Thorsten Fleiter MD, PRESENTER: Nothing to Disclose

Abstract: HTML Purpose: Sixteen-slice CT enables increased anatomical coverage and longitudinal (z-axis) resolution; however, thin-slice examinations often result in hundreds of images. The purpose of this study was to compare the effectiveness of five input devices used to navigate large CT data sets of the chest and to facilitate the detection of pulmonary nodules. Methods and Materials: An axial image navigation system was interfaced with five input devices as in †. This study compared a mouse(ms), the ShuttlePro jog wheel (jw)(Contour Design), a force-feedback joystick (js), a trackball (tb) and a gamepad (gp)(Logitech). Each device provided prototype controls for a variable speed cine mode and to incrementally step forward and backward through the images. Five chest scans were retrospectively selected for this study on the basis of having 4-6 small nodules (average 4.8±0.83 nodules, measured diameter 2.8±1.2 mm) as read by an expert (N.W.) using axial and 15 mm slab MIP views. The data sets were acquired using a Philips MX8000 IDT 16-slice CT scanner with a 1-1.5 mm slice thickness and an average of 250 images. After a training period of about one minute per device, three radiologist read the lung region of each case 1-5 times per device for a total of 44 reviews. The time to first nodule, Tf, total review time, Tt, and number of nodules detected per case Nd were recorded. Likert scales, ranging from high=5 to low=1, were used to assess device preference, comfort level, and potential fatigue. Reference: † Sherbondy A., et al, RSNA 2002 Results: The navigation system and input devices were used to complete all reviews with an average Tt=5.27 ±1.36 minutes; the mouse Tt=4.2 ±0.913 was faster than the joystick, Tt= 6.00±1.29 minutes (p<0.05). The average Tf=30.5±28.6 seconds; the mouse, Tf=19.2±18.7 seconds, and the trackball, Tf=16.1±8.1 seconds, were faster than the joystick, Tf=55.7±43.4 seconds (p<0.05). The average Nd was 5.5±2.4 nodules. The average preference scores of tb=2.1 were significantly lower than the jw=4.0, gp=3.7, ms=3.5, js=3.3 (p<0.05). The comfort scores were ms=4.3, jw=4.0, gp=3.3, js=3.3, tb=2.3; fatigue scores were jw=1.3, gp=1.7, js=1.9, ms=2.0,tb = 3.3 (highest fatigue). Conclusion: This preliminary study, based on detection of pulmonary nodules, suggests that the mouse input device was the fastest and that the joystick was the slowest in terms of review time. The trackball had the lowest preference scores. Future studies will include multi-organ review and device controls for slab slice thickness, rendering methods, and non-axial views. (J.H.Y. is an employee of Philips Medical Systems.) Questions about this event email: jeffrey.yanof@philips.com

Fleiter MD, T, Evaluation of Five Input Devices For Navigating Large MS-CT Data Sets Using Chest Scan Review Time and the Detection of Pulmonary Nodules.  Radiological Society of North America 2003 Scientific Assembly and Annual Meeting, November 30 - December 5, 2003 ,Chicago IL. http://archive.rsna.org/2003/3100288.html