Учебники / Computer-Aided Otorhinolaryngology-Head and Neck Surgery Citardi 2002
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FIGURE 8.4 Digital video recorder/player: (A) Sony DSR-20 DVCAM video recorder with a 60 minute DVCAM videotape (accepts both 60 and 40 minutes tapes); (B) Sony DSR-V10 Video Walkman mini-recorder (accepts only 40 minutes mini DVCAM tape).
8.4.5 Digital Video Recorder/Player
Digital DV or DVCAM camcorders support the recording of digital images in their built-in recorder. The images may be reviewed on the built-in LCD screen. These devices may also be connected to an external monitor for the review of the digital images stored in the devices. Finally, an LCD projector may be used to project the images on a larger screen.
The newest storage medium for digital video camcorders includes a miniDVCAM tape. DVCAM tape is utilized in digital video recorders/players, representative models of which are illustrated in Figure 8.4. Figure 8.4A demonstrates the Sony DSR-20 DVCAM recorder (approximately $3,500), which is useful for medical documentation on a 60or 40-minute DVCAM tape. The Sony DSRV10 Video Walkman mini-recorder (approximately $2,300) is shown in Figure 8.4B. Both models offer digitized capture of video images arising from either an analog or a digital source. Digital recorders from a digital signal offer video images of higher quality than are available with conventional analog videotape. Both models are portable, and the Sony DSR-V10 has a built-in LCD screen for viewing image capture.
8.4.6 Color Printers
Color printers are commonly available in various types (ink jet, dye sublimation, color laser) in a wide selection, whose features and prices vary greatly. As is the case with all hardware devices, printers with more features have decreased in cost as technology has progressed over time. Figure 8.5A illustrates the Olympus P-330 digital printer (approximately $400), a model that is able to print images
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FIGURE 8.5 Digital color printers: (A) Olympus P-330 digital printer; (B) Canon BJC8200 bubble jet printer; (C) Sony UP-5500 dye-sublimation professional digital printer.
from digital image storage cards without the need for an initial download from computer. Some printers are able to print directly from storage cards, but generally they tend to be more costly than conventional printers. However, these digital printers offer convenience, obviating the need for a computer. Figure 8.5B illustrates a Canon BJC-8200 bubble jet printer (approximately $300), an example of a conventional printer, which requires that a computer download capture images before printing. Such ink jet printers generally offer inexpensive prints of adequate quality. Publication quality pictures may be obtained by using a professional photo paper.
Dye sublimation color printers are expensive but produce superior quality images that are most suitable for publication. The senior author uses the Sony UP-5500 digital color printer (approximately $8,000), a professional dye sublimation color printer (Figure 8.5C). Much less expensive dye sublimation printers are now available from various other companies.
8.4.7 Digital LCD Projector
To present images in a conference setting, one may use a digital projector. Some of the currently available models are presented in Figure 8.6. Figure 8.6A shows the Sony VPL-PX31 LCD projector (2800 ANSI lumens) (approximately $7,500). Figure 8.6B illustrates the Sony VPL-PX1 SuperLiteTm Portable LCD projector (1000 ANSI lumens) (approximately $4,500). The Sony VPL-CX1 SuperLiteTm LCD projector (550 ANSI lumens) (approximately $2,500) is shown in Figure 8.6C, and Figure 8.6D demonstrates the Mitsubishi X70UX XGA LCD projector (1100 ANSI lumens) (approximately $4,500). There are many other models available from companies such as Epson and NEC.
Technological advances in terms of image brightness and projector portability continue to improve. Some digital LCD projectors project images directly
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FIGURE 8.6 Digital LCD projectors: (A) Sony VPL-PX31 LCD projector; (B) Sony VPL-PX1 SuperLiteTm Portable LCD projector; (C) Sony VPL-CX1 SuperLiteTm LCD projector; (D) Mitsubishi X70UX XGA LCD projector.
from storage cards. The availability of such an LCD projector may obviate the need for slide carousels, or even a computer, in presentations.
8.5 ADVANTAGES OF DIGITAL IMAGING
There are numerous advantages of digital imaging [5–13]. In terms of quality, early digital cameras were criticized for inferior photograph quality compared to 35 mm film cameras. However, as technology has improved, current megapixel cameras produce images comparable to that of 35 mm film. With regard to convenience, digital images are immediately available for preview on the LCD screen. Images may then be assessed in terms of quality and content at the time of capture, without the delays that are inherent in film development [10]. Images of unsatisfactory quality may be discarded, saving memory space. Cost issues tend to favor digital photography. Although there is the initial cost of hardware to establish the digital system, there are no ongoing costs for film purchase or development [10]. There are costs involved in printing digital images, but most conventional ink jet printers offer inexpensive, good quality hard copies of captured images. Dye sublimation and color laser printers offer superior image quality, but at a higher cost. In terms of image manipulation, software programs allow for easy annotation of images through the addition of graphics or text. Photographic artifacts may be removed, and color balance, brightness, or contrast may be optimized [5]. Some models of digital still cameras allow in-camera editing of images without the need for download to a computer.
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The clinical advantages of digital imaging include photodocumentation for the medical record and data archive. Physical findings on examination may be documented and stored as part of a patient’s chart. Digital images may also facilitate patient counseling. Archiving digital images on removable storage media allows for compact storage with easy and rapid retrieval of images. The standard 1.44 MB floppy disk is nearly universal and provides an inexpensive medium for sharing captured images with patients. Although the cost for storing images (in terms of cents per MB) is greater for a floppy disk than for other higher capacity media (such as CD-R or CD-RW), cost per disk is less for floppy disks, and the convenience of floppy disks should not be discounted.
The efficient data archive possible with digital images also has educational applications. Interactive CD-ROMs utilize digitized images for the instruction of medical students, residents, or practitioners. Computer software programs significantly improve the speed and efficiency by which images may be cataloged and retrieved in comparison with the traditional method of sifting through numerous videotapes, photographs, and/or slides.
Digitized images may be easily duplicated and disseminated without degradation in image quality [7]. The distribution of data over a hospital network or the Internet allows for rapid and economical teleconferencing. Compression improves the speed by which images may be transmitted for remote viewing or instruction. The increasing availability of greater bandwidth communications provides for near-instantaneous transmission of images.
8.6 DISADVANTAGES OF DIGITAL IMAGING
Although digital cameras have made significant technological advances over the past several years, there are still shortcomings to this technology. The control and flexibility of photographic features available with traditional film cameras are not yet uniformly available on consumer level digital still cameras. The power requirements for most digital cameras, whose LCD viewscreens require substantial power, result in significantly shorter battery life compared to film cameras. The internal memory within current digital cameras are so limited that, unless large capacity removable storage cards are used, few high-resolution images may be captured before they must be downloaded to the computer.
The implementation of any new technology often requires establishing new infrastructure. Many conference rooms are not yet equipped for the presentation of digital images, necessitating the conversion from a digital medium to traditional 35 mm slides [10]. Not all health care environments have the resources or infrastructure necessary to implement a digital system [2,3]. For those who wish to establish a digital system, competing technologies provide greater choice of formats, but deciding upon a particular system may be difficult. Once a digital
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system has been purchased, professional and technical staff must become familiar with this new technology [10].
The ease with which digital images may be manipulated to enhance picture quality raises new concerns regarding the ethics of publication and presentation [5,12]. Digital images may be tampered with for falsification to an extent not feasible with previous media.
Finally, in light of the ease of transmission of digital images over a network or the Internet, attention should be paid to issues of security and patient confidentiality [6].
8.7CLINICAL APPLICATIONS
IN OTOLARYNGOLOGY–HEAD AND NECK SURGERY
Digital imaging has many potential uses in the field of otolaryngology. Figure 8.7 illustrates a side-by-side comparison of image quality of analog video images and digital computer images. The high quality of the captured digital images is evident in Figures 8.7A and B. Such high-quality digital images are immediately available for review at the time of capture without the need for film development. Images may be annotated by the addition of labels, such as the patient’s name and the date of examination. The images may then be stored on a 1.44 MB floppy disk in the patient’s chart. A copy may also be presented to the patient. The images may be downloaded to a computer for archive, and representative images may be then projected for presentation and education. If necessary, images may be shared with consulting colleagues by electronic transmission.
FIGURE 8.7 Comparison of analog video and digital computer images: (A) comparison between laryngoscopic video and computer images; (B) comparison between laryngoscopic still video and still computer images.
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Figure 8.8 demonstrates some examples of the clinical applications of digital imaging in otolaryngology and head and neck surgery. As shown in Figures 8.8A, B, and C, facial plastic surgeons may catalog preoperative and postoperative images of patients for comparison, counseling, and education. Captured images provide much more illustrative information than either descriptive text or coarse drawings. Figure 8.8D demonstrates the right auricle with herpetic lesion. Figure 8.8E shows a close-up view of this lesion. The captured image may be zoomed in or out in the digital camera itself by using the zoom button of the camera. The image can also be moved to the right or to the left or centered. The intraoral digital image can be taken using the cheek retractors as shown in Figure 8.8F. Any lesion of the head and neck may be recorded. Digital images may be
FIGURE 8.8 Clinical applications in otolaryngology–head and neck surgery: (A–C) photographs of the face (frontal, basal and lateral views); (D) digital photograph of the auricle with herpetic lesions; (E) close-up view of the same patient showing the details of the skin lesion; (F) digital image of teeth; (G) preoperative CT scan of sinuses; (H) computer graphics of endoscopic sinonasal anatomy and laryngostroboscopic view of vocal fold cyst (adapted from Ref. 8); (I) Computer graphics of endoscopic sinonasal anatomy and laryngostroboscopic view of vocal fold cyst (adapted from Ref. 8).
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used to document intraoperative findings and surgical specimens. This may prove helpful for medicolegal documentation. As shown in Figure 8.8G, preoperative sinus computed tomography (CT) scans may be photographed by digital still cameras. Figures 8.8H and I show computer graphics prepared for publication in textbooks [8].
Two types of digital imaging systems useful for functional endoscopic sinus surgery (FESS) are illustrated in Figures 8.9A and B. These types of computeraided surgery systems provide improved localization for maximimal safety during FESS.
The Kay Digital Strobo Recording System (DVRS) illustrated in Figure 8.9C is useful for laryngology. Voice disorders may be evaluated with highquality stroboscopic images superimposed with electrophysiological information. During laryngostroboscopy, any given segment of the image may be captured
FIGURE 8.9 Clinical applications in otolaryngology-head and neck surgery: (A) com- puter-aided endoscopic sinus surgery (Insta Trak system); (B) Computer-aided endoscopic sinus surgery (Stealth Station system) (adapted from Ref. 14); (C) Kay Digital Strobo Recording System (DVRS); (D) Pentax Electronic Videolaryngoscopy System EPM 1000/ 3300.
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for a detailed study. The Pentax Electronic Videolaryngoscopy System EPM 1000/3300 shown in Figure 8.9D also provides high-quality digital images of the larynx.
8.8DESCRIPTIONS OF CURRENT DIGITAL IMAGE CAPTURE SYSTEMS
The features of digital image capture devices continue to improve while their costs continue to decrease. Two of the most up-to-date systems currently available are presented here. Their descriptions serve not as product endorsement but rather convey the state of technological capability at the time of this writing. In selecting a digital image capture system, one should choose the system that allows fast capture time.
Figure 8.10 illustrates the Stryker SDC Pro digital capture device (approximately $14,000), which can be used to record still images or video segments. Housed within the device are a CPU (central processing unit) and hard drive that can capture digital images or streaming video onto a write-able compact disk
FIGURE 8.10 Stryker SDC Pro digital capture device.
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(CD-R). The CD has become the de facto standard for data storage, since it may be accessed from almost any computer system using either a Macintosh or Windows-based operating system. A single CD may hold approximately 650 images captured in bitmap (BMP) format, or approximately 12,000 images in compressed Joint Photographic Expert Group (JPEG) format. Alternatively, a single CD may record up to 20 minutes of continuous video. Alternatively, a CD may contain a mixture of both still images and digital video.
Included with the Stryker SDC Pro system is the SDC Image Pro software package for digital annotation of captured still images or video segments. Image quality may be adjusted digitally using a variety of image control functions, and the results are immediately displayed on the console. Still images and video segments are conveniently organized by patient name and date of examination for later retrieval or for import into other software programs, such as Microsoft PowerPoint. The SDC Pro system has an image capture time of less than one second.
Shown in Figure 8.11, the Sony DKC-CM30 digital still camera (approximately $2,000) captures still images and does not capture video segments. A C-
FIGURE 8.11 Sony DKC-CM30 digital still camera with a Nagashima endoscope attached. The insert shows a digitized laryngeal image on the LCD viewscreen located on the back of the camera.
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mount lens may be attached to the camera to accept a variety of rigid telescopes for endoscopic examination. The number of images that may be taken depends on the resolution selected. Up to 30 images may be captured in high resolution, or up to 120 images may be captured in standard resolution. The inset image of Figure 8.11 illustrates a digitized laryngeal image on the LCD viewscreen on the back of the camera. Since the capture time of the Sony DKC-CM30 is slow, this camera is not currently recommended for digital photography of moving subjects.
8.9 CONCLUSIONS
The convenience and features of digital imaging systems will likely result in their continued integration into health care delivery as technology improves and prices fall. The ease with which images may be manipulated and transmitted mandates attention to the ethical presentation and distribution of these images. Furthermore, the storage and transmission of digital images requires a uniform and flexible network, which permits ease of operation. A digital system for image capture, storage, and distribution is currently a useful adjunct to traditional film-based systems, but the replacement of film by digital media may not be too far in the future.
ACKNOWLEDGMENTS
The authors would like to thank Dr. Michael Willett and Dr. Ken Yanagisawa for their assistance during the preparation of this chapter.
REFERENCES
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