Image-guided Radiofrequency Ablation Research Articles

Advances in radiofrequency ablation: mechanism of action and technology.

Radiofrequency ablation (RFA) is a minimally invasive treatment modality that utilizes high-frequency alternating current to destroy targeted tissues through thermal ablation. This manuscript provides an overview of the advancements in RFA, focusing on its mechanism of action and technological innovations. RFA technology was first introduced in the early 1900's, and its use has expanded and evolved, especially in its current utility in the treatment of painful conditions. As the technology has evolved, new techniques, applications and modalities have expanded its use and improved its efficacy. RFA works by applying radiofrequency energy through specialized electrodes, leading to resistive heating and coagulation necrosis. Its advantages include precise tissue targeting, minimal invasiveness, reduced complications, and faster recovery compared to traditional surgical interventions. Technological advancements in RFA have led to improved treatment outcomes. Multi-electrode systems allow for larger ablation zones. Image-guided RFA improves treatment planning and minimizes damage to healthy tissues. Cooled-tip and perfusion electrodes address limitations such as heat sink effects, enhancing RFA's efficacy in challenging anatomical regions. These developments have expanded RFA's applications to liver tumors, lung tumors, renal tumors, cardiac arrhythmias, and chronic pain syndromes. In conclusion, RFA has emerged as a safe and effective thermal ablation technique. Understanding its mechanism of action and integrating advanced technologies have significantly enhanced treatment outcomes. Continued research and innovation in RFA hold immense potential for further improving patient care and outcomes.

R-MFE-TCN: A correlation prediction model between body surface and tumor during respiratory movement.

2D CT image-guided radiofrequency ablation (RFA) is an exciting minimally invasive treatment that can destroy liver tumors without removing them. However, CT images can only provide limited static information, and the tumor will move with the patient's respiratory movement. Therefore, how to accurately locate tumors under free conditions is an urgent problem to be solved at present. The purpose of this study is to propose a respiratory correlation prediction model for mixed reality surgical assistance system, Riemannian and Multivariate Feature Enhanced Temporal Convolutional Network (R-MFE-TCN), and to achieve accurate respiratory correlation prediction. The model adopts a respiration-oriented Riemannian information enhancement strategy to expand the diversity of the dataset. A new Multivariate Feature Enhancement module (MFE) is proposed to retain respiratory data information, so that the network can fully explore the correlation of internal and external data information, the dual-channel is used to retain multivariate respiratory feature, and the Multi-headed Self-attention obtains respiratory peak-to-valley value periodic information. This information significantly improves the prediction performance of the network. At the same time, the PSO algorithm is used for hyperparameter optimization. In the experiment, a total of seven patients' internal and external respiratory motion trajectories were obtained from the dataset, and the first six patients were selected as the training set. The respiratory signal collection frequency was 21Hz. A large number of experiments on the dataset prove the good performance of this method, which improves the prediction accuracy while also having strong robustness. This method can reduce the delay deviation under long window prediction and achieve good performance. In the case of 400ms, the average RMSE and MAE are 0.0453 and 0.0361mm, respectively, which is better than other research methods. The R-MFE-TCN can be extended to respiratory correlation prediction in different clinical situations, meeting the accuracy requirements for respiratory delay prediction in surgical assistance.

Magnetic resonance imaging-guided radiofrequency ablation of breast cancer: a current state of the art review.

With a gradual increase in breast cancer incidence and mortality rates and an urgent need to improve patient prognosis and cosmetology, magnetic resonance imaging (MRI)-guided radiofrequency ablation (RFA) therapy has attracted wide attention as a new treatment method for breast cancer. MRI-RFA results in a higher complete ablation rate and extremely low recurrence and complication rates. Thus, it may be used as an independent treatment for breast cancer or adjuvant to breast-conserving surgery to reduce the extent of breast resection. Furthermore, with MRI guidance, accurate control of RFA can be achieved, and breast cancer treatment can enter a new stage of minimally invasive, safe, and comprehensive therapy. With progress in MR thermometry technology, the applications of MRI are expected to broaden.

Fibroblast growth factors induce hepatic tumorigenesis post radiofrequency ablation

Image-guided radiofrequency ablation (RFA) is used to treat focal tumors in the liver and other organs. Despite potential advantages over surgery, hepatic RFA can promote local and distant tumor growth by activating pro-tumorigenic growth factor and cytokines. Thus, strategies to identify and suppress pro-oncogenic effects of RFA are urgently required to further improve the therapeutic effect. Here, the proliferative effect of plasma of Hepatocellular carcinoma or colorectal carcinoma patients 90 min post-RFA was tested on HCC cell lines, demonstrating significant cellular proliferation compared to baseline plasma. Multiplex ELISA screening demonstrated increased plasma pro-tumorigenic growth factors and cytokines including the FGF protein family which uniquely and selectively activated HepG2. Primary mouse and immortalized human hepatocytes were then subjected to moderate hyperthermia in-vitro, mimicking thermal stress induced during ablation in the peri-ablational normal tissue. Resultant culture medium induced proliferation of multiple cancer cell lines. Subsequent non-biased protein array revealed that these hepatocytes subjected to moderate hyperthermia also excrete a similar wide spectrum of growth factors. Recombinant FGF-2 activated multiple cell lines. FGFR inhibitor significantly reduced liver tumor load post-RFA in MDR2-KO inflammation-induced HCC mouse model. Thus, Liver RFA can induce tumorigenesis via the FGF signaling pathway, and its inhibition suppresses HCC development.

The Short-term Efficacy of Contrast-enhanced Ultrasound (CEUS) and Gd-EOB-DTPA-enhanced Magnetic Resonance Imaging (MRI) Fusion Imaging-guided Radiofrequency Ablation (RFA) for Colorectal Liver Metastasis (CRLM).

This study is to explore the efficacy of contrast-enhanced ultrasound (CEUS) / Gd-EOB-DTPA-enhanced magnetic resonance imaging (MRI) fusion imaging-guided（fusion group）radiofrequency ablation (RFA) versus conventional ultrasound imaging-guided (conventional group) RFA for colorectal cancer liver metastases (CRLM) in a short-term. From December 2020 to December 2021, patients who underwent imaging-guided RFA of CRLM at our hospital with available CT/MRI images were enrolled consecutively. 22 patients with 46 lesions had undergone conventional group RFA whereas 29 patients with 63 lesions had undergone fusion group RFA. The lesion detection rate, technical success, local tumor progression (LTP) and complications were calculated. In this retrospective study, 51 patients with 130 lesions were diagnosed with CRLM. However, there were 12 lesions and 9 lesions invisible in the conventional group and fusion group, respectively. The lesion detection rate on the fusion imaging was significantly higher than on the US or CEUS in the fusion group (P＜0.05). There were no significant differences of the detection rate between the conventional group and the fusion group (P=0.207). In both groups, the technical success rate was 100%. For local tumor progression (LTP), there were no significant differences between the two groups (P＞0.05). The complications after ablation had no significant differences between the two groups (P=0.97). CEUS/ Gd-EOB-DTPA-enhanced MRI fusion imaging is a safe and effective method for RFA in the management of CRLM patients, and it may improve the therapeutic effect by detecting small lesions early.

Case report of trans-renal ablation procedures for a recurrent pheochromocytoma in von Hippel-Lindau disease

Pheochromocytoma is one of recurrent tumors in patients with von Hippel-Lindau (VHL) disease. For patients with bilateral adrenal glands, unilateral adrenalectomy is the treatment of choice; however, for patients with a single adrenal gland, hemiadrenalectomy or tumorectomy can be performed instead of adrenalectomy to preserve adrenal function. Currently, adrenalectomy is recommended even if recurrent pheochromocytomas occur in the residual adrenal tissue. Consequently, adrenal insufficiency cannot be avoided in these patients. Percutaneous radiofrequency ablation (RFA) is used as an alternative treatment for preserving adrenal function; however, RFA is difficult to perform when major organs are present in the approaching pathway. The trans-hepatic approach is the only reported safe route to approach a right adrenal tumor to avoid pneumothorax. In this case report, we performed percutaneous RFA and hydrodissection through the left renal parenchyma to treat a recurrent pheochromocytoma in the small residual left adrenal tissue, which is surrounded by several critical organs. Our goal was to show our experience of image-guided trans-renal RFA and hydrodissection in a patient with VHL disease.

Selection of kilovolt based on body mass index reduced radiation dose for computed tomography-guided radiofrequency ablation of liver tumors

Selection of kilovolt based on body mass index reduced radiation dose for computed tomography-guided radiofrequency ablation of liver tumors

Fusion imaging-guided radiofrequency ablation with artificial ascites or pleural effusion in patients with hepatocellular carcinomas: the feasibility rate and mid-term outcome

Purpose: To investigate the feasibility rate and the mid-term outcomes of fusion imaging-guided radiofrequency ablation (RFA) with artificial ascites or pleural effusion of hepatocellular carcinomas (HCCs) based on tumor locations. Materials and Methods: In this single-center retrospective study, 456 patients with single HCCs ≤4 cm were referred for RFA from April 2019 to April 2020. The tumor locations were classified into a conventional location (CL) and difficult location (DL, close to the diaphragm/heart/major vessels/bile ducts/gastrointestinal tract/kidneys). This study assessed the feasibility rate of CT/MRI-US fusion system-guided RFA with artificial ascites or pleural effusion and the therapeutic outcomes including technical success, technique efficacy, and local tumor progression (LTP) according to tumor location. Cumulative LTP rates were estimated using the Kaplan–Meier method. Results: 235 of 456 (51.5%) patients had HCCs in DL. Ablation was feasible in 431 of 456 (94.5%) patients. The feasibility rate was significantly lower in DL group than in CL group (89.8% [211/235] vs. 99.5% [220/221], p < 0.001). The technical success and technique efficacy rates were 100% [211/211] vs. 99.5% [219/220] and 98.6% [208/211] vs. 100% [220/220] in DL and CL groups, respectively (p > 0.05). The estimated 1-, 2-, and 3-year cumulative LTP rates in DL group were 1.0%, 2.5%, and 2.5%, respectively, and were not significantly different from the 2.3%, 3.9%, and 3.9% observed in CL group (p = 0.456). Conclusion: Fusion imaging-guided RFA with artificial ascites or pleural effusion could decrease technically infeasible cases and provide comparable LTP rates for HCCs in DL to HCCs in CL.

Image-Guided Radiofrequency Ablation for Joint and Back Pain: Rationales, Techniques, and Results.

Image-guided minimally invasive radiofrequency ablation (RFA) of sensory nerves has emerged as a treatment option for pain and swelling associated with advanced symptomatic joint and spine degeneration to bridge the gap between optimal medical therapy and surgical treatments. RFA of articular sensory nerves and the basivertebral nerve use image-guided percutaneous approaches resulting in faster recovery time and minimal risks. The current published evidence indicates clinical effectiveness; however, further research must be performed comparing other conservative treatments with RFA to understand further its role in different clinical settings, such as osteonecrosis. This review article discusses and illustrates the applications of RFA for treating symptomatic joint and spine degeneration.

Prediction of Protumorigenic Effects after Image-Guided Radiofrequency Ablation of Hepatocellular Carcinoma Using Biomarkers

PurposeTo perform radiofrequency (RF) ablation of hepatocellular carcinoma (HCC) and to assess serological and histopathological markers of tumorigenesis in distant untreated tumors to determine whether these were associated with unfavorable outcomes such as early relapse and increased biological aggressiveness. Materials and MethodsThe study cohort comprised 13 patients from a prospective single-arm study. All patients underwent 2 ablation sessions of multifocal HCC nodules 14 days apart. Core biopsy samples of untreated tumors were acquired at baseline and at the time of the second ablation session. Samples were stained immunohistochemically with Ki-67 (proliferation) and CD34 (microvasculature). Blood plasma was obtained at baseline and 2 days after the initial ablation session and analyzed for hepatocyte growth factor (HGF), vascular endothelial growth factor C, and angiopoietin-2 using an enzyme-linked immunosorbent assay. The clinical follow-up period ranged from 7 to 25 months. Patients were stratified as responders (complete remission or limited and delayed recurrence at >6 months; n = 6) or nonresponders (any recurrence within 6 months or >3 new tumors or any new tumor of >3 cm thereafter; n = 7). ResultsIn 3 of 7 nonresponders, the Ki-67 index markedly increased in untreated tumors, whereas Ki-67 was stable in all responders. Microvascular density strongly increased in a single nonresponder only. HGF and angiopoietin-2 increased by >30% in 3 of 7 and 4 of 7 nonresponders, respectively, whereas they were stable or decreased in responders. Overall, ≥2 biomarkers were elevated in 6 of 7 (85.7%) nonresponders, whereas 4 of 6 responders demonstrated no increased biomarker and 2 patients demonstrated increase in 1 biomarker only (P = .002). ConclusionsRF ablation of HCC can produce protumorigenic factors that induce effects in distant untreated tumors. These may potentially function as biomarkers of clinical outcome.

Role of percutaneous CT-guided radiofrequency ablation in treatment of intra-articular, in close contact with cartilage and extra-articular osteoid osteomas: comparative analysis and new classification system.

We investigated procedural safety, technical and clinical outcomes of the percutaneous image-guided radiofrequency ablation (PRFA) of intra-articular (IA), intra-articular close to cartilage (IACC), and extra-articular (EA) osteoid osteomas (OO). We proposed a new radiologic classification for osteoid osteoma depending on the degree and location of sclerosis which may correlate with technical failure and/or difficulties. According to the inclusion criteria, we enrolled consecutive patients who were referred to the investigation center from June 2018 to January 2022. After clinical and CT imaging features were suggestive for the diagnosis of OO, all the patients were treated by percutaneous CT-guided RFA with a standardized technique. Biopsy of the lesion was not performed in all patients. A retrospective analysis was conducted to assess the procedure's technical, primary clinical, and secondary clinical successes, recurrence rate, and complications. We classified all the OOs according to a new proposed classification of the site and the amount of sclerosis. A total number of 55 patients were enrolled in our study according to the inclusion criteria. The mean age of the enrolled patients was 24.07 ± 14.71years (ranges from 7 to 57years). The M/F ratio was roughly 2:1. The mean follow-up was 20.18 ± 12.60months (ranges from 2 to 44months). EA group included 36 patients, IA included 5 and IACC included 14 patients. Technical success was achieved in all cases of IA and IACC groups. Technical success in the EA group was 97.22% (1 technical failure). Primary clinical success was 100%, 92.85%, and 91.66% for IA, IACC, and EA groups, respectively. Accordingly, the recurrence rate was 5.88% in EA, and 7.14% in IACC, while no recurrence occurred in the IA group. No complications occurred. The secondary success rate of the 3 cases of recurrence was 100%. PRFA proved to be a safe procedure with a high rate of success for OO treatment even in intra-articular lesions in close contact with cartilage. This study showed that the results in terms of technical and clinical success are comparable for IA OO, IACC OO, and EA OO, even if the recurrence rate was higher in EA OO. Our proposed new classification of the degree and location of sclerosis may correlate to technical failure, but further studies with a larger number of patients are needed for validation.

Short and long-term efficacy of image-guided laser and radiofrequency ablation therapies: a prospective monocentric and single-operator study

Short and long-term efficacy of image-guided laser and radiofrequency ablation therapies: a prospective monocentric and single-operator study

Remodeling of the Lumbar Facet Joint After Full Endoscopic Resection for Lumbar Osteoid Osteoma: Case Report and Literature Review.

Osteoid osteoma (OO) is a common benign bone tumor; however, approximately 25% of cases have spine involvement. It is often treated by image-guided radiofrequency ablation to break down the nidus. Few reports have described full endoscopic resection of the lesion, but none have described postoperative remodeling of the lumbar facet joint after surgical resection of an OO. The study aimed to describe a rare case of remodeling of the lumbar facet joint and then delineate the least invasive surgical technique of endoscopic resection of an OO. A 26-year-old man presented with severe left buttock pain and sciatica that worsened at night and was relieved by ibuprofen. Magnetic resonance imaging indicated a left inferior facet of an L3 mass-like lesion. A thin-section computed tomography image revealed a nidus, which was compatible with an OO. Full endoscopic resection was performed to completely remove the nidus of the OO. At the 2-year follow-up, the patient was symptom-free and computed tomography images indicated new bone formation. The present case and literature review demonstrate that endoscopic resection is safe and effective for managing a posterior element of lumbar OO. Furthermore, this technique allows complete removal of the nidus with minimal damage to surrounding structures and leads to remodeling of the resection site. Patients with OO involving the posterior element of the spine can present with buttock and radicular pain, mimicking lumbar disc herniation. OO can be successfully removed by the full endoscopic method and remodeling of the resected site can be anticipated.

Safety and Efficacy of Ultrasound-Guided Radiofrequency Ablation for Benign Nonfunctional Thyroid Nodules in Children: A Retrospective Study of 62 Patients with Over Four Years of Follow-Up.

Background: Image-guided radiofrequency ablation (RFA) for benign nonfunctional thyroid nodules in adults has been shown to be effective and safe, but few trials address the use of RFA in children. Therefore, this study was designed to assess the efficacy and safety of RFA application to benign nonfunctional thyroid nodules in children. Methods: A retrospective study of RFA for 70 benign nonfunctional thyroid nodules in 62 children with four-year follow-up was conducted. Volume reduction ratio (VRR), technique efficacy, regrowth rate, symptom score, and cosmetic score were calculated to evaluate the efficacy. Complications and side effects were recorded. Logistic regression analysis was performed to identify risk factors, and subgroup analyses were performed. Results: Patients were followed up for at least four years (59.1 ± 10.5 months, range 48-85 months). After RFA treatment, the VRR and technique efficacy rates were highest at the first year* (77.5% and 91.4%, respectively) but decreased by four years (55.1% and 81.4%, respectively). The symptom score decreased from 4.0 ± 2.1* to 0.8 ± 1.6 (Z = -6.82, p < 0.001), and the cosmetic score decreased from 3.3 ± 0.7 to 1.3 ± 0.9 (Z = -7.0, p < 0.001).* The nodule regrowth rate was 22.9%, of which 56.3% of cases represented loss of efficacy. In the cases of loss of efficacy, 66.7% had greater volume than their initial presentation. Patients who received a second RFA treatment due to loss of efficacy lost efficacy again. Bilateral nodules, low vascularity, and low cystic components were independent risk factors correlating with technique efficacy. Bilateral nodules correlated with low VRR, low efficacy rate, and high regrowth rate. Nodules with a higher proportion of cystic components had higher VRR. The overall complication rate was 4.8%. Conclusions: RFA was effective in reducing the volume of benign nonfunctional thyroid nodules in children, providing significant symptomatic relief with a good safety profile during short- and long-term follow-up. RFA is a good minimally invasive treatment modality for selected pediatric patients, and it may not be appropriate for the treatment of bilateral thyroid nodules in children.

Arteriovenous Malformation of the Uterus: A Review and Update.

Arteriovenous malformation of the uterus (AVMU) is a very rare and uncommon condition, because it has been documented that less than 100 cases of AVMU have been reported in the literature. AVMU is potentially a life-threatening condition with regard to the fact that some cases of AVMU could manifest with profuse bleeding from the uterus via the vagina. AVMU could either be congenital AVMU which is less common or acquired AVMU with pregnancy noted to have a role to play in the pathogenesis of AVMUs. The true incidence of AVMU is stated to be difficult to ascertain in view of the fact that some cases of bleeding that have been caused by AVMU do tend to conservative, medical management and many of these AVMUs could remain undiagnosed. The most common manifestations of AVMUs tend to be abnormal uterine bleeding that could be episodic, intermittent, continuous, mild or torrential which could lead to severe anaemia or shock. Some AVMUs could be found incidentally based upon radiology imaging for a different condition. Other symptoms of AVMUs do include: Metrorrhagia; Menorrhagia; Bleeding following a miscarriage; Bleeding following dilatation and curettage; Bleeding subsequently after hysterectomy; Bleeding associated with trophoblastic disease; Bleeding following caesarean section; Post-partum haemorrhage; Intermittent vaginal bleeding; Continuous vaginal bleeding; Post-menopausal bleeding; Acute abdominal pain with hemoperitoneum; Pallor; Dizziness; Weakness; Drowsiness; Being unwell following delivery of a baby; Bleeding following therapeutic abortion; Tachycardia; Supra-pubic pain at times; hypotension. Diagnosis of AVMU tends to be made based upon radiology imaging with utilization of ultrasound scan / Doppler scan of the uterus and pelvis, Contrast Computed Tomography scan, and Contrast Magnetic Resonance Imaging Scan, as well as by selective angiography which tends to be ensued by treatment with embolization of the feeding vessels to the AVMU. The treatment of AVMUs these days has ranged between conservative and medical management that includes hormones for small AVMUs, Hysterectomy, which tends to be a definitive treatment that removes the AVMU but does leave the individual not being able to maintain her future fertility, as well as selective angiography and super-selective embolization of the uterine arterial branches feeding the AVMU, which does tend to maintain the future fertility of the patients and which has the advantage of being undertaken under local anaesthesia. Questions that should be on the minds of clinicians include should doppler ultrasound scan of the uterus be undertaken with regard to all women who develop persistent vaginal bleeding pursuant to or during management of miscarriage, considering that there are very few interventional radiologists in many hospitals. This means that selective angiography plus super-selective embolization cannot be undertaken in district hospitals should all women who have suspected AVMU that have severe bleeding that may require surgical operation be referred to a tertiary hospital so that they could possibly benefit from the undertaking of selective angiography and embolization of their AVMUs instead of hysterectomy to enable them to maintain their future fertility? It is also important for clinicians to be made aware of the existence of AVMUs so that they could appreciate the risk factors as well as the clinical manifestations who should be suspected of possibly having AVMUs. Clinicians also need to learn about various conservative and expectant methods of treating AVMUs including hormonal treatment. Clinicians also need to appreciate the future implications for future fertility of women who have AVMUs. Possible treatment options that have not been utilized for the treatment of AVMUs include: (a) Radiology image-guided cryotherapy of AVMU, (b) Radiology image-guided radiofrequency ablation of AVMU, and (c) Radiology Image-guided Irreversible electroporation of AVMU. There is a global need for the training of more interventional radiologists all over the world including in the developing countries as well as some of the developed countries to that they can undertake embolization of AVMUs as well as they can provide various interventional radiology treatment options for various other conditions.

Computed tomography guided radiofrequency ablation of osteoid osteoma in children: a single center's experience.

To report a single center's experience evaluating the efficacy and safety of computed tomography-guided radiofrequency ablation for the treatment of osteoid osteoma in children. Institutional database research identified 33 symptomatic patients (≤ 18years of age; male/female ratio: 21/12, mean age 13.09 ± 3.66) with osteoid osteoma who were treated by CT-guided RFA. Technical and clinical success as well as complication rates were recorded. The duration of the procedure, the number of computed tomography scans and the results of the biopsy were assessed. Pain, prior, the following morning and 1week, 1/6/12months after the procedure were compared by means of a numeric visual scale (NVS) questionnaire. Mean lesion size was 8.28 ± 4.24mm. Mean follow-up was 23.33 ± 17.61months (range 12-62). Mean pain score prior to radiofrequency ablation was 9.06 ± 0.80 NVS units. On week 1 and 1/6/12months, all patients were pain-free reporting 0 NVS units (p < 0.05). The mean procedure time was 54min (range 51-59) and a mean of 7 CT scans were performed during the ablation session. RF electrode was successfully placed in the center of the nidus in all cases. In our study, none of our patient experienced recurrence of the pain, nor complications. The present study demonstrates that percutaneous CT-guided radiofrequency ablation constitutes a safe and effective technique for osteoid osteoma treatment in children.

Image-Guided Thermal Ablation in De Novo Renal Tumor Arising in Kidney Allograft: 3-Year Follow-Up. A Case Report

De novo tumors in renal allograft recipients are a severe complication during long-term follow-up after transplantation and may require transplantectomy. Herein we present a case of de novo renal tumor arising in the renal allograft, treated with the less invasive image-guided radiofrequency ablation (RFA) with long-term follow-up. A tumor was detected during the routine annual follow-up in a patient with good renal function who underwent renal transplantation in 1989. Computed tomography (CT) showed a mass in the allograft whose shape, vascularization, and density suggested the presence of a solid, malignant mass, located in the upper renal pole, that measured 17 mm. CT-guided RFA was performed successfully, and the outcome was verified by an immediate control CT after the intervention. No residual pathologic tissue, major bleeding, or damage to the adjacent parenchyma was evidenced. The patient was discharged with stable renal function. CT scan and ultrasound were performed 3, 6, 12, 18, 24, and 36 months after RFA. No signs of change in renal function, recurrence, neovascularization, or damage to the adjacent microcirculation were observed during the 3-year follow-up. In conclusion, percutaneous RFA of small renal tumors occurring in renal allografts can be considered a function-sparing, safe, and effective therapeutic option when difficult surgical removal may be anticipated. Our experience also supports the need for yearly renal allograft ultrasound follow-up for early identification of small neoplasm than can be treated less invasively.

Percutaneous image-guided radiofrequency ablation for adrenal tumours: a systematic review

To undertaken a systematic review of the technical success and technique efficacy rates of percutaneous image-guided radiofrequency ablation (RFA) for adrenal tumours. Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, the electronic databases MEDLINE, EMBASE, and PubMed were searched for relevant studies from inception to the third week of January 2020. Only studies reporting effectiveness rates of percutaneous RFA for adrenal tumours were included. Data regarding sample size, tumours, effectiveness rates, outcomes, and complications were extracted in duplicate and recorded. A total of 15 studies evaluating 292 individuals with 305 tumours were included. Patient selection criteria included age ≥18 years, contraindication to surgical intervention, and no uncorrected coagulopathy. Cumulative technical success, primary technique efficacy, and secondary technique efficacy rates were 99%, 95.1% and 100%, respectively, indicating optimal immediate control of adrenal tumours. Technical success and technique efficacy rates of primary adrenal tumours were higher than adrenal metastases; however, formal statistical analyses were precluded due to lack of comparative studies. Local tumour progression rates for adrenal metastases were 20.3% at 3 months, 26.3% at 6 months, and 29.3% at 12 months. Overall survival rates for adrenal metastases were 81.8% at 6 months, 59.6% at 12 months, and 62.9% at 18 months. The intraprocedural complication rate was 30.2%, with the most frequency reported complication being procedural hypertensive crisis. The findings of this study suggest percutaneous image-guided RFA is a safe and efficacious procedure. Further studies are warranted to define patient selection criteria and long-term outcomes.

Imaging-guided radiofrequency ablation of osteoid osteoma in typical and atypical sites: Long term follow up.

PurposeTo assess efficacy and safety of imaging-guided radiofrequency ablation (RFA) of Osteoid Osteoma (OO) in both typical and atypical sites.Methods and materialsBetween January 2014 and March 2019, 102 consecutive percutaneous RFA were performed and retrospectively reviewed. The procedures were performed using a RFA bipolar ablation system (Covidien, exposed tip of 0.7-1cm), under Computed Tomography (CT) guidance or using a navigation system (Masmec) under CT and Cone Beam CT (CBCT) guidance. Patients were followed up over 24 months. Clinical success and recurrences were considered on the base of established criteria. In patients with clinical failure and/or imaging evidence of relapse, retreatment was considered.ResultsAdministered power per-procedure was ≤8 W (mean temperature, 90°C). The pre-procedure average value of visual analog scale (VAS) was 8.33+/-0.91. Primary and secondary success rate 96.08% (98/102) and100% (102/102), respectively. No major complication was described. Technical success was proved in every patient by CT scan acquisition after needle positioning. Relapse and tumour location were significantly correlated (p-value = 0.0165). The mean dose-length product was 751.55 mGycm2. Advanced bone healing was noted in 68 lesions after 1y-follow up and in 86 lesions after 2y-follow up.ConclusionImaging-guided percutaneous RFA is a highly effective technique for OO, both in typical and atypical sites. CT or CBCT guidance, navigation systems and operator experience grant the technical success, which is the most crucial parameter affecting outcome.

Early results for iCMR in atrial flutter

Abstract Funding Acknowledgements Type of funding sources: None. Background As a standard of care, ablation of typical atrial flutter involves performing cardiac catheterization under x-ray fluoroscopy. The unique ability of magnetic resonance (MR) to provide real-time functional imaging in multiple views without ionizing radiation exposure has the potential to be a powerful tool for diagnostic and interventional procedures. Real-time MR imaging-guided radiofrequency (RF) ablation has been used as a part of clinical trials. Objective To implement the MR imaging-guided RF ablation of typical atrial flutter in the clinical routine. Methods From January to July 2020, 15 consecutive patients with typical atrial flutter have been referred for ablation. Patient preparation, conscious sedation and groin puncture took place inside the 1.5 Tesla MR scanner as a part of an MR-only workflow. The catheter advancement as well as the RF ablation procedure have been performed under direct visualisation of catheters with integrated micro-coils using an interactive sequence with active tip tracking and automatic slice positioning in the plane where the catheter tip has been detected. During catheter advancement a single frontal plane has been used to visualize the passage of the catheter through femoral veins and inferior vena cava. With both diagnostic and ablation catheters in the right atrium, an axial stack of balanced steady-state free precession acquisitions has been acquired and used to reconstruct planes in the short- and long cardiac axis. These have been used to provide a "left- and right anterior oblique" view familiar to an interventional electrophysiologist. The subsequent catheter placement and ablation have been performed under direct visualisation in these two planes (see figure). Results The ablation was successful in 14 patients, one patient had to undergo a conventional procedure on the following day. The mean time to reach right atrium and coronary sinus was 4 [3,5] and 7 [6,10] minutes, respectively. The mean total ablation duration and procedure time was 18 [12,26] and 43 [33,58] minutes, respectively. There were no adverse events. Conclusion The implementation of the MR imaging-guided RF ablation of typical atrial flutter in the clinical routine is feasible and leads to similar success rates and procedure times as the conventional fluoroscopy-based ablation. Abstract Figure.