Safety and Efficacy of Radiofrequency Ablation for Nonfunctioning Benign Thyroid Nodules in Children and Adolescents in 14 Patients over a 10-Year Period

PurposeTo evaluate the efficacy and safety of radiofrequency (RF) ablation for nonfunctioning benign thyroid nodules in children and adolescents.Materials and MethodsFourteen pediatric patients (10 female, 4 male; mean age 15.7 ± 2.3 years, range 12–19 years) with nonfunctioning benign thyroid nodules (mean longest diameter 3.7 ± 1.1 cm, range 2.0–5.6 cm) treated with the use of RF ablation from 2005 to 2015 were evaluated. The inclusion criteria for RF ablation therapy were (i) age <20 years, (ii) benign cytological confirmation by ≥2 separate fine-needle aspiration or core needle biopsies, (iii) pressure symptoms or cosmetic problems caused by thyroid nodules, (iv) absence of any suspicious feature as determined with the use of ultrasound (US), (v) normal serum levels of thyroid hormone and thyrotropin, and (vi) follow-up of >6 months. RF ablation was performed with the use of an RF generator and an 18-gauge internally cooled electrode. RF ablation was performed under local anesthesia without conscious sedation or general anesthesia. Changes in nodules on follow-up US, changes in symptomatic and cosmetic scores, and complications arising during or after RF ablation were evaluated.ResultsMean follow-up period was 36.9 ± 21.7 months (range 6–69 months). At last follow-up visits, mean longest nodule diameter and volume had decreased significantly (3.7 ± 1.1 cm vs 1.4 ± 0.9 cm and 14.6 ± 13.3 mL vs 1.7 ± 4.4 mL; P < 0.001). Both cosmetic and compressive symptoms significantly improved (3.8 ± 0.6 vs 1.4 ± 0.6 and 3.4 ± 1.0 vs 0.1 ± 0.4; P < 0.001). The mean number of ablation sessions was 2.1 ± 1.2 (range 1–5 sessions) and no major complication was encountered during or after RF ablation.ConclusionsRF ablation might be a safe and effective treatment modality for nonfunctioning benign thyroid nodules in children and adolescents.     

Radiofrequency Ablation for the Palliative Treatment of Bone Metastases: Outcomes from the Multicenter OsteoCool Tumor Ablation Post-Market Study (OPuS One Study) in 100 Patients

PurposeTo evaluate the effectiveness of radiofrequency (RF) ablation as measured by change in worst pain score from baseline to 3 mo after RF ablation for the palliative treatment of painful bone metastases.Materials and MethodsOne hundred patients (mean age, 64.6 y) underwent RF ablation for metastatic bone disease and were followed up to 6 mo. Subjects’ pain and quality of life were measured before RF ablation and postoperatively by using the Brief Pain Index and European Quality of Life questionnaires. Opioid agent use and device-, procedure-, and/or therapy-related adverse events (AEs) were collected.ResultsEighty-seven patients were treated for tumors involving the thoracolumbar spine and 13 for tumors located in the pelvis and/or sacrum. All ablations were technically successful, and 97% were followed by cementoplasty. Mean worst pain score decreased from 8.2 ± 1.7 at baseline to 3.5 ± 3.2 at 6 mo (n = 22; P < 0.0001 for all visits). Subjects experienced significant improvement for all visits in average pain (P < .0001), pain interference (P < .0001), and quality of life (P < .003). Four AEs were reported, of which 2 resulted in hospitalization for pneumonia and respiratory failure. All 30 deaths reported during the study were attributed to the underlying malignancy and not related to the study procedure.ConclusionsResults from this study show rapid (within 3 d) and statistically significant pain improvement with sustained long-term relief through 6 mo in patients treated with RF ablation for metastatic bone disease.     

A Bicentric Propensity Score Matched Study Comparing Percutaneous Computed Tomography–Guided Radiofrequency Ablation to Magnetic Resonance–Guided Focused Ultrasound for the Treatment of Osteoid Osteoma

PurposeTo assess the safety and efficacy of computed tomography–guided radiofrequency (RF) ablation and magnetic resonance–guided focused ultrasound (MRgFUS) in the treatment of osteoid osteoma with a long-term follow-up study.Materials and MethodsDatabase research was performed at 2 different centers with experience in musculoskeletal interventions. Both centers, one performing RF ablation and the other MRgFUS, identified 116 patients who underwent either RF ablation or MRgFUS procedures for the treatment of symptomatic osteoid osteoma and retrospectively evaluated data regarding pain scores using a visual analog scale (VAS). Complications were recorded according to the Cardiovascular and Interventional Radiological Society of Europe classification system. Propensity score matching for multiple variables was performed. Pain scores before and after therapy were compared.ResultsOf 116 patients treated, 61 and 55 underwent RF ablation and MRgFUS, respectively. Before treatment, the mean reported pain in the 2 groups were 9.1 ± 0.88 (RF ablation) and 8.7 ± 0.73 (MRgFUS) VAS units. After treatment, a statistically significant (P < .00001) overall reduction in pain symptomatology was recorded. No statistically significant difference was observed between the mean values of pain after treatment in both groups (P = .256). Over a mean of >2 years of follow-up, 4 cases of relapse (RF ablation, 1; MRgFUS, 3) and 1 complication (RF ablation) were observed. The analysis from propensity score matching that identified a matched cohort of 48 patients showed similar results.ConclusionsThe 2 techniques for the treatment of osteoid osteoma resulted in profound and similar pain relief. The presence of thick cortical bone over the nidus can reduce the effectiveness of MRgFUS.     

Transarterial Chemoembolization Followed by Radiofrequency Ablation for Hepatocellular Carcinoma: Impact of the Time Interval between the Two Treatments on Outcome

PurposeTo compare the efficacy of radiofrequency (RF) ablation after transarterial chemoembolization within or beyond 30 days for medium-large or multiple recurrent hepatocellular carcinomas (HCCs).Materials and MethodsIn this single-center retrospective study conducted from 2007 through 2015, 135 patients with a single recurrent HCC (>3 cm) or multiple (2–5 tumors) recurrent HCCs underwent transarterial chemoembolization plus RF ablation. A total of 62 patients underwent RF ablation after transarterial chemoembolization within 30 days (sequential group) and 73 patients underwent RF ablation after transarterial chemoembolization beyond 30 days (delayed group). Outcomes of interests included overall survival (OS), progression-free survival (PFS), and complete response (CR) rate.ResultsThe median OS and PFS were 49.8 and 38.0 months for sequential group, and 31.0 and 11.6 months for the delayed group. The sequential group experienced significantly better OS (hazard ratio [HR]: 0.517; P = .002) and PFS (HR, 0.621; P = .021). Among patients with multiple tumors or a single tumor >5 cm, the sequential group still had significantly longer OS (P = .022; P = .018, respectively) and PFS (P = 0.042; P = .036, respectively) than the delayed group, although no significant differences were observed among patients with solitary 3- to 5-cm tumors (P = .138; P = .803, respectively). The sequential group had a significantly better CR rate than the delayed group (85.4% vs. 68.5%, respectively; P = .035). Significant predictors of OS and PFS included maximum tumor size, number of tumors, and time interval between transarterial chemoembolization and RF ablation.ConclusionsTransarterial chemoembolization plus sequential RF ablation within 30 days was more effective for recurrent HCCs than transarterial chemoembolization plus delayed RF ablation. The time interval within 30 days is required for treating large or multiple HCCs but may not be necessary for solitary medium-sized HCC.     

Impact of the Ablative Margin on Local Tumor Progression after Radiofrequency Ablation for Lung Metastases from Colorectal Carcinoma: Supplementary Analysis of a Phase II Trial (MLCSG-0802)

PurposeTo explore what extent of ablative margin depicted by computed tomography (CT) immediately after radiofrequency (RF) ablation is required to reduce local tumor progression (LTP) for colorectal cancer (CRC) lung metastases.Materials and MethodsThis retrospective study was undertaken as a supplementary analysis of a previous prospective trial. Seventy patients (49 men and 21 women; mean age ± standard deviation, 64.9 years ± 10.6 years) underwent RF ablation for CRC lung metastases, and 95 tumors that were treated in the trial and followed up with CT at least 12 months after RF ablation were evaluated. The mean tumor size was 1.0 cm ± 0.5 cm. The ablative margin was estimated as the shortest distance between the outer edge of the tumor and the surrounding ground-glass opacity on CT obtained immediately after RF ablation. The impact of the ablative margin on LTP was evaluated using logistic regression analysis. Multivariate logistic regression analysis was also performed to identify the risk factors for LTP. The result was validated with multivariate logistic regression applying a bootstrap method (1,000 times resampling).ResultsThe mean ablative margin was 2.7 mm ± 1.3 (range, 0.4–7.3 mm). LTP developed in 6 tumors (6%, 6/95) 6–19 months after RF ablation. The LTP rate was significantly higher when the margin was less than 2 mm (P = .023). A margin of <2 mm was also found to be a significant factor for LTP (P = .048) on multivariate analysis and validated using the bootstrap method (P = .025).ConclusionsAn ablative margin of at least 2 mm is important to reduce LTP after RF ablation for CRC lung metastases.     

Juxtametallic Bipolar Bone Radiofrequency Ablation: Thermal Monitoring in an Ex-Vivo Model with Specimen MRI and Histopathologic Correlation

PurposeTo measure the ablation zone temperature and nontarget tissue temperature during radiofrequency (RF) ablation in bone containing metal instrumentation versus no metal instrumentation (control group).Materials and MethodsEx vivo experiments were performed on 15 swine vertebrae (control, n = 5; titanium screw, n = 5; stainless steel screw, n = 5). Screws and RF ablation probe were inserted identically under fluoroscopy. During RF ablation (3 W, 5 minutes), temperature was measured 10 mm from RF ablation centerpoint and in muscle contacting the screw. Magnetic resonance (MR) imaging, gross pathologic, and histopathologic analyses were performed on 1 specimen from each group.ResultsAblation zone temperatures at 2.5 and 5 minutes increased by 12.2 °C ± 2.6 °C and 21.5 °C ± 2.1 °C (control); 11.0 °C ± 4.1 °C and 20.0 °C ± 2.9 °C (juxta-titanium screw), and 10.0 °C ± 3.4 °C and 17.2 °C ± 3.5 °C (juxta–stainless steel) screw; differences among groups did not reach significance by analysis of variance (P = .87). Mixed-effects linear regression revealed a statistically significant increase in temperature over time in all 3 groups (4.2 °C/min ± 0.4 °C/min, P < .001). Compared with the control, there was no significant difference in the temperature change over time for titanium (?0.3 °C/min ± 0.5 °C/min, P = .53) or steel groups (?0.4 °C/min ± 0.5 °C/min, P = .38). The mean screw temperature at the final time point did not show a statistically significant change compared with baseline in either the titanium group (?1.2 °C ± 2.3 °C, P = .50) or steel group (2.6 °C ± 2.9 °C, P = .11). MR imaging and pathologic analyses revealed homogeneous ablation without sparing of the peri-hardware zones.ConclusionsAdjacent metallic instrumentation did not affect the rate of or absolute increase in temperature in the ablation zone, did not create peri–metallic ablation inhomogeneities, and did not result in significant nontarget heating of muscle tissue in contact with the metal instrumentation.     

Combination of Microwave Ablation and Percutaneous Osteoplasty for Treatment of Painful Extraspinal Bone Metastasis

PurposeTo evaluate the efficacy and safety of microwave (MW) ablation combined with percutaneous osteoplasty (POP) on painful extraspinal bone metastases.Materials and MethodsIn this retrospective study, 50 adult patients with 56 extraspinal bone metastasis lesions, who suffered from refractory moderate to severe pain, were treated with MW ablation and POP. Changes in quality of life were evaluated based on the Visual Analog Scale (VAS), daily morphine consumption, and the Oswestry Disability Index (ODI) before and immediately after the procedure and during follow-up times.ResultsTechnical success was achieved in all patients. Mean preoperative VAS score and morphine dose were 7.0 ± 2.6 (range, 3–10) and 66.7 ± 33.2 mg (range, 10–120 mg), respectively. Mean postoperative VAS scores and daily morphine doses were as follows: 1 day, 3.5 ± 2.1 and 36.1 ± 25.8 mg (P < .05); 1 week, 1.5 ± 1.7 and 12.2 ± 14.8 mg (P < .001); 1 month, 0.9 ± 1.4 and 5.7 ± 10.0 mg (P < .001); and 3 months, 0.6 ± 1.2 and 4.7 ± 8.4 mg (P < .001). A significant decrease in the ODI score was also observed (P < .05). Periprocedural death was not observed. A pathologic fracture occurred in 1 (2%) patient with femoral metastasis, and local infection was observed in 2 (4%) patients. Minor cement leakage occurred in 4 (8%) patients with no symptomatic or intra-articular extravasation. No local tumor progression occurred in patients with imaging follow-up.ConclusionsMW ablation combined with POP is an effective and safe treatment for painful extraspinal bone metastases, which can significantly relieve pain and improve quality of life.     

Outcomes of Hemorrhoidal Artery Embolization from a Multidisciplinary Outpatient Interventional Center

PurposeTo evaluate the safety and efficacy of outpatient transarterial embolization for symptomatic refractory internal hemorrhoids.Materials and MethodsRetrospective analysis of 134 patients who underwent hemorrhoidal artery embolization (HAE) for symptomatic internal hemorrhoids between August 2021 and June 2022 (76 men and 58 women) was performed. The mean age was 54.9 years, with a mean Goligher hemorrhoid grade (HG) of 2.1. Branches of the superior rectal artery (SRA) or middle rectal artery supplying the corpus cavernosum recti were embolized with both spherical particles and microcoils. Standard-of-care evaluations were performed at baseline and the 1 month follow-up, which included hemorrhoid-related pain (HRP) (0–10), hemorrhoid symptoms score (HSS) (5–20), quality of life (QoL) (0–4), French bleeding score (FBS) (0–9), and HG (0–4). Clinical success was defined as improvement of symptoms without additional treatment.ResultsEmbolization of at least 1 hemorrhoidal artery was achieved in 133 (99%) of the 134 patients. The mean number of SRA branches embolized per patient was 2.9 ± 1.0. Clinical success was seen in 93% (124 of 134) of patients at the 1-month follow-up, with 10 patients requiring repeat embolization. There were significant improvements in all mean outcomes at 1 month: HSS (11–7.8; P < .01), HRP (4.1–1.3; P < .01), QoL (2.2–0.8; P < .01), FBS (4.4–2.2; P < .01), and HG (2.3–1.2; P < .05). There were no severe adverse events.ConclusionsHAE is a safe and effective outpatient treatment for refractory symptomatic internal hemorrhoids in the short term.     

Stereotactic Body Radiotherapy for Stage I Renal Cell Carcinoma: National Treatment Trends and Outcomes Compared to Partial Nephrectomy and Thermal Ablation

PurposeTo assess use of stereotactic body radiotherapy (SBRT) for stage I renal cell carcinoma (RCC) and compare outcomes with thermal ablation and partial nephrectomy (PN).Materials and MethodsThe 2004–2015 National Cancer Database was investigated for histopathologically proven stage I RCC treated with PN, cryoablation, radiofrequency (RF) or microwave (MW) ablation, or SBRT. Patients were propensity score–matched to account for potential confounders, including patient age, sex, race, comorbidities, tumor size, histology, grade, tumor sequence, administration of systemic therapy, treatment in academic vs nonacademic centers, treatment location, and year of diagnosis. Overall survival (OS) was evaluated with Kaplan-Meier plots, log-rank tests, and Cox proportional hazards models.ResultsA total of 91,965 patients were identified (SBRT, n = 174; PN, n = 82,913; cryoablation, n = 5,446; RF/MW ablation, n = 3,432). Stage I patients who received SBRT tended to be older women with few comorbidities treated at nonacademic centers in New England states. After propensity score matching, a cohort of 636 patients was obtained with well-balanced confounders between treatment groups. In the matched cohort, OS after SBRT was inferior to OS after PN and thermal ablation (PN vs SBRT, hazard ratio [HR] = 0.29, 95% confidence interval [CI] 0.19–0.46, P < .001; cryoablation vs SBRT, HR = 0.40, 95% CI 0.26–0.60, P < .001; RF/MW ablation vs SBRT, HR = 0.46, 95% CI 0.31–0.67, P < .001). Compared with PN, neither cryoablation nor RF/MW ablation showed significant difference in OS (cryoablation vs PN, HR = 1.35, 95% CI 0.80–2.28, P = .258; RF/MW ablation vs PN, HR = 0.64, 95% CI 0.95–2.55, P = .079).ConclusionsCurrent SBRT protocols show lower OS compared with thermal ablation and PN, whereas thermal ablation and PN demonstrate comparable outcomes.     

Factors Associated with Hospital Length of Stay and Adverse Events following Percutaneous Ablation of Lung Tumors

PurposeTo explore the association between risk factors established in the surgical literature and hospital length of stay (HLOS), adverse events, and hospital readmission within 30 days after percutaneous image-guided thermal ablation of lung tumors.Materials and MethodsThis bi-institutional retrospective cohort study included 131 consecutive adult patients (67 men [51%]; median age, 65 years) with 180 primary or metastatic lung tumors treated in 131 sessions (74 cryoablation and 57 microwave ablation) from 2006 to 2019. Age-adjusted Charlson Comorbidity Index, sex, performance status, smoking status, chronic obstructive pulmonary disease (COPD), primary lung cancer versus pulmonary metastases, number of tumors treated per session, maximum axial tumor diameter, ablation modality, number of pleural punctures, anesthesia type, pulmonary artery–to–aorta ratio, lung densitometry, sarcopenia, and adipopenia were evaluated. Associations between risk factors and outcomes were assessed using univariable and multivariable generalized linear models.ResultsIn univariable analysis, HLOS was associated with current smoking (incidence rate ratio [IRR], 4.54 [1.23–16.8]; P = .02), COPD (IRR, 3.56 [1.40–9.04]; P = .01), cryoablations with ≥3 pleural punctures (IRR, 3.13 [1.07–9.14]; P = .04), general anesthesia (IRR, 10.8 [4.18–27.8]; P < .001), and sarcopenia (IRR, 2.66 [1.10–6.44]; P = .03). After multivariable adjustment, COPD (IRR, 3.56 [1.57–8.11]; P = .003) and general anesthesia (IRR, 12.1 [4.39–33.5]; P < .001) were the only risk factors associated with longer HLOS. No associations were observed between risk factors and adverse events in multivariable analysis. Tumors treated per session were associated with risk of hospital readmission (P = .03).ConclusionsIdentified preprocedural risk factors from the surgical literature may aid in risk stratification for HLOS after percutaneous ablation of lung tumors, but were not associated with adverse events.     

Endovascular Venous Stenosis and Thrombosis Large Animal Model: Angiographic,Histological, and Biomechanical Characterizations

PurposeTo characterize an ovine endovascular radiofrequency (RF) ablation-based venous stenosis and thrombosis model for studying venous biomechanics and response to intervention.Materials and MethodsUnilateral short-segment (n = 2) or long-segment (n = 6) iliac vein stenoses were created in 8 adult sheep using an endovenous RF ablation technique. Angiographic assessment was performed at baseline, immediately after venous stenosis creation, and after 2-week (n = 6) or 3-month (n = 2) survival. Stenosed iliac veins and the contralateral healthy controls were harvested for histological and biomechanical assessment.ResultsAt follow-up, the short-segment RF ablation group showed stable stenosis without occlusion. The long-segment group showed complete venous occlusion/thrombosis with the formation of collateral veins. Stenosed veins showed significant wall thickening (0.28 vs 0.16 mm, P = .0175) and confluent collagen deposition compared with the healthy controls. Subacute nonadherent thrombi were apparent at 2 weeks, which were replaced by fibrous luminal obliteration with channels of recanalization at 3 months. Stenosed veins demonstrated increased longitudinal stiffness (448.5 ± 5.4 vs 314.6 ± 1.5 kPa, P < .0001) and decreased circumferential stiffness (140.8 ± 2.6 vs 246.0 ± 1.6 kPa, P < .0001) compared with the healthy controls.ConclusionEndovenous RF ablation is a reliable technique for creating venous stenosis and thrombosis in a large animal model with histological and biomechanical attributes similar to those seen in humans. This platform can facilitate understanding of venous biomechanics and testing of venous-specific devices and interventions.     

Radiofrequency Ablation of Facial Venolymphatic Malformations: Assessment of Efficacy and Safety and the Role of Injectable Electrodes

PurposeTo evaluate the efficacy and safety of ultrasound (US)-guided radiofrequency (RF) ablation in the treatment of facial microcystic lymphatic malformations (mLMs) or mixed venolymphatic malformations (VLMs) and to introduce the “induced-paralysis” technique with the use of an injectable electrode to minimize neural complications.Materials and MethodsData from patients with symptomatic facial mLMs or mixed VLMs who underwent US-guided RF ablation in 2014–2017 were retrospectively reviewed. Computed tomography (CT) and/or magnetic resonance (MR) imaging was used to localize any functional structures close to the target lesion. Treatment outcome was assessed by 4-point cosmetic grading score (CGS). Treatment outcome was compared between patients with vs without a functional structure close to the lesion and those treated with a noninjectable vs an injectable electrode. Immediate and late complications were assessed during follow-up.ResultsData from 15 patients were evaluated. Initial CGS and median volume were significantly decreased at the last follow-up in all patients (from 4 to 1 and from 7 mL to 0.7 mL, respectively; P < .05). Treatment outcome differed significantly between those with and without a functional structure on CT or MR imaging (P < .05) but showed no difference between noninjectable (n = 9) and injectable electrodes (n = 6). Two cases of transient cranial nerve palsy were seen in the noninjectable electrode group.ConclusionsUS-guided RF ablation is effective in patients with facial mLMs or mixed VLMs. The induced-paralysis technique with an injectable electrode has the potential to ensure technical safety without compromising efficacy.     

Value of 18F-FDG PET/MR Imaging in the Early Evaluation of Treatment Response following Radiofrequency Ablation of Liver Cancer in a Rabbit Model

PurposeTo test the hypothesis that ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) and magnetic resonance (MR) imaging can detect early residual tumor following radiofrequency (RF) ablation of liver cancer using a VX2 tumor model.Materials and MethodsTwenty-four rabbits with VX2 liver tumors were randomly divided into 3 groups (n = 8/group): Group 1 without RF ablation treatment, Group 2 with complete ablation, and Group 3 with partial ablation. An ¹⁸F-FDG PET/MR imaging scan was obtained within 2 hours after RF ablation. The maximum standardized uptake values (SUV) of the nontreated liver tumor, benign periablational enhancement (BPE), residual tumor, ablated tumor, and adjacent liver parenchyma and mean SUV of the normal liver were measured. The ratios of maximum SUV for these targets to the mean SUV of the normal liver (TNR) were calculated and compared.ResultsThe mean TNR of the nontreated liver tumors in Group 1 was significantly greater than that of the adjacent liver parenchyma (8.68 ± 0.71 vs 1.89 ± 0.26, P < .001). In Group 2, the mean TNR of BPE was significantly greater than that of the adjacent liver parenchyma (2.85 ± 0.20 vs 1.86 ± 0.25, P < .001). In Group 3, the mean TNR of the residual tumor was significantly greater than that of BPE (8.64 ± 0.59 vs 2.78 ± 0.23, P < .001), which was significantly greater than that of completely ablated tumor (2.78 ± 0.23 vs 0.50 ± 0.06, P < .001).Conclusions¹⁸F-FDG PET/MR imaging may serve as a promising imaging tool for the early detection of viable residual tumors due to incomplete tumor ablation.     

Transcatheter CT Hepatic Arteriography Compared with Conventional CT Fluoroscopy Guidance in Percutaneous Thermal Ablation to Treat Colorectal Liver Metastases: A Single-Center Comparative Analysis of 2 Historical Cohorts

PurposeTo evaluate safety and efficacy of CT hepatic arteriography compared with conventional CT fluoroscopy guidance in percutaneous radiofrequency (RF) and microwave (MW) ablation to treat colorectal liver metastases (CRLM).Materials and MethodsThis single-center comparative, retrospective study analyzed data of 108 patients treated with 156 percutaneous ablation procedures (42 CT fluoroscopy guidance [25 RF ablation, 17 MW ablation]; 114 CT hepatic arteriography guidance [18 RF ablation, 96 MW ablation]) for 260 CRLM between January 2009 and May 2019. Local tumor progression-free survival (LTPFS) was assessed using univariate and multivariate Cox proportional hazard regression analyses. LTPFS and overall survival (OS) were estimated using the Kaplan-Meier method.ResultsThere were no complications related to the transarterial catheter procedure. CT hepatic arteriography proved superior to CT fluoroscopy regarding 2-year LTPFS (18/202 [8.9%] vs 19/58 [32.8%]; P < .001, respectively). CT hepatic arteriography versus CT fluoroscopy (hazard ratio = 0.28; 95% confidence interval, 0.15–0.54; P < .001) and MW ablation versus RF ablation (hazard ratio = 0.52; 95% confidence interval, 0.24–1.12; P = .094) were positive predictors for longer LTPFS. Multivariate analysis revealed that CT hepatic arteriography versus CT fluoroscopy (hazard ratio = 0.41; 95% confidence interval, 0.19–0.90; P = .025) was associated with a significantly superior LTPFS. OS was similar between the 2 cohorts (P = .3).ConclusionsWhile adding procedure time and marginal patient burden, transcatheter CT hepatic arteriography–guided ablation was associated with increased local disease control and superior LTPFS compared with conventional CT fluoroscopy. CT hepatic arteriography represents a safe and valid alternative to CT fluoroscopy, as it reduces the number of repeat ablations required without adding risk or detrimental effect on survival.     

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

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

Antitumor Immunity Augmented by Combining Radiofrequency Ablation with Anti–CTLA-4 Therapy in a Subcutaneous Murine Hepatoma Model

PurposeTo evaluate whether antitumor immunity is enhanced by combining radiofrequency (RF) ablation and anti-cytotoxic T-lymphocyte–associated protein 4 (CTLA-4) therapy and to evaluate its effect on untreated tumors.Materials and MethodsFirst, 40 mice with tumors established in the bilateral flanks were randomly divided into 4 groups: the control group, the RF ablation-alone group, the anti-CTLA-4-alone group, and the RF ablation + anti-CTLA-4 group. In each group, 8 mice were used for untreated tumor evaluation and survival observation, and another 2 mice were killed for histopathologic study. Then, a rechallenge test was performed in another 32 mice to determine whether systemic antitumor immunity was established.ResultsAlthough the volume of the untreated tumors continued to increase until the end of the observation in all groups, tumor growth rates in the RF ablation + anti-CTLA-4 group were significantly smaller than tumor growth rates in the other 3 groups (all P < .05). The overall survival time of mice in the RF ablation + anti-CTLA-4 group was significantly longer than that of mice in the other 3 groups (all P < .05). Histopathologic studies of the untreated tumors showed more CD4-and CD8+ lymphocyte infiltration in mice from the RF ablation + anti-CTLA-4 group than in mice from the other 3 groups (all P < .05). After a tumor rechallenge, tumor rejection was apparent in 75% of the mice in the RF ablation + anti-CTLA-4 group, in 25% of the mice in the RF ablation group, and in 0% of the mice in the control and anti-CTLA-4 groups.ConclusionsThis study demonstrated that RF ablation-induced systemic antitumor immunity was enhanced by the combined use of anti-CTLA-4 therapy in a multi-subcutaneous murine hepatoma model.     

Creation of an Ex Vivo Renal Perfusion Model to Investigate Microwave Ablation

This study hypothesized that an ex vivo renal perfusion model can create smaller microwave ablation (MWA) measurements during perfused states compared with nonperfused states across multiple device settings. Nine bovine kidneys, a fluoroscopic compatible perfusion model, and a commercially-available clinical MWA system were used to perform 72 ablations (36 perfused and 36 nonperfused) at 9 different device settings. Comparing perfused and nonperfused ablations at each device setting, significant differences in volume existed for 6 of 9 settings (P < .05). Collapsed across time settings, the ablation volumes by power were the following (perfused and nonperfused, P value): 60 W, 2.3 cm³ ± 1.0 and 7.2 cm³ ± 2.7, P < .001; 100 W, 5.4 cm³ ± 2.1 and 11.5 cm³ ± 5.6, P < .01; and 140 W, 11.2 cm³ ± 3.7 and 18.7 cm³ ± 6.3, P < .01. Applied power correlated with ablation volume: perfused, 0.021 cm³/W and R = 0.462, P = .004, and nonperfused, 0.029 cm³/W and R = 0.565, P < .001. These results support that an ex vivo perfused organ system can evaluate MWA systems and demonstrate heat sink perfusion effects of decreased ablation size.     

Liver Tumor Ablation Procedure Duration and Estimated Patient Radiation Dose: Comparing Positron Emission Tomography/CT and CT Guidance

PurposeTo compare procedure duration and patient radiation dose in positron emission tomography/computed tomography (PET/CT) and CT-guided liver tumor ablation procedures.Materials and MethodsIn this retrospective, case-control study, 275 patients underwent 368 image-guided ablation procedures to treat 537 tumors. Radiologists used PET/CT guidance for 117 procedures and CT guidance for 251 procedures. PET/CT-guided procedures were performed by one radiologist (C: P.B.S.). All 3 radiologists (A: J.G.S., B: a radiologist who is not an author on this article, and C: P.B.S.) performed CT-guided procedures. Potential confounders included patient demographics, clinical and tumor characteristics, and procedural variables.ResultsThe mean duration and estimated patient radiation dose of PET/CT-guided procedures performed by radiologist C were 21.5 ± 4.9 minutes longer and 0.7 ± 2.8 mSv higher than CT-guided procedures performed by all radiologists in an unadjusted comparison. Adjusting for confounding, mean duration and estimated dose of PET/CT-guided procedures performed by radiologist C were 28.3 ± 3.8 minutes longer (P < .0001) and 6.2 ± 2.9 mSv higher (P = .03) than CT-guided procedures performed by the same radiologist. Comparing CT-guided procedures performed by all 3 radiologists, adjusted mean durations and estimated patient doses of procedures by the least experienced radiologist, radiologist A, and the second most experienced radiologist, radiologist B, were 24.2 ± 5.1 (P < .0001) and 18.1 ± 8.9 (P = .04) minutes longer and 13.1 ± 3.7 (P < .001) and 14.5 ± 6.4 (P = .02) mSv higher, respectively, than procedures performed by the most experienced radiologist, radiologist C.ConclusionsPET/CT-guided liver ablations had a slightly longer duration with slightly higher estimated patient radiation dose than similar CT-guided liver ablations. Procedure duration and patient dose do not appear to be major impediments to the emerging field of PET/CT-guided tumor ablation.     

Iatrogenic Arterioportal Fistula Caused by Radiofrequency Ablation of Hepatocellular Carcinoma: Clinical Course and Treatment Outcomes

PurposeTo analyze the clinical course and treatment outcomes of patients with iatrogenic arterioportal fistula (APF) caused by radiofrequency (RF) ablation of hepatocellular carcinoma (HCC).Materials and MethodsAmong the 1,620 hepatocellular carcinoma patients treated by RF ablation between January 2012 and August 2017, 99 who developed APF after RF ablation were included in this retrospective study. Depending on the extent of portal vein enhancement on arterial phase images, APF was classified as massive or nonmassive. The patients’ clinical course was investigated and statistically evaluated by univariable and multivariable analyses.ResultsThrombocytopenia (odds ratio [OR] = 3.939; 95% confidence interval [CI], 1.141–13.598) was the only risk factor for developing massive APF. Eleven patients underwent embolotherapy (technical success rate, 90.9%) and no patients experienced serious adverse events within 30 days of the procedure. Patients with massive APF (66.7%) had a significantly higher chance of a Child-Pugh score increase than did the patients with nonmassive APF (13.6%) (P < .001). Massive APF had a significantly lower chance of natural regression than did nonmassive APF (P < .001). Child-Pugh B (OR = 17.739; 95% confidence interval, 2.361–133.279) and massive APF without treatment (OR = 11.061; 95% confidence interval, 1.257−97.341) were independent risk factors for liver failure that led to death of liver transplant within 1 year after RF ablation.ConclusionsMassive APF caused by RF ablation is mostly irreversible and significantly worsens patients’ outcomes, but may be effectively treated with embolotherapy.     

Clinical Outcomes of Percutaneous Biliary Endoscopy: A 7-Year Single-Institution Experience

PurposeTo evaluate safety and effectiveness of percutaneous biliary endoscopy (PBE) performed on patients ineligible for surgery or endoscopic retrograde cholangiopancreatography.Materials and MethodsRetrospective review was conducted for all patients who underwent PBE at a single academic institution between June 2013 and February 2020; 39 patients underwent 58 choledochoscopy sessions, and 21 patients underwent 48 cholecystoscopy sessions. Choledochoscopy indications included stone removal (23 of 39 patients) or biliary stenosis evaluation (19 of 39 patients). Cholecystoscopy indications included calculous cholecystitis (18 of 21 patients) and symptomatic cholelithiasis (3 of 21 patients). Technical success, procedural and fluoroscopy times, and tube-free survival were assessed.ResultsFor all PBEs performed for stone clearance, using disposable endoscopes led to shorter mean ± SD procedural (128.7 minutes ± 56.2 vs 240.2 minutes ± 184.6; P < .01) and fluoroscopy times (10.7 minutes ± 7.9 vs 16.5 minutes ± 12.0; P = .01) than using reusable endoscopes. Increasing institutional experience was associated with reduced procedural time (β = −56.73; P < .001). Choledochoscopy technical success was 94.8% with 1 adverse event of bile duct perforation with bile leak requiring drainage. For patients with choledocholithiasis, biliary drains were removed in 14 (60.9%) patients, with a mean tube-free survival of 22.1 months ± 23.8. For cholecystoscopy, technical success was 93.8% with no adverse events. Cholecystostomy tubes were removed in 15 (71.4%) patients, with a mean tube-free survival of 7.5 months ± 8.8.ConclusionsThis study supports PBE as a safe and feasible option for nonsurgical patients or those with altered anatomy precluding endoscopic retrograde cholangiopancreatography. Moreover, PBE may result in tube-free survival.