Telepathology and pathology at distance: an overview. (1/91)

Telepathology is probably the latest addition to the world of pathology. The costs of pathologic tests have increased, the requirements for shortened turnaround time are omnipresent and we are all aware of the current litigious environment. Telepathology is one of the answers to at least some of these requests. Here we review the current status of telepathology in the world of telemedicine; compare differences, similarities and applications of static and dynamic telepathology; and give a short introduction to the basic setup of a telepathology laboratory.  (+info)

Multiresolution browsing of pathology images using wavelets. (2/91)

Digitized pathology images typically have very high resolution, making it difficult to display in their entirety on the computer screen and inefficient to transmit over the network for educational purposes. Progressive zooming of pathology images is desirable despite the availability of inexpensive networking bandwidth. An efficient progressive image resolution refining system for on-line distribution of pathology image using wavelets has been developed and is discussed in this paper. The system is practical for real-world applications, pre-processing and coding each 24-bit image of size 2400 x 3600 within 40 seconds on a Pentium II PC. The transmission process is in real-time. Besides its exceptional speed, the algorithm has high flexibility. The server encodes the original pathology images without loss. Based on the image request from a client, the server dynamically generates and sends out the part of the image at the requested scale and quality requirement. The algorithm is expandable for medical image databases such as PACS.  (+info)

Image sampling in static telepathology for frozen section diagnosis. (3/91)

BACKGROUND: A frozen section diagnostic service is often not directly available in small rural or mountain hospitals. In these cases, it could be possible to provide frozen section diagnosis through telepathology systems. Telepathology is based on two main methods: static and dynamic. The former is less expensive, but involves the crucial problem of image sampling. AIMS: To characterise the differences in image sampling for static telepathology when undertaken by pathologists with different experience. METHODS: As a test field, a previously studied telepathology method based on multimedia email was adopted. Using this method, three pathologists with different levels of experience sampled images from 155 routine frozen sections and sent them to a distant pathology institute, where diagnoses were made on digital images. After the telepathology diagnoses, the glass slides of both the frozen sections and the definitive sections were sent to the remote pathologists for review. RESULTS: Four of 155 transmissions were considered inadequate by the remote pathologist. In the remaining 151 cases, the telepathology diagnosis agreed with the gold standard in 146 (96.7%). There was no significant divergence between the three pathologists in their sampling of the images. Each case comprised five images on average, acquired in four minutes. The overall time for transmission was about 19 minutes. CONCLUSIONS: The results suggest that in routine frozen section diagnosis an inexperienced pathologist can sample images sufficiently well to permit remote diagnosis. However, as expected, the internet is too unreliable for such a time dependent task. An improvement in the system would involve integrated real time features, so that there could be interaction between the two pathologists.  (+info)

Methods and limits of digital image compression of retinal images for telemedicine. (4/91)

PURPOSE: To investigate image compression of digital retinal images and the effect of various levels of compression on the quality of the images. METHODS: JPEG (Joint Photographic Experts Group) and Wavelet image compression techniques were applied in five different levels to 11 eyes with subtle retinal abnormalities and to 4 normal eyes. Image quality was assessed by four different methods: calculation of the root mean square (RMS) error between the original and compressed image, determining the level of arteriole branching, identification of retinal abnormalities by experienced observers, and a subjective assessment of overall image quality. To verify the techniques used and findings, a second set of retinal images was assessed by calculation of RMS error and overall image quality. RESULTS: Plots and tabulations of the data as a function of the final image size showed that when the original image size of 1.5 MB was reduced to 29 KB using JPEG compression, there was no serious degradation in quality. The smallest Wavelet compressed images in this study (15 KB) were generally still of acceptable quality. CONCLUSIONS: For situations where digital image transmission time and costs should be minimized, Wavelet image compression to 15 KB is recommended, although there is a slight cost of computational time. Where computational time should be minimized, and to remain compatible with other imaging systems, the use of JPEG compression to 29 KB is an excellent alternative.  (+info)

Intra-hospital use of a telepathology system. (5/91)

Utilization of telepathology systems to cover distant geographical areas has increased recently. However, the potential usefulness of similar systems for closer distances does not seem to be widely appreciated. In this study, we present data on the use of a simple telepathology system connecting the pathology department and the intra-operative consultation room within the operating theaters of the hospital. Ninety-eight frozen section cases from a past period have been re-evaluated using a real-time setup. Forty-eight of the cases have been re-evaluated in the customary fashion; allowing both ends to communicate and cooperate freely. Fifty of the cases, however, were evaluated by the consultant while the operating room end behaved like a robot; moving the stage of the microscope, changing and focusing the objectives. The deferral rate was lower than the original frozen section evaluations. Overall, the sensitivity was 100%, specificity 98%, negative predictive value 96, 5% and positive predictive value 100%. No significant difference was found for the diagnostic performances between the cooperative and robotic simulation methods.Our results strengthen the belief that telepathology is a valuable tool in offering pathology services to remote areas. The far side of a hospital building can also be a remote area and a low cost system can be helpful for intraoperative consultations. Educational value of such a system is also commendable.  (+info)

The optimum time to employ telephotoscreening to detect retinopathy of prematurity. (6/91)

PURPOSE: Labor-intensive screening of infants in the neonatal intensive care units is the only way to detect retinopathy of prematurity (ROP). Our purpose is to determine if RetCam 120 photos, acquired by a neonatal nurse, can be used to screen for ROP by performing 2 screening examinations, at 32 to 34 weeks (exam 1) and at 38 to 40 weeks (exam 2) post-conceptional age. METHODS: RetCam examinations are performed by a nurse on infants at exam 1 and exam 2 intervals. At the same time, an examination is performed by an experienced ophthalmologist. Masked readers evaluate the photos for ROP and determine if each eye will progress to prethreshold or threshold disease. The data are compared to the clinical course of the eyes. RESULTS: Forty-six eyes were photographed at exam 1 and 50 eyes at exam 2 from July 1, 1999, to December 15, 1999. Sensitivity and specificity of detecting ROP were 76% and 100% for exam 2 and 46% and 100% for exam 1. Sensitivity and specificity of predicting prethreshold disease were 64% and 97% for exam 2 and 33% and 100% for exam 1. Sensitivity and specificity of predicting threshold were both 100% at exam 2 and 0% (one photo in category) and 95% at exam 1. CONCLUSION: A potential reason for low sensitivity is technical limitations of the Retcam, such as the difficulty in capturing peripheral retina in small eyes and the need for a better lid speculum.  (+info)

An experimental inter-expert telepathology network using static imaging. (7/91)

AIMS: To set up a network for remote consultation using static imaging telepathology via Internet connection between pathologists in different European countries, and to collect some numerical and subjective impressions on the usefulness of this form of telepathology. METHODS: A static image remote consultation network between 11 pathologists in nine European countries was set up; all pathologists were equipped with the same telepathology system. The pathologists formed three subject oriented subgroups concerned with prostate, melanoma, and soft tissue sarcoma pathology. Each pathologist sent and received a small number of cases, and data on each case were collected and analysed. The whole experiment was controlled through a World Wide Web site. RESULTS: A total of 56 case consultations on 34 different cases were exchanged. The average case document contained seven images, and contained 1.97 Mbytes of data. For cases in which data were recorded, average case preparation and remote consultation time was 55 minutes and 9.2 minutes, respectively. Transmission times averaged 3.9 minutes. In subjective impressions, reservations were expressed in several cases regarding the confidence that could be given to the diagnosis from the images presented. CONCLUSIONS: Remote consultation by telepathology via the Internet is now technically feasible and reasonably user friendly, but is only suitable as a method of disease diagnosis in some cases.  (+info)

Robotic telepathology for intraoperative remote diagnosis using a still-imaging-based system. (8/91)

The aim of the present study was to assess whether a telemicroscopy system based on static imaging could provide a remote intraoperative frozen section service. Three pathologists evaluated 70 consecutive frozen section cases (for a total of 210 diagnoses) using a static telemicroscopy system (STeMiSy) and light microscopy (LM). STeMiSy uses a robotic microscope, enabling full remote control by consultant pathologists in a near real-time manner. Clinically important concordance between STeMiSy and LM was 98.6% (95.2% overall concordance), indicating very good agreement. The rates of deferred diagnoses given by STeMiSy and LM were comparable (11.0% and 9.5%, respectively). Compared with the consensus diagnosis, the diagnostic accuracy of STeMiSy and LM was 95.2% and 96.2%. The mean viewing time per slide was 3.6 minutes, and the overall time to make a diagnosis by STeMiSy was 6.2 minutes, conforming to intraoperative practice requirements. Our study demonstrates that a static imaging active telepathology system is comparable to dynamic telepathology systems and can provide a routine frozen section service.  (+info)