A prospective, controlled trial of eight-bit, 16-bit, and 24-bit digital color images in electronic endoscopy

A new method for objective identification and measurement of airway lumen in paediatric flexible videobronchoscopy

BACKGROUND

Accurate measurements of airway and lesion dimensions are important to the developmental progress of paediatric bronchoscopy. The malacia disorders are an important cause of respiratory morbidity in children, but no methods are currently available to measure these lesions or the airway lumen accurately. A new measurement technique is described here.

METHODS

The magnification power of a paediatric videobronchoscope was defined and a simple and user friendly computer based program (Image J) was used to develop an objective technique (colour histogram mode technique, CHMT) for measurement of the airway lumen.

RESULTS

In vivo intra-observer and inter-observer repeatability coefficients for repeated area measurements from 28 images using the Bland-Altman method were 0.9 mm2 and 1.6 mm2, respectively. The average intraclass correlation coefficient for repeated measurements of area was 0.93. In vitro validation measurements using a 2 mm diameter tube resolved radii measurements to within 0.1 mm (coefficient of variability 8%). An "acceptable result" was defined in 92% of 734 images completed with the CHMT alone and 8% with its modification. The success rate for two of three images being within 10% of each other's area was 100%. Measurements of cricoid cross sectional areas from 116 patients compared with expected airway areas for age derived from endotracheal tube sizes were comparable.

CONCLUSIONS

The CHMT method of identifying and measuring airway dimensions is objective, accurate, and versatile and, as such, is important to the future development of flexible videobronchoscopy.

Endoscopic data acquisition and storage

Recent developments in the field of digital image acquisition and storage provide new opportunities for recording endoscopic procedures for use in the medical record and remote access for education and consultation. This article reviews the recent literature in the field of endoscopy.

Fully endoscopic vascular decompression of the glossopharyngeal nerve

Microvascular decompression of the glossopharyngeal nerve is an effective treatment of patients with glossopharyngeal neuralgia in whom compression of the nerve by a blood vessel is implicated in the pathogenesis of the disease. The standard surgical technique uses a binocular operating microscope for intra-operative visualization. Growing experience with posterior fossa endoscopy, however, has suggested that endoscopes may provide more comprehensive anatomical views of cerebellopontine angle. This report describes the case of a patient suffering from glossopharyngeal neuralgia who underwent fully endoscopic vascular decompression of the glossopharyngeal nerve. During this procedure the endoscope was used to survey the posterior fossa, guide the placement of insulating sponges, and conduct a final assessment of the intervention. We found the endoscope ideally suited to the constricted operating space of the posterior fossa, allowing for accurate localization and careful separation of the pathological vascular conflict with minimal brain retraction and no damage to surrounding structures. The versatility of endoscopy allows for superior visual appreciation of neurovascular conflicts in the posterior fossa. To date, endoscopy has primarily been used to supplement microscopy in cranial nerve decompression surgery. This report demonstrates how the endoscope can be used as the sole imaging modality in glossopharyngeal nerve decompression, with excellent results.

Detection of retinal lesions after telemedicine transmission of digital images

PURPOSE/BACKGROUND

To assess whether loss of image resolution or colour and subsequent telemedicine transmission of digital images affects the accuracy of retinal lesion detection by ophthalmologists when compared with the original transparencies.

METHODS

Fifteen ophthalmologists of different experience independently scored 11 retinal images for pathological signs. The images were presented as either transparencies or colour and monochrome digital images, which had been transmitted via telephone lines to a geographically remote location. One patient's eye was also imaged using scanning laser ophthalmosocopy (SLO) which produced a dynamic black and white digital image. ANOVA analysis was performed.

RESULTS

Total scores were higher for transparencies than colour (p = 0.0003) or black and white digital images (p = 0.00006). Expert observers (n = 5) considered separately showed no significant difference of accuracy between transparencies and either colour digital (p = 0.09) or monochrome digital images (p = 0.11). Experts were better than trainees at detecting pathology from less familiar images: total score (p = 0.02), colour digital (p = 0.03), monochrome digital (p = 0.02) and SLO images (p = 0.004).

CONCLUSION

Experienced observers can identify sight-threatening retinal pathology from poorer-resolution digital images that have been transmitted by telemedicine. They can also adapt to viewing less familiar images such as black and white digital or SLO images.

The virtual anatomy practical: a stereoscopic 3D interactive multimedia computer examination program

Continuing advances in computer visualization and interface technologies have enabled development of "virtual reality" programs that allow users to perceive and to interact with objects in artificial three-dimensional environments. Such technologies were used to create an image database and program for administering a practical examination in human gross anatomy. Stereoscopic image pairs of prepared laboratory dissections were digitized from multiple views of the thorax, abdomen, pelvic region, and upper and lower extremities. For each view, the stereo pairs were interlaced into a single, field-sequential stereoscopic picture using an image processing program. The resulting color-corrected, interlaced image files were organized in a database stored on a large-capacity hard disk. Selected views were provided with structural identification pointers and letters (A and B). For each view, appropriate two-part examination questions were spoken by a human narrator, digitally recorded, and saved as universal audio format files on the archival hard disk. Images and digital narration were organized in an interactive multimedia program created with a high-level multimedia authoring system. At run-time, 24-bit color 3D images were displayed on a large-screen computer monitor and observed through liquid crystal shutter goggles. A 90-second interval timer and tone were provided to give student users a time limit for each question comparable to that of a conventional practical examination. Users could control the program and select regional "subexams" using a mouse and cursor to point-and-click on screen-level control words ("buttons").

Effect of the diameter of the endoscope and of surgeon training on the duration and quality of laparoscopic surgery in a rabbit model

STUDY OBJECTIVE

To evaluate the effect of diameter of the endoscope on the duration and quality of laparoscopic surgery.

DESIGN

Prospective, randomized trial (Canadian Task Force classification I).

SETTING

Centre for Surgical Technologies.

SUBJECTS

Sixty adult, female, New Zealand, white rabbits.

INTERVENTION

Two series of laparoscopic nephrectomies, one each performed by an experienced and an inexperienced surgeon comparing 10-, 5-, 4-, and 2-mm endoscopes.

MEASUREMENTS AND MAIN RESULTS

Besides duration of surgery and occurrence of bleeding, the quality of dissection was scored by adding scores of dissection of renal vessels, ureters, and kidneys. During consecutive nephrectomies, the duration of surgery (p = 0. 001) and occurrence of bleeding (p = 0.02) decreased, whereas the quality of dissection increased (p = 0.002), demonstrating the learning curve, mainly for the less experienced surgeon. Duration of surgery (p = 0.04) decreased and quality of dissection increased (p = 0.05) when the larger endoscope was used. This was the case only for the less experienced surgeon, whereas for the experienced surgeon it had only a slight effect on learning curve.

CONCLUSION

These results confirm a learning curve of nephrectomy consisting of some 20 animals. In addition, the endoscope diameter and thus quality of image affect both duration and quality of surgery, especially for less experienced surgeons.