Lung Ablation: Indications and Techniques

Abstract

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.

Keywords: ablation; interventional radiology; lung; lung cancer.

Fig. 1

( a ) Suboptimal lateral approach for biopsy of lung nodule. Respiratory motion and rib cage movement increases the rate of pneumothorax and targeting the tumor difficult. ( b ) With increasing pneumothorax, there is displacement of needle out of lung and change in approach and trajectory.

Fig. 2

( a ) Inferior vena cava leiomyosarcoma with metastasis to periphery of right upper lobe (arrow). ( b ) Microwave ablation antenna was placed via tangential approach to avoid back burn into the pleura. ( c ) Coaxial needle was placed from different approach for pleural anesthesia and to provide insulation and intercostal nerve protection (arrow). Note the extent of pleural anesthesia injected is ∼10 mL of lidocaine. ( d ) Postablation demonstrates ablation zone with no bronchopleural fistula.

Fig. 3

( a ) Lung carcinoma in the right middle lobe (arrow). ( b ) Microwave ablation antenna was placed in the tumor via direct approach with the shaft less than 3 cm in lung parenchyma. ( c ) Postablation there was an ablation tract extending from lung into pleural space with potential bronchopleural fistula (BPF). A tangential approach as demonstrated in Fig. 2 would be preferred to avoid this BPF.

Fig. 4

( a ) Primary lung carcinoma in superior segment of right lower lobe. ( b, c ) Axial and coronal images demonstrate two cryoablation probes placed in a tangential approach along length of the tumor to allow for better coverage, better steering, and for the probe to be well within lung tissue to avoid the ice ball from extending into the pleura along the probe shaft. ( d ) Following third cycle of ablation using 3 F, 3 PT, 7 F, 3 PT, and 10 F cycles. The bleeding is confined to the lobe. ( e ) To avoid spillage of thawed tumor and hemorrhage into rest of lung via transbronchial spillage, probes are removed and patient is turned to keep the ablation zone dependent. Bleeding is usually contained within the lobe.

Fig. 5

( a, b ) Recurrent mesothelioma after pleurectomy with the recurrence (arrow) in close proximity of atherosclerotic left anterior descending (LAD). ( c ) A coaxial needle was placed in the mediastinum to provide track anesthesia, and mediastinal access to induce pneumomediastinum (arrow). Cryoablation probe was placed into the tumor. ( d ) Up to 50 mL of air was injected (arrow) which allowed for separation of tumor from LAD and successful, uneventful ablation.

Fig. 6

Locations that may be preferable for one technology over another. Radiofrequency ablation (orange) is preferred for tumors less than 3 cm and in the center of the lung with limited heat sink. Microwave ablation (red) is preferred for tumors smaller than 3 cm, but can be used for tumors larger than 3 cm and can be used near vessels to avoid heat sink. Cryotherapy (blue) is preferred in periphery of the lung, chest wall, bone, and close to large airways.

Fig. 7

Approach to the management of pneumothorax intra or postablation. CXR, chest radiograph; PTX, pneumothorax.

Fig. 8

( a ) Colorectal metastasis to left upper lobe (arrows). ( b ) One month postcryoablation of both tumors simultaneously. Postablation zone as anticipated. ( c, d ) Patient presented with extensive pneumomediastinum and subcutaneous emphysema. High-resolution CT scan shows a bronchopleural fistula. ( e ) Coaxial needle was placed at the level of bronchopleural fistula (BPF) and 2 mL over 15 seconds COSEAL (biocompatible polyethylene glycol polymer) was injected. This polymer rapidly cross-links with proteins in tissue to immediately adhere. ( f ) Postprocedure CT scan demonstrates occlusion of the BPF.

Fig. 9

Follow-up schema (by month postprocedure) for ablation patient during 1st year and thereafter. A baseline PET/CT is preferred to confirm extent of thoracic and extrathoracic disease. This scan should be reviewed along with IO consult. Postablation at 1 week; CXR with IO clinic visit to evaluate for late complications and follow-up planning. Postablation at 1 month; chest CT with IO clinic visit. This scan is used as baseline for imaging follow-up and response evaluation. Postablation at 3 and 9 months; chest CT with IO clinic visit. Postablation at every 6 months for 24 months; PET/CT with IO consult. After 24 months, the frequency can be increased to every 12 months. If PET/CT is not possible, chest and abdominal scan can be obtained. CXR, chest radiograph; IO, interventional oncology; PET/CT, positron emission tomography/computed tomography.