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: This study aimed to estimate the effectiveness of a full digital, high definition video system for laryngeal observations. A newly available, full digital, high definition video camera and high definition video monitor were used. With an endoscopic adaptor and rigid telescope, laryngoscopy and stroboscopy were performed on patients with various kinds of laryngeal lesions. All laryngeal lesions were observed and recorded by the full digital, high definition video camera without incident. The image quality for laryngoscopy and stroboscopy was far superior to that of a conventional video system, including video-endoscopy. Even tiny structures or lesions could clearly be visualised on the monitor. The still image obtained from the full digital, high definition video camera was 1920 x 1080 pixels and was comparable to that obtained from a still camera. Full digital, high definition video cameras are now commonplace products and can easily be applied to patients with laryngeal disorders. They provide superior laryngeal images, compared with conventional video systems. Furthermore, high definition video systems are cheaper than proprietary medical video systems. We consider our system to represent an accessible technique of gaining superior laryngeal observation in otolaryngological clinics.The Journal of Laryngology & Otology 02/2008; 122(1):78-81. · 0.68 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. · 0.79 Impact Factor
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ABSTRACT: Laparoscopic surgery requires surgeons to rely on visual clues for discrimination among differing tissues and for depth of field on a two-dimensional screen. High definition (HD) provides a superior image. If there is a measurable advantage with HD television (TV), the increase in the cost of the technology would be justified. A digital three-chip CCD camera with a standard monitor (SD system) and a true HD camera (1,080 pixels) with a 16:9-ratio HD monitor (HD system) were compared in clinical and laboratory settings. Three experiments were performed: (1) subjective visual evaluation of the HD and SD systems during actual surgical cases, (2) subjective visual evaluation in a controlled laboratory surgical setting with simultaneous parallel recording, and (3) three laparoscopic surgical task evaluations in a laboratory setting, namely, task A (metric analysis of participants on the surgical simulator), task B (simple eye-hand coordination performance), and task C (knot tying). All 53 participants subjectively evaluated HD as superior to SD in the laboratory setting and during actual surgery. In task B, there was no significant difference between SD and HD (dominant hand: p = 0.19; nondominant hand: p = 0.07). In task C, the knot-tying time was significantly less when performed with HD (mean, 173 +/- 84 s vs 214 +/- 107 s; p = 0.003). Most importantly, subjects with less skill (more documented time required in the basic module on a surgical simulator) improved significantly in the knot-tying task with the HD system (R = 0.631; p = 0.005). All the participants preferred HD to SD. High definition significantly improved laparoscopic knot tying, which requires precise depth perception, proving that HD is more than just a pretty picture.Surgical Endoscopy 11/2007; 21(10):1849-54. · 3.43 Impact Factor