquartile range [IQR], 33-39.5 years). Patient and procedural characteristics were reviewed retrospectively. Tolerance and outcomes in terms of pain and patient satisfaction were evaluated.

RESULTS

The median follow-up duration was 13.5 months (IQR, 1.1-37.7 months) after cryoablation. The median pain-free survival rate was 93.8% (95% confidence interval [CI], 77.3-98.4) at 6 months and 82.7% (95% CI, 58.8-93.5) after 12 months. Pain decreased from a median of 8/10 (IQR, 7-9) on the visual analog scale to 0/10 (IQR, 0-1) at the last follow-up (P < .0001). The median Patient Global Impression of Change score recorded at the last follow-up was 1/7 (IQR, 1-2). The efficacy rate of cryoablation to avoid secondary surgery was 92.8% (39/42) per patient and 93.6% (44/47) per nodule treated. Four patients (9.5%, 4/42) experienced an adverse event in the days following the procedure, and 1 patient (2%) experienced a severe adverse event.

CONCLUSIONS

Percutaneous cryoablation is safe and effective in significantly reducing pain and obtaining local control of EE.

Percutaneous MR Imaging-Guided Laser Ablation for the Treatment of Symptomatic Cervicofacial Vascular Malformations

PURPOSE

To evaluate the safety and effectiveness of percutaneous magnetic resonance (MR) imaging-guided laser ablation for the treatment of symptomatic soft tissue vascular malformations (VMs) in the face and neck.

MATERIALS AND METHODS

An institutional review board-approved retrospective review was undertaken of all consecutive patients who underwent MR imaging-guided and monitored laser ablation for treatment of symptomatic, cervicofacial soft tissue VM. Preablation and postablation MR imaging findings were independently reviewed. Preablation and postablation VM sizes were documented. Preablation T2 signal characteristics and enhancement patterns as well as postablation change in both signal and enhancement were semiquantitatively assessed. Changes in VM size were compared using a paired t test.

RESULTS

Thirteen patients (women, 9; age, 14.5-69.5 years) with 13 VMs were treated for moderate-to-severe pain (n = 4), swelling/mass effect (n = 8), or predominantly cosmesis (n = 1) with 22 total ablation sessions. The baseline maximum VM diameter was 5.7 cm ± 4.2. At baseline, all VMs (100%) demonstrated variable T2-weighted signal hyperintensity and enhancement. For painful VM, the baseline pain score was 8 ± 1. Clinical follow-up was available for 10 patients. Of patients with available follow-up, 3 (100%) treated for moderate-to-severe pain and 7 (100%) treated for swelling/mass effect reported subjective complete or partial symptomatic relief. The patient treated predominantly for cosmetic reasons was lost to follow-up. Two patients (15.4%) experienced minor adverse events by the Society of Interventional Radiology standards. There were no major adverse events.

CONCLUSIONS

MR imaging-guided and monitored percutaneous laser ablation is safe and effective for the treatment of symptomatic, cervicofacial VMs.

Image-Guided Percutaneous Ablation for Primary and Metastatic Tumors

Image-guided percutaneous ablation methods have been further developed during the recent two decades and have transformed the minimally invasive and precision features of treatment options targeting primary and metastatic tumors. They work by percutaneously introducing applicators to precisely destroy a tumor and offer much lower risks than conventional methods. There are usually shorter recovery periods, less bleeding, and more preservation of organ parenchyma, expanding the treatment options of patients with cancer who may not be eligible for resection. Image-guided ablation techniques are currently utilized for the treatment of primary and metastatic tumors in various organs including the liver, pancreas, kidneys, thyroid and parathyroid, prostate, lung, bone, and soft tissue. This article provides a brief review of the various imaging modalities and available ablation techniques and discusses their applications and associated complications in various organs.

Body Interventional MRI for Diagnostic and Interventional Radiologists: Current Practice and Future Prospects

Clinical use of MRI for guidance during interventional procedures emerged shortly after the introduction of clinical diagnostic MRI in the late 1980s. However, early applications of interventional MRI (iMRI) were limited owing to the lack of dedicated iMRI magnets, pulse sequences, and equipment. During the 3 decades that followed, technologic advancements in iMRI magnets that balance bore access and field strength, combined with the development of rapid MRI pulse sequences, surface coils, and commercially available MR-conditional devices, led to the rapid expansion of clinical iMRI applications, particularly in the field of body iMRI. iMRI offers several advantages, including superior soft-tissue resolution, ease of multiplanar imaging, lack of ionizing radiation, and capability to re-image the same section. Disadvantages include longer examination times, lack of MR-conditional equipment, less operator familiarity, and increased cost. Nonetheless, MRI guidance is particularly advantageous when the disease is best visualized with MRI and/or when superior soft-tissue contrast is needed for treatment monitoring. Safety in the iMRI environment is paramount and requires close collaboration among interventional radiologists, MR physicists, and all other iMRI team members. The implementation of risk-limiting measures for personnel and equipment in MR zones III and IV is key. Various commercially available MR-conditional needles, wires, and biopsy and ablation devices are now available throughout the world, depending on the local regulatory status. As such, there has been tremendous growth in the clinical applications of body iMRI, including localization of difficult lesions, biopsy, sclerotherapy, and cryoablation and thermal ablation of malignant and nonmalignant soft-tissue neoplasms. Online supplemental material is available for this article. ^©RSNA, 2021.

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

PURPOSE

To evaluate the safety and effectiveness of percutaneous magnetic resonance (MR) imaging-guided laser ablation and cryoablation for the treatment of symptomatic soft tissue vascular anomalies (VAs) of the trunk and extremities.

MATERIALS AND METHODS

An institutional review board-approved retrospective review was undertaken of all pediatric and adult patients who underwent MR imaging-guided and monitored laser ablation and/or cryoablation for the treatment of symptomatic peripheral soft tissue VA. Preablation and postablation MR imaging was independently reviewed. Pain scores on the visual analog scale (0 to 10) and self-reported subjective symptomatic improvement were assessed. Change in VA size and pain scores were compared using a paired t test.

RESULTS

Thirty patients (24 females; age, 10-75 years) with 34 VAs were treated for moderate to severe pain (n = 27) or swelling/mass effect (n = 3) with 60 total ablation sessions. The baseline maximum VA diameter was 9.5 cm ± 8.6. At baseline, all VAs (100%) demonstrated variable T2-weighted signal hyperintensity and enhancement. The baseline pain score was 6.4 ± 1.6. Clinical follow-up was available for 23 patients. At a mean follow-up time of 12.2 months ± 10.1, 19 of 20 (95%) patients treated for pain and 2 of 3 (67%) patients treated for swelling/mass effect reported partial or complete symptomatic relief. There was a significant decrease in the postablation pain scores (-5.7 ± 1.0, P < .001) and maximum VA size (-2.3 cm ± 2.7, P = .004), with >50% reduction in VA T2 signal (59%) and enhancement (73%). Nine of 30 (30%) patients experienced minor complications.

CONCLUSIONS

MR imaging-guided and monitored percutaneous laser ablation and cryoablation appear to be safe and effective for the treatment of symptomatic peripheral soft tissue VAs.

Standards of care for Kasabach-Merritt phenomenon in China

Kasabach-Merritt phenomenon (KMP) is a rare disease that is characterized by severe thrombocytopenia and consumptive coagulation dysfunction caused by kaposiform hemangioendothelioma or tufted hemangioma. This condition primarily occurs in infants and young children, usually with acute onset and rapid progression. This review article introduced standardized recommendations for the pathogenesis, clinical manifestation, diagnostic methods and treatment process of KMP in China, which can be used as a reference for clinical practice.

Image-guided tumor ablation in gynecologic oncology: Review of interventional oncology techniques and case examples highlighting a collaborative, multidisciplinary program

As interventional oncology services within radiology mature, image-guided ablation techniques are increasingly applied to recurrent gynecologic malignancies. Ablation may be performed using thermal techniques like cryoablation, microwave ablation, or radiofrequency ablation, as well as non-thermal ones, such as focused ultrasound or irreversible electroporation. Feasibility and approach depend on tumor type, size, number, anatomic location, proximity of critical structures, and goals of therapy. Current indications include local control of limited metastatic disease or palliation of painful bone metastases refractory or unsuitable to conventional therapies. Technical aspects of these procedures, including methods to protect nearby critical structures are presented through illustrative examples. Cases amenable to image-guided ablation include, but are not limited to, hepatic or pulmonary metastases, musculoskeletal metastases, retroperitoneal nodal metastases, pelvic side wall disease, abdominal wall disease, and vaginal or vulvar tumors. Protective maneuvers, such as hydro-displacement of bowel, neuromonitoring, and retrograde pyeloperfusion through ureteral stents, permit safe ablation despite close proximity to vulnerable nerves or organs. Image-guided ablation offers an alternative modality to achieve local tumor control without the risks associated with surgery or systemic treatment in appropriately selected patients. A multidisciplinary approach to use of image-guided ablation includes collaboration between gynecologic oncology, interventional radiology, anesthesia, urology and radiation oncology teams allowing for appropriate patient-centered case selection. Long-term follow up and additional studies are needed to determine the oncologic benefits of such techniques.

Interventional Techniques for Bone and Musculoskeletal Soft Tissue Tumors: Current Practices and Future Directions - Part I. Ablation

Musculoskeletal (MSK) image-guided oncologic intervention is an established field within radiology. Numerous studies have described its clinical benefits, safety, cost effectiveness, patient satisfaction, and improved quality of life, thereby establishing image-guided oncologic intervention as a preferred pathway in treating patients presenting with specific benign MSK tumors. But there is a paradigm shift on the horizon because these techniques may also support established pillars (surgery, systemic treatment, radiotherapy) in the treatment of malignant MSK tumors. Unlike benign tumors, where they are used as primary therapy lines with curative intent, such interventions can be selected for malignant tumors as adjuvant treatment in painful or unstable bone or soft tissue lesions or as more palliative therapy strategies. Using examples from our clinical practices, we elaborate on the benefits of applying a multidisciplinary approach (traditionally involving MSK radiologists, oncologists, orthopaedic surgeons, microbiologists, pathologists, physiotherapists, and pain management experts), ideally within a sarcoma treatment center to deliver a patient-specific therapy plan and illustrate methods to assess the benefits of this model of care.In this article, we review the current repertoire of ablation techniques, demonstrate why such procedures offer value-based alternatives to conventional treatments of specific tumors, and reflect on future directions. Additionally, we review the advantages and limitations of each technique and offer guidance to improve outcomes.

The Role of Interventional Radiologists in the Treatment of Congenital Lymphatic Malformations

Lymphatic malformations are low-flow vascular malformations that are typically apparent in the pediatric population and can cause significant functional limitations and effects on quality of life. While surgical resection has historically been the mainstay of therapy, percutaneous sclerotherapy has garnered increasing popularity due to its efficacy and low complication rates. The role of interventional radiology in the multidisciplinary management of these often complex malformations requires thorough understanding of the disease process. This article will review the pathophysiology, clinical presentation, imaging workup, and management options of lymphatic malformations. Special attention will be devoted to available sclerosants, the mammalian target of rapamycin inhibitor sirolimus, and complex lymphatic anomalies.

MRI-guided percutaneous sclerotherapy of venous malformations: initial clinical experience using a 3T MRI system

PURPOSE

Venous malformations (VMs) are low-flow vascular anomalies that are commonly treated with image-guided percutaneous sclerotherapy. Although many VMs can be safely accessed and treated using ultrasonography and fluoroscopy, some lesions may be better treated with magnetic resonance imaging (MRI)-guided sclerotherapy. The aim of this study is to evaluate the feasibility, efficiency, and outcomes of MRI-guided sclerotherapy of VMs using a 3T MRI system.

METHODS

Six patients with VMs in the neck (n = 2), chest (n = 1), and extremities (n = 3) underwent sclerotherapy with 3T MRI guidance. Feasibility was assessed by calculating the technical success rate and procedural efficiency. Efficiency was evaluated by using planning, targeting, intervention, and total procedure times. Outcomes were assessed by measuring VM volumes before and after sclerotherapy, patient-reported pain scores, and occurrence of complications.

RESULTS

Technical success was achieved in all 6 procedures. There was a non-significant 30% decrease in mean VM volume after the procedure (P = .350). The procedure resulted in a decrease in mean pain score (on an 11-point scale) of 2.6 points (P = .003). After the procedure, 4 patients reported complete pain resolution, 1 reported partial pain resolution, and 1 reported no change in pain. Procedural efficiency was consistent with similar sclerotherapy procedures performed at our institution. There were no major or minor complications.

CONCLUSION

3T MRI guidance is feasible for percutaneous sclerotherapy of VMs, with promising initial technical success rates, procedural efficiency, and therapeutic outcomes without complications.

Percutaneous MR-Guided Cryoablation of Low-Flow Vascular Malformation: Technical Feasibility, Safety and Clinical Efficacy

PURPOSE

To retrospectively assess the technical feasibility, safety and clinical efficacy of percutaneous MR-guided cryoablation of low-flow vascular malformations (LFVM).

MATERIALS AND METHODS

Between July 2013 and May 2019, 9 consecutive patients (5 male; 4 female; mean age 39.4 ± 15.3 years, range 15-68) underwent MR-guided cryoablation of LFVM. Patients were treated due to pain in all cases. Procedural data, complications and clinical results were analyzed.

RESULTS

Technical success defined as complete coverage of the LFVM by the iceball without involvement of nearby non-target thermal-sensitive structures was achieved in 9/9 (100%) cases. Mean procedure time was 122 ± 20 min (range 90-150); 2-6 cryoprobes (mean 3.7 ± 1.2) and 2-4 freezing cycles (mean freezing time 19.8 ± 11.8 min; range 4-40) were applied. No complications were noted. Mean time from the first treatment to the last follow-up was 548 days (range 30-1776). Persistent/recurring pain was noted in 3/9 cases (33%) 30, 133 and 639 days after cryoablation, respectively, and was related in all cases to MR-confirmed local residual/recurring disease. A second cryoablation treatment was performed in these 3 cases with complete pain control at the last available follow-up (153, 25, 91 days, respectively). In the whole population, at mean 161 days (range 25-413) after the last treatment, on the numerical pain rate scale, pain significantly dropped from mean 6.4 ± 2.1 (range 3-9/10) before CA to mean 0.3 ± 0.9 (range 0-3/10) after (p = 0.009).

CONCLUSIONS

Percutaneous MR-guided cryoablation is technically feasible, safe and effective for the treatment of symptomatic LFVM.

LEVEL OF EVIDENCE

Level 3b, retrospective cohort study.

Improved MR-thermometry during hepatic microwave ablation by correcting for intermittent electromagnetic interference artifacts

MRI-guided microwave ablation (MWA) is a minimally invasive treatment for localized cancer. MR thermometry has been shown to be able to provide vital information for monitoring the procedure in real-time. However, MRI during active MWA can suffer from image quality degradation due to intermittent electromagnetic interference (EMI). A novel approach to correct for EMI-contaminated images is presented here to improve MR thermometry during clinical hepatic MWA. The method was applied to MR-thermometry images acquired during four MR-guided hepatic MWA treatments using a commercially available MRI-configured microwave generator system. During the treatments MR thermometry data acquisition was synchronized to respiratory cycle to minimize the impact of motion. EMI was detected and corrected using uncontaminated k-space data from nearby frames in k-space. Substantially improved temperature and thermal damage maps have been obtained and the treatment zone can be better visualized. Our ex vivo tissue sample study shows the correction introduced minimal errors to the temperature maps and thermal damage maps.

Cryoablation of low-flow vascular malformations

PURPOSE

We aimed to evaluate the safety and effectiveness of cryoablation in the treatment of low-flow malformations, specifically venous malformation (VM) and fibroadipose vascular anomaly (FAVA).

METHODS

We conducted a retrospective review of 11 consecutive patients with low-flow malformations (14 lesions; 9 VM, 5 FAVA), median lesion volume 10.8 cm3, (range, 1.8-55.6 cm3) with a median age of 19 years (range, 10-50 years) who underwent cryoablation to achieve symptomatic control. Average follow-up was at a median of 207 days postprocedure (range, 120-886 days). Indications for treatment included focal pain and swelling. Technical success was achieved if the cryoablation ice ball covered the region of the malformation that corresponded to the patient's symptoms. Clinical success was considered complete if all symptoms resolved and partial if some symptoms persisted but did not necessitate further treatment.

RESULTS

The technical success rate was 100%. At 1-month follow-up, 13 of 14 lesions (93%) had a complete response and one (7%) had a partial response. At 6-month follow-up 12 of 13 (92%) had a complete response and 1 (8%) had a partial response. A total of 6 patients underwent primary cryoablation. Out of 9 VM cases, 7 had prior sclerotherapy and 2 had primary cryoablation. Out of the 5 FAVA cases, 1 had prior sclerotherapy and the remaining 4 cases underwent primary cryoablation. There were 3 minor complications following cryoablation including 2 cases of skin blisters and 1 case of transient numbness. These complications resolved with conservative management.

CONCLUSION

Cryoablation is safe and effective in the treatment of low-flow vascular malformations, either after sclerotherapy or as primary treatment.

MR imaging features of presumed retroclavicular and periscapular intermuscular vascular plexi - An observational, anatomic study

OBJECTIVE

To describe MR imaging features of presumed vascular plexi in the periscapular (PSC) and retroclavicular (RC) locations.

MATERIALS/METHODS

443 consecutive MR studies performed as "brachial plexus" protocol (axialT1-W and sagittal STIR) were reviewed for presence, size and characteristics of PSC and RC plexi.

RESULTS

Presumed PSC and RC vascular plexi were present in 10%. Both plexi more commonly occurred on the left side. Percutaneous biopsy (n = 1) yielded no vascular neoplasm.

CONCLUSION

RC and PSC vascular plexi are commonly encountered on routine brachial plexus MR imaging and may represent variant vascular networks, as they are frequently found on the contralateral asymptomatic side.

MR-Guided Sclerotherapy for the Treatment of Low-Flow Vascular Malformations

Low-flow vascular malformations are congenital lesions that can occur throughout the body. Treatment of these lesions is indicated to ameliorate pain, cosmetic disfigurement, and functional impairment. The first-line treatment of low-flow vascular malformations is percutaneous sclerotherapy. Traditionally, sclerotherapy is performed with a combination of ultrasound and fluoroscopy. However, malformations that are deep in the abdomen and pelvis or are obscured by overlying fascia or scar may be difficult to be visualized with ultrasound and fluoroscopy. MR-guided sclerotherapy has emerged as an alternative modality that can be used to needle guidance and sclerosant monitoring. In this review, we discuss the historical and current use of MR-guided sclerotherapy for the treatment of low-flow vascular malformations.

Treatment of Low-Flow Vascular Malformations of the Extremities Using MR-Guided High Intensity Focused Ultrasound: Preliminary Experience

Five patients with painful vascular malformations of the extremities that were refractory to standard treatment and were confirmed as low-flow malformations on dynamic contrast-enhanced magnetic resonance (MR) imaging were treated with MR imaging-guided high intensity focused ultrasound. Daily maximum numeric rating scale scores for pain improved from 8.4 ± 1.5 to 1.6 ± 2.2 (P = .004) at a median follow-up of 9 months (range, 4-36 mo). The size of the vascular malformations decreased on follow-up MR imaging (median enhancing volume, 8.2 mL [0.7-10.1 mL] before treatment; 0 mL [0-2.3 mL] after treatment; P = .018) at a median follow-up of 5 months (range, 3-36 mo). No complications occurred.

Role of interventional radiology in the management of musculoskeletal soft-tissue lesions

The lesions of the soft tissues are rare and extremely heterogeneous; even if the surgical treatment is usually the standard therapy, the role of the interventional radiology (IR) in this field is growing up for multiple reasons. First, because the imaging alone usually is not able to ensure a definitive diagnosis, IR has a basic role in the staging: the percutaneous biopsy is infact an irreplaceable step. Moreover, biopsy is necessary not only for histologic evaluations but also for the biochemical and molecular studies. Furthermore, the proved safety and effectiveness of IR in a multiple oncologial applications prompt a wider use also in this field.

Epithelioid hemangioma of the scapula treated with chemoembolization and microwave ablation: Α case report

Bone epithelioid hemangiomas are classified within benign vascular tumours but are commonly misdiagnosed as low-grade angiosarcomas or epithelioid hemangioendotheliomas. Current therapeutic interventions include various treatment options but local recurrence or distal lymph node involvement has been reported. We report a rare case of scapular epithelioid hemangioma that was initially treated using a combination of chemoembolization and microwave ablation. This combination has not been previously reported in the literature regarding the management of this tumour. A year after the first course of treatment, the tumour size has been reduced more than 70% and the patient has remarkable clinical improvement. Results reported in this case study demonstrated that combination of chemoembolization and microwave ablation is a feasible, safe and effective technique in the treatment of bone epithelioid hemangiomas. Even if the tumour is still present afterwards, a substantially smaller surgical excision will be needed.

How to Perform a Routine Cryoablation Under MRI Guidance

In the last decade, the spectrum of interventional magnetic resonance imaging (MRI)-guided procedures, including percutaneous ablation, has substantially grown, and among the available MRI-compatible ablative techniques, cryoablation is progressively gaining a predominant position.The aim of the present narrative review is to discuss the technical requirements necessary to perform a percutaneous MRI-guided cryoablation in a closed-bore machine; to highlight the relative advantages and drawbacks; and to briefly summarize the results available in the literature.

Percutaneous Ultrasound-Guided Cryoablation for Symptomatic Plantar Fibromas

PURPOSE

Here, we report our experience in treating painful plantar fibromas with percutaneous cryoablation.

METHODS

We retrospectively identified patients with symptomatic plantar fibromas who underwent percutaneous ultrasound-guided cryoablation between June 2014 and June 2015. In total, four patients (two male, two female) with five plantar fibromas undergoing a total of seven ablation procedures were identified. Each procedure was performed under general anesthesia using a single freeze-thaw cycle. The electronic medical record, procedure reports, and pain scores from a brief pain inventory administered before and after treatment were reviewed. Average and worst pain in 24 h, and time to peak symptom improvement post-procedure were compared. Complications were reviewed using the SIR classification.

RESULTS

Five plantar fibromas were treated (mean size 2.2 ± 1.6 cm). Four of five lesions were present for more than 6 years, and 1/5 was present for less than 1 year. Surgical excision was previously performed on 3/5 lesions, all with short-term recurrence. Mean worst pain score in 24 h and average pain score in 24 h (scale of 10) at initial evaluation were 7.1 ± 1.8 and 5.8 ± 1.9, reduced after cryoablation to 0.8 ± 0.8 and 0.4 ± 0.6, respectively. Average time to symptom improvement was 2.8 ± 0.98 weeks (range 2-4 weeks). All patients reported improved ambulation and weight-bearing, and complete cessation of pain medication after treatment. The improvement was sustained on follow-up at 12 months. No major complications occurred. Minor complications occurred in 3/5 patients.

CONCLUSIONS

Early experience with percutaneous ultrasound-guided cryoablation to treat painful plantar fibromas suggests that it is a safe and effective treatment option, with early and near-complete symptom improvement.

Percutaneous Image-Guided Cryoablation in Vascular Anomalies

Understanding and management of vascular anomalies has always been intriguing. These disorders exhibit an expected pattern of clinical presentation and progression, and characteristic imaging findings. Significant progress in understanding and treating patients with vascular anomalies has been made in the past quarter century. Newer multidisciplinary domains for treating these disorders with medical drugs and less invasive image-guided or surgical procedures are constantly evolving. Vascular anomalies can exhibit aggressive tumor-like behavior resulting in recurrence or persistent symptoms after treatment. Thermal ablation has been widely used in tumor treatment. This has generated interest on using thermal ablation for treating vascular anomalies. Percutaneous image-guided cryoablation is increasingly used for this purpose as compared with other ablation technologies. Availability of small caliber cryoprobes and the ability to monitor the freeze zone in real time have made this an attractive option to interventional radiologists. These experiences are relatively new and limited. It is helpful to understand the emerging role of this technology in the treatment of vascular anomalies.

Percutaneous cryoablation of symptomatic venous malformations as a second-line therapeutic option: a five-year single institution experience

PURPOSE

To report the mid-term outcomes of percutaneous cryoablation (PCA) performed as second-line therapeutic option of venous malformations (VM).

MATERIAL AND METHODS

From 2011 to 2015, PCA was offered in 24 patients (mean age: 31 years, range: 12-64) as second-line treatment for recurrence of symptoms after sclerotherapy and when resection was not possible (due to lesion location or previous failure) or refused by the patient. Adverse effects were recorded, disease-free survival (DFS) and local tissue control (LTC) rates were calculated based on symptoms and volume evolution.

RESULTS

Mean follow-up was 18.7 months (6-48). Nine (37.5%, 9/24) adverse effects occurred and three (12.5%, 3/24) were severe. Mean pain assessed by visual analog scale (VAS) was 41.7 mm (0-80) before treatment and 20.3 mm (0-80) (p=0.01) after. Mean volume decreased significantly after treatment from 22.4 cm³ (0.9-146) to 8.35 cm³ (0-81.3) (p<0.001). Pain recurred in nine patients and size of one lesion increased. The DFS and LTC rates were 54% [95%CI: 22.94-77.27] and 93.33% [61.26-99.03] at 24 months, respectively. Only VM volume >10 cm³ was associated with a higher risk of local recurrence (p=0.05).

CONCLUSION

PCA as second-line treatment appears to be safe and effective for local control of VM according to mid-term results.

KEY POINTS

• Percutaneous cryoablation of venous malformations appeared well tolerated. • Size of venous malformations decreased significantly after percutaneous cryoablation (p<0.001). • Pain decreased significantly after percutaneous cryoablation of venous malformations (p=0.01).

Mid-term outcomes after percutaneous cryoablation of symptomatic abdominal wall endometriosis: comparison with surgery alone in a single institution

OBJECTIVES

To compare the outcomes of percutaneous image-guided cryoablation of symptomatic abdominal wall endometriosis (AWE) versus surgery alone.

METHODS

From 2004 to 2016, cryoablation or surgery alone was performed under local (n = 5) or general anaesthesia (n = 15) for AWE in a single institution in 7 (mean age, 36.1 years) and 13 (mean age, 31.9 years) patients, respectively. Fifteen lesions were treated by cryoablation (mean size, 2.3 cm; range, 0.5-7 cm) and 16 by surgery (2.5 cm; 1.1-3.4 cm). Tolerance, efficacy and patient and procedural characteristics were compared.

RESULTS

Median follow-up was 22.5 (range, 6-42) months after cryoablation and 54 (14-149) after surgery. The median procedure and hospitalisation durations were 41.5 min (24-66) and 0.8 days (0-1) after cryoablation, and 73.5 min (35-160) and 2.8 days (1-12 days) after surgery (both P = 0.01). Three patients (23.1%) had severe complications and nine aesthetic sequels (69.2%) after surgery, none after cryoablation (P = 0.05). The median 12- and 24-month symptom free-survival rates were 100% and 66.7% (95% CI, 5.4; 94.5) after cryoablation and 92% (55.3; 98.9) after surgery at both time points (P = 0.45).

CONCLUSIONS

Cryoablation presents similar effectiveness to surgery alone for local control of AWE while reducing hospitalisation duration and complications. Any aesthetic sequels were associated with the cryoablation treatment.

KEY POINTS

• Hospitalisation is shorter after cryoablation than after surgery of abdominal wall endometriosis. • A significantly lower rate of complications is observed after cryoablation compared to surgery. • Cryoablation of abdominal wall endometriosis presents similar effectiveness to surgery alone. • A significant reduction of pain is observed 6 months after treatment. • A significant reduction of abdominal wall endometriosis is observed at 6 months.

Percutaneous Image-Guided Cryoablation as Second-Line Therapy of Soft-Tissue Venous Vascular Malformations of Extremities: A Prospective Study of Safety and 6-Month Efficacy

PURPOSE

To report the safety and short-term efficacy of percutaneous image-guided cryoablation performed as second-line therapy of venous vascular malformations (VVM) of extremities.

MATERIALS AND METHODS

In this non-blinded, no-randomized trial, cryoablation was proposed in 14 patients presenting with symptomatic VVM for recurrences after treatment. Eligibility criteria were: cryoablation feasible, localization at least 5 mm from skin and nerves, absence of contra-indication for anesthesia. Safety was evaluated by the common terminology criteria for adverse events (AE). Clinical response was assessed by evaluating pain at day 7, month 2 and 6 using visual analog scale; quality of life before cryoablation and at 2 and 6 months after using questionnaire. Evolution of volume was evaluated by MRI at 6 months. Comparison was performed using the Wilcoxon test.

RESULTS

A technical success was observed in all cases. While 11 patients (78.6%) presented AE (13 grade 1-2 and 3 grade 3), only two severe AE (grade 3) related to cryoablation occurred in two patients (14.3%) during the 6-month follow-up: one immediate sciatic paralysis and one delayed paresthesia. A clinical response was observed in 12 patients (85.7%) at 6 months. Pain decreased significantly from 42.5 ± 14.2 mm before the intervention to 11.8 ± 17.9 mm at 6 months (P = 0.002). A significant decrease in the mean volume from 12.8 ± 14.3 to 3 ± 2.7 cm³ was observed at 6 months (P = 0.002).

CONCLUSION

Percutaneous cryoablation is a promising alternative treatment for sclerotherapy-resistant venous malformations. However, to improve safety, careful patient selection and treatment planning will be mandatory.

Non-invasive magnetic resonance-guided high intensity focused ultrasound ablation of a vascular malformation in the lower extremity: a case report

Introduction

Therapy of choice for symptomatic vascular malformations consists of surgery, sclerotherapy, or embolization. However, these techniques are invasive with possible complications and require hospitalization. We present a novel non-invasive technique, i.e., magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) ablation, for the treatment of a vascular malformation in a patient. This technique applies high-intensity sound waves transcutaneously to the body and is fully non-invasive. MRI guidance is the novel aspect of HIFU treatments and is used for exquisite delineation and localization of the lesion and accurate real-time temperature monitoring during tissue ablation. MR-HIFU is a well-established treatment option for uterine fibroids and is currently being investigated for, e.g., bone tumors, breast cancer, prostate cancer, and liver cancer. MR-HIFU of vascular malformations has not been a topic of research yet.

Case description

Volumetric MR-HIFU ablation of a vascular malformation in the lower extremity of an 18-year-old male patient was performed. Temperatures of 62–80 °C were reached in the target lesion with sonications of 4 × 4 × 8 mm using powers of 200 W for <20 s. At 1-month follow-up, the patient reported qualitatively sustained reduction of pain and normal motor function. Three-month follow-up imaging indicated successful nidus destruction, which resulted in reduction of >30 % of the tumor volume. After 13 months, pain score was reduced to <2 after extreme exertion for several hours and to 0 for daily activities.

Discussion and evaluation

Radiofrequency ablation and cryoablation are minimally invasive techniques that have been tried on low-flow vascular malformations with inconsistent results. Furthermore, both techniques require probe insertion, which is associated with risks of wound infection and hospitalization. Since MR-HIFU is truly non-invasive, these risks are negligible.

Conclusions

In conclusion, we reported a successful non-invasive treatment of a vascular malformation with MR-HIFU in a clinical patient including long-term follow-up data for the first time. The patient reported qualitatively sustained pain reduction up to 13 months post treatment.