Current trends in image-guided chest interventions.

Interventional radiology (IR) is a rapidly expanding medical subspecialty and refers to a range of image-guided procedural techniques. The image guidance allows real-time visualization and precision placement of a needle, catheter, wire and device to deep body structures through small incisions. Advantages include reduced risks, faster recovery and shorter hospital stays, lower costs and less patient discomfort. The range of chest interventional procedures keeps on expanding due to improved imaging facilities, better percutaneous assess devices and advancing ablation and embolization techniques. These advances permit procedures to be undertaken safely, simultaneously and effectively, hence escalating the role of IR in the treatment of chest disorders. This review article aims to cover the latest developments in some image-guided techniques of the chest, including thermal ablation therapy of lung malignancy, targeted therapy of pulmonary embolism, angioplasty and stenting of mediastinal venous/superior vena cava occlusion, pulmonary arteriovenous malformation treatment and bronchial artery embolization for haemoptysis.

First Human Use of a New Robotic-Assisted Fiber Optic Sensing Navigation System for Small Peripheral Pulmonary Nodules.

BACKGROUND: We tested a new, investigational robotic-assisted bronchoscope system with a remotely controlled catheter to access small peripheral bronchi with real-time driving under live visualization and distal tip articulation of the catheter. The unique catheter remains stationary once located at the biopsy position. OBJECTIVES: The primary objectives of this study were to evaluate the safety and feasibility of a new shape-sensing robotic bronchoscope system to bronchoscopically approach and facilitate the sampling of small peripheral pulmonary nodules of 1-3 cm. Secondary objectives included evaluating procedural characteristics and early performance trends associated with the use of the new robotic bronchoscope system. METHODS: Subjects were enrolled according to study eligibility criteria at a single center. Navigation pathways were semi-automatically created using pre-procedure CT scans. Simultaneous (real-time) viewing of actual and virtual bronchi was used real time during navigation to the displayed target. An endobronchial ultrasound mini-probe was used to confirm lesion location. Flexible 19- to 23-G needles specifically designed to accommodate tight bend radii in transbronchial needle aspiration were used along with conventional biopsy tools. Enrolled subjects completed follow-up visits up to 6 months after the procedure. RESULTS: The study included 29 subjects with a mean lesion size of 12.2 ± 4.2, 12.3 ± 3.3, and 11.7 ± 4.1 mm in the axial, coronal, and sagittal planes, respectively. The CT bronchus sign was absent in 41.4% of cases. In 96.6% of cases, the target was reached, and samples were obtained. No device-related adverse events and no instances of pneumothorax or excessive bleeding were observed during the procedure. Early performance trends demonstrated an overall diagnostic yield of 79.3% and a diagnostic yield for malignancy of 88%. CONCLUSION: This new robotic-assisted bronchoscope system safely navigated to very small peripheral airways under continuous visualization, and through maintenance of a static position, it provides a unique sampling capability for the biopsy of small solitary pulmonary nodules.

Risk stratification in the investigation of pulmonary nodules in a high-risk cohort: positron emission tomography/computed tomography outperforms clinical risk prediction algorithms.

BACKGROUND: Clinical prediction models and 18-fluorine-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG-PET/CT) are used for the assessment of solitary pulmonary nodules (SPN); however, a biopsy is still required before treatment, which carries risk. AIM: To determine the combined predictive benefit of one such model combined with modern PET/CT data to improve decision-making about biopsy prior to treatment and possibly reduce costs. METHODS: Patients with a SPN undergoing 18F-FDG-PET/CT from January 2011 to December 2012 were retrospectively identified; 143 patients met inclusion criteria. PET/CT studies were rated (5-point visual scale), and CT characteristics were determined. Tissue was obtained by endobronchial ultrasonography with guide sheath (EBUS-GS), CT-guided biopsy and/or surgery. EBUS-transbronchial needle aspiration (TBNA) was used instead of nodule biopsy if there were PET-positive sub-centimetre lymph nodes. RESULTS: The prediction model yielded an area under the receiver operating characteristic curve (AUC-ROC) of 64% (95% confidence interval (CI) 0.55-0.75). PET/CT increased this to 75% (95% CI 0.65-0.84). The 11% improvement is statistically significant. PET/CT score was the best single predictor for malignancy. A PET score of 1-2 had a specificity of 100% (CI 0.73-1.0), whereas a score of 4-5 had a sensitivity of only 76% (CI 0.68-0.84). No significant difference in clinical prediction scores between groups was noted. PET/CT showed the greatest benefit in true negatives and in detecting small mediastinal lymph nodes to allow EBUS-TBNA with a higher diagnostic rate. Cost analysis did not support a policy of resection-without-tissue diagnosis. CONCLUSION: PET/CT improves the clinical prediction of SPN, but its greatest use is in proving benignity. High PET scores had high false positive rates and did not add to clinical prediction. PET should be incorporated early in decision-making to allow for more effective biopsy strategies.

Percutaneous CT-guided thermal ablation as salvage therapy for recurrent non-small cell lung cancer after external beam radiotherapy: A retrospective study.

PURPOSE: The aim of this study was to evaluate radiofrequency ablation (RFA) and microwave ablation (MWA) as a viable salvage option for patients with locally recurrent non-small cell lung cancer (NSCLC) after radiotherapy. MATERIALS AND METHODS: This retrospective study was conducted on patients who had received thermal ablation for recurrent NSCLC post-curative radiotherapy. Medical records and follow-up imaging with computed tomography (CT) and PET-CT were analysed to determine time to local progression (TTLP) and overall survival (OS). TTLP was determined according to the modified RECIST criteria. RESULTS: Twelve patients, mean age 71 ± 7 years, received 17 thermal ablation sessions, with RFA performed for four lesions and MWA for 13. Nine tumours were squamous cell cancers (SCC) and eight were adenocarcinomas. Eleven tumours had recurred post-external beam radiation and one post-stereotactic body radiation therapy. Mean tumour size was 34.2 ± 12.8 mm, tumour stages prior to radiotherapy were Ia (2), Ib (3), IIa (4), IIb (1) and III (2). Follow-up period was 19 ± 11 months. Overall median TTLP was 14 months (95% CI: 8, 19), and median OS was 35 months (95% CI: 12, 58). Mean TTLP for tumours <30 mm was 23 months and for tumours >30 mm 14 months (p = 0.20). Recurrence rates reduced from 50% after initial ablation to 20% with a second ablation. Complication rate for pneumothorax requiring intervention was 17%. CONCLUSION: Both RFA and MWA ablation prolonged local tumour control with minimal morbidity in this study group of recurrent NSCLC after radiotherapy.

Physician-performed ultrasound can accurately screen for a vulnerable intercostal artery prior to chest drainage procedures.

BACKGROUND AND OBJECTIVE: Laceration of the intercostal artery during pleural procedures is a rare but serious complication. This study evaluates the utility of thoracic ultrasound (US) to screen for a vulnerable vessel compared with the gold standard computed tomography (CT). METHODS: Before undergoing contrast-enhanced CT chest, thoracic US was performed on 50 patients with a high-end and portable machine, and an attempt made to visualize the vessel at three positions across the back to the axilla. These positions were labelled with radio-opaque fiducial markers. On both US and CT images, the location of the vessel at each position, relative to the overlying rib, was calculated and compared. RESULTS: The vessel was unshielded by a rib according to CT in 114 of the 133 positions. The sensitivity, specificity and negative predictive value of portable US to image the vessel, when it was within the intercostal space on CT, was 0.86, 0.30 and 0.27 respectively. The performance of a high-end machine was not significantly different. The median time required for a pulmonologist to locate the vessel was 42 s and 18 s for the portable and high-end US respectively. CONCLUSIONS: US can be used to screen for a vulnerable vessel prior to pleural procedures, in a time amenable to use in clinical practice. Further, it is achievable by a pulmonologist using a portable US machine. If thoracentesis or chest tube insertion is being performed on a patient at increased risk of bleeding, screening for a vulnerable vessel with US prior to beginning the procedure is recommended.

Thoracic ultrasound demonstrates variable location of the intercostal artery.

BACKGROUND: Ultrasound (US) guidance is advocated to reduce complications from thoracocentesis or intercostal catheter (ICC) insertion. Although imaging of the intercostal artery (ICA) with Doppler US has been reported, current thoracic guidelines do not advocate this, and bleeding from a lacerated ICA continues to be a rare but serious complication of thoracocentesis or ICC insertion. OBJECTIVES: It was the aim of this study to describe a method to visualise the ICA at routine US-guided thoracocentesis and map its course across the posterior chest wall. METHOD: The ICA was imaged in 22 patients undergoing US-guided thoracocentesis, at 4 positions across the back to the axilla. Its location, relative to the overlying rib, was calculated as the fraction of the intercostal space (ICS) below the inferior border of that rib. RESULTS: An ICA was identified in 74 of 88 positions examined. The ICA migrated from a central 'vulnerable' location within the ICS near the spine (0.28, range 0.21-0.38; p < 0.001) towards the overlying rib (0.08, range 0.05-0.11; p < 0.001) in the axilla. CONCLUSIONS: The ICA can be visualised with US and is more exposed centrally within the ICS in more posterior positions; however, there is a marked variation between individuals, such that the ICA may lie exposed in the ICS even as far lateral as the axilla. Future studies need to identify which patients are at risk for a 'low-lying' ICA to further define the role of US imaging of the ICA during thoracocentesis or ICC insertion.

Long-term outcome following microwave ablation of early-stage non-small cell lung cancer.

INTRODUCTION: This study aimed to evaluate the long-term outcome of microwave ablation (MWA) of early-stage non-small cell lung cancer (NSCLC), including response to treatment and survival. METHODS: This retrospective study was conducted on consecutive patients who underwent computed tomography-guided MWA of early-stage NSCLC (no evidence of nodal or distant metastasis) from November 2010 to December 2014 at our institution. Data were collected from systematic review of patient charts and imaging. Procedural complications, response to treatment and survival were assessed. RESULTS: 34 early-stage (T1a-T3N0M0) NSCLCs in 30 patients were treated with a total of 41 MWA sessions. There were no intraprocedural or 30-day post-procedural deaths. The most common complication was pneumothorax, encountered in 24 (59%) microwave ablation sessions, six (15%) of which required chest tube insertion. Over a median computed tomography follow-up period of 39 months (range 3-89), 24 (71%) NSCLCs demonstrated local control, while 10 (29%) demonstrated local progression. Nodal/distant progression was more common than local progression, with 15 of the 30 patients (50%) having nodal or distant metastases at follow-up. Patient survival status was followed up over a median period of 56.5 months (range 10-107). Median overall survival and 5-year overall survival were 56.5 months (95% confidence interval, 26-not reached) and 46.7% (95% confidence interval, 31.8-68.4), respectively. CONCLUSION: MWA is safe and effective at achieving local control of early-stage NSCLC and may prolong patient survival. Nodal or distant metastases were the dominant manifestations of disease progression at long-term follow-up.

High-riding superior pericardial recess: a pitfall in the upper mediastinum.

The high-riding superior pericardial recess is an anatomical entity both radiologists and respiratory physicians should be aware of. Recognition that this high-riding portion of the recess is of water attenuation, that it connects to the inferior portion of the superior pericardial recess, and that it does not exert mass effect on adjacent structures should help avert misdiagnosis and subsequent inappropriate treatment.

Azygos arch valves at computed tomography angiography and pitfalls related to its variety in appearance and function.

OBJECTIVE: To evaluate the prevalence of azygos arch valves and assess azygos valve insufficiency at computed tomography angiography (CTA) of the chest or body with high rate contrast material injection. METHODS: Three hundred twenty-one CTAs using high intravenous injection rates (3-5 mL/second) of 300 mgI/mL contrast material were retrospectively evaluated for the presence of contrast material reflux from the superior vena cava into the azygos vein. Among the patients with contrast material reflux, azygos valves were identified within the azygos arch. Age, sex, and site of contrast material injection were analyzed. Azygos valve insufficiency was considered to be present if there was contrast material within the azygos vein posterior to the azygos valve. RESULTS: Of the 321 examinations, 191 (59.5%) showed reflux into the azygos vein. There was no significant difference in frequency of reflux into the azygos vein between right and left arm injection site (56.4% vs 63.5%, P = 0.20) or male and female patients (63.4% vs 55.0%, P = 0.12). No difference in mean age was noted between patients with reflux and those without it (P = 0.97). Azygos valves were identified in 124 (64.9%) of 191 CTA examinations with contrast reflux and pitfalls related to their appearance variety are discussed. No significant difference was found in valve frequency between male and female patients (66.0% vs 63.4%, P = 0.70). Contrast material posterior to the visible azygos valve was present in 66 (53.2%) of 124 examinations. CONCLUSIONS: Azygos arch valves are a common finding on CTA. They come in various sizes and shapes, and many of them show features of insufficiency.

Delayed complications following microwave ablation of lung tumours.

The majority of complications following microwave ablation (MWA) of lung tumours are immediately evident, however, delayed complications do occasionally occur. The radiologist plays a major role in identifying and in guiding the management of these complications. This pictorial essay explores the imaging appejmironce of several potentially life-threatening delayed complications of pulmonary MWA.

Safety and efficacy of microwave ablation for medically inoperable colorectal pulmonary metastases: Single-centre experience.

INTRODUCTION: To evaluate the safety and therapeutic efficacy of percutaneous microwave ablation (MWA) for colorectal pulmonary metastases. METHODS: Retrospective review of CT-guided lung MWA at a single tertiary institution. Adverse events within 30 days of MWA were considered procedure-related complications. Imaging follow-up was with 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT and contrast-enhanced CT. Response of index tumours was assessed using modified response evaluation criteria in solid tumours (mRECIST). RESULTS: The CT-guided lung MWA was performed in 14 patients with treatment of 20 colorectal pulmonary metastases during 19 procedures. Mean follow-up from completion of the treatment protocol was 24.4 ± 11.8 months. Primary and secondary technique effectiveness rates were 75% and 50% respectively. Mean pre- and post-procedural carcino-embryonic antigen (CEA) levels were 7.9 ± 10.8 µg/L and 2.5 ± 2.1 µg/L respectively. Procedure-related complications were major in three procedures (15.8%) and minor in six procedures (31.6%). No procedure-related deaths occurred. CONCLUSION: Microwave ablation is safe and efficacious in the local control of colorectal pulmonary metastases. The frequent systemic disease progression despite local control would favour a minimally invasive treatment option over invasive surgery in the setting of oligometastatic disease.

Is Digital Tomosynthesis on Par With Computed Tomography for the Detection and Measurement of Pulmonary Nodules?

Chest digital tomosynthesis (DT) has potential advantages compared to computed tomography (CT) such as radiation dose reduction. However, the role of DT in pulmonary nodule management remains investigative. We compared DT against CT for pulmonary nodule detection and size measurement. A clinical population comprising 54 nodules from 30 patients and a screening population comprising 42 nodules from 52 patients were included. Scans were independently read by two radiologists. Agreement in nodule measurements between readers and between modalities was assessed by Bland-Altman analysis using a 95% level of significance. The DT true positive fraction for the two readers was 0.44 and 0.39 in the clinical population, and 0.10 and 0.05 in the screening population. No significant inter-modality bias was observed between DT and CT measurements of nodule size, but the range of variation between modalities was approximately 30%. Inter-reader DT measurements also showed no significant bias, with a range of variation of approximately 15%. We conclude that DT has poor nodule detection sensitivity compared to CT. However, DT showed good measurement reproducibility and may be useful for monitoring growth of existing pulmonary nodules.

The wanderlust of a gallstone: a case report of intrathoracic migration of a gallstone post complicated cholecystectomy mimicking lung cancer.

Gallstones migrating into the right hemithorax post complicated cholecystectomy may be misdiagnosed for lung cancer, especially in the context of a distant history of cholecystectomy, poor recall of medical history and incomplete patient data. We present a case of a female patient with heavy smoking history who presented to our emergency department with haemoptysis and mild weight loss. Imaging workup showed an 18F-fludeoxyglucose positron emission tomography-positive heterogeneous nodule with central calcification in the right lower lobe, carrying lung cancer as a differential diagnosis. The resected specimen revealed an inflammatory pseudomass formed around a gallstone. This case illustrates the importance of knowing the spectrum of clinical and radiological presentation of a gallstone migrating into the right hemithorax, in order to prompt appropriate management and prevent misdiagnosis and mistreatment.

Percutaneous microwave ablation for early-stage non-small cell lung cancer (NSCLC) in the elderly: a promising outlook.

INTRODUCTION: Microwave ablation (MWA) is a relatively new minimally invasive treatment option for lung cancer with substantially lower morbidity and mortality than surgery. This retrospective study was performed to evaluate the safety, effectiveness and follow-up imaging of MWA in the elderly aged 75 years and above. METHODS: Eleven percutaneous computed tomography (CT)-guided MWA of early-stage non-small cell lung cancer (NSCLC) were performed in 10 patients aged 75 years and older. All but one patient were treated with a high-powered MWA system delivering maximally 140 W. Follow-up with CT and fludeoxyglucose-positron emission tomography (FDG-PET) was carried out over a maximum period of 30 months and a median period of 12 months. RESULTS: There were no peri-procedural deaths or major complications. Seven patients were disease free at the time of manuscript submission. Three patients showed growth of the treated lesions, one patient aged 90 years deceased due to unknown cause after approximately 18 months. One patient presented with local progression and disseminated metastatic disease at 12 months; he is still alive. One patient showed increasing soft tissue at the ablation site 15 months post-treatment. Three consecutive core biopsies over 2 months failed to confirm tumour recurrence. CONCLUSIONS: MWA therapy is a promising option of treating early-stage NSCLC in the elderly with good treatment outcome and negligible morbidity. Determining successful treatment outcome may be challenging at times as local tissue increase and PET-CT positivity do not seem to necessarily correlate with reccurrence of malignancy.

Major complications of high-energy microwave ablation for percutaneous CT-guided treatment of lung malignancies: Single-centre experience after 4 years.

PURPOSE: To evaluate the rate of major complications related to percutaneous computed tomography (CT)-guided microwave ablation (MWA) of primary and secondary lung malignancies performed at our institution over a 4-year period. METHODS: From May 2010 to September 2014, 70 MWAs were performed on 51 patients. All major intra- and post-procedural complications (as defined by the classification proposed by the Society of Interventional Radiology) were retrospectively analysed. The results were correlated with a systematic review of the available literature on MWA in the lung. RESULTS: Major complications were encountered in 14 out of 70 ablations (20%). Twenty-one separate major complications were encountered (some ablations lead to more than one major complication). One death occurred within 30 days of ablation, though the relationship to the procedure remains uncertain. Other major complications included: nine pneumothoraces requiring drain insertion (12.9%), four cases of large effusion requiring drainage (5.7%), two cases of significant pulmonary haemorrhage altering clinical management (2.9%), two infections (2.9%), one case of mechanical failure (1.4%), one chest wall burn (1.4%) and one case of pleural seeding (1.4%). Major complications were much more likely to occur if the nodule was located within 7 mm from the pleura. CONCLUSION: MWA of pulmonary tumours carries moderate risk; nevertheless, the usually manageable complications should not deter from undertaking a potentially curative therapy for poor surgical candidates.

Would you bet on PET? Evaluation of the significance of positive PET scan results post-microwave ablation for non-small cell lung cancer.

Fluodeoxyglucose-positron emission tomography (FDG-PET) imaging is an acknowledged modality for the follow-up of solid tumours treated with thermal ablation, with persistent or new FDG uptake at the ablation site considered to be a reliable indicator of local recurrence. Several cases of proven false-positive FDG-PET scans are illustrated in this pictorial essay with uptake at the site of the ablated tumour, remote from the ablated lesion and in mediastinal and hilar lymph nodes. Positive FDG-PET scans post-thermal ablation of lung tumours therefore cannot always reliably predict local tumour recurrence or nodal spread. It is important to be familiar with FDG uptake patterns post-ablation and their significance. FDG-PET avid lesions post-ablation may require histological confirmation before further therapy is planned or management is changed.

Pulmonary radiofrequency ablation--an international study survey.

BACKGROUND: The lung is the most common site for primary cancer worldwide as well as being a common site of metastases for various malignancies. Percutaneous radiofrequency ablation (RFA) is rapidly evolving as a new minimally invasive tool for the treatment of pulmonary tumors. PATIENTS AND METHODS: A questionnaire was sent by e-mail to 14 centres around the world, which we knew or thought were performing percutaneous pulmonary RFA, to retrospectively survey their experience in this field including the number of ablations done to date, indications, method, peri- and postprocedural complications. RESULTS: Seven centers reported 493 percutaneous procedures in lung tumors. Two deaths have been reported. Complications were subdivided into major and minor complications. Pneumothorax occurred in up to 30% of interventions with less than 10% requiring intercostal drainage. Pleural effusion requiring aspiration occurred in less than 10% of cases. CONCLUSION: With almost 500 procedures done to date, percutaneous pulmonary RFA appears to be a safe, minimally invasive tool for local pulmonary tumor control with negligible mortality, little morbidity, short hospital stay and gain in quality of life.

Dispersive pad site burns with modern radiofrequency ablation equipment.

Pad burns during or after radiofrequency ablation (RFA) are a skin complication probably underreported in the literature. We report on 4 severe pad burns, deep second and third degree, in 3 patients undergoing radiofrequency ablation of liver malignancies, 1 percutaneously and the other 2 after laparotomy. All burns occurred at the leading edge or at the corner of the pads attached to the patients' thighs. Potential causes leading to the burns are discussed. Current dispersive pad designs do not prevent the leading edge phenomenon and subsequent burns. Further developmental work in the pad design with the possibility of skin temperature monitoring via temperature sensors under the leading pad edge is needed.

High-powered percutaneous microwave ablation of stage I medically inoperable non-small cell lung cancer: a preliminary study.

PURPOSE: To retrospectively evaluate the feasibility and outcome of using high-powered percutaneous microwave ablation (MWA) in treating medically inoperable early stage non-small cell lung cancer. MATERIALS AND METHODS: From November 2010 to June 2012, 15 patients underwent CT-guided MWA of 15 tumours in 16 sessions. One patient had a second ablation session for local tumour progression. Each tumour had a diameter of 40 mm or less (median 24 mm). Treatment outcome was evaluated using modified response evaluation criteria in solid tumours criteria based on follow-up contrast-enhanced CT studies and 18-F fluorodeoxyglucose positron emission tomography scans. RESULTS: Thirty-three ablation cycles of 15 tumours were performed in 16 sessions (2.1 per session), with a median duration of 2.5 min per ablation. Treatment was completed in all cases with no 30-day mortality. At a median follow-up period of 1 year, local progression was identified following 5/16 (31%) ablation sessions. Eleven out of 16 (69%) of MWAs had shown local treatment response, with 9/11 displaying complete response and 2/11 displaying partial response. Local progression on follow up was predominantly seen in pleural-based tumours that were greater than 30 mm in longest axial diameter (4/5 cases). The main adverse event was a pneumothorax, which occurred in 10/16 (63%) of procedures, but a chest tube was only required in 2/16 (13%) cases. CONCLUSION: Percutaneous MWA in early stage non-small cell lung cancer is well tolerated and has promising midterm outcomes.