Safety and Effectiveness of Track Cauterization for Lung Cryoablation.

PURPOSE: To evaluate the safety and effectiveness of track cauterization for lung cryoablation through comparison of postprocedural adverse event (AE) rates. MATERIALS AND METHODS: Fifty-nine patients who underwent 164 percutaneous lung cryoablation procedures between 2013 and 2018 were included in this retrospective study. The study cohort was subdivided by whether track cauterization was conducted or not at the end of the procedure. The study cohort was also subdivided by the number of probes (1-2 probes vs 3-4 probes). Postablation AE rates were assessed by immediate and delayed (at 1 month or later) AEs, pneumothorax, hemothorax, pleural effusion, and whether intervention was required. Univariate and multivariate logistic regression analyses were used to compare differences in AE rates. RESULTS: Patients who underwent procedures with track cautery were 2.6 times less likely to exhibit pleural effusion (P = .017). Patients who underwent procedures conducted with a higher number of probes were 3.8 times more likely to receive interventions (P < .001), 1.6 times more likely to experience pneumothorax (P = .037), and 2.1 times more likely to experience pleural effusion (P = .003). History of lung surgery, increased number of probes, size of the probe, and absence of track cautery were noted to be significant predictors of AEs and need for interventions (all P < .05). CONCLUSIONS: Track cauterization in lung cryoablation was proven to reduce pleural effusion, but no difference in pneumothorax or delayed AEs was noted. The use of fewer probes was associated with a lower rate of AEs.

Ablation of Stage I-II Non-Small Cell Lung Cancer in Patients With Interstitial Lung Disease: A Multicenter Retrospective Study.

BACKGROUND. Treatment options for patients with interstitial lung disease (ILD) who develop stage I-II non-small cell lung cancer (NSCLC) are severely limited, given that surgical resection, radiation, and systemic therapy are associated with significant morbidity and mortality. OBJECTIVE. The aim of this study was to evaluate the safety and efficacy of percutaneous ablation of stage I-II NSCLC in patients with ILD. METHODS. This retrospective study included patients with ILD and stage I-II NSCLC treated with percutaneous ablation in three health systems between October 2004 and February 2023. At each site, a single thoracic radiologist, blinded to clinical outcomes, reviewed preprocedural chest CT examinations for the presence and type of ILD according to 2018 criteria proposed by the American Thoracic Society, European Respiratory Society, Japanese Respiratory Society, and Latin American Thoracic Society. The primary outcome was 90-day major (grade ≥ 3) adverse events, based on Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. Secondary outcomes were hospital length of stay (HLOS), local tumor control, and overall survival (OS). RESULTS. The study included 33 patients (19 men, 14 women; median age, 78 years; 16 patients with Eastern Cooperative Oncology Group performance status ≤ 1) with ILD who underwent 42 percutaneous ablation sessions (21 cryoablations, 11 radiofrequency ablations, 10 microwave ablations) of 43 NSCLC tumors ((median tumor size, 1.6 cm; IQR, 1.4-2.5 cm; range, 0.7-5.4 cm; 37 stage I, six stage II). The extent of lung fibrosis was 20% or less in 24 patients; 17 patients had imaging findings of definite or probable usual interstitial pneumonia. The 90-day major adverse event rate was 14% (6/42), including one CTCAE grade 4 event. No acute ILD exacerbation or death occurred within 90 days after ablation. The median HLOS was 1 day (IQR, 0-2 days). Median imaging follow-up for local tumor control was 17 months (IQR, 11-32 months). Median imaging or clinical follow-up for OS was 16 months (IQR, 6-26 months). Local tumor control and OS were 78% and 77%, respectively, at 1 year and 73% and 46% at 2 years. CONCLUSION. Percutaneous ablation appears to be a safe and effective treatment option for stage I-II NSCLC in the setting of ILD after multidisciplinary selection. CLINICAL IMPACT. Patients with ILD and stage I-II NSCLC should be considered for percutaneous ablation given that they are frequently ineligible for surgical resection, radiation, and systemic therapy.

Technical Feasibility and Safety of Repeated Computed Tomography-Guided Transthoracic Intratumoral Injection of Gene-Modified Cellular Immunotherapy in Metastatic NSCLC.

INTRODUCTION: To assess the technical feasibility and safety of repeated percutaneous computed tomography (CT)-guided transthoracic biopsies and intratumoral injections of gene-modified dendritic cells in metastatic NSCLC. METHODS: A total of 15 patients with 15 NSCLC lesions measuring greater than 1.0 cm underwent two cycles of intratumoral biopsies and CCL21 dendritic cell injections separated by 7 days. All needle placements and injections were done under CT guidance. Clinical and imaging follow-up was done approximately 4 weeks after the first procedure. Safety and feasibility were determined as: (1) safety and feasibility similar to that of single-needle biopsy, and (2) an absence of serious adverse events defined as grade greater than or equal to three according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. RESULTS: A total of 30 percutaneous, transthoracic intratumoral biopsies and injections into the lung cancer were performed, two cycles (at d 0 and 7) received by each patient (311 biopsies and 96 intratumoral injections). All percutaneous cases achieved technical success with respect to needle placement for both biopsy and injection of CCL21 dendritic cells. Only minor complications were observed (grade <3), including pneumothorax (n = 10, 33%) and small postbiopsy hemorrhage (n = 2, 7%). Pneumothorax was moderate (n = 1) or trace (n = 9), with resolution of the moderate pneumothorax after manual aspiration without chest tube placement. No patient required chest tube placement. No other complications or serious adverse effects related to the biopsy or dendritic cell injection were noted. All patients were in stable condition after up to 4 hours in the recovery unit and were discharged home on the same day. No procedure-related complications were observed on imaging or clinical follow-up at 4 weeks. CONCLUSIONS: Repeated percutaneous, transthoracic CT-guided biopsies and intratumoral gene-modified cell-based immunotherapy injections into lung cancers are technically feasible, safe, and reproducible. There were no procedure-related serious (defined as grade ≥3) adverse events.

Society of Interventional Radiology Multidisciplinary Position Statement on Percutaneous Ablation of Non-small Cell Lung Cancer and Metastatic Disease to the Lungs: Endorsed by the Canadian Association for Interventional Radiology, the Cardiovascular and Interventional Radiological Society of Europe, and the Society of Interventional Oncology.

PURPOSE: To state the Society of Interventional Radiology's position on the use of image-guided thermal ablation for the treatment of early stage non-small cell lung cancer, recurrent lung cancer, and metastatic disease to the lung. MATERIALS AND METHODS: A multidisciplinary writing group, with expertise in treating lung cancer, conducted a comprehensive literature search to identify studies on the topic of interest. Recommendations were drafted and graded according to the updated SIR evidence grading system. A modified Delphi technique was used to achieve consensus agreement on the recommendation statements. RESULTS: A total of 63 studies, including existing systematic reviews and meta-analysis, retrospective cohort studies, and single-arm trials were identified. The expert writing group developed and agreed on 7 recommendations on the use of image-guided thermal ablation in the lung. CONCLUSION: SIR considers image-guided thermal ablation to be an acceptable treatment option for patients with inoperable Stage I NSCLC, those with recurrent NSCLC, as well as patients with metastatic lung disease.

Outcomes with multi-disciplinary management of central lung tumors with CT-guided percutaneous high dose rate brachyablation.

BACKGROUND: Centrally located lung tumors present treatment challenges given their proximity to mediastinal structures including the central airway, esophagus, major vessels, and heart. Therapeutic options can be limited for medically inoperable patients, particularly if they have received previous thoracic radiotherapy. High dose rate (HDR) brachyablation was developed to improve the therapeutic ratio for patients with central lung tumors. The purpose of this study is to report initial safety and efficacy outcomes with this treatment for central lung malignancies. METHODS: From September 2015 to August 2019, a total of 25 patients with 37 pulmonary tumors were treated with percutaneous HDR brachyablation. Treatment was delivered by a multi-disciplinary team of interventional radiologists, pulmonologists, and radiation oncologists. Twenty-three patients received a median dose of 21.5 Gy (range 15-27.5) in a single fraction, whereas two patients received median dose of 24.75 Gy (range 24-25.5) over 2-3 fractions. Tumor local control (LC) was evaluated by Response Evaluation Criteria in Solid Tumors v1.1. Treatment-related toxicities were graded by Common Terminology Criteria for Adverse Events v5.0, with adverse events less than 90 days defined as acute, and those occurring later were defined as late. LC, progression-free survival (PFS), and overall survival (OS) rates were estimated by the Kaplan-Meier method. RESULTS: Of 37 treated tumors, 88% were metastatic. Tumor location was central and ultra-central in 24.3% and 54.1%, respectively. Average tumor volume was 11.6 cm3 (SD 12.4, range 0.57-62.8). Median follow-up was 19 months (range 3-48). Two-year LC, PFS, and OS were 96.2%, 29.7%, and 65.5%, respectively. Thirteen of 39 (33.3%) catheter implantation procedures were associated with trace minor pneumothorax requiring no intervention, 1 (2.5%) procedure with minor radiographic pulmonary hemorrhage, and 4 (10.3%) with major pneumothorax requiring chest tube insertions. All procedural complications resolved within 24 h from treatment. Acute grade 1-2 toxicity was identified in 4 patients, whereas none developed late toxicity beyond 90 days of follow-up. CONCLUSION: Percutaneous HDR brachyablation is a safe and promising treatment option for centrally located primary and metastatic lung tumors. Future comparisons with stereotactic body radiotherapy and other ablative techniques are warranted to expand multi-disciplinary management options.

Society of Interventional Radiology Quality Improvement Standards on Percutaneous Ablation of Non-Small Cell Lung Cancer and Metastatic Disease to the Lungs.

PURPOSE: To provide guidance on quality improvement thresholds for outcomes and complications of image-guided thermal ablation for the treatment of early stage non-small cell lung cancer, recurrent lung cancer, and metastatic disease. MATERIALS AND METHODS: A multidisciplinary writing group conducted a comprehensive literature search to identify studies on the topic of interest. Data were extracted from relevant studies and thresholds were derived from a calculation of 2 standard deviations from the weighted mean of each outcome. A modified Delphi technique was used to achieve consensus agreement on the thresholds. RESULTS: Data from 29 studies, including systematic reviews and meta-analyses, retrospective cohort studies, and single-arm trials were extracted for calculation of the thresholds. The expert writing group agreed on thresholds for local control, overall survival and adverse events associated with image-guided thermal ablation. CONCLUSION: SIR recommends utilizing the indicator thresholds to review and assess the efficacy of ongoing quality improvement programs. When performance falls above or below specific thresholds, consideration of a review of policies and procedures to assess for potential causes, and to implement changes in practices, may be warranted.

Cryoablation for Palliation of Painful Bone Metastases: The MOTION Multicenter Study.

Purpose: To assess the clinical effectiveness of cryoablation for palliation of painful bone metastases. Materials and Methods: MOTION (Multicenter Study of Cryoablation for Palliation of Painful Bone Metastases) (ClinicalTrials.gov NCT02511678) was a multicenter, prospective, single-arm study of adults with metastatic bone disease who were not candidates for or had not benefited from standard therapy, that took place from February 2016 to March 2018. At baseline, participants rated their pain using the Brief Pain Inventory-Short Form (reference range from 0 to 10 points); those with moderate to severe pain, who had at least one metastatic candidate tumor for ablation, were included. The primary effectiveness endpoint was change in pain score from baseline to week 8. Participants were followed for 24 weeks after treatment. Statistical analyses included descriptive statistics and logistic regression to evaluate changes in pain score over the postprocedure follow-up period. Results: A total of 66 participants (mean age, 60.8 years ± 14.3 [standard deviation]; 35 [53.0%] men) were enrolled and received cryoablation; 65 completed follow-up. Mean change in pain score from baseline to week 8 was -2.61 points (95% CI: -3.45, -1.78). Mean pain scores improved by 2 points at week 1 and reached clinically meaningful levels (more than a 2-point decrease) after week 8; scores continued to improve throughout follow-up. Quality of life improved, opioid doses were stabilized, and functional status was maintained over 6 months. Serious adverse events occurred in three participants. Conclusion: Cryoablation of metastatic bone tumors provided rapid and durable pain palliation, improved quality of life, and offered an alternative to opioids for pain control.Keywords: Ablation Techniques, Metastases, Pain Management, Radiation Therapy/OncologySupplemental material is available for this article.© RSNA, 2021.

Treatment of Post-Ablation Bronchopleural Fistula Using Percutaneous Synthetic Hydrogel Surgical Sealant: Initial Experience of Safety and Efficacy.

Purpose Bronchopleural fistula is a rare but serious complication of lung ablation, as it is difficult to treat and is associated with a high mortality rate. Standard therapy often relies on surgical pleurodesis, which can be particularly problematic in patients with poor baseline lung function. A minimally invasive treatment option for bronchopleural fistula may offer an alternative to surgery for appropriate patients. This case series describes the technique, safety and efficacy of percutaneously administered synthetic hydrogel surgical sealant in the treatment of post-ablation bronchopleural fistula in five patients. Materials and methods Retrospective chart review was carried out in five consecutive patients identified to have had BPF after lung ablation between 2009 and 2017 who were treated with percutaneous administration of synthetic hydrogel surgical sealant using CT guidance. Results The procedure was successfully carried out in all patients without immediate complications, and complete resolution of air leak was achieved in four of five patients (80%). Up to the most recent follow-up, no evidence of delayed complications or recurrent air leak was present (follow-up range 1 week-8 years). Conclusion The authors' initial experience shows that targeted surgical sealant is a potentially safe and effective alternative treatment of post-ablation persistent air leak.

Alternatives to Surgery for Early-Stage Non-Small Cell Lung Cancer: Thermal Ablation.

Thermal ablation involves the application of heat or cold energy to the lung under image guidance to eradicate tumors. It is indicated for treatment of early-stage non-small cell lung cancer in nonsurgical patients. Ablation technologies have advanced, such that nearly all small tumors can now be treated safely and effectively. Ablation does not cause a lasting decline in pulmonary function tests and may therefore be used to treat multiple synchronous and metachronous lung tumors, a chief advantage over other treatments. Large series with intermediate- and long-term data have been reported showing favorable overall survival, similar to radiation therapy.

Interventional Radiology Image-Guided Suprapubic Cystostomy Using Trocar versus Seldinger Technique: A Comparative Analysis of Outcomes and Complications.

OBJECTIVE: To compare two techniques-trocar and Seldinger-for performing percutaneous suprapubic cystostomy. MATERIALS AND METHODS: 125 patients, mean age 71.8 ± 16.5 years (range, 15-102 years), underwent primary suprapubic cystostomy from January 2013 to December 2018. Trocar access (N = 60) was performed as a single step using a puncture cannula without guidewire access. Seldinger access (N = 65) involved needle puncture, guidewire placement, and serial dilation. A retrospective review of patient records was conducted. RESULTS: All procedures were technically successful. Mean catheter size was 13.1 ± 2.0 and 13.9 ± 2.0 French for trocar and Seldinger, respectively (P = .044). Mean procedure time was significantly reduced using trocar technique, 12.4 ± 7.7 versus 25.7 ± 12.1 minutes (P <.001), and was associated with lower anxiolytic dose, 1.2 ± 0.8 versus 1.9 ± 1.1 mg midazolam (P = .003), and less radiation exposure, 20.2 ± 59.5 versus 100.7 ± 98.5 mGy (P <.001). Catheter occlusion was the most common complication (28.8%), followed by UTI (13.6%) and bladder spasm (8.0%). All but 2 complications were classified as Clavien-Dindo grade I or II. Catheter occlusion was more frequent in the trocar group (41.7% vs 16.9%, P = .003), while bladder spasms were more frequent in the Seldinger group (13.8% vs 1.7%, P = .018). CONCLUSION: Suprapubic cystostomy via trocar is associated with faster procedure time, lower anxiolytic dose, and less radiation. While major complications are rare, catheter occlusion is a common occurrence that may be overlooked. Although we detected more occlusions with trocar technique, this may be confounded by a catheter-tract size discrepancy.

Lung Ablation: Indications and Techniques.

Lung ablation is ever more recognized since its initial report and use almost two decades ago. With technological advancements in thermal modalities, particularly microwave ablation and cryoablation, better identification of the cohort of patients who best benefit from ablation, and understanding the role of imaging after ablation, image-guided thermal ablation for primary and secondary pulmonary malignancies is increasingly recognized and accepted as a cogent form of local therapy.

Updates on Current Role and Practice of Lung Ablation.

Interventional oncology and management of thoracic malignancies with ablative techniques are becoming ever more recognized therapeutic options. With increased understanding, development, and utility of the ablative techniques, the indications are expanding and efficacy improving. Lung cancer was among the first indications for lung ablation and remains most challenging with multiple therapeutic options. For inoperable patients, the current literature demonstrates equivalent survivals between ablation, sublobar resection, and stereotactic body radiation. Oligometastatic disease remains the most common indication for lung ablation and is gaining acceptance among the oncology community, as lung ablation provides limited patient downtime, repeatability, and minimal to no loss of respiratory function. Other indications for ablation are being explored, including recurrent mesothelioma, drop metastasis from thymoma, and limited pleural metastasis, with excellent local control of tumor and limited complications. Follow-up after ablation is essential to detect early complications, observe the natural evolution of the ablation zone, and detect recurrence. Standardized imaging follow-up allows for these goals to be achieved and provides a framework for oncology practice. In this article, the role of ablation in the management of thoracic neoplasms and postablation imaging features are reviewed. The radiologists, in particular, thoracic radiologists should be able to identify candidates who can benefit from ablation familiarize themselves with postablation imaging features, and recognize the evolution of the postablation zone and hence detect early recurrence.

Percutaneous Transthoracic Treatment of Ascending Aortic and Root Pseudoaneurysms: Procedural Aspects and Guidance with the Use of Multimodality Imaging.

Open repair of ascending aortic pseudoaneurysms (AAPs) is currently the standard of care, but it is associated with high morbidity and mortality. A single-center retrospective experience of 4 patients after cardiac surgery undergoing 5 percutaneous transthoracic embolization procedures is presented. In 3 of the 4 patients, the primary outcome of complete thrombosis was achieved after the first procedure, with a mean follow-up time of 11.5 months. In all 5 procedures, the patients tolerated the procedure well without associated acute complications. Percutaneous transthoracic embolization of AAPs offers an alternate minimally invasive treatment pathway for prohibitive-risk candidates.

Imaging and Management of Intrathoracic Renal Cell Carcinoma Metastases.

OBJECTIVE: Renal cell carcinoma (RCC) has a propensity to metastasize to the chest, with the lungs being the most common distant metastatic site. The histologic subtype of RCC has implications for prognosis. CONCLUSION: Significant advances have been made in the management of metastatic RCC, both in systemic and locoregional therapies. The aim of this article is to review appearances of intrathoracic metastases from RCC and to discuss treatment considerations.

Comparison of Double-Freeze versus Modified Triple-Freeze Pulmonary Cryoablation and Hemorrhage Volume Using Different Probe Sizes in an In Vivo Porcine Lung.

PURPOSE: To determine size of ablation zone and pulmonary hemorrhage in double-freeze (DF) vs modified triple-freeze (mTF) cryoablation protocols with different probe sizes in porcine lung. MATERIALS AND METHODS: In 10 healthy adult pigs, 20 pulmonary cryoablations were performed using either a 2.4-mm or a 1.7-mm probe. Either conventional DF or mTF protocol was used. Serial noncontrast CT scans were performed during ablations. Ablation iceball and hemorrhage volumes were measured and compared between protocols and probe sizes. RESULTS: With 1.7-mm probe, greater peak iceball volume was observed with DF compared with mTF, although difference was not statistically significant (16.1 mL ± 1.9 vs 8.8 mL ± 3.6, P = .07). With 2.4-mm probe, DF and mTF produced similar peak iceball volumes (14.0 mL ± 2.8 vs 14.6 mL ± 2.7, P = .88). Midcycle hemorrhage was significantly larger with DF with the 1.7-mm probe (94.3 mL ± 22.2 vs 19.6 mL ± 2.1, P = .02) and with both sizes combined (93.2 mL ± 17.5 vs. 50.9 mL ± 12.6, P = .048). Rate of hemorrhage increase was significantly higher in DF (10.4 mL/min vs 5.1 mL/min, P = .003). End-cycle hemorrhage was visibly larger in DF compared with mTF across probe sizes, although differences were not statistically significant (P = .14 for 1.7 mm probe, P = .18 for 2.4 mm probe, and P = .07 for both probes combined). Rate of increase in hemorrhage during the last thaw period was not statistically different between DF and mTF (3.0 mL/min vs 2.8 mL/min, P = .992). CONCLUSIONS: mTF reduced rate of midcycle hemorrhage compared with DF. With mTF, midcycle hemorrhage was significantly smaller with 1.7-mm probe; although noticeably smaller with 2.4-mm probe, statistical significance was not achieved. Iceball size was not significantly different across both protocols and probe types.

Feasibility and Safety of Intrathoracic Biopsy and Repeat Biopsy for Evaluation of Programmed Cell Death Ligand-1 Expression for Immunotherapy in Non-Small Cell Lung Cancer.

Purpose To determine feasibility and safety of biopsy and repeat biopsy for assessment of programmed cell death ligand-1 (PD-L1) status. Materials and Methods This retrospective analysis reviewed 101 patients who underwent transthoracic core needle biopsy for the KEYNOTE-001 (MK-3475) clinical trial of pembrolizumab, an antiprogrammed cell death-1 therapy for non-small cell lung cancer, from May 2012 to September 2014. Sixty-one male patients (mean age, 66.1 years; range 36-83 years) and 40 female patients (mean age, 66.8 years; age range, 36-90 years) were included. Data collected included population characteristics, treatment history, target location, size, and depth from pleura. Adequacy of the tissue sample for diagnostic testing and rates of biopsy-related complications were assessed. Statistical analysis was performed by using univariate and multivariate generalized linear models to determine significant risk factors for biopsy complications. Results A total of 110 intrathoracic biopsies were performed, and 101 (91.8%) were performed as repeat biopsies subsequent to a previous percutaneous or bronchoscopic biopsy or previous surgical biopsy or resection. More than 84.5% (93 of 110) of biopsies were performed in patients who had undergone previous local or systemic therapy. Specimens were adequate for evaluation of PD-L1 expression in 96.4% of biopsies. Procedure-related complications occurred in 28 biopsies (25.4%); pneumothorax was most common (22.7%). Overall mean number of core needle biopsy samples obtained was 7.9 samples. Conclusion Image-guided transthoracic core needle biopsy is an effective method for obtaining tissue for PD-L1 expression analysis. © RSNA, 2017.

Non-small cell lung cancer clinical trials requiring biopsies with biomarker-specific results for enrollment provide unique challenges.

BACKGROUND: Clinical trials in lung cancer increasingly require patients to provide fresh tumor tissue as a prerequisite to enrollment. The effects of this requirement on enrollment rates, enrollment durations, and patient selection have not been fully elucidated. METHODS: The authors retrospectively reviewed data generated by patients who consented to 1 or more interventional lung cancer clinical trials at the University of California-Los Angeles Jonsson Comprehensive Cancer Center between January 2013 and December 2014. Trials were considered to require a biopsy when enrollment was conditional on the procurement of tissue without intervening therapy between procurement and enrollment. RESULTS: In total, 311 patients underwent 368 screening incidents for 1 or more of 19 trials. Trials that required a new biopsy had a longer median screening duration (34 vs 14 days) than trials that did not require a biopsy (P < .001). Trials that required a biopsy had a greater screen failure rate (49.1% vs 26.5%; P < .001), which was largely driven by patients who did not undergo the required biopsy or lacked the required biomarker. Worsening performance status led to the majority of screen failures (56.5%) among biomarker-eligible patients. CONCLUSIONS: Although the scientific benefits of obtaining a new biopsy and requiring specific results for trial enrollment are clear, these requirements lead to a lengthening of the screening period, which, in some patients, is associated with clinical decline before enrollment. Implications for the interpretation of data from studies of this design should be explored. Cancer 2017;123:4800-7. © 2017 American Cancer Society.

Percutaneous Cryoablation for the Treatment of Recurrent Malignant Pleural Mesothelioma: Safety, Early-Term Efficacy, and Predictors of Local Recurrence.

PURPOSE: To determine safety and early-term efficacy of CT-guided cryoablation for treatment of recurrent mesothelioma and assess risk factors for local recurrence. MATERIALS AND METHODS: During the period 2008-2012, 24 patients underwent 110 cryoablations for recurrent mesothelioma tumors in 89 sessions. Median patient age was 69 years (range, 48-82 y). Median tumor size was 30 mm (range, 9-113 mm). Complications were graded using Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v4.0). Recurrence was diagnosed on CT or positron emission tomography/CT by increasing size, nodular enhancement, or hypermetabolic activity and analyzed using the Kaplan-Meier method. Cox proportional hazards model was used to determine covariates associated with local tumor recurrence. RESULTS: Median duration of follow-up was 14.5 months. Complications occurred in 8 of 110 cryoablations (7.3%). All but 1 complication were graded CTCAE v4.0 1 or 2. No procedure-related deaths occurred. Freedom from local recurrence was observed in 100% of cases at 30 days, 92.5% at 6 months, 90.8% at 1 year, 87.3% at 2 years, and 73.7% at 3 years. Tumor recurrence was diagnosed 4.5-24.5 months after cryoablation (mean 5.7 months). Risk of tumor recurrence was associated with a smaller ablative margin from the edge of tumor to iceball ablation margin (multivariate hazard ratio 0.68, CI 0.48-0.95, P = .024). CONCLUSIONS: CT-guided cryoablation is safe for local control of recurrent mesothelioma, with a low rate of complications and promising early-term efficacy. A smaller ablative margin may predispose to tumor recurrence.

Defining New Metrics in Microwave Ablation of Pulmonary Tumors: Ablation Work and Ablation Resistance Score.

PURPOSE: To investigate pulmonary microwave ablation metrics including ablation work, ablation resistance score, and involution. MATERIALS AND METHODS: Retrospective review was performed of 98 pulmonary tumor ablations using the NeuWave Certus Microwave Ablation System (NeuWave Medical, Madison, Wisconsin) in 71 patients (32 men and 39 women; mean age, 64.7 y ± 11.5). Ablation work was defined as sum of (power) * (time) * (number of antennas) for all phases during an ablation procedure. Ablation zone was measured on CT at 3 time points: after procedure, 1-3 months (mean 47 d), and 3-12 months (mean 292 d). Ablation zones were scored based on location for pulmonary lobe (upper = 1, middle/lingula = 2, lower = 3) and region (peripheral = 1, parenchymal = 2, central = 3), and the 2 were summed for ablation resistance score. RESULTS: Ablation zone on CT at 1-3 months was significantly smaller in regions with higher ablation resistance score (P < .05). There was a significant correlation between ablation work and ablation zone measured on CT performed after procedure (P < .001), at 1-3 months (P < .001), and at 3-12 months (P < .05). Ablation zone significantly decreased from after procedure to 1-3 months (P < .001) and from 1-3 months to 3-12 months (P < .001), with change from after procedure to 1-3 months significantly greater (P < .01). CONCLUSIONS: Pulmonary microwave ablation zone is significantly smaller in regions with higher ablation resistance score. Ablation work correlates to ablation zone with a nonlinear involution pattern in the first year and may be useful for planning before the procedure.

Percutaneous Image-Guided Musculoskeletal Tumor Treatments.

OBJECTIVE: The purpose of this article is to review the current guidelines and recommendations for percutaneous image-guided treatment of musculoskeletal tumors. CONCLUSION: With the ongoing technologic advances, it is essential that the musculoskeletal interventionalist is familiar with the current tools and techniques available for the treatment of soft-tissue and bone tumors. Fortunately, many of these tools are readily available in a standard interventional radiology department and can be easily applied to the musculoskeletal system.