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PubMed2000

Reproducibility of visual activation in functional MR imaging and effects of postprocessing.

BACKGROUND AND PURPOSE: Functional MR imaging studies of the brain should be interpreted in the context of their reproducibility. We assessed the reproducibility of visual activation measured by functional MR imaging and analyzed the effect of image transformation to standard space. METHODS: Seven healthy volunteers were studied twice with echo-planner functional MR imaging at 1.5 T during visual stimulation. The studies were separated by an interval of 2 to 7 days. Functional images were analyzed after spatial normalization to the space described by Talairach and Tournoux and/or after coregistration of the images of the second study with the images of the first study. The number of active voxels for each study was determined at three thresholds. In addition, the change in the center of the mass of activation, the mean change in signal intensity, and the mean t value within the activated area were measured. These reproducibility indexes were calculated for the spatially normalized and nonnormalized data for each subject. RESULTS: Variations in visual activation were observed between the two studies in the same individual as well as across subjects. There was no evidence of an effect from image transformation on reproducibility on any of the measures. CONCLUSION: Our findings show that the reproducibility of activation in functional MR imaging may be much more variable across subjects than suggested in previous studies. The use of different types of image transformation (coregistration, spatial normalization) does not significantly affect the reproducibility of visual activation.

Adult↗

PubMed1995

Quantitative immunohistochemistry using the CAS 200/486 image analysis system in invasive breast carcinoma: a reproducibility study.

We evaluated the intra- and inter-observer reproducibility of quantitative immunohistochemical (IHC) analyses using the Cell Analysis Systems (CAS) 200/486 image analyzer of Estrogen Receptor (ER), Progesterone Receptor (PR), proliferation-associated nuclear protein (Ki67), HER-2/neu (c-erbB-2) protein over-expression and cathepsin D (CD) in 20 randomly-selected invasive breast carcinomas. Qualitative analysis of IHC Epidermal Growth Factor Receptor (EGF-R) was also assessed in this study for comparative purposes. Duplicate blind assessments by the same observer showed excellent correlations for all quantitative IHC features (P < 0.001; P = 0.004 for neu). However, the immuno-quantitative analyses results between the 3 different operators showed lower correlation coefficient values, thus being less reproducible. This resulted in systematic differences and bias between the observers. This was also clear from the overall agreement between the 3 observers which was 70% for ER, 70% for PR, 56% for Ki67, 79% for c-erbB-2 and 75% for CD. The qualitative visual assessments of EGF-R, expressed as either positive or negative, showed a 75% agreement between observers and 85% intra-observer agreement (comparable to quantitative digital image processing results). The same results were obtained with kappa statistics. A further analysis of the factors causing the lack of reproducibility was performed. For quantitative IHC, segmentation of stored and retrieved digitized images was quite reproducible between and within well-trained observers. However, variation between different fields of vision of one and the same section showed large variations for most cases. Therefore, differences in sampling of fields within a section appeared to be the major cause of lack of reproducibility between observers, although segmentation differences still added slightly to the inter-observer variations. Accordingly, a strict sampling protocol of fields of vision is mandatory to obtain reproducible quantitative IHC results. It is clear from the present study that so-called random (but in fact, at convenience) selection of fields of vision for measurement is not a sufficient guarantee of adequacy of the sampling.

Breast Neoplasms↗

PubMed1994

Reproducibility of thallium-201 exercise SPECT studies.

UNLABELLED: A detailed analysis of intrapatient reproducibility of exercise SPECT thallium studies is presented. METHODS: Twenty patients in stable condition were re-examined with exercise-redistribution SPECT201 Tl within 3-9 days without intervening procedures. At peak stress, 3.5 mCi 201Tl were given intravenously 1 min prior to exercise termination. SPECT imaging started at 5 and 180 min. Acquisition and processing protocols were the same for all studies. Coronary angiography was performed on 19 patients and showed coronary artery disease (CAD) in 18, and no CAD in one; one patient did not have coronary arteriography. RESULTS: For 16 of 20 patients, exercise levels and ECG were comparable for both studies. Ten patients reproduced ST-segment depression; two reproduced angina; one had left bundle branch block (LBBB) on both studies after 1 min of exercise. The remaining seven patients had no ECG changes or symptoms during exercise. Four of 20 (20%) thallium scans differed: three in degree of redistribution and one (5%) in presence of a second stress defect. In three of four patients whose thallium studies showed some nonreproducibility, there were differences in exercise. Thallium results were identical in 15 of 16 patients whose ECG/exercise tests were reproducible (94%). Interobserver agreement was 95%. CONCLUSION: There was excellent reproducibility of 201Tl SPECT scintigraphy in patients who reproduced exercise test performance and symptoms.

Coronary Angiography↗

PubMed1997

Subjective breast cancer grading. Analyses of reproducibility after application of Bayesian belief networks.

OBJECTIVE: To examine the influence of Bayesian belief networks (BBNs) on the reproducibility of subjective breast cancer grading. STUDY DESIGN: Twenty samples were analyzed for intraobserver and 128 samples for interobserver reproducibility using the Bloom-Richardson and Helpap grading systems. The expression of diagnostic features was evaluated subjectively, and for each a decision it was determined to what extent it represented one of the different outcomes. Evidence was then entered, for each diagnostic feature, into four different BBNs, recently described for breast cancer grading, in the form of a relative likelihood ratio vector. RESULTS: With all cases considered, the use of decision support based on the Bloom-Richardson and Helpap grading systems did not improve intraobserver reproducibility. This was found to be 68% and 80% in subjective gradings, respectively, and 60% and 70% in the BBN-supported method. Interobserver reproducibility was not improved (58% and 70% in subjective gradings and 51-59% based on assessment with decision support). However, when only cases associated with high beliefs were considered, both intraobserver reproducibility (agreement rose from 68% to 93%) and interobserver reproducibility (agreement rose from 60% to 87%) of BBN-supported gradings exceeded the results of subjective assessments. CONCLUSION: The results showed that the observers did not reach the same diagnosis (or grade) and that their observational assessment of histologic features lacked agreement. Since BBNs reflected only the data entered, poor agreement existed in the contribution to the final diagnostic belief by the different features and, ultimately, in belief in the final decision.

Bayes Theorem↗

PubMed1997

Induced sputum to assess airway inflammation: a study of reproducibility.

BACKGROUND: Infiltration of the airways mucosa with activated inflammatory cells appears to be a major factor in the pathogenesis of asthma and other airway diseases. Examination of sputum provides a direct method to investigate airway inflammation non-invasively. OBJECTIVES: The aim of the present study was to evaluate the reproducibility of cell counts on cytospins and fluid phase (eosinophil cationic protein, ECP) measurements in a selected portion of induced sputum. We aimed to confirm the validity of the tecnique by comparing measurements between stable asthmatics, allergic rhinithis and healthy subjects. METHODS: Sputum was induced with hypertonic saline (4.5%) twice within one week in 53 stable asthmatics, 16 subjects with seasonal rhinitis (out of the pollen season), and 19 healthy subjects. Reproducibility was examined within sample (two different plugs of the same sample) between sample (two specimens of induced sputum obtained within one week) and between examiners on stable subjects taking into account sample size, number of examinations per patients and Confidence Interval (CI) of the estimates. RESULTS: We have found that the method is highly reproducible within sample and between examiners for all types of cells and fluid phase measurements of ECP. It is reproducible between sample for eosinophils, macrophages, neutrophils and ECP, but not for lymphocytes and weakly for epithelial cells. Sputum from asthmatics, in comparison with the sputum of healthy subjects and subjects with rhinitis had higher eosinophils (asthmatics: 12.2% +/- 12.9, rhinitis: 0.4 +/- 0.8, normals: 0.4 +/- 0.7 (%) and ECP (asthmatics: 827 +/- 491 microg/L, rhinitis: 127 +/- 82 normals: 157 +/- 203). No significant differences were found between healthy subjects and subjects with rhinitis. Eosinophil counts were inversely correlated with FEV1 (r = -0.37) expressed as percentage of predicted, but not significantly correlated with PC20 methacholine (r = -0.28) or blood eosinophils (r = 0.26). CONCLUSIONS: The importance of this study is the confirmation, within important statistical guidelines for a study of reproducibility, that the methods examined are reproducible and valid.

Adult↗

PubMed1998

[Reproducibility and wave analysis of multifocal electroretinography].

We studied the reproducibility of multifocal electroretinography by repeated measurements in normal subjects. We also analyzed the amplitude and implicit time of the waves. Nine healthy eyes including myopic cases (-4.1 D on average) of 9 normal males, aged 19 to 42 years, were the objects of study. We used a (Visual Evoked Response Imaging System III (VERIS III), by TOMEY Corp.) for multifocal electroretinography. Each eye was examined 4 times on different days. The stimulus elements consisted of 103 hexagons. The net recording time was 4 minutes. We used the coefficient of variation (standard deviation/average) of 4 measurements of response density as index of reproducibility. Poor fixation and blinking were important factors that affected the reproducibility. In all the 9 eyes, reproducibility of multifocal electroretinography, expressed as average of the coefficient of variation of all regions, was 22% on average. In 6 eyes with good fixation and without blinking, the reproducibility was 15% on average. In 6 eyes with good reproducibility, we analyzed three parameters of the focal response waves: all traces, quadrants and rings, as well as the amplitude and latency of the waves. These data served as controls. Our studies showed that the response density correlated closely with the amplitude and not with the latency in normal subjects.

Adult↗

PubMed1988

Day to day reproducibility of Doppler sonographic measurements in patients with valvular aortic stenosis.

High reproducibility of Doppler gradient measurements is necessary for both the reliable noninvasive assessment of the severity of aortic stenosis and for repeated follow-up examinations in individual patients. We therefore studied day to day reproducibility of Doppler sonographically measured peak pressure drops in 46 patients with valvular aortic stenosis. Clinically stable patients were examined twice within 29 +/- 18.2 days by the same examiner. Peak pressure drop (PPD) and peak flow velocity differed between the two examinations by 8.6 +/- 7.0 (range 0-29) mmHg and by 0.25 +/- 0.18 (range 0-0.7) m/s, respectively. Reproducibility was comparable in patients with excellent, good, and moderate quality examinations, but was lower in the 6 patients with poor quality examination. Variability of PPD, but not of peak flow velocity was higher (p less than 0.05) in patients with severe (PPD greater than 60 mmHg) stenosis. Reproducibility was comparable in patients with or without concomitant aortic incompetence and in patients with normal or reduced left ventricular function. Similar reproducibility was obtained in patients with heart rate changes below or above 10 beats/min between the two examinations. It is concluded that good reproducibility of Doppler measurements in patients with aortic stenosis allows reliable noninvasive assessment of the severity of the stenosis. In follow-up studies of patients with mild to moderate aortic stenosis increases in peak flow velocity in excess of 15% (mean day to day variability +2 SD) are highly indicative of the true progress of the stenosis.

Aged↗

PubMed1984

Reproducibility of aerobic and anaerobic thresholds in 20-50 year old men.

The reproducibility of the aerobic (AerT) and the anaerobic (AnT) threshold was studied in 33 men aged 20-50 years. They completed two maximal exercise tests on a bicycle ergometer. The thresholds, as VO2 (1 X min-1), were determined visually by two investigators using both the blood lactate and the respiratory indices. The respiratory variables were measured with a computerized breath-by-breath method; samples of venous blood were drawn every 2nd min and analysed enzymatically for lactate. The reproducibility of the AerT (r = 0.94) and of the AnT (r = 0.96) were equally good. The AnT can be determined either from blood lactate concentrations (AnTLa) or from ventilatory and gas exchange response (AnTr) during a 2-min incremental exercise test. They both also showed similar reproducibility: r = 0.93 for the AnTLa and r = 0.95 for the AnTr. The work rate and the measured physiological variables at the AerT and AnT, except for the blood lactacte concentration, were very reproducible. Age did not affect the reproducibility of the thresholds. The poor reproducibility of blood lactate concentration of the AnT confirmed our previous opinion that the fixed blood lactate levels of 2 and 4 mmol X 1(-1) are poor indicators of AerT and AnT.

Adult↗

PubMed1991

Short- and long-term reproducibility of cardiovascular tests of autonomic function in normal subjects.

Ten healthy normal subjects participated in a follow-up study in which the reproducibility of noninvasive cardiovascular autonomic function testing was studied. The tests used were the Valsalva manoeuvre, deep and quiet breathing, standing upright and isometric handgrip exercise. These tests were performed six times within a 2-year period. The reproducibility of these autonomic function tests within a day was evaluated in a separate study involving nine healthy subjects. In this study the tests were performed three times between 08.00 and 15.00. The results indicate that indices based on R-R interval ratios during testing were highly reproducible; that the indices remain reproducible over a 2-year follow up period and that reproducibility within a day was similar to that within longer time periods. The reproducibility of pressor responses to isometric exercise was poor. It is concluded that indices based on R-R ratios are suitable for use in follow up studies of autonomic function.

Adult↗

PubMed2003

Reproducibility of the blood flow index as noninvasive, bedside estimation of cerebral blood flow.

OBJECTIVE: To investigate the feasibility and reproducibility of the blood flow index (BFI) method for measuring cerebral blood flow. DESIGN AND SETTING: Prospective functional study in pediatric intensive care. PATIENTS AND PARTICIPANTS: 14 consecutive patients with median age of 2 months (range 1 days-11 years) requiring artificial ventilation, invasive arterial blood pressure monitoring, and central venous access. INTERVENTIONS: The first passage of an intravenous indocyanine green (ICG) bolus through the cerebral vasculature was monitored by noninvasive near-infrared spectroscopy. BFI was calculated by dividing maximal ICG absorption change by rise time. Reproducibility was evaluated by six ICG injections at 5-min intervals. RESULTS: Of all ICG injections 6% were canceled, and 4% were eliminated due to injection failures. Median BFI of 17 reproducibility determinations was 71 (range 12-213) and median coefficient of variation (CV) of BFI was 10% (4.9-18.5). The quantity of ICG bolus did not affect the CV (0.1 vs. 0.3 mg ICG/kg). Eight reproducibility tests in patients after cardiac surgery had smaller CV than the others, and the eight in newborns had higher CV than in older children. Patient parameters such as arterial blood pressure, endtidal CO(2), and percutaneous oxygen saturation were stable and showed CV below 2% during reproducibility determination. CONCLUSIONS: The BFI method allows rapid and repeated measurements of CBF with good feasibility and reproducibility. As a relative but not absolute measure of CBF, BFI seems to be suited for clinical evaluation of intraindividual CBF changes during determination of cerebrovascular reactivities or during therapeutic interventions.

Blood Circulation Time↗

PubMed1985

Comparison of the performance and reproducibility of various serological methods and diagnostic kits for the detection of rubella antibodies.

For rubella antibody detection performance and reproducibility of standard laboratory methods and newer assay systems have been evaluated. IgM antibody detection in sucrose density gradient ultracentrifugation (SDG) was compared with two commercial ELISAs and the non-commercial anti-my-hemadsorption immunosorbent technique. The two ELISAs proved to be more sensitive than the SDG even if done with a long incubation hemagglutination inhibition test (HAI) to increase sensitivity. Additional tests showed that the sensitivity of the SDG could be increased by using ELISA instead of HAI. The reproducibility of all tests was good. In 205 assays the ELISA enzygnost IgM showed a coefficient of variation (CV) with its reference serum of 6.3% for titers, while the CV for absorbance was 37.8%. With ELISA rubazyme M the same reference serum gave a CV of 13.7% in 149 subsequent assays. In 12 and 13 assays in the anti-my-hemadsorption immunosorbent technique the CV varied with the height of the reference serum used between 4.7 and 18.7%. Antibody detection using HAI was compared with IgG antibody detection using two commercial ELISAs and a commercial single radial hemolysis test (SRH). In 592 assays with a low positive control serum the HAI gave a CV of 6.0%. With the ELISA enzygnost a CV of 7.7% for the titers was obtained in 72 assays, but for absorbances the CV was 39.4%. The CV for the kit internal low positive control in 148 assays with the ELISA rubazyme was 26.8%. As with HAI the reproducibility of the SRH was good. The same control serum used in the HAI gave a CV of 6.2% in 418 subsequent assays. Because of the good reproducibility and sensitivity the SDG can now be replaced by newer techniques which are less expensive and time consuming. Interference with rheumatoid factor was only observed in the ELISA enzygnost if sera were not pretreated with latex adsorbents. The reproducibility of our HAI was comparable to that of the SRH while the results obtained with the two commercial ELISAs were less reproducible. Until it is known, that antibodies detected with the newer techniques are able to prevent re-infection, it would be unwise to reject the HAI completely for the determination of immunity status.

Antibodies, Viral↗

PubMed1989

Influence of infarct age on reproducibility of ventricular tachycardia induction in a canine model.

The inducibility and reproducibility of ventricular tachycardia were evaluated in 97 dogs after myocardial infarction produced by single stage coronary artery ligation. Arrhythmia induction was performed with use of an endocardial electrode catheter positioned at the right ventricular apex before each study. An aggressive protocol of programmed stimulation was used, employing up to seven extrastimuli and three attempts at arrhythmia induction in each study. Electrophysiologic study was performed in individual dogs at the following times after infarction: 1) 7.7 +/- 0.3 and 15 +/- 0.2 days (34 consecutive dogs); 2) 14 +/- 0.6 and 26 +/- 1.7 days (24 selected dogs); 19 +/- 2 and 43 +/- 3 days (12 selected dogs); 4) 36 +/- 2 and 60 +/- 6 days (8 selected dogs); and 5) 59 +/- 12 and 130 +/- 10 days (3 selected dogs). Inducibility of ventricular tachycardia decreased significantly from 74% 1 week after infarction to 41% 2 weeks after infarction. Thus, early reproducibility was low (48%). Reproducibility increased thereafter, with 88% of the dogs having reproducible ventricular tachycardia between 2 and 4 weeks (p less than 0.025) and 100% having reproducibly inducible ventricular tachycardia between 4 weeks and 4 months after infarction. Dogs with no inducible arrhythmia early after infarction did not develop inducible ventricular tachycardia or fibrillation at later studies. Twelve dogs developed spontaneous ventricular tachycardia or sudden arrhythmic death late after infarction. Overall, 22% of dogs with inducible ventricular tachycardia with a cycle length greater than 140 ms developed spontaneous ventricular tachycardia or sudden death. Arrhythmia induction decreases significantly during the 1st 2 weeks after myocardial infarction, but long-term reproducibility of ventricular tachycardia induced greater than or equal to 2 weeks after infarction is very high. This canine model of long-term, reliably inducible ventricular tachycardia is suitable for investigation of antiarrhythmic drugs, surgery and other interventions.

Animals↗

PubMed1986

Reproducibility of hyperventilation of cold dry air in children with cystic fibrosis.

Wheezing is a significant problem in some patients with cystic fibrosis. Currently available tests are not reliable at determining whether this wheezing is due to co-existent asthma or to the underlying pulmonary disease. The reproducibility of hyperventilation of cold dry air (HVCDA) was studied over eight days in 11 children with cystic fibrosis. A group with mild lung disease were selected to minimize the variability due to underlying pulmonary disease. Fifty-six per cent of subjects had consistent responses to HVCDA. A test of reproducibility was performed on the respiratory heat exchange, the percentage fall in FEV1 after HVCDA and the ratio of these two (R). Respiratory heat exchange was found to be highly reproducible with a reproducibility co-efficient of 0.97. The percentage fall in FEV1 after HVCDA and R were not reproducible over the eight-day period. Hyperventilation of cold dry air did not give reproducible results in children with cystic fibrosis, suggesting that a single test may not be suitable for judging bronchial liability.

Adolescent↗

PubMed2001

Improving the reproducibility of QT dispersion measures.

BACKGROUND: The low reproducibility of the QT dispersion (QTD) method is a major reason why it is not used in clinics. The purpose of this study was to develop QT dispersion parameters with better reproducibility and identification of patients with a high risk of ventricular arrhythmia or death. METHODS AND RESULTS: Three institutions using different methods for measuring QT intervals provided QT databases, which included more than 3500 twelve-lead surface ECGs. The data represented low and high risk subjects from the following groups: the normal population EpiSet (survivors vs dead from cardiovascular causes), acute myocardial infarction patients AmiSet (survivors vs dead) and remote myocardial infarction patients ArrSet (with vs without a history of ventricular arrhythmia). The EpiSet, AmiSet, and the ArrSet contributed with N = 122, 0, and 110 ECGs for reproducibility analysis, and 3244, 446, and 100 ECGs for the analysis of prognostic accuracy. The prognostic accuracy was measured as the area under the Receiver Operator Curve. The QT intervals were divided into six QT pairs; the longest pair consisted of the longest and the shortest QT intervals etc. The QT dispersion trend (QTDT) was defined as the slope of the linear regression of the N longest QT pairs after estimation of missing QT intervals by interpolation of measured QT intervals. The QTMAD and the QTSTD methods were defined as twice the mean absolute deviation and the standard deviation of the N longest QT pairs. The reproducibility was improved by 27% and 19% in the EpiSet and the ArrSet relative to the reproducibility of QTD. The accuracy improved for the EpiSet and the ArrSet and was maintained for the AmiSet. CONCLUSIONS: By using the three longest and the three shortest QT intervals in QTDT, QTMAD, or QTSTD, the reproducibility improved significantly while maintaining or improving the prognostic accuracy compared to QTD.

Aged↗

PubMed2002

Permeation and skin absorption: reproducibility of various industrial reconstructed human skin models.

Human reconstructed skin models could be very useful tools to quantify percutaneous permeation and absorption. Before using such models, the reproducibility in the same batch and/or various batches, i.e. the relevance of the results obtained, must be verified. The reproducibility of 3 industrial models--EpiDerm, Episkin and SkinEthic--was tested regarding the permeation and skin absorption of 3 topically applied compounds (with a large range of physicochemical properties): lauric acid, caffeine and mannitol. For all the models, the intrabatch reproducibility was greater than the interbatch reproducibility. According to the batches tested, the larger difference in terms of reproducibility between the 3 models was observed in the case of mannitol, a very poor permeant. In this case, the best reproducibility was observed with EpiDerm and Episkin. Moreover, the rank order of the 3 compounds applied, in terms of permeation and skin absorption, was the same as that expected from ex vivo human skin. Such results revealed human skin models as a promising means to test in vitro permeation and percutaneous absorption of topical products.

Drug Evaluation, Preclinical↗

PubMed1981

Comparative reproducibility and validity of systems for assessing cardiovascular functional class: advantages of a new specific activity scale.

Reproducibility and validity are prerequisites for a useful clinical scale. We therefore prospectively tested the reproducibility and validity of the New York Heart Association criteria and the Canadian Cardiovascular Society criteria for the assessment of cardiac functional class and compared these criteria with a new Specific Activity Scale based on the metabolic costs of specific activities. The New York Heart Association estimates made by two physicians had a reproducibility of only 56%, and only 51% of the estimates agreed with treadmill exercise performance. Functional estimates based on the Canadian Cardiovascular Society criteria were significantly more reproducible (73%), but not significantly more valid. The Specific Activity Scale was as reproducible as the Canadian Cardiovascular Society criteria, and its 68% validity was significantly higher than the validities of the other systems. The easily administered Specific Activity Scale was equally reproducible and valid when used by a nonphysician. It was especially better than the other systems for the evaluation of true class II patients and was significantly less likely to underestimate treadmill performance. Although no set of questions can perfectly predict exercise tolerance, the Specific Activity Scale deserves wider prospective testing.

Canada↗

PubMedDate not supplied

Reproducibility of the clinical criteria (ABCDE rule) and dermatoscopic features (7FFM) for the diagnosis of malignant melanoma.

Dermatoscopy improves the sensitivity and the specificity in the diagnosis of melanoma. Although the reproducibility of dermatoscopic features has been the subject of research, no study up to now has compared the reproducibility of dermatoscopic features to the reproducibility of the clinical criteria of the ABCDE rule. For this reason we decided to examine the reproducibility of the clinical ABCDE rule and of our diagnostic dermatoscopic method 7FFM, as well as of the individual criteria of both. A total of 73 dermatologists attended three dermatoscopic courses and examined a set of clinical and dermatoscopic slides of 50 pigmented skin tumors. Agreement % and K value for a kappa statistical analysis have been calculated to evaluate inter-rater reliability. The clinical and the dermatoscopic methods showed similar values of concordance: clinical score 2 mean agreement = 68%, mean K = 0.44; clinical score 3 mean agreement = 73%, mean K = 0.61; 7FFM mean agreement = 83%, mean K = 0.64. The clinical criteria A, B, and C and the dermatoscopic features of our method presented similar values of concordance as well: clinical criteria mean K range 0.35-0.25, dermatoscopic features mean K range 0.62-0.25. The dermatoscopic features of our method 7FFM show a good reproducibility after a short training program, similar to the reproducibility of the clinical criteria of the ABCDE rule for the diagnosis of melanoma.

Algorithms↗

PubMed2001

Reproducibility of retinal mapping using optical coherence tomography.

OBJECTIVE: To assess the reproducibility of retinal thickness measurement using commercially available mapping software of optical coherence tomography (OCT). METHODS: Six radial scans, 6 mm long and centered on the fixation point, were performed on 10 eyes of 10 healthy volunteers and 10 eyes of 10 diabetic patients with clinically significant macular edema. Retinal thickness was measured automatically using the mapping software of OCT in the 9 macular Early Treatment Diabetic Retinopathy Study areas and in a central area 500 microm in diameter. Measurement reproducibility was tested by means of 3 series of scans performed by 2 different observers on 2 different days. Results were assessed by their repeatability and intraclass correlation coefficients (ICCs). RESULTS: In healthy subjects, intraobserver, interobserver, and intervisit reproducibility of retinal thickness measurements were excellent, with a repeatability coefficient of less than 7 microm and ICCs of greater than 0.89. In diabetic patients, the repeatability coefficient was less than 21 microm in all areas of the macula except one, with an ICC of greater than 0.98. Relative variations in measurements were small in both healthy and diabetic subjects, with reproducibilities of +/- 5% and +/- 6%, respectively. CONCLUSION: Retinal mapping software of OCT allows reproducible measurement of retinal thickness in both healthy subjects and diabetic patients with macular edema.

Adult↗