Lung radiofrequency ablation: post-procedure imaging patterns and late follow-up

Complications related to radiofrequency ablation of lung tumors: CT findings and review

Radiofrequency ablation is a treatment option for primary and secondary lung tumors, particularly in non-surgical patients. Although it is considered a safe and effective procedure, various complications can occur. Most of these adverse events are self-limiting and can be treated conservatively; however, some may be severe and require intervention. Radiologists play a pivotal role in the diagnosis and follow-up of these conditions, aiding in their early identification and management in clinical practice. They must be familiar with the expected and unexpected imaging post-procedure features. This article reviews the main complications of radiofrequency ablation of lung tumors and their associated CT findings.

[Laparoscopic ultrasound-guided radiofrequency ablation of uterine fibroid: A retrospective study]

OBJECTIVE

To assess clinical and radiological efficacy and safety of laparoscopic ultrasound-guided radiofrequency ablation of uterine leiomyomas.

MATERIAL AND METHODS

Thirty-three patients with symptomatic uterine leiomyomas FIGO type 2 to 7, have undergone a laparoscopic ultrasound-guided radiofrequency ablation at Croix Rousse University Hospital Center (Hospices civils de Lyon) and at Saint-Vincent de Paul Hospital in Lille, between June 2020 and December 2022. The characteristics of each myoma and the symptoms were assessed with pelvic MRI and with Higham score, SSS and HRQL scores preoperatively and at 6 months.

RESULTS

A total of 54 fibroids have been treated in 33 patients. We observed a significant decrease of the volume 6 months after the surgery, on average 21mL (55.97 vs. 74.37mL, 95% CI [7.13-34.88], P=0.001). The maximum diameter of each fibroid was also significantly reduced on average 11.78mm (41.89 vs. 52.06, 95% CI [8.83-14.73], P<0.05). We noticed a significant decrease of the NRS for dysmenorrhea on average 2.79 points (2.1 vs. 4.89, 95% CI [1.14-4.42], P<0.05). There was also a trend to improvement of menorrhagia, assess by Higham score. Indeed, 70.8% of the patients had menorrhagia. Menorrhagia was improved of 108,3 points with an average Higham score before surgery of 197.3 versus 87.9 after surgery (95% CI [47.9-168.8], P=0.001). Concerning UFS-QOL score: the symptom severity score (SSS) decreased on average 33 points, testifying of symptom improvement (27.04 vs. 60.89, 95% CI [22.92-43.39], P<0.001) and the HRQL score increased on average 20 points testifying quality of life improvement (65.57 vs. 42.7, 95% CI [15.83-37.85]. P<0.001). No severe adverse event has been reported.

CONCLUSION

In this first French study about radiofrequency ablation. We confirm its efficiency for improvement of symptoms and quality of life but other study is mandatory to confirm the safety of this procedure in particular in patients with a wish to conceive.

Lung microwave ablation: Post-procedure imaging features and evolution of pulmonary ground-glass nodule-like lung cancer

PURPOSE

To retrospectively examine the imaging characteristics of chest-computed tomography (CT) following percutaneous microwave ablation (MWA) of the ground-glass nodule (GGN)-like lung cancer and its dynamic evolution over time.

MATERIALS AND METHODS

From June 2020 to May 2021, 147 patients with 152 GGNs (51 pure GGNs and 101 mixed GGNs, mean size 15.0 ± 6.3 mm) were enrolled in this study. One hundred and forty-seven patients underwent MWA procedures. The imaging characteristics were evaluated at predetermined time intervals: immediately after the procedure, 24-48 h, 1, 3, 6, 12, and ≥18 months (47 GGNs).

RESULTS

This study population included 147 patients with 152 GGNs, as indicated by the results: 43.5% (66/152) adenocarcinoma in situ, 41.4% (63/152) minimally invasive adenocarcinoma, and 15.1% (23/152) invasive adenocarcinoma. Immediate post-procedure tumor-level analysis revealed that the most common CT features were ground-glass opacities (93.4%, 142/152), hyperdensity within the nodule (90.7%, 138/152), and fried egg sign or reversed halo sign (46.7%, 71/152). Subsequently, 24-48 h post-procedure, ground-glass attenuations, hyperdensity, and the fried egg sign remained the most frequent CT findings, with incidence rates of 75.0% (114/152), 71.0% (108/152), and 54.0% (82/152), respectively. Cavitation, pleural thickening, and consolidation were less frequent findings. At 1 month after the procedure, consolidation of the ablation region was the most common imaging feature. From 3 to 12 months after the procedure, the most common imaging characteristics were consolidation, involutional parenchymal bands and pleural thickening. At ≥18 months after the procedure, imaging features of the ablation zone revealed three changes: involuting fibrosis (80.8%, 38/47), consolidation nodules (12.8%, 6/47), and disappearance (6.4%, 3/47).

CONCLUSIONS

This study outlined the anticipated CT imaging characteristics of GGN-like lung cancer following MWA. Diagnostic and interventional radiologists should be familiar with the expected imaging characteristics and dynamic evolution post-MWA in order to interpret imaging changes with a reference image.

Hematoma-Filled Pneumatocele after CT-Guided Percutaneous Transthoracic Needle Lung Biopsy: Two Case Reports

CT-guided percutaneous transthoracic needle biopsy (PTNB) plays a key role in the diagnosis of pulmonary abnormalities. Although the procedure is considered safe and effective, there exists a potential for complications, such as pneumothorax, hemorrhage, hemoptysis, air embolism, and tumor seeding. However, pneumatoceles after CT-guided PTNB have been rarely reported. Herein, we report two cases of pneumatoceles that developed immediately after PTNB for primary lung cancer. A pneumatocele filled with hematoma should be considered in cases with a newly developed nodule along the needle tract during short-term follow-up CT after PTNB.

Early enlarging cavitation after percutaneous microwave ablation of primary lung cancer

PURPOSE

This retrospective study assessed the incidence rate, risk factors, and clinical course of early enlarging cavitation after percutaneous microwave ablation (MWA) of primary lung cancer (PLC).

METHODS

This study included 557 lesions of 514 patients with PLC who underwent CT-guided percutaneous MWA between 1 January 2018 and 31 December 2021. Of these patients, 29 developed early enlarging cavitation and were enrolled in the cavity group, and 173 were randomly enrolled in the control group. Early enlarging cavitation of the lung was defined as the development of a cavity ≥30 mm within 7 days after MWA.

RESULTS

Overall, 31 (5.57%, 31/557 tumors) early enlarging cavitations occurred at an average of 5.83 ± 1.55 d after MWA. The risk factors were lesion contact with a large vessel (diameter ≥3 mm), lesion contact with the bronchus (diameter ≥2 mm), and a large ablated parenchymal volume. The cavity group had a higher incidence rate of delayed hydropneumothorax (12.9%) and bronchopleural fistula (9.68%) than the control group, resulting in a longer hospitalization (9.09 ± 5.26 days). Until Dec 31, 2022, 27 cavities disappeared after a mean of 217.88 ± 78.57 d (range, 111-510 d), two persisted, and two were lost to follow-up.

CONCLUSIONS

Early enlarging cavitation occurred in 5.57% PLC cases that underwent MWA, causing serve complications and longer hospitalization. The risk factors were ablated lesion contact with large vessels and bronchi, as well as a larger ablated parenchymal volume.

Clinical practice guidelines on image-guided thermal ablation of primary and metastatic lung tumors (2022 edition)

The main contents of the Clinical Practice Guidelines on Image-Guided Thermal Ablation (IGTA) of Primary and Metastatic Lung Tumors (2022 Edition) include the following: epidemiology of primary and metastatic lung tumors; the concepts of the IGTA and common technical features; procedures, indications, contraindications, outcomes evaluation, and related complications of IGTA on primary and metastatic lung tumors; and limitations and future development.

Factors Associated with Pulmonary Function Changes in Patients Undergoing Microwave Ablation for Pulmonary Ground-Glass Nodules

Purpose: Microwave ablation has become an alternative treatment for pulmonary ground-glass nodules (GGN) and is widely accepted by clinicians. However, its effect on lung function remains unknown. Therefore, this retrospective study aimed to explore pulmonary function changes and associated risk factors in patients undergoing computed tomography (CT)-guided microwave ablation (MWA) for treating pulmonary GGN. Materials and Methods: Thirty-five patients diagnosed with pulmonary GGN on thin-layer chest CT and enhanced CT were examined. Patients unable or unwilling to undergo thoracoscopic surgery underwent CT-guided simultaneous percutaneous core needle biopsy and MWA. Pulmonary function tests (PFT) were performed before ablation and 3 days and 6 months post-ablation. Forced expiratory volume in one second (FEV1), FEV1%, forced vital capacity (FVC), maximal voluntary ventilation (MVV), and peak expiratory flow (PEF) values pre- and post-MWA were analysed. Linear regression analysis was used to examine the correlation between ablation volume and changes in PFT findings 3 days post-ablation. Associations between patient characteristics, rates of postoperative complications, and PFT findings were analysed. Results: Forty-eight lesions were completely ablated and examined intraoperatively. There were significant differences in pre- and post-operative PFT findings on day 3 but not at 6 months. The mean ablation volume after 3 days of 11.4 ± 6.3 cm³ was positively correlated with changes in FEV1, MVV, and PEF values. Patients' age (mean, 59.4 ± 13.0 years) positively correlated with changes in PEF values. The rates of change in FVC and MVV values were significantly higher with multiple pulmonary nodules than with isolated pulmonary nodule. PFT findings were similar between patients who experienced or did not experience complications (eg, pneumothorax and pleural effusion). Conclusions: Pulmonary function could be impaired shortly after MWA. PFT findings may correlate with age, ablation volume, and number of ablated lesions. In most patients, pulmonary function returned to the preoperative state after 6 months.

Electromagnetic bronchoscopy guided microwave ablation for early stage lung cancer presenting as ground glass nodule

Background

Patients with early-stage lung cancer are sometimes medically inoperable, and for patients with multiple primary lung cancers, surgical resection alone sometimes proves to be impractical. Local treatments like microwave ablation (MWA) are investigational alternatives for these patients. Most reported MWA procedures for lung cancers are performed percutaneously under CT guidance. MWA navigated by electromagnetic bronchoscopy (ENB) has been limitedly studied. In this study, we aimed to evaluate the safety and feasibility of MWA under ENB guidance in patients with inoperable early-stage lung cancers or multiple primary lung cancers which cannot be completely resected.

Methods

From June 2019 to December 2020, preliminary attempts of ENB-guided MWA were made in five medically inoperable patients with a single early-stage lung cancer and ten patients with multiple primary lung cancers which were difficult to resect at the same time. For patients with concomitant pulmonary nodules which needed surgical resection, thoracoscopic resections were performed following ENB-guided MWA. The safety, feasibility, and technique effectiveness of treatments were evaluated.

Results

ENB-guided MWA for 15 ground glass nodules (GGNs) in 15 patients was completed in accordance with the planned protocol. Biopsy of 13 GGNs showed malignancy. Five patients received simple ENB-guided MWA without simultaneous surgical resection and ten patients received simultaneous surgical resection for 13 concomitant pulmonary nodules. CT scan by the first postoperative week showed technique effectiveness of ablation for 11 nodules indicated for MWA. Four patients had mild complications after the procedure and recovered shortly after treatment.

Conclusions

For medically inoperable patients with a single GGN manifesting early-stage lung cancer and patients with multiple primary early-stage lung cancers which cannot be resected at the same time, ENB-guided MWA might be a safe and feasible alternative local treatment, whether combined with surgical resection or not. However, large, prospective, randomized, multicenter studies are needed to confirm its role in the treatment of early-stage lung cancer.

[Expert Consensus for Thermal Ablation of Pulmonary Subsolid Nodules (2021 Edition)]

"The Expert Group on Tumor Ablation Therapy of Chinese Medical Doctor Association, The Tumor Ablation Committee of Chinese College of Interventionalists, The Society of Tumor Ablation Therapy of Chinese Anti-Cancer Association and The Ablation Expert Committee of the Chinese Society of Clinical Oncology" have organized multidisciplinary experts to formulate the consensus for thermal ablation of pulmonary subsolid nodules or ground-glass nodule (GGN). The expert consensus reviews current literatures and provides clinical practices for thermal ablation of GGN. The main contents include: (1) clinical evaluation of GGN, (2) procedures, indications, contraindications, outcomes evaluation and related complications of thermal ablation for GGN and (3) future development directions.
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[Expert Consensus for Thermal Ablation of Pulmonary Subsolid Nodules (2021 Edition)]

"The Expert Group on Tumor Ablation Therapy of Chinese Medical Doctor Association, The Tumor Ablation Committee of Chinese College of Interventionalists, The Society of Tumor Ablation Therapy of Chinese Anti-Cancer Association and The Ablation Expert Committee of the Chinese Society of Clinical Oncology" have organized multidisciplinary experts to formulate the consensus for thermal ablation of pulmonary subsolid nodules or ground-glass nodule (GGN). The expert consensus reviews current literatures and provides clinical practices for thermal ablation of GGN. The main contents include: (1) clinical evaluation of GGN, (2) procedures, indications, contraindications, outcomes evaluation and related complications of thermal ablation for GGN and (3) future development directions.
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