New trends in head and neck imaging

Summary The development of novel imaging techniques has exerted a larger influence on medical science than have any other advances in the last decade. The following occurrence are now evident in imaging for all medical disciplines: reduced use of ionizing radiation, abandonment of invasive methods, real-time properties, visualization of functional parameters, digitalization and pooling of information, as well as interaction of user with image information. A wide variety of imaging methods is now available clinically for the study of head and neck diseases. However, only picture archiving and communication systems (PACS) can efficiently handle and integrate information coming from multiple imaging modalities, such as computed tomography, magnetic resonance imaging, positron emission tomography, digital subtraction angiography and digital radiography. Such systems also incorporate image workstations that the surgeon can use for preoperative planning and even perioperative assistance. Current PACS are reviewed, since their future use may change the operating theater and also change surgical strategies.     

Analysis of laryngeal movement by digital subtraction laryngography.

Fine movement of laryngeal components was analyzed by digital subtraction laryngography with the use of a digital fluorography system. Two kinds of image processing modes, the super pulse image subtraction mode and the time interval difference mode, were used for this purpose. By the super pulse image mode, the distance and extent of movement of laryngeal components at vocal initiation and during phonation could be observed. By the time interval difference mode, the amount and direction of motion for a certain interval and fine movement, such as vocal initiation, were determined.     

Preliminary evaluation of stroboscopy system using multiple light sources for observation of pathological vocal fold oscillatory pattern

OBJECTIVES: Laryngostroboscopy is used to check the oscillatory patterns of the vocal folds. However, the use of one single flash timing cannot give a clear view of abnormal vocal fold oscillations that have multiple fundamental frequencies. Visualization of such complex vocal fold movements will be helpful in the diagnosis of diplophonia, a pathological condition in which the vocal folds produce multiple tones at the same time. METHODS: We developed a new stroboscopy-based technique using multiple light-emitting diodes (LEDs) and image analysis. Specific flash timings for each LED, suitable for accurate visualization, were determined on a computer according to an algorithm based on frequency analysis. The image analysis extracted the necessary parts of the captured images to yield a clear slow-motion view of the oscillations. The series of visualization procedures took advantage of the narrow-spectrum light property of LEDs, thereby yielding a degradation-free picture. RESULTS: Feasibility tests using a mechanical vocal fold model demonstrated that this computer-assisted system allows observation of the pathological oscillatory patterns as one single video. They would not be clearly visualized by conventional stroboscopy. CONCLUSIONS: Because of its relatively simple use and inexpensive construction, the proposed technique can become one potential option for clinical assessment of pathological vocal fold oscillations.     

The visible ear: a digital image library of the temporal bone

High-fidelity computer-based modeling, simulation and visualization systems for the study of temporal bone anatomy and training for middle ear surgery are based on a sequence of digital anatomical images, which must cover a large tissue volume and yet display details in high resolution and with high fidelity. However, the use of existing image libraries by independent developers of virtual models of the ear is limited by copyright protection and low image resolution. A fresh frozen human temporal bone was CT-scanned and serially sectioned at 25 microm and digital images of the block surface were recorded at 50- to 100-microm increments with a Light Phase(TM) single-shot camera back attachment. A total of 605 images were recorded in 24-bit RGB resolution. After color correction and elimination of image size variation by differential cropping to 15.4 cm x 9.7 cm, all images were resampled to 3,078 x 1,942 pixels at a final resolution of 50 microm/pixel and stored as 605 one-Mb JPEG files together with a three-dimensional viewer. The resulting complete set of image data provides: (1) a source material suitable for generating computer models of the human ear; (2) a resource of high-quality digital images of anatomical cross sections from the human ear, and (3) a PC-based viewer of the temporal bone in three perpendicular planes of section.     

Sound lateralization regarding amplitude and time factors in various forms of hearing loss

The ability to localize the sound source was investigated in 70 patients with hypoacusis of various type and degree, using interaural differences in time and intensity. The dichotic method of signal presentation was employed which made it possible to separately vary sound excitation of each ear. Isolated use of interaural differences in terms of time and amplitude was investigated by measuring lateralization thresholds, i.e. minimal interaural differences in time and intensity perceived as a displacement of the acoustic image from the head midline. It was found that lateralization of the acoustic image in response to interaural time and intensity differences followed different patterns. The precision of time lateralization depended on the level of hearing impairment and on binaural hearing asymmetry with respect to tone perception thresholds. The precision of intensity lateralization was dependent on the type of hypoacusis. The lowest thresholds of intensity lateralization were seen in patients with chronic adhesive otitis while the highest thresholds were detected in patients with 1st degree otosclerosis. It is recommended to use tests for measuring lateralization thresholds in terms of time and intensity in order to perform differential diagnostics of hearing impairment and functional prediction of hearing improvement interventions in otosclerosis and chronic otitis.     

Image guidance: A survey of attitudes and use

BACKGROUND: The aim of this study was to determine access to, usage of, and attitudes toward image guidance in endoscopic sinus and anterior skull base surgery. METHODS: We performed a survey of American Rhinologic Society members. RESULTS: Of 1050 surveys mailed, 340 (32.4%) were returned and scored. Image guidance was available to 86% of respondents. Eighteen percent of respondents did not use image guidance in any cases, and 25% used it in up to 10% of cases. Eight percent of respondents used image guidance in >90% of cases. Respondents felt the primary indication for this technology is in revision or advanced cases. Seventy percent of respondents felt image guidance was not typically indicated for a primary total ethmoidectomy and >90% of respondents felt it was either a relative or absolute indication for revision frontal sinus exploration, modified Lothrop procedure, or closure of cerebrospinal fluid leak. Attitudes of the respondents did not vary by year of residency completion or by the use of image guidance during residency. Current access to image guidance was associated with a higher likelihood of feeling it was indicated. CONCLUSION: The majority of respondents had access to image guidance. Many feel it is a relative or absolute indication for revision and advanced endoscopic sinus and skull base procedures. A very small minority used this technology in all cases. The results of this survey reflect the opinion of the respondents. They do not necessarily reflect the views of the American Rhinologic Society or of practicing otolaryngologists in general.     

人工智能在鼻咽癌诊疗中的研究进展

探讨利用人工智能(AI)技术在鼻咽部病理学、影像学和内镜学等海量医学图像大数据的基础上建立学习模型,实现鼻咽癌医学图像的AI辅助诊疗决策系统,从而辅助医师对鼻咽癌的诊断更为精准,让治疗更加个性化。AI在鼻咽癌诊疗方面处于研究阶段,尚未真正在临床开展和应用。针对目前AI在鼻咽癌诊疗中的研究情况作一综述,进一步探讨其存在的问题和未来发展方向。     

Xeroradiography and otolaryngology

As a diagnostic tool, a new horizon in otolaryngology has become apparent in the past several years. It is known as xeroradiography and is a convenient technique requiring minimal patient cooperation and enjoying excellent acceptability for both patients and physicians. Speed, efficiency and consistently high image quality make xeroradiography suitable for otolaryngologic applications in the office, as well as in operating and emergency rooms. All tissue densities are represented in a single image, eliminating the need for taking two films of different densities, while radiation exposure is the same. Now popular for use in mammography, the technique is especially useful for detailed studies of the areas of interest to otolaryngologists. Certain inherent disadvantages in the technique are mentioned and guidelines are given to make these disadvantages an acceptable trade-off in actual application.     

A randomized controlled trial: is water better than a standard lubricant in nasendoscopy?

Objectives: Previous studies have shown that nasendoscopy is made easier with the use of lubrication at the expense of the quality of the view obtained, but had no effect on the discomfort or pain experienced by the patient. We set out to determine whether the advantages of lubrication with a standard lubricant (KY Jelly) could be achieved by using water, without incurring the same disadvantages. Design: Single blind randomized controlled trial. Setting: Outpatient Departments at two District General Hospitals. Participants: One hundred and fifty participants selected sequentially from patients requiring a nasendoscopy where the endoscope would be passed far enough to view the larynx. Patients requiring topical anaesthetic were excluded. Methods: Patients were randomly assigned to have either water or standard lubricant applied to the nasendosope prior to nasendoscopy. Levels of pain experienced by the patient were recorded on a visual analogue score as well as visual analogue scores from the clinician for the levels of difficulty in passing the endoscope. All participants who were entered the study completed the study. Endoscopy was performed by all grades of medical staff. Main outcome measures: Levels of pain experienced by the participants were assessed by a visual analogue scale. Difficulty of passing the scope was indicated by the endoscopist using a visual analogue scale, as was the quality of image obtained. Results: Endoscopists found the insertion of the endoscope was easier and the image better when water was used rather than KY Jelly. There was no significant difference in reported in levels of pain experienced by the patient. Conclusion: Although the use of water as a lubricant during nasendoscopy confers no additional benefit in term of the levels of pain suffered by patients during the procedure, it makes the insertion of the endoscope easier and provides a better quality image than standard lubrication.     

Physician experience with an optical image guidance system for sinus surgery

OBJECTIVES/HYPOTHESIS: Intraoperative guidance systems have been developed which use infrared tracking technology to assist with anatomical localization during sinus surgery. Although the introduction of this technology is intended to increase the safety and efficacy of sinus surgery, little is known about its actual impact in the clinical setting. The objective of this report was to study the application and utilization of an image guidance system shared by multiple sinus surgeons in a specialty hospital. STUDY DESIGN: Combined prospective case study and retrospective analysis of physician surveys. METHODS: An optical-based image guidance system (LandmarX, Xomed, Inc., Jacksonville, FL) was used by 34 physicians to perform 754 sinonasal surgeries over a 2.5-year period at Massachusetts Eye and Ear Infirmary. In 19 cases, system registration was repeated during surgery to measure the effect of fiducial placement on system accuracy. RESULTS: The measured accuracy of anatomical localization at the start of surgery (mean value, 1.69 +/- 0.38 mm) was comparable to the perceived accuracy of 1 to 3 mm that was reported by 79% of surgeons surveyed. Operating room time (mean period, 130.6 +/- 41.1 min) correlated with the surgical procedure performed (P < .05), but not with the disease stage or revision rate. According to a majority of surgeons, use of the image guidance equipment increased operating room time by 15 to 30 minutes during initial cases and by 5 to 15 minutes once experience with the equipment had been acquired. More than 90% of surgeons anticipated their continued use of the image guidance equipment for sinus surgery at a similar or greater level in the future. CONCLUSION: An optical-based image guidance system can be successfully integrated into a multisurgeon operating room environment. Use of the system provides accurate anatomical localization during sinus surgery and results in a relatively high level of physician satisfaction.     

Image-guided surgery of the sinuses: current technology and applications

Image-guided surgery has been established as an important adjunctive tool for rhinologic surgery. The technology has evolved since the middle of the last century and continues to do so at a rapidly increasing rate. A number of systems exist, each with its relative benefits and drawbacks. Image guidance can assist the endoscopic sinus surgeon by confirming position within challenging anatomic fields. Many issues remain, however, before the widespread application of this technology can be justified. Many advantages exist, but significant limitations are also evident. Nonetheless, the role of image guidance in routine and advanced paranasal sinus surgery is certain to grow. Discussion and debate of the issues regarding the use of image guidance are likely to grow with it.     

Indirect microlaryngostroboscopy

Use of the operating microscope for indirect microlaryngoscopy in routine office practice has been broadened by the development of a supplementary system which offers indirect microlaryngostroboscopy as a practical tool for routine laryngological practice. The supplementary system has been adapted to the Zeiss operating microscope equipped with a 300 mm objective. The original light source on the microscope is replaced by a stroboscopic bulb which flashes in synchrony with the output of an audible tone generator. The tone generator is used to guide the patient's vocalization during the examination, and, thereby, produces a stop-action image of the vocal cords. Its use in conjunction with clinical judgment by the examiner can aid in the diagnosis and treatment of various dysfunctions of the vocal cords.     

A new generation videokymography for routine clinical vocal fold examination

OBJECTIVE: This study aims to introduce a new-generation videokymographic system, which provides simultaneous laryngoscopic and kymographic image, for routine clinical vocal fold examination. STUDY DESIGN: The authors explored a new imaging method for diagnosis and evaluation of voice disorders. METHODS: The new-generation videokymographic system includes two charge-coupled device image sensors, a color area image sensor, and a monochromic high-speed line-scan image sensor. The high-speed line-scan image sensor is used to capture the kymogram, and the color area image sensor is used to obtain the laryngoscopic image. The two images can be displayed simultaneously on a video monitor or stored in a standard video recorder. Three subjects with nonpathologic voice were investigated in detail with the new videokymographic system. RESULTS: The high-quality laryngoscopic image and kymogram can be used directly for clinical purposes with no further postprocessing. The scan position of the kymogram is always indicated in the laryngoscopic image, which provides feedback for the operator to easily locate the expected scanning position. All varieties of vocal fold vibration, including irregular vibrations, phonation onset and offset, can be observed with the presented method. The continuous kymogram of the vocal fold vibration can be retrieved from a kymographic image sequence for quantitative analysis. CONCLUSIONS: The new-generation videokymography provides a simple, quick means to investigate vocal fold vibration, especially for voice disorders. It can emerge as an important tool for routine clinical vocal fold examination.     

Auditory image perception and analysis: the basis for hearing.

The premise of this paper is that the auditory system's primary function is its ability to determine the sources of sound. Auditory image perception and analysis are defined as the basis for sound source determination. Few studies in the literature have focused on understanding these abilities and the paper argues that more attention should be paid to auditory image perception and analysis. Four questions are posed for understanding auditory image formation and seven physical variables are described which might be used for auditory image perception. The paper relates auditory image perception and analysis to a number of other topics in the hearing sciences in order to reinforce the argument that auditory image perception and analysis are the basis of hearing.     

Colour texture analysis for quantitative laryngoscopy

OBJECTIVE: Whilst considerable progress has been made in enhancing the quality of indirect laryngoscopy and image processing, the evaluation of clinical findings is still based on the clinician's judgement. The aim of this paper was to examine the feasibility of an objective computer-based method for evaluating laryngeal disease. MATERIAL AND METHODS: Digitally recorded images obtained by 90 degree- and 70 degree-angled indirect rod laryngoscopy using standardized white balance values were made of 16 patients and 19 healthy subjects. The digital images were evaluated manually by the clinician based on a standardized questionnaire, and suspect lesions were marked and classified on the image. Following colour separation, normal vocal cord areas as well as suspect lesions were analyzed automatically using co-occurrence matrices, which compare colour differences between neighbouring pixels over a predefined distance. RESULTS: Whilst colour histograms did not provide sufficient information for distinguishing between healthy and diseased tissues, consideration of the blue content of neighbouring pixels enabled a correct classification in 81.4% of cases. If all colour channels (red, green and blue) were regarded simultaneously, the best classification correctness obtained was 77.1%. CONCLUSIONS: Although only a very basic classification differentiating between healthy and diseased tissue was attempted, the results showed progress compared to grey-scale histograms, which have been evaluated before. The results document a first step towards an objective, machine-based classification of laryngeal images, which could provide the basis for further development of an expert system for use in indirect laryngoscopy.     

High-resolution petrous bone imaging using multi-slice computerized tomography

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p < 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.     

诊治颈动脉体瘤4例体会

报告诊治4例颈动脉体瘤的体会。认为彩色Doppler超声（彩超）检查和颈动脉造影，尤其是数字减影血管造影（DSA）对诊断颈动脉体瘤具有较高的价值。本病的唯一治疗方法是手术；术前应行颈总动脉压迫锻炼，为手术创造条件；术式的选择主要根据术前彩超和DSA结果，以及术中所见肿瘤与颈动脉的关系而定。     

Optical quality of the nasendoscope with and without the endosheath

With the increasing use of the endosheath in clinical practice, we set out to investigate the quality of the nasendoscope image produced with and without an endosheath. It has been suggested by some users that the endosheath degrades the image. We used a spectrophotometer to assess the optical transmission of the endosheath and found no selective chromatic absorption. However, on requesting nine experienced users to document whether they could differentiate between the sheathed and unsheathed endoscope, a significantly correct answering pattern was obtained in repeated blinded experiments. This suggests that individuals can distinguish between the sheathed and unsheathed nasendoscope view and that the image is indeed altered when an endosheath is employed.     

Endoscope-assisted image-guided approach to the pituitary gland: preliminary cadaveric study

The microscopic transsphenoidal approach to the pituitary gland is the current standard technique used by neurosurgeons to operate the pituitary gland. The endoscopic transsphenoidal approach to the pituitary gland is a current trend because more neurosurgeons are becoming familiar with the use of endoscopes. The use of associated image-guided surgery (or surgical navigation technology; these names are equivalent and are used interchangeably) allows a precise approach that increases the safety and efficacy of a surgical procedure. The InstaTrack system (GE Medical Systems Navigation and Visualization, Inc., Lawrence, MA) is a frameless electromagnetic navigational system used in this study. The objectives of this preliminary and conceptual cadaveric study (three heads) are to get familiarized with the use of image guidance and the study of the endoscopic anatomy of this region and to investigate the technical requirements and benefits of possible future shifting from microscopic towards endoscopic image guidance.