Blinded evaluation of the effects of high definition and magnification on perceived image quality in laryngeal imaging.
ABSTRACT Advances in commercial video technology have improved office-based laryngeal imaging. This study investigates the perceived image quality of a true high-definition (HD) video camera and the effect of magnification on laryngeal videostroboscopy.
We performed a prospective, dual-armed, single-blinded analysis of a standard laryngeal videostroboscopic examination comparing 3 separate add-on camera systems: a 1-chip charge-coupled device (CCD) camera, a 3-chip CCD camera, and a true 720p (progressive scan) HD camera. Displayed images were controlled for magnification and image size (20-inch [50-cm] display, red-green-blue, and S-video cable for 1-chip and 3-chip cameras; digital visual interface cable and HD monitor for HD camera). Ten blinded observers were then asked to rate the following 5 items on a 0-to-100 visual analog scale: resolution, color, ability to see vocal fold vibration, sense of depth perception, and clarity of blood vessels. Eight unblinded observers were then asked to rate the difference in perceived resolution and clarity of laryngeal examination images when displayed on a 10-inch (25-cm) monitor versus a 42-inch (105-cm) monitor. A visual analog scale was used. These monitors were controlled for actual resolution capacity.
For each item evaluated, randomized block design analysis demonstrated that the 3-chip camera scored significantly better than the 1-chip camera (p < .05). For the categories of color and blood vessel discrimination, the 3-chip camera scored significantly better than the HD camera (p < .05). For magnification alone, observers rated the 42-inch monitor statistically better than the 10-inch monitor.
The expense of new medical technology must be judged against its added value. This study suggests that HD laryngeal imaging may not add significant value over currently available video systems, in perceived image quality, when a small monitor is used. Although differences in clarity between standard and HD cameras may not be readily apparent on small displays, a large display size coupled with HD technology may impart improved diagnosis of subtle vocal fold lesions and vibratory anomalies.
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ABSTRACT: Surgeons performing laparoscopic surgery have strong biases regarding the quality and nature of the laparoscopic video monitor display. In a comparative study, we used a unique computerized sensing and analysis system to evaluate the various types of monitors employed in laparoscopic surgery. We compared the impact of different types of monitor displays on an individual's performance of a laparoscopic training task which required the subject to move the instrument to a set of targets. Participants (varying from no laparoscopic experience to board-certified surgeons) were asked to perform the assigned task while using all three display systems, which were randomly assigned: a conventional laparoscopic monitor system (2D), a high-definition monitor system (HD), and a stereoscopic display (3D). The effects of monitor system on various performance parameters (total time consumed to finish the task, average speed, and movement economy) were analyzed by computer. Each of the subjects filled out a subjective questionnaire at the end of their training session. A total of 27 participants completed our study. Performance with the HD monitor was significantly slower than with either the 3D or 2D monitor (p < 0.0001). Movement economy with the HD monitor was significantly reduced compared with the 3D (p < 0.0004) or 2D (p < 0.0001) monitor. In terms of average time required to complete the task, performance with the 3D monitor was significantly faster than with the HD (p < 0.0001) or 2D (p < 0.0086) monitor. However, the HD system was the overwhelming favorite according to subjective evaluation. Computerized sensing and analysis is capable of quantitatively assessing the seemingly minor effect of monitor display on surgical training performance. The study demonstrates that, while users expressed a decided preference for HD systems, actual quantitative analysis indicates that HD monitors offer no statistically significant advantage and may even worsen performance compared with standard 2D or 3D laparoscopic monitors.Surgical Endoscopy 04/2010; 24(11):2743-8. · 3.31 Impact Factor
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ABSTRACT: At present, it is difficult to identify a gold standard for endoscopic staging of laryngeal cancer, especially considering the large number of endoscopic instruments available. We have coined the term multistep endoscopy to describe a method for staging laryngeal precancerous and neoplastic lesions that sequentially uses several endoscopic tools including high definition white light endoscopy (HDTV), stroboscopy and autofluorescence endoscopy. During the period from November 2007 to November 2009, 140 patients with a suspect laryngeal lesion underwent multistep endoscopy at the Department of Otorhinolaryngology at Martini Hospital in Turin. All patients were subjected to a series of endoscopic examinations in indirect laryngoscopy (white light endoscopy coupled to a HDTV camera, laryngostroboscopy, indirect autofluorescence) followed by white light endoscopy coupled to a HDTV camera and autofluorescence in direct microlaryngoscopy. The aim of the present prospective study was to evaluate the utility of multistep endoscopy in the diagnostic work-up of laryngeal lesions. Multistep endoscopy showed a higher sensitivity and "biological" predictive value in early cancer and precancerous lesions of the larynx (sensitivity, 97.9%; specificity, 90.5%) compared to individual endoscopic tools. It allows for better therapeutic planning of superficial lesions and more accurate orientation when performing mapping biopsies on diffuse lesions. In our opinion, more widespread use of indirect autofluorescence endoscopy during follow-up may be warranted to search for synchronous/metachronous second tumours of the upper aerodigestive tract.Acta otorhinolaryngologica Italica: organo ufficiale della Società italiana di otorinolaringologia e chirurgia cervico-facciale 04/2012; 32(3):175-81. · 1.44 Impact Factor
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ABSTRACT: Though theoretically superior to standard 2D visualization, 3D video systems have not yet achieved a breakthrough in laparoscopy. The latest 3D monitors, including autostereoscopic displays and high-definition (HD) resolution, are designed to overcome the existing limitations. We performed a randomized study on 48 individuals with different experience levels in laparoscopy. Three different 3D displays (glasses-based 3D monitor, autostereoscopic display, and a mirror-based theoretically ideal 3D display) were compared to a 2D HD display by assessing multiple performance and mental workload parameters and rating the subjects during a laparoscopic suturing task. Electromagnetic tracking provided information on the instruments' pathlength, movement velocity, and economy. The usability, the perception of visual discomfort, and the quality of image transmission of each monitor were subjectively rated. Almost all performance parameters were superior with the conventional glasses-based 3D display compared to the 2D display and the autostereoscopic display, but were often significantly exceeded by the mirror-based 3D display. Subjects performed a task faster and with greater precision when visualization was achieved with the 3D and the mirror-based display. Instrument pathlength was shortened by improved depth perception. Workload parameters (NASA TLX) did not show significant differences. Test persons complained of impaired vision while using the autostereoscopic monitor. The 3D and 2D displays were rated user-friendly and applicable in daily work. Experienced and inexperienced laparoscopists profited equally from using a 3D display, with an improvement in task performance about 20 %. Novel 3D displays improve laparoscopic interventions as a result of faster performance and higher precision without causing a higher mental workload. Therefore, they have the potential to significantly impact the further development of minimally invasive surgery. However, as shown by the custom-built 3D mirror display, this effect can be improved, thus stimulating further research.Surgical Endoscopy 03/2014; · 3.31 Impact Factor