8 Laryngeal Photography and Documentation Laryngeal photodocumentation is an essential component of patient assessment, treatment planning, and facilitation of communication between physicians, therapists, patients, and students. Photodocumentation reduces ambiguity of subjective descriptions of laryngeal pathology. This establishes baseline findings, simplifies secondary assessments, outcome reviews, medicolegal proceedings, and permits objective comparison between visits. Clinical Pearls Benefits of laryngeal photodocumentation •Communication •Teaching •Preoperative planning •Medicolegal documentation •Comparison/follow-up Photography is the art or science of creating durable images by recording light on an image sensor (digitally) or a light-sensitive material (photographic film). To capture a photographic image, light passes through or is reflected by the subject medium into a glass lens, which bends it into a focused image that is captured and recorded on a grid of microscopic-sized light-sensitive elements during a timed exposure. Photographers control the camera lens to expose the light recording material by shutter speed (duration of exposure) and diameter of light (aperture). The medium on which light is recorded can be a film or an electronic image sensor. In digital cameras, exposed light falls onto a solid-state image sensor known as a charge-coupled device (CCD). The CCD is a solid silicon chip comprising a tightly packed grid of photocell receptors (photosites) that each record the intensity of exposed light after it has passed through red-, blue-, and green-colored filters. Each photosite generates a single pixel. The greater the number of pixels on a chip, the higher the resolution and greater the detail and quality of the image. Each pixel is converted into a numeric value determined by the color and intensity of light sensed during the photographic exposure. Internal software then converts the numeric data into an image storage format (e.g., JPEG, TIFF). Image files are compressed via mathematical algorithms to facilitate storage on a memory chip, internal hard drive, USB, or other storage devices. The resulting image is stored electronically but can be reproduced on paper or film. A triple-chip camera has three separate image sensors that record three sequential exposures of one CCD with a rotating filter and maximizes color depth, intensity, and clarity. Videography is the process of capturing images on a film medium such as videotape, disk, and digital media. It records horizontal and vertical synchronization signals that are interlaced to form a video frame1 and then are presented quickly enough for the viewer to perceive motion. As with digital cameras, video cameras also incorporate a CCD as the analog device for detecting the image. The image is then digitized using an analog-to-digital converter. Every field is captured and stored in real time. Given the massive number of images required to represent motion accurately, the video information is compressed via compression–decompression (CODEC) algorithms into media files, for example, MPEG. Once created, the files can be stored on a variety of media devices such as personal computer’s hard drive, digital video disk (DVD), and USB. A media player is then required to load and control playback of digitized media (audio and video). The first laryngeal images were rendered by detailed artistic illustrations. This was the standard approach of documentation for 25 years until the first successful photographs of the human larynx were recorded by Lennox Browne in 1883,2 followed a year later by Thomas French of New York3,4 using a laryngeal mirror, sunlight reflected off a head mirror, and a single lens camera. The photographic devices used to obtain these images were innovative, yet cumbersome to use, and lacking in resolution and color. Further contributions came from Garel5 and Clerf6 who described their methods for recording stereoscopic laryngeal pictures. In the 1940s, Holinger and Brubaker published a series of articles on the use of the Holinger-Brubaker endoscopic camera for obtaining color photographs using an open-tube system with proximal illumination and a proximal optical system7,8; this was a major advancement in laryngeal photodocumentation. In 1993, a technique of laryngeal photography using rigid telescopes was described by Benjamin,9 which was then extrapolated to indirect laryngoscopy in the clinical setting.10 Traditionally, a 35-mm single-lens reflex (SLR) camera was used to collect images in conjunction with a laryngeal mirror, a laryngoscope (flexible and rigid), and an operating microscope; however, the advancement of technology has transitioned practice to include the use of digital imaging. The National Aeronautics and Space Administration (NASA) initially used digital imaging in the 1960s to map the surface of the moon, but it was not until the early 1990s that the first commercial digital camera became available. Initial comparisons between 35-mm and digital camera images yielded conflicting results; however, image quality for diagnostic purposes is comparable and the benefits of digital imaging far outweigh any limitations that might exist.11 The benefits of digital photography include rapid image production, quick and easy assessment of images for quality, deletion of poor images and capture of improved images, image quality longevity, improved ease of editing and storage, ease of publication, record sharing, communication, comparison, and rapid advancement of telemedicine. Its limitations include lower image resolution, limited depth of field (affected by distance of camera from endoscope and shutter size) detail, continuously evolving technology, and image backup files. Clinical Pearls Advantages of digital imaging •Immediate image quality assessment •Image sharing (communication, publication, patient information, medicolegal) •Image editing •Storage (archiving, organization, longevity) •Cost Dynamic videography of the larynx was developed in 1937, but it was much later adopted in the clinical setting because of its high cost. Farnsworth was the first to use high-speed motion picture to capture the vocal folds in motion.12 This was further developed by Holinger and Brubaker in the 1940s7,8 with their open-tube system with proximal illumination, but continued to remain in use primarily as a research tool until the 1980s when Yanagisawa began to advocate the use of commercially available analog video recorders, tape-based video systems, and color printers for the education of peers, learners, patients, and treatment planning.13–15 Similar to the replacement of film with digital imaging, analog video has been replaced by digital video. Photodocumentation begins in the office setting. It is at this time that the initial images/video will be obtained that will establish the diagnosis and provide baseline characteristics of a patient’s presenting complaint. Setup and optimization of laryngeal imaging is thus crucial and is detailed below. The room and equipment should be arranged such that it is convenient for the clinician and comfortable for the patient. An upright examining chair that can be adjusted by height and angle is ideal for the positioning of the patient. Positioning of the clinician’s equipment should be within reach of the examining chair with easy access to shutter controls (often in the form of a foot pedal). •Laryngoscope selection: Laryngeal visualization can be performed with either a rigid telescope or a flexible endoscope. Rigid laryngoscopy is typically performed using a 10-mm telescopic laryngeal endoscope with a 70-degree forward angle. The rigid laryngoscope has greater built-in magnification that provides superior image quality to flexible fiberoptic endoscopes.16 The flexible endoscope permits the clinician to evaluate the larynx while performing a greater range of dynamic phonatory behaviors. Traditional flexible laryngoscopes transmit the visual image via fiberoptic channels to the camera positioned at the eyepiece; newer “chip-tip” cameras have the CCD camera positioned at the distal aspect of the flexible laryngoscope allowing a more magnified view with greater resolution than provided by the traditional flexible laryngoscope, thus narrowing the gap between rigid and flexible endoscopy. •Camera selection: Available camera options include attaching a stand-alone 35-mm or digital camera to the head of an endoscope; however, this can be bulky and difficult to maneuver. In addition, the standard digital screen is small and difficult to appreciate the details of focus and resolution. A more convenient option is the use of a camera head attached to an endoscopic tower. Camera shutter can be controlled at the head of the camera or from a remote control such as a foot pedal. •Light source: Typically available light sources include halogen (constant) and xenon (strobe) light sources. Ideally, halogen lighting is used to establish static parameters, while stroboscopic lighting is used to evaluate dynamic parameters such as mucosal wave. The hazards of illumination on the interpretation of the examination have been well described17; therefore, the choice of light source should result in a natural looking image that remains consistent from patient to patient and from examination to examination.
Principles of Photography
Photography
Videography
History of Laryngeal Imaging
Laryngeal Photography
Videography
Office-Based Photo/Video Documentation
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