A new approach to computer-aided spine surgery: fluoroscopy-based surgical navigation

A new computer-based navigation system for spinal surgery has been designed. This was achieved by combining intraoperative fluoroscopy-based imaging using conventional C-arm technology with freehand surgical navigation principles. Modules were developed to automate digital X-ray image registration. This is in contrast to existing computed tomography- (CT) based spinal navigation systems, which require a vertebra-based registration procedure. Cross-referencing of the image intensifier with the surgical object allows the real-time image-interactive navigation of surgical tools based on one single registered X-ray image, with no further image updates. Furthermore, the system allows the acquisition and real-time use of multiple registered images, which provides an advanced multi-directional control (pseudo 3D) during surgical action. Stereotactic instruments and graphical user interfaces for image-interactive transpedicular screw insertion have been developed. A detailed validation of the system was performed in the laboratory setting and throughout an early clinical trial including eight patients in two spine centers. Based on the resulting data, the new technique promises improved accuracy and safety in open and percutaneous spinal surgery.     

A new approach to computer-aided spine surgery: fluoroscopy-based surgical navigation

A new computer-based navigation system for spinal surgery has been designed. This was achieved by combining intraoperative fluoroscopy-based imaging using conventional C-arm technology with freehand surgical navigation principles. Modules were developed to automate digital X-ray image registration. This is in contrast to existing computed tomography- (CT) based spinal navigation systems, which require a vertebra-based registration procedure. Cross-referencing of the image intensifier with the surgical object allows the real-time image-interactive navigation of surgical tools based on one single registered X-ray image, with no further image updates. Furthermore, the system allows the acquisition and real-time use of multiple registered images, which provides an advanced multi-directional control (pseudo 3D) during surgical action. Stereotactic instruments and graphical user interfaces for image-interactive transpedicular screw insertion have been developed. A detailed validation of the system was performed in the laboratory setting and throughout an early clinical trial including eight patients in two spine centers. Based on the resulting data, the new technique promises improved accuracy and safety in open and percutaneous spinal surgery.     

Digital imaging in remote diagnosis of burns

Images are capable of giving an accurate representation of skin color and have been used extensively in teaching about and researching burn therapy. The advance from analogue to digital imaging allows the remote transmission of the clinical information contained in the digital image of a burn, using a suitable system. The large size of these image files reduces transmission speed and makes data compression desirable. Compression, by means of the JPEG algorithm, of up to 50 times the original size of 38 digital images of burns suffered by 22 consecutive patients did not lessen its great usefulness in determining the depth of burn injuries, according to a group of experts in burn care. The success rate was close to 90%, both for non-compressed images in original BMP format (mean size:1500 Kb) and for compressed images with a Q index of 50 (30 Kb files), when compared with the clinical diagnoses confirmed one week after the accident.     

Real Photographic Prints from Digital Images

BACKGROUND: Digital photography is emerging as a standard method of documenting preoperative, intraoperative, and postoperative results in the clinical setting. While hard copies of these electronic images can be quickly and easily generated on color laser or inkjet printers, there are times when it is necessary to generate a true photographic print of an image, either for insurance documentation or to meet the publication requirements of a peer-reviewed journal. Standard inkjet and laser printers are unable to generate true photographic prints. OBJECTIVE: To identify a rapid, cost-effective means of generating high-quality photographs of digital images. METHODS: We describe the use of on-line service bureaus with digital photographic printers to obtain high-quality photographic prints of patient images. RESULTS: From as little as 49 cents per print, a color or black-and-white print of a color image can be generated by an on-line service bureau to satisfy the need for a photographic quality hard copy. CONCLUSIONS: While color laser or inkjet printers allow physicians to generate their own hard copies of electronic patient images, photographic quality images are at times needed to satisfy requirements for insurance documentation or publication in peer-reviewed journals. Use of on-line service bureaus is the most cost-effective way that we have found to obtain high-quality photographic color or black-and-white prints from electronically stored patient images.     

A new method of skin erythrosis evaluation in digital images

In the clinical field, reproducible and comparable assessments of skin color are needed for objective evaluation of lesions and efficacy of treatments. In order to provide objective, quantitative color information in skin lesions, devices such as reflectance spectrophotometer and reflectance colorimeter have been successfully used during the past decade, though they are too expensive and technically complex to be handled in routine clinical situations. Reflectance skin color measurements require direct contact of the probe with the skin, and the compression significantly influences readings. Color measurements obtained from digitized images have been proposed as a simple and cost-effective way to evaluate skin color and promote efficacy of treatments. The disadvantage is its direct and close relation to the ambient light: even if an accurate control of subject illumination is provided, readings vary between different laboratories. We propose a standard system for computerized color image analysis of skin erythrosis modification after Intense Pulsed Light (IPL) treatments, making it possible to compare readings taken by different observers in different environmental light conditions. The goal of our study is the introduction of fixed color internal controls in digital imaging in order to calculate a normalization factor of measurements, resulting not in a method of absolute quantification of erythema or erythrosis but in a method that provides the possibility of translation and comparison of the red values between systems in different environmental conditions. Between December 2004 and May 2005 we evaluated 30 patients at the Department of Plastic and Reconstructive Surgery at the University "La Sapienza" of Rome. Three points of standard colored paper (Red Green Blue) were applied with a plastic pattern (standard intersection lines) and white point in non involved area for skin control. For every patient we took a series of pictures pre-treatment and after a standard cycle of 5/6 IPL. We evaluate the grade of reproducibility of our procedure with a careful analysis of pre-treatment digital images obtained in different environmental conditions. The statistic analysis of the standard deviation between the values of R obtained (using different light conditions), and the respective normalized valor (normalized to the referent image), did not show any significant statistical difference and allows us to achieve our goal: the reproducibility of the results.     

Effect of ambient light and bit depth of digital radiograph on observer performance in determination of endodontic file positioning.

OBJECTIVES: To examine the effects of the luminance and bit depth of digital image on observer performance for determination of endodontic file positioning. STUDY DESIGN: Using extracted premolar teeth, no. 08 K-file was placed into the canal and positioned so that the tip was either flush or 1 mm short of the radiologic root apex. The samples were imaged with both conventional and digital radiographs at 8 and 12 bits. Eleven observers read the images under dark and bright condition, and receiver operating characteristics analysis was performed. Additionally, the interpreting time was measured. RESULTS: The 12-bit images showed similar observer performance compared with conventional images, and better than the 8-bit images. The interpretation time for bright condition and 8-bit images was longer than for dark condition and 12-bit images. CONCLUSION: Twelve-bit digital images were preferred to 8-bit for accurate determination of endodontic file position.     

Image-guided endoscopic spine surgery: Part I. A feasibility study

STUDY DESIGN: A feasibility study was performed to determine the efficacy of computer assistance in endoscopic spine surgery. OBJECTIVES: To assess a new method for computer assistance based on image guidance during thoracoscopic or any endoscopic spine procedure. To evaluate the reproducibility, the sensitivity and the reliability of the technique first in vitro and second in clinical use. SUMMARY OF BACKGROUND DATA: The computer-based, image-guided surgery is now a routine tool used in open spine surgery. Exposure of the anatomy of the vertebra is needed for registration. This methodology is inapplicable in endoscopic approach. Fluoroscopic-based navigation combines the technology of image-guided surgery and C-arm fluoroscopy. The navigation is based on the fluoroscopic images acquired before surgery. This technology is applicable to endoscopic surgery but the navigation is based on fluoroscopic image. The computed tomography images are not exploited. There are no published data on a technique that allows image-guided surgery based on computed tomography and magnetic resonance imaging. METHOD: A laboratory study was performed on a thoracic human spine. One vertebra was marked on the right lateral side of the body with five titanium marks. A percutaneous reference frame was specifically designed to be placed in the pedicle of the same marked vertebrae. The reference frame acted as a 3D localizer and a registration tool. The spine model was scanned including the reference frame. A standard Stealth station treatment guidance platform (Medtronic, Sofamor Danek, Memphis, TN) was used for simulation. The registration was obtained using the reference frame. Twenty navigation procedure trials were done and the error was recorded based on the distance between the anatomical point and the corresponding virtual one. RESULTS: Registration was always possible using the stealth station and a standard spine navigational software (spine 3, Medtronic Sofamor Danek, Memphis, TN). The mean error after registration given by the computer was 0.96 mm. The mean error recorded during the navigation simulation was 1.6 mm. CONCLUSIONS: This technique allows the possibility of computed tomography and magnetic resonance imaging-based, image-guided endoscopic surgery. It is probable that in the near future, as image fusion technology improves, the fluoronavigation based on fluoroscopic images would enable to navigate on multimodal images. Otherwise the technique described in this article is the only reproducible one that allows computed-tomography-based computer assistance during endoscopic procedures.     

数字化骨科临床研究平台的构建及应用

目的 构建一组能在个人电脑(PC)上高速运行的三维可视化数字骨科临床研究平台系统.方法 2007年1月至2009年6月,收集三组资料,包括:自多层螺旋CT机图像工作站导出的300余例涉及骨创伤、关节、脊柱、骨肿瘤患者的薄层原始数据(DICOM格式);部分应用较为广泛的内置入物器械原型;20名健康志愿者(男10名,女10名;年龄21～30岁,平均24.5岁)的全身多层螺旋CT机扫描后的薄层原始数据.应用计算机及信息通讯领域的前沿技术,通过改进算法、改进人机交互方式、软硬件性能优化及相关逆向工程技术,创建一组能容纳海量数据及便于临床医牛广泛参与的数字化骨科临床研究平台软件包.结果 通过整合交叉学科前沿技术及大量的创新性工作,创建多功能数字化骨科临床研究平台,并将其命名为Superlmage系统.Superlmage系统能在目前丰流配置的PC上高速运行,自由编辑,兼容Windows XP/Vista、Unix及Linux等操作系统,数据读取支持主流品牌CT机导出的DICOM3.0标准数据,并实现了高精度的三维霞建成像;伪彩渲染的多平面重组成像;高速、便捷的三维图像交互式分割及编辑.SuperImage系统还附带一组信息丰富的数字化资料库,包括三维数字化骨骼、数字化内置人物虚拟模型器械库及患者数字化信息资料库,且支持数字化远程动态信息交互.结论 数字化骨科临床研究平台可满足临床医生的日常工作及科研需求,如精准的术前设计、术后随访、高败的数字化资料管理、远程信息交互、仿真的数字化虚拟教学及部分数字骨科解剖学研究等.     

Characterization of port wine stain skin erythema and melanin content using cross-polarized diffuse reflectance imaging

BACKGROUND AND OBJECTIVES: Objective methods to assess quantitatively port wine stain (PWS) blanching in response to laser therapy are needed to improve laser therapeutic outcome. Previous studies have attempted to assess objectively PWS color based on point measurement devices. To date, these approaches have typically been limited by a number of factors such as small test area and need for contact. To address these issues, a cross-polarized diffuse reflectance imaging system and color image analysis method has been developed to evaluate quantitatively erythema and melanin content in PWS skin. STUDY DESIGN/MATERIALS AND METHODS: A cross-polarized diffuse reflectance system has been constructed to acquire high resolution digital images while minimizing artifacts such as glare, shadowing, and nonuniform illumination effects that can compromise image fidelity. Furthermore, an image analysis algorithm has also been developed to analyze normal and PWS skin in terms of CIEL*a*b* color space parameters. Using the algorithm, images of color space intensity, L*, and saturation, a*, indices have been calculated to extract quantitative metrics of melanin and erythema, respectively. RESULTS: Compared to the cross-polarized diffuse reflectance image, the a* index image enhanced the contrast in regions of high and low erythema and seems to have quasi correlation with the L* index image. In the presented PWS patient example, the relative a* index difference (Deltaa*) image showed less erythema in PWS skin after laser treatment when compared to pre-treatment values. CONCLUSIONS: Our cross-polarized imaging system and color image analysis method is a simple, noncontact technique that can indirectly provide quantitative measurement of erythema and melanin content in PWS skin.     

Ein neues Konzept der Integration von Bilddatenbanken in eine umfassende Patientendokumentation

Image processing and archiving are of increasing importance in the practice of modern medicine. Particularly due to the introduction of computer-based investigation methods, physicians are dealing with a wide variety of analogue and digital picture archives. On the other hand, clinical information is stored in various text-based information systems without integration of image components. The link between such traditional medical databases and picture archives is a prerequisite for efficient data management as well as for continuous quality control and medical education. At the Department of Orthopedic Surgery, University of Berne, a software program was developed to create a complete multimedia electronic patient record. The client-server system contains all patients' data, questionnaire-based quality control, and a digital picture archive. Different interfaces guarantee the integration into the hospital's data network. This article describes our experiences in the development and introduction of a comprehensive image archiving system at a large orthopedic center.     

Thirty-five millimeter versus digital photography: comparison of photographic quality and clinical evaluation

The objective of this article is to assess the quality of digital images versus standard 35-mm photodocumentation and to undertake a comparative assessment of 35-mm and digital photography in a clinical setting in facial plastic surgery. For evaluation of image quality, 10 subjects had images captured via a conventional 35-mm single lens reflex (SLR) camera and a digital camera under identical lighting conditions. The digital images were transferred to computer hard drive and processed for production of slides. Direct side-by-side comparison of projected images was performed by the authors. The standard photographic slides were of slightly finer detail and crispness than the computer-generated images. In a clinical setting, the quality of both the 35-mm and digital photographs enables complete preoperative evaluation and assessment of postsurgical outcome.     

International transmission of uncompressed endoscopic surgery images via superfast broadband Internet connections

Background Although telecommunication is increasing in popularity, poor-quality images sent through a narrowband network limit its use in the medical field. Methods Kyushu University Hospital in Japan and four hospitals in Korea were linked via superfast broadband Internet connection. The digital video transfer system, which can transmit digital videos without loss of image quality, was used, and the bandwidth was 30 Mbps per line. Results Of the 16 teleconferences conducted, 6 demonstrated real-time endoscopic surgery. In addition to the surgical images, preoperative diagnostic images, images of the operating room, and images of the staff in the conference room were transmitted to facilitate discussion. The network remained stable, and the sound delay was restricted to less than 0.3 s. In the other 10 teleconferences, recorded video images were used for discussion. Conclusions The authors have established a high-quality, practical teleconference system that is economical and easy to use in clinical practice. This system shows promise for remote education beyond geographic borders.     

Towards scarless surgery: an endoscopic ultrasound navigation system for transgastric access procedures.

OBJECTIVE: Scarless surgery is an innovative and promising technique that may herald a new era in surgical procedures. We have created a navigation system, named IRGUS, for endoscopic and transgastric access interventions and have validated it in in vivo pilot studies. Our hypothesis is that endoscopic ultrasound procedures will be performed more easily and efficiently if the operator is provided with approximately registered 3D and 2D processed CT images in real time that correspond to the probe position and ultrasound image. MATERIALS AND METHODS: The system provides augmented visual feedback and additional contextual information to assist the operator. It establishes correspondence between the real-time endoscopic ultrasound image and a preoperative CT volume registered using electromagnetic tracking of the endoscopic ultrasound probe position. Based on this positional information, the CT volume is reformatted in approximately the same coordinate frame as the ultrasound image and displayed to the operator. RESULTS: The system reduces the mental burden of probe navigation and enhances the operator's ability to interpret the ultrasound image. Using an initial rigid body registration, we measured the mis-registration error between the ultrasound image and the reformatted CT plane to be less than 5 mm, which is sufficient to enable the performance of novice users of endoscopic systems to approach that of expert users. CONCLUSIONS: Our analysis shows that real-time display of data using rigid registration is sufficiently accurate to assist surgeons in performing endoscopic abdominal procedures. By using preoperative data to provide context and support for image interpretation and real-time imaging for targeting, it appears probable that both preoperative and intraoperative data may be used to improve operator performance.     

Influence of spatial resolution and bit depth on detection of small caries lesions with digital receptors.

OBJECTIVE: The aim of this study was to compare the caries diagnostic accuracy among intraoral digital receptor systems that provide images in more than one resolution and bit depth. STUDY DESIGN: Eighty noncavitated extracted human teeth were radiographed and analyzed by the following digital systems: Digora Optime (Soredex) 8-bit high- and 8-bit super-resolution, VistaScan (Dürr) 8-bit high- and 8-bit max-resolution and 16-bit high- and 16-bit max-resolution, Dixi2 (Planmeca) 8-bit and 12-bit depths. Insight Film was included as a reference. Six observers scored caries lesions in each tooth surface. The teeth were sectioned and microscopy served as validation. Two-way analysis of variance tested differences in sensitivity, specificity, positive and negative predictive values, and overall accuracy (true positives + true negatives) between the modalities. RESULTS: There were 160 approximal surfaces examined, and histology showed 63% sound, 31% enamel, and 6% dentinal lesions. Sensitivity was not significantly different within each brand except for VistaScan 8-bit max-resolution, which showed higher sensitivity than the 2 VistaScan high-resolution modalities (P = .003). Digora super-resolution showed higher sensitivity than almost all the other modalities (P < .02), but had lower specificity than all other systems, among which there were no differences. Overall accuracy was significantly lower for Digora high-resolution than for Dixi2 and VistaScan max-resolution modalities (P < .03); there were no differences among the other modalities. CONCLUSION: Caries diagnostic accuracy seems to be little influenced by an increase in spatial resolution and bit depth from 8-bit to 12- or 16-bit within digital radiographic system brands. Between systems, the Digora super-resolution images provided higher sensitivity, but lower specificity than most of the other receptors.     

Techno Pearls for Digital Image Management

BACKGROUND: The past decade has provided a paradigm shift in image management. Technological advances have enabled affordable, high-quality digital clinical photography. In addition, this technology has enabled doctors to easily compose and present multimedia lectures with programs such as Microsoft PowerPoint. Since most practitioners already possess large numbers of conventional slides and photographs, digitization is required to convert these to a usable format. Depending on the type of image and resolution, it can take anywhere from 30 seconds to several minutes to scan each slide. This drawback delays or prevents many practitioners from switching to digital technology. OBJECTIVE: Using a digital camera and the XP version of Windows, some common tasks associated with digital images and PowerPoint presentations may be simplified and facilitated. METHODS: Using common digital cameras and computer image editing software, slides, photographs, radiographs, and textbook images may be digitized in seconds with adequate quality for most common clinical and educational applications. In addition, the use of new dual monitor functionality is discussed. This new technology comes standard with Windows XP and allows the use of two monitors simultaneously, allowing the user to view thumbnail images on one monitor and the PowerPoint presentation on the other monitor. Images may be dragged and dropped into the presentation, thereby avoiding repetitive menu commands. RESULTS: The author shows several techniques and shortcuts to assist the clinical practitioner in digitizing slides and facilitating the management of these images in PowerPoint presentations. CONCLUSION: A digital camera can be used to adequately digitize most slide pictures, and these images can be managed in a more simple and direct manner utilizing the Windows XP operating system that is shipping with most new computers.     

A trial of digitization and digital analysis of analog clinical images of bladder cancer

Owing to the recent developments in computed radiography and the picture archiving and communication system, all clinical images of bladder cancer can now be digitized, and recording, archiving, transportation and analysis of these images is becoming popular. We analyzed various kinds of analog images of bladder cancer after they were digitized via a simple image analyzer. The image analyzers we utilized were very useful for us to understand and become familiar with digitization of analog images of bladder cancer as well as digital analysis.     

A simple way to take pictures during endoscopic procedures

PURPOSE: We describe a new method of taking pictures from endoscopic images using a digital photo camera coupled to the endoscopic lens without an adapter. MATERIALS AND METHODS: We used a digital camera with 3.3 megapixel resolution and 6 x optical zoom. The camera was coupled to the endoscopic lens with no special adapter. The image was accompanied through the LCD (liquid crystal display) visor, and the picture was taken with the flash button on and with no macro resource. The image was then enlarged by optical and digital zoom before being easily stored in photo files at the personal computer. RESULTS: The quality of the photos obtained by this method was at least similar to that of traditional photos, and the data were promptly stored. CONCLUSIONS: We describe a simple method of taking pictures from endoscopic images with the additional advantage of a facility to edit and store the photographs.     

Initial clinical experience with video-cystoscope

The endoscopic image processing system which has a very small change coupled device (CCD) at the distal tip of an endoscope, can give us a quite different imaging information from the conventional optical endoscopes, of which the main functions were just to "see inside the human body". The advantage of this endoscopic image processing system has been well recognized but, since the scope diameter could not be made smaller due to the size limitations of the CCD chip itself, the system has not been utilized in the field of Urology. In cooperation with Olympus Optical Co., we have studied a system called Urological Video Information System (UVIS) in order to utilize the image processing system for Urology. In our system a special light source with RGB light output is utilized together with a conventional optical cystoscope and a video converter is connected to the eyepiece of the scope in order to observe endoscopic images on the monitor. Endoscopic images can be stored in an image filing system when necessary. The image quality of UVIS is inferior to that of the conventional cystoscopes at the moment and there are several other technical problems to solve but, as witnessed in the field of Gastroenterology, it is expected that this kind of electronic system will become much more important in the future. This report covers the current problems and some considerations of them as an initial study.     

肩关节镜临床登记系统的构建与应用研究

目的通过网络数据库技术及图像后处理技术，借助智能手机应用及医院互联网内、外网界面，初步建立肩关节镜临床登记系统。 方法运用院内数字化建设及互联网大数据技术构建肩关节镜围术期宣教、核心临床信息登记、术后随访、影像信息收集、科研数据统计分析及功能量表等复合评估体系。 结果临床登记系统获得了接受肩关节镜手术患者的人口学信息、围术期临床核心数据、影像学相关信息及各类功能评分量表信息等，建立了科室微网模块服务及网页式联合手机应用界面信息推送服务。 结论肩关节镜临床登记系统初步实现临床管理及科研系统和登记系统间的信息交互，建立了本院特色鲜明的"互联网"肩关节镜临床登记系统及随访公众号，实现临床资料的精细化管理。     

Automated documentation and analysis of burn size

The digital recording and processing of information on burn size provides a useful adjunct to the care of patients with burn injuries in the critical care setting. Record keeping is improved and accuracy is enhanced using a simple, portable system based on the widely available IBM Personal Computer. Diagramming burns on a graphic outline of a human body with color coding of burn depth produces a visual representation of the burned patient. Computations of areas of burn are automatically produced from the graphic images.