Peripheral tumour targeting using open-source virtual bronchoscopy with electromagnetic tracking: a multi-user pre-clinical study.

Objectives: The goal was to demonstrate the utility of open-source tracking and visualisation tools in the targeting of lung cancer.Material and methods: The study demonstrates the first deployment of the Anser electromagnetic (EM) tracking system with the CustusX image-guided interventional research platform to navigate using an endobronchial catheter to injected tumour targets. Live animal investigations validated the deployment and targeting of peripheral tumour models using an innovative tumour marking routine.Results: Novel tumour model deployment was successfully achieved at all eight target sites across two live animal investigations without pneumothorax. Virtual bronchoscopy with tracking successfully guided the tracked catheter to 2-12 mm from the target tumour site. Deployment of a novel marker was achieved at all eight sites providing a reliable measure of targeting accuracy. Targeting accuracy within 10 mm was achieved in 7/8 sites and in all cases, the virtual target distance at marker deployment was within the range subsequently measured with x-ray.Conclusions: Endobronchial targeting of peripheral airway targets is feasible using existing open-source technology. Notwithstanding the shortcomings of current commercial platforms, technological improvements in EM tracking and registration accuracy fostered by open-source technology may provide the impetus for widespread clinical uptake of electromagnetic navigation in bronchoscopy.

Navigated bronchoscopy: a technical review.

BACKGROUND: Navigated bronchoscopy uses virtual 3-dimensional lung model visualizations created from preoperative computed tomography images often in synchronization with the video bronchoscope to guide a tool to peripheral lesions. Navigated bronchoscopy has developed fast since the introduction of virtual bronchoscopy with integrated electromagnetic sensors in the late 1990s. The purposes of the review are to give an overview and update of the technological components of navigated bronchoscopy, an assessment of its clinical usefulness, and a brief assessment of the commercial platforms for navigated bronchoscopy. METHODS: We performed a literature search with relevant keywords to navigation and bronchoscopy and iterated on the reference lists of relevant papers, with emphasis on the last 5 years. RESULTS: The paper presents an overview of the components necessary for performing navigated bronchoscopy, assessment of the diagnostic accuracy of different approaches, and an analysis of the commercial systems. We were able to identify 4 commercial platforms and 9 research and development groups with considerable activity in the field. Finally, on the basis of our findings and our own experience, we provide a discussion on navigated bronchoscopy with focus on the next steps of development. CONCLUSIONS: The literature review showed that the peripheral diagnostic accuracy has improved using navigated bronchoscopy compared with traditional bronchoscopy. We believe that there is room for improvement in the diagnostic success rate by further refinement of methods, approaches, and tools used in navigated bronchoscopy.

Bronchoscope-induced displacement of lung targets: first in vivo demonstration of effect from wedging maneuver in navigated bronchoscopy.

BACKGROUND: The accuracy of navigated bronchoscopy relies on a best possible correlation between the preoperative computed tomography images used for planning and the actual tumor position during bronchoscopy. Change in lung structure during the procedure may reduce success rate. The size of the lung changes during breathing, which may be predicted and at least partly compensated by a navigation system. We have studied the effect of the bronchoscopy itself, to see if and how the procedure causes further distortions, which might be harder to predict and compensate. METHODS: Using newly developed lung tracking sensors, we have measured the movement of individual lung segments during a bronchoscopy session in pigs. The bronchoscope was moved stepwise forward, ending in a wedge position, where it is often positioned when collecting peripheral biopsy specimens during conventional bronchoscopy. RESULTS: The influence of the bronchoscope on lung segment movement was minimal while positioned in the trachea, main bronchus, or lobe bronchus. However, in the wedge position, it displaced the lung targets and reduced the natural respiratory motion. CONCLUSIONS: A bronchoscope placed in a wedge position displaces lung targets and affects their respiratory behavior. As an image navigation system guides the operator towards a position dictated by the preoperative computed tomography, the displacement found in this study may cause the operator to miss the target. This may be part of the explanation for the limited success rates reported in the literature for navigated bronchoscopy.

[Teleradiologic follow up of patients treated with aortic stent grafting]. / Teleradiologisk oppfølging av pasienter behandlet med stentgraft i aorta.

BACKGROUND: A study has confirmed the possibility of follow up in the local hospital of patients who have undergone endovascular repair. We present a cost analysis of such a regimen compared to follow up at a university hospital. MATERIAL AND METHODS: By using discharge data from the Norwegian Patient Register we identified a group of patients which could have been followed up at their local hospital for their stent-grafted abdominal aortic aneurysm and estimated the cost effects of performing follow ups locally. RESULTS: The cost analysis showed a potential for cost savings from local follow ups, especially from moving from inpatient care at the university hospital to outpatient care locally. The result of this cost analysis differs from other Norwegian studies of teleradiology by identifying a possibility for more cost-effective treatment. INTERPRETATION: Using teleradiology to follow up these patients will free up capacity in the university hospital. Most probably, other groups of patients can also be followed up by teleradiology. The university hospitals can use this freed-up capacity for new patients. Teleradiology could lead to more efficient use of health care facilities, which should be in the interest of the health authorities.

Three-dimensional teleradiology for surveillance following endovascular aortic aneurysm repair: a feasibility study.

PURPOSE: To study the feasibility of 3-dimensional (3D) teleradiology in surveillance of patients treated with stent-grafts for abdominal aortic aneurysm (AAA). METHODS: Between April 2002 and November 2003, 8 AAA patients (7 men; median age 73 years, range 62-84) with stent-grafts had follow-up computed tomograms (CT) performed at their local hospital and transmitted without loss across a broadband connection to the university hospital. On both monitors, the radiologists were presented with the complete CT axial dataset, sagittal and coronal reformatted slices, and a 3D volume-rendered reconstruction. The two radiologists were then able to simultaneously perform measurements and real-time manipulations of the axial and 3D pictures, which were discussed over the telephone or using a videoconferencing unit. Patient satisfaction, the radiologists' evaluation of the method, and the potential cost savings were explored. RESULTS: Twelve follow-up CT scans were performed on the 8 patients. The time for transmission over the teleradiological network averaged 5 minutes, and the evaluation required 15 minutes at the university hospital. The overall technical quality of the images was rated as good by the university radiologist. In 11 studies, the stent-grafts were satisfactory, but a type III endoleak was detected in one 5.5-year-old stent-graft. Neither radiologist had a problem identifying the endoleak. Patients had confidence that the examination at the local hospital was of good quality; they all felt that they received good care and were pleased with avoiding travel to the university hospital. From the economic analysis, an annual savings of 40,000 Euros (USD 52,304) was projected, mostly due to avoiding hospital stays and outpatient consultations at the university hospital. CONCLUSIONS: The experiences from this study are encouraging, but a larger series will be necessary for a thorough evaluation of 3D teleradiology as a surveillance method for aortic stent-graft patients.