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At least 415 records · Page 23Linked to original sources

Stereo nonmydriatic digital-video color retinal imaging compared with Early Treatment Diabetic Retinopathy Study seven standard field 35-mm stereo color photos for determining level of diabetic retinopathy.

OBJECTIVE: To evaluate the ability to determine clinical levels of diabetic retinopathy, timing of next appropriate retinal evaluation, and necessity of referral to ophthalmology specialists using stereoscopic nonmydriatic digital-video color retinal images as compared with Early Treatment Diabetic Retinopathy Study (ETDRS) seven standard field 35-mm stereoscopic color fundus photographs. DESIGN: Prospective, clinic-based, comparative instrument validation study. PARTICIPANTS: Fifty-four patients (108 eyes) with type 1 or type 2 diabetes mellitus selected after chart review from a single center to include the full spectrum of diabetic retinopathy. METHODS: Nonsimultaneous 45 degrees -field stereoscopic digital-video color images (JVN images) were obtained from three fields with the Joslin Vision Network (JVN) system before pupil dilation. Following pupil dilation, ETDRS seven standard field 35-mm stereoscopic color 30 degrees fundus photographs (ETDRS photos) were obtained. Joslin Vision Network images and ETDRS photos were graded on a lesion-by-lesion basis by two independent, masked readers to assess ETDRS clinical level of diabetic retinopathy. An independent ophthalmology retina specialist adjudicated interreader disagreements in a masked fashion. MAIN OUTCOME MEASURES: Determination of ETDRS clinical level of diabetic retinopathy, timing of next ophthalmic evaluation of diabetic retinopathy, and need for prompt referral to ophthalmology specialist. RESULTS: There was substantial agreement (kappa = 0.65) between the clinical level of diabetic retinopathy assessed from the undilated JVN images and the dilated ETDRS photos. Agreement was excellent (kappa = 0.87) for suggested referral to ophthalmology specialists for eye examinations. Comparison of individual lesions between the JVN images and the ETDRS photos and for interreader comparisons were comparable to the prior ETDRS study. CONCLUSIONS: Undilated digital-video images using the JVN system were comparable photographs for the determination of diabetic retinopathy level. The results validate the agreement between nonmydriatic JVN images and dilated ETDRS photographs and suggest that this digital technique may be an effective telemedicine tool for remotely determining the level of diabetic retinopathy, suggesting timing of next retinal evaluation and identifying the need for prompt referral to ophthalmology specialists. Thus, the JVN system would be an appropriate tool for facilitating increased access of diabetic patients into recommended eye evaluations, but should not be construed as a paradigm that would replace the need for comprehensive eye examinations.

Adult↗

Gallbladder carcinoma: a video image analysis of AgNOR distribution and its relation to tumour stage and grade.

The amount and distribution of interphase argyrophilic nucleolar organizer regions (AgNORs) was studied in 51 gallbladder surgical specimens including 32 primary carcinomas, 10 adenomas and 9 cases of chronic cholecystitis with calculi. The mean nuclear AgNOR area (NORA) and the AgNOR distribution score (NORDS), i.e. the percentage of cells carrying nucleolar aggregates with more than 6 distinct silver dots, were evaluated in 200 epithelial nuclei per specimen by means of automated image analysis and direct counting respectively. Statistical analysis (variance analysis and Student-Neuman-Keuls' test) performed on the pooled mean AgNOR values showed a significant difference (p < 0.001) between carcinomas and non-carcinomatous lesions. Both NORA and NORDS highly discriminated carcinomas with histopathological grade 4 versus cases with grade 1, 2 or 3 (p < 0.001); a less statistically significative p value (< 0.05) was encountered when NORDS values of well differentiated grade 1 carcinomas and adenomas were compared. The NORA parameter permitted the discrimination of stage IV versus stage I carcinomas (p < 0.001), while carcinomas in stage IV and those in stage II were distinguished with a p < 0.05; the NORDS parameter allowed also to distinguish stage IV from both stage I or II tumours (p < 0.001). Our results indicate that the above-mentioned AgNOR parameters may be utilized as additional, more objective quantitative criteria in the clinical-pathological assessment of the outcome of gallbladder carcinomas.

Adenoma↗

Correlation of histology, cytogenetics and proliferation fraction (Ki-67 and PCNA) quantitated by image analysis in meningiomas.

Sixty meningiomas were classified histologically according to the WHO criteria and analyzed cytogenetically. The Ki-67 and PCNA proliferation fractions (PRFs) were assessed by immunhistochemistry. The staining results were quantified by TV-image analysis (Miamed, Leica, Germany). Within meningiomas of WHO-grade II/III and those with complete or partial deletion of # 1p, we found a significantly higher mean and maximal Ki-67 PRFs than in those of WHO-grade I and those with all other karyotypes. This was not the case for PCNA PRFs. No differences in PRFs were detectable between histological subtypes. Although these results were obtained after measurement of five high power fields (HPFs) only, the heterogeneity of PRF distribution within the tumors was high. Even after the measurement of 100 HPFs, the 95% confidence intervals were in a range of 18% to 34.3% PRF. This finding seems to be responsible for the moderate interobserver reproducibility of image analytical determination of PRF (r = 0.74). Nevertheless, there was a good correlation between subjective and objective image analytical assessment of PRF (r = 0.83). The significance of the maximum Ki-67 PRF per specimen implies the possibility of selecting those areas which show the highest fraction of positively stained nuclei for measurement, avoiding the problem of intraslide heterogeneity. Thus the time needed for image analytical quantification may be reduced.

Biomarkers, Tumor↗

Immunohistochemical expression of p53 protein, mitotic index and nuclear morphometry in primary malignant melanoma of the skin.

The immunohistochemical expression of the p53 tumor suppressor protein and the nuclear morphometric parameters were studied in 80 primary skin melanomas. The mitotic index was counted in 64 tumors. In 95% of the tumors p53 positive nuclei were detected, but in only 31% of the cases was the proportion of positive nuclei 3% or higher. The mitotic indices and the mean nuclear areas were not significantly different in melanomas with different p53 expression levels. The p53 positive nuclei had a larger mean nuclear area than the p53 negative nuclei. p53 expression did not increase with melanoma thickness. In Cox's stepwise proportional hazards model, the ratio of mean nuclear long and short axis and melanoma thickness had independent prognostic value, while the level of p53 expression, the mitotic index, and the mean nuclear area were not significantly associated with survival. We conclude that the nuclei expressing p53 protein are larger than p53 negative nuclei. The level of immunohistochemical expression of p53 is low in primary skin melanoma, and it is not valuable as a general prognostic marker for this tumor. p53 expression is not associated with melanoma thickness, indicating that high p53 expression is not a late phenomenon in the progression of this tumor.

Adolescent↗

Computer-aided melanoma diagnosis.

This article presents a snapshot of fast-moving research into the application of digital imaging technology to in vivo computer-aided diagnosis of early melanoma. It is written from the perspective of a researcher with a keen interest in bringing this technology to physicians' offices. The primary emphasis is on reviewing the existing literature, supplemented by unpublished material relating to a particular system and as yet unpublished research studies.

Biopsy, Needle↗

Can we safely diagnose pigmented lesions from stored video images? A diagnostic comparison between clinical examination and stored video images of pigmented lesions removed for histology.

Rapid expansion of communication technology has permitted the clinician to perform a consultation with a patient located at a different site. Assuming adequate diagnostic accuracy, it could theoretically be possible to use telemedical techniques as a triage tool. Images of pigmented lesions sent by the primary care physician could be viewed by the consultant dermatologist, and those with banal lesions spared from attending clinic. Previous studies assessing diagnostic accuracy of images of lesions have used 'face-to-face' diagnoses as the 'gold standard'. We set out to compare diagnostic accuracy of image examination compared with that of clinical examination, using histological examination as the diagnostic benchmark. We found that pigmented lesions may be diagnosed as accurately by stored video image evaluation as by conventional clinical examination. None of the malignant skin tumours was misdiagnosed as benign in either group. Whilst these results are encouraging in terms of the clinical safety of store-and-forward imaging, the inability to examine the whole patient or to palpate the lesions may limit the acceptability of the technique severely. Further evaluation of the cost : benefit ratio of such a system to the health care provider must be undertaken before considering this technique as a potential adjunct to managing outpatient referrals.

Adolescent↗

Pathology residents' use of a Web-based tutorial to improve Gleason grading of prostate carcinoma on needle biopsies.

Little is known about pathology residents' ability to Gleason grade or their ability to learn surgical pathology using Internet-based technology. A free Web-based program (available at www.pathology. jhu.edu/prostate) was developed that consisted of 20 pretutorial images for grading, 24 tutorial images, and the same 20 posttutorial images for Gleason grading. The grading images were selected from cases that had a consensus Gleason grade from 10 uropathology experts. In 2.5 months, 255 residents visited the website, and 151 (59%) completed it. Of those who completed the website, their year in training was known in 85 (56%): 1st year, 25.8%; 2nd year, 20%; 3rd year, 22.3%; 4th year, 14.1%; 5th year, 15.3%; and 6th year, 2.4%. Eighty percent learned Gleason grading in residency versus being self-taught, and 66% were male. In a multivariate analysis, higher pretutorial scores were associated with both their year in training (P = .001) and their hospital size (P = .003). Improvements in grading posttutorial were not related to the residents' year in training. Overall, the website significantly improved grading in 11 of 20 images and had no effect in 9 of 20 images. Improvements were noted in 1 of 1 Gleason score 4; 2 of 7 Gleason score 5 to 6; 2 of 6 Gleason score 7; and 6 of 6 Gleason score above 7 tumors. In summary, a Web-based tutorial improved Gleason grading accuracy by pathology residents to an equal extent regardless of their year in training. It is more difficult to teach residents to grade Gleason scores 5 to 7 tumors, and additional training should be concentrated in this area.

Biopsy, Needle↗

Telecytology: intraobserver and interobserver reproducibility in the diagnosis of cervical-vaginal smears.

Telecytologic diagnosis of cervical-vaginal smears is potentially useful because it could allow more efficient use of cytopathologist resources and expertise. A pathologist in one location could, in principle, review cytotechnologists' findings using a video display hundreds or thousands of miles away. Currently, bandwidth restrictions limit practical implementation of such a system to review of fields that had been selected for review by the cytotechnologist. The purpose of our investigation was to evaluate how well this type of review correlates with a review in which the entire slide is available for examination by the pathologist. We prospectively selected 100 consecutive cervical-vaginal smears over an 11-day period in August 1999. For each smear, 4 to 12 fields containing abnormal cells from each slide were digitally imaged. Each of 3 pathologists reviewed all digitized images and all glass slides. Diagnoses based on selected digitized images were compared with those based on conventional pathologist review. The kappa statistic, a measure of chance-corrected agreement (reproducibility), was calculated in each setting. Overall, intraobserver and interobserver reproducibility of cervical-vaginal smear diagnoses is fair to excellent. The use of remote digital images for pathologist review did not introduce large (2-step) diagnostic disagreements. The disagreement between a pathologist's glass slide and digital diagnoses is less than that for different pathologists reviewing glass slides, although interobserver differences were even greater in the interpretation of digital images.

Cytodiagnosis↗

The virtual mole clinic: preliminary results from the Plymouth skin cancer screening study using telemedicine.

This study evaluated a skin cancer screening service between primary and secondary care in Plymouth using a store and forward telemedicine system. The primary objective was to minimize the time from a patient presenting to a GP with a suspicious lesion to the lesion being assessed and diagnosed by a plastic surgeon. This study retrospectively assessed the practical, technical and operational aspects of incorporating telemedicine into everyday practice and patient satisfaction. Both the GP practice and plastic surgeons were equipped with the appropriate technology for creating, transmitting and accessing an electronic telemedicine record (ETR) via an ISDN 2 line. Patients with suspicious lesions accessed the GP via Mole Check Clinics. The GP captured and transmitted an ETR consisting of digital images and relevant clinical data. In a virtual mole clinic, the plastic surgeon accessed and reviewed the ETR. The expert opinion was entered directly into the ETR and transmitted to the GP within 48 hours. All patients were offered a face-to-face consultation at a real mole clinic within 7 days. Outcomes demonstrated patient and clinician satisfaction and the ability to deliver high quality diagnostic images and resulting expert opinion. This study informed a larger study for future applications of telemedicine.

Humans↗

Diffusion of telemedicine: a knowledge barrier perspective.

Telemedicine, broadly defined as the use of information technology (IT) to deliver medical services over distances, is one proposed solution to problems of accessibility, quality, and costs of medical care. Although telemedicine applications have proliferated in recent years, their diffusion has remained low in terms of the volume of consultations. In this study, we extend Attewell's theory of knowledge barriers to explain why diffusion of telemedicine remains low. A longitudinal, embedded multiple case study of telemedicine programs in three medical centers in Boston, Massachusetts, reveals that, in addition to technical knowledge barriers, as suggested by Attewell, there are economic, organizational, and behavioral knowledge barriers that inhibit the diffusion of telemedicine. The lowering of these barriers entails intensive learning efforts by champions of applications within adopter organizations. They need to develop technically feasible, medically valid, reimbursable, and institutionally supported applications in order to justify the value of telemedicine and engender consistent and frequent use by physicians.

Boston↗

Teleoncology in the Department of Defense: a tale of two systems.

Two telemedicine networks were developed for the purpose of conducting multidisciplinary oncology ("teleoncology") conferences. The infrastructure of each system differed: one system was Internet-based; the other was delivered via Integrated Services Digital Network (ISDN) lines. The purpose of this study was to describe the infrastructure and cost, consultative process, technical aspects, and conference format of the two teleoncology programs. The two systems' technical aspects, participant satisfaction with the systems, and conference participation were compared qualitatively. Assessment of the technical aspects of the systems suggested that each had distinct advantages. Survey results indicated that provider satisfaction with the technical and logistical aspects of each type of teleoncology conference was high. The present study may prove helpful for individuals who are considering implementing their own teleoncology programs.

Government Agencies↗

Experience-related differences in diagnosis from medical images displayed on monitors.

OBJECTIVE: To compare diagnostic accuracy using conventional versus monitor-displayed medical images in order to determine if years of experience as a board-certified clinician influences diagnostic performance in either modality. MATERIALS AND METHODS: In separate observer performance studies, six radiologists and six pathologists differing in years of experience viewed clinical images, once in the conventional modality (X-ray film or light microscopy) and once using a monitor display. Readers also were surveyed regarding their experience with digital/video display systems. RESULTS: In both studies, performance was similar for conventional and monitor modalities. For the conventional displays, there was a positive correlation between years of clinical experience and performance. For the monitor displays, however, there was a strong negative correlation between years of clinical experience and performance. Performance using the monitor displays correlated highly with experience using digital/video systems in general. CONCLUSION: More exposure to and use of monitor displays, such as recreational video games and computers, may influence positively the clinician-monitor display system interaction and improve diagnostic performance.

Data Display↗

Accuracy of interpretation of microscopic images of cytologic, hematologic, and histologic specimens using a low-resolution desktop video conferencing system.

OBJECTIVE: To determine the accuracy of interpretation of microscopic images for pathologic study transmitted over Switched-56 lines using a desktop interactive video conferencing system. MATERIALS AND METHODS: In subjective studies, two systems were connected using null-modem cables, which allowed evaluation of different bandwidths from 56 kbps to 384 kbps. Objective studies were done with two systems connected at distant sites via paired Switched-56 lines that produced an effective bandwidth of 112 kbps. A video camera mounted on a microscope was attached to the sending system. The resolution of the video image on the video conferencing system was 352 x 288 lines. Cases for cytology, hematology, and histopathology studies were selected from archives; one pathologist transmitted microscopic images, and a second pathologist made interpretations. The three pathologists were Board certified with similar experience that ranged from 20 to 35 years. Categories of interpretations or observations were predetermined for each study to allow the data on agreement between the direct microscopic interpretation or observation and that recorded by the receiving pathologist to be corrected for agreement attributable to chance alone. The results were analyzed using the kappa statistic. RESULTS: In the subjective studies, image degradation prevented interpretation while the microscope stage was moved. This problem occurred at all bandwidths tested. Image quality limited microscopic details. Organisms < 1 micron in diameter could not be seen reliably. In objective cytologic studies, overall agreement was recorded on 89 of 99 observations. In the four categories of specimens, observed agreement ranged from 0.778 to 0.958, and kappa was 0.704 to 0.948. For hematology specimens, overall agreement was found on 69 of 80 observations; observed agreement on eight types of nucleated blood cells ranged from 0.5 to 1.0, and kappa was 0.429 to 1.0. Poorer color definition and image quality prevented accurate identification of lymphoblasts and eosinophils in particular. For histologic specimens, overall agreement was obtained on 56 of 66 observations, observed agreement on four categories of histologic change ranged from 0.73 to 0.93, and kappa was 0.47 to 0.9. CONCLUSIONS: The desktop interactive video conferencing system, as configured in this study, was unsuitable for making definitive diagnoses from transmitted microscopic images.

Cell Biology↗

Dermatopathology via a still-image telemedicine system: diagnostic concordance with direct microscopy.

OBJECTIVE: To determine the concordance of dermatopathology diagnosis by still-image telemedicine technology and direct microscopy. MATERIALS AND METHODS: Skin specimens (N = 79) were examined by a dermatopathologist using a still-image phone system, and the diagnoses were compared with those made by the same dermatopathologist 1 year earlier by direct microscopy. The telemedical diagnoses were reached first without, and then with, patient histories. RESULTS: When the patient history was available, identical diagnoses were made in 66 of the 79 cases (84% concordance rate). Without patient history, the concordance rate was 80%. The diagnostic concordance rate for the diagnosis of benign nevocytic nevi, inflammatory diseases, and benign and malignant non-squamous cell carcinoma neoplasms was statistically significantly greater than the concordance rate for the diagnosis of squamous cell carcinoma and squamous cell carcinoma in situ (P = 0.005). CONCLUSIONS: The diagnostic concordance rate achieved by teledermatopathology using a still-image phone system fell short of the 99% intraobserver diagnostic concordance rate using direct microscopy.

Humans↗