virtX - evaluation of a computer-based training system for mobile C-arm systems in trauma and orthopedic surgery.

OBJECTIVES: Operating room personnel (ORP) operating mobile image intensifier systems (C-arms) need training to produce high quality radiographs with a minimum of time and X-ray exposure. Our study aims at evaluating acceptance, usability and learning effect of the CBT system virtX that simulates C-arm based X-ray imaging in the context of surgical case scenarios. METHODS: Prospective, interventional study conducted during an ORP course with three groups: intervention group 1 (training on a PC using virtX), and 2 (virtX with a C-arm as input device), and a control group (training without virtX) - IV1, IV2 and CG. All participants finished training with the same exercise. Time needed to produce an image of sufficient quality was recorded and analyzed using One-Way-ANOVA and Dunnett post hoc test (alpha = .05). Acceptance and usability of virtX have been evaluated using a questionnaire. RESULTS: CG members (n = 21) needed more time for the exercise than those of IV2 (n = 20): 133 +/- 55 vs. 101 +/- 37 sec. (p = .03). IV1 (n = 12) also performed better than CG (128 +/- 48 sec.), but this was not statistically significant. Seventy-nine participants returned a questionnaire (81% female, age 34 +/- 9 years, professional experience 8.3 +/- 7.6 years; 77% regularly used a C-arm). 83% considered virtX a useful addition to conventional C-arm training. 91% assessed virtual radiography as helpful for understanding C-arm operation. CONCLUSIONS: Trainees experienced virtX as substantial enhancement of C-arm training. Training with virtX can reduce the time needed to perform an imaging task.

Simplifying the exploration of volumetric images: development of a 3D user interface for the radiologist's workplace.

Volumetric imaging (computed tomography and magnetic resonance imaging) provides increased diagnostic detail but is associated with the problem of navigation through large amounts of data. In an attempt to overcome this problem, a novel 3D navigation tool has been designed and developed that is based on an alternative input device. A 3D mouse allows for simultaneous definition of position and orientation of orthogonal or oblique multiplanar reformatted images or slabs, which are presented within a virtual 3D scene together with the volume-rendered data set and additionally as 2D images. Slabs are visualized with maximum intensity projection, average intensity projection, or standard volume rendering technique. A prototype has been implemented based on PC technology that has been tested by several radiologists. It has shown to be easily understandable and usable after a very short learning phase. Our solution may help to fully exploit the diagnostic potential of volumetric imaging by allowing for a more efficient reading process compared to currently deployed solutions based on conventional mouse and keyboard.

Pre-operative dynamic interactive exploration of complex articular fractures using a novel 3D navigation tool.

OBJECTIVES: Trauma surgeons possess specific anticipative pathoanatomical and procedural domain knowledge that can be used for information extraction from original CT image data. This knowledge so far remains unused in clinical workflow and surgeons do not take an active part in the process of image generation and processing. The objectives of our work are to propose and employ a strategy to directly involve surgeons in a dynamic image exploration process and to exemplarily assess the clinical use of this approach for pre-operative diagnosis of complex articular fractures. METHODS: We used an interactive 3D navigation tool with a novel human-computer interface for the exploration of articular fractures of two selected anatomical structures. The system offers dynamic interaction with a virtual 3D reconstruction model and the possibility to create on-the-fly oblique multiplanar reformations by tracking hand movements. Three expert surgeons performed exemplary explorations and rated the use of the method for preoperative diagnosis in informal interviews. RESULTS: The approach and the system were well received by the three surgeons. The dynamic interaction was rated to be helpful in understanding fracture morphology. Two examples--a radius and a calcaneal fracture--are presented. CONCLUSIONS: Surgeons with their specific domain knowledge should be involved in the process of image processing. The benefit of using oblique multiplanar reformations for pre-operative planning in articular fractures appears to be substantial and they should therefore be included in radiological and surgical textbooks. Further evaluation is necessary to assess the use of interactive exploration systems in routine diagnosis.