Optimal route planning for image-guided EBUS bronchoscopy

The staging of the central-chest lymph nodes is a major lung-cancer management procedure. To perform a staging procedure, the physician first uses a patient's 3D X-ray computed-tomography (CT) chest scan to interactively plan airway routes leading to selected target lymph nodes. Next, using an integrated EBUS bronchoscope (EBUS = endobronchial ultrasound), the physician uses videobronchoscopy to navigate through the airways toward a target node's general vicinity and then invokes EBUS to localize the node for biopsy. Unfortunately, during the procedure, the physician has difficulty in translating the preplanned airway routes into safe, effective biopsy sites. We propose an automatic route-planning method for EBUS bronchoscopy that gives optimal localization of safe, effective nodal biopsy sites. To run the method, a 3D chest model is first computed from a patient's chest CT scan. Next, an optimization method derives feasible airway routes that enables maximal tissue sampling of target lymph nodes while safely avoiding major blood vessels. In a lung-cancer patient study entailing 31 nodes (long axis range: [9.0 mm, 44.5 mm]), 25/31 nodes yielded safe airway routes having an optimal tissue sample size = 8.4 mm (range: [1.0 mm, 18.6 mm]) and sample adequacy = 0.42 (range: [0.05, 0.93]). Quantitative results indicate that the method potentially enables successful biopsies in essentially 100% of selected lymph nodes versus the 70-94% success rate of other approaches. The method also potentially facilitates adequate tissue biopsies for nearly 100% of selected nodes, as opposed to the 55-77% tissue adequacy rates of standard methods. The remaining nodes did not yield a safe route within the preset safety-margin constraints, with 3 nodes never yielding a route even under the most lenient safety-margin conditions. Thus, the method not only helps determine effective airway routes and expected sample quality for nodal biopsy, but it also helps point out situations where biopsy may not be advisable. We also demonstrate the methodology in an image-guided EBUS bronchoscopy system, used successfully in live lung-cancer patient studies. During a live procedure, the method provides dynamic real-time sample size visualization in an enhanced virtual bronchoscopy viewer. In this way, the physician vividly sees the most promising biopsy sites along the airway walls as the bronchoscope moves through the airways.

Efficient Bronchoscopic Video Summarization

Bronchoscopy enables many minimally invasive chest procedures for diseases such as lung cancer and asthma. Guided by the bronchoscope's video stream, a physician can navigate the complex three-dimensional (3-D) airway tree to collect tissue samples or administer a disease treatment. Unfortunately, physicians currently discard procedural video because of the overwhelming amount of data generated. Hence, they must rely on memory and anecdotal snapshots to document a procedure. We propose a robust automatic method for summarizing an endobronchial video stream. Inspired by the multimedia concept of the video summary and by research in other endoscopy domains, our method consists of three main steps: 1) shot segmentation, 2) motion analysis, and 3) keyframe selection. Overall, the method derives a true hierarchical decomposition, consisting of a shot set and constituent keyframe set, for a given procedural video. No other method to our knowledge gives such a structured summary for the raw, unscripted, unedited videos arising in endoscopy. Results show that our method more efficiently covers the observed endobronchial regions than other keyframe-selection approaches and is robust to parameter variations. Over a wide range of video sequences, our method required on average only 6.5% of available video frames to achieve a video coverage = 92.7%. We also demonstrate how the derived video summary facilitates direct fusion with a patient's 3-D chest computed-tomography scan in a system under development, thereby enabling efficient video browsing and retrieval through the complex airway tree.

'If this…, then…' - Resource allocation in a finite world

BACKGROUND

Tasks in general practice can be divided into three areas: acute care, planned secondary and tertiary prevention, and primary prevention. There is some evidence that the demands placed on practitioners by the second and third areas can decrease the time available for the first.

OBJECTIVE

To assess the work load of general practitioners and the evidence around benefit for effort, and suggest some strategies for making the most of available time.

DISCUSSION

Time wasting in general practice can be doctor-generated, role-generated or Medicare/government-generated. Doctor-generated time wasting includes doing things for which there is evidence of futility and may comprise investigations, screening and specific treatments. Appropriate workforce deployment can reduce role-generated time wasting. Medicare/government-generated waste occurs when there are financial incentives for health care providers to persist in activities with little evidence of benefit, or even evidence of no benefit. GPs need to actively plan to achieve a balance in providing care in the three areas of general practice.

Are they safe in there? - patient safety and trainees in the practice

BACKGROUND

Due to the projected increase of medical graduates and general practice registrars, a rapid increase in new trainers and practices is required. The resulting mix of relatively inexperienced trainers and trainees makes the examination of the important question of patient safety even more pertinent.

OBJECTIVE

To describe practical techniques that look beyond the door of the closed consulting room to detect unconscious incompetence in trainees.

DISCUSSION

Trainees can both be conscious of their incompetence and ask for help, or unconscious of their incompetence. Many articles have been written on teaching trainees who ask for help, but it is the trainee who does not ask for help who may be at most risk of serious problems, and therefore compromise patient safety. Formative assessment and feedback should be used to empower trainees as self-regulated learners. There are seven principles of good feedback practice that help develop self-regulation. This article provides practical teaching tips for supervisors in general practice.

Why haven't I changed that? Therapeutic inertia in general practice

BACKGROUND

There are multiple gaps between evidence and practice in our health system. The relatively new concept of 'therapeutic inertia' is useful to understand why these gaps persist. It is defined as 'failure of healthcare providers to initiate or intensify therapy when indicated' and 'recognition of the problem, but failure to act'.

OBJECTIVE

This article explores the development of therapeutic inertia and its causes, and other concepts useful in closing gaps in general practice, including addressing emotional decisional making by doctors.

DISCUSSION

Clinical inertia is the original term used to describe gaps in practice; and therapeutic inertia is now used interchangeably with it. The author illustrates his practice's approach to overcoming therapeutic inertia. The National Institute for Clinical Studies was set up in Australia to get the best available evidence from health and medical research into everyday practice to help close these gaps.

A cardiovascular risk clinic using home BP monitoring

BACKGROUND

Hypertension is the most common chronic condition managed in general practice, but blood pressure (BP) control is often suboptimal. Home blood pressure (HBP) monitoring can be more accurate than office based BP (OBP) monitoring, with HBP readings approximately 10/5 mmHg lower than OBP in the same patients.

METHODS

Hypertensive patients from a single general practice were invited to a cardiovascular risk review clinic using HBP monitoring. Outcome measures were BP reading, BP meeting adjusted target of 120/80 if aged <65 years or 130/85 if aged >65 years, owning home BP monitor, numbers enrolling and numbers attending 12 month follow up.

RESULTS

Of 524 eligible patients, 414 (79%) enrolled in the clinic, of whom 89% completed the trial. At 12 months, HBP control rates rose from 29.9% to 44.8%, with mean HBP falling 5.2/3.2 mmHg (p<0.001). Home BP monitor ownership rose from 54.3 to 82.9%.

DISCUSSION

This is the first study in standard Australian general practice using both a comprehensive clinic approach and HBP readings exclusively. This study provided a feasible management protocol and practical clinical performance indicators that could be used for a randomised controlled trial. Significantly better control rates were achieved compared with published studies for BP control.