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PubMed1988

Reproducibility of intra-abdominal pressure when lifting.

Reproducibility of intra-abdominal pressure (IAP) variation was investigated in fifteen young male subjects when lifting three loads, 49, 98 and 147 N, with three speeds of movement, slow, fast and spontaneous, and starting from four standing postures: trunk erect, trunk forward flexed at 30, 60, and 90 degrees of dorsolumbar inclination. Each lift was replicated five times successively and the whole protocol was replicated at one a week interval. The intra-individual variability in IAP response was assessed using the standard deviation of each series of ten lifts. Results showed that variability of peak IAP increased with the load and with the lifting speed. This effect of speed was especially observed for light loads and in forward bending postures. Trunk posture had in itself no significant effect on IAP reproducibility. However, when the variations in the moment acting at lumbar level were taken into account by considering the IAP to moment ratio, the reproducibility of the response was not affected by the load but only by the trunk posture. Reproducibility was lower in the erect posture than in the three flexed positions. It is suggested that this difference relates to the importance in each posture of the moment acting at the shoulder with respect to the total moment acting at lumbar level.

Abdomen↗

PubMed1986

Reproducibility of histamine inhalation in asthmatics.

The reproducibility of the changes in FEV, induced by inhalation of histamine, was studied in adult asthmatics. Histamine was inhaled from a Hudson nebulizer, delivering 0.3 ml/min, at tidal breathing through one minute. FEV was measured immediately before and two minutes after cessation of the inhalation. Identical concentrations of histamine were inhaled by the individual patient on every challenge. Reproducibility was studied on the same day, with one day inbetween the histamine challenges and with 12 weeks inbetween two challenges. When reproducibility during the same day was studied an average fall in FEV of 34% was found after the first inhalation and 34% decrease was found after the second challenge. When histamine challenge were done on two following days the fall in FEV was 25% on the first day and 28% on the second day. The average fall in FEV was 34% and 28% when reproducibility was studied with an interval of 12 weeks. No statistically significant difference was found between any of the compared challenges.

Adult↗

PubMed1987

Reproducibility and reliability of first pass radionuclide ventriculography with Au-195m. Validation of Au-195m radionuclide ventriculography.

Au-195m is a radio-isotope with an ultra-short half-life with which multiple sequential evaluations of ventricular function can be made. In order to evaluate the reliability and reproducibility of analyses of overall and regional ventricular function by radio-isotope ventriculography with Au-195m we studied 10 healthy volunteers and 12 patients with coronary artery disease. Each subject underwent 4 first-pass studies: 1 with Tc-99m and, 10 minutes later, 3 with Au-195m (2 basal studies separated by 3-5 minutes interval and, 10 minutes later, 1 after s.l. nitroglycerin administration). Regional wall motion was analyzed and ejection fraction and peak count rate were determined in each test. Our study showed that the ejection fraction obtained with Au-195m was reproducible (r = 0.98) and correlated well with the ejection fraction determined by using Tc-99m (r = 0.98). The values of the peak count rate obtained with Tc-99m were higher than those obtained with Au-195m. Due to the specially designed collimator and the technical characteristics of the gamma-camera we used, we were able to record sufficiently high count-rates to evaluate regional wall motion, and this analysis was also found to be reliable and reproducible. After s.l. nitroglycerin administration, normal volunteers showed a significant increase of ejection fraction in comparison with basal acquisitions (p less than 0.05), while a wide range of responses was observed in the group of patients with coronary artery disease. We conclude that radio-isotope ventriculography with Au-195m is reliable and reproducible and could be a valid method of monitoring rapid variations induced in overall and regional left ventricular function.

Adult↗

PubMed1980

Reproducibility of syphilis serology results.

In order to evaluate the stability and reproducibility of syphilis serology qualitative results, the results reported on replicate specimens in the College of American Pathologists Quality Evaluation Program during 1978 were examined. There is evidence of good stability of syphilis serology specimens and reproducibility of qualitative results separated in time by as much as nine months for specimens that are nonreactive or highly reactive. However, there is evidence of lack of such stability and reproducibility of weakly reactive specimens. There is no striking difference in these results for the RPR card or VDRL test. The FTA-ABS test is more stable over time. There is some indication that the lack of stability and reproducibility of weakly reactive specimens is primarily a function of the stability of the specimen, with laboratory performance playing a secondary role.

Pathology, Clinical↗

PubMed1996

The inter-observer reproducibility of Lasègue's sign in patients with low back pain in general practice.

BACKGROUND: The spectrum of low back pain patients in general practice differs significantly from that in an orthopaedic clinic. The most frequent specific cause of low back pain is nerve-root irritation or compression caused by intervertebral protrusion, and the diagnosis is still problematic. Testing for Lasègue's sign could be a useful way of detecting high-risk patients, but so far the reproducibility of the test has been measured only in hospital-based studies. AIM: To assess the inter-observer reproducibility of Lasègue's sign in general practice. METHOD: Fifteen General practitioners from Amsterdam and the surrounding areas tested all consecutive low back pain patients who visited them during a period of two years for Lasègue's sign. The test was repeated within two weeks in two samples: sample I consisted of 50 consecutive low back pain patients; sample II consisted of all patients who had pelvic tilt, scoliosis, or positive Lasègue's sign. RESULTS: In sample I, the observation was repeated in 49 patients. The Kappa coefficient was 0.33, and the proportions of positive and negative agreement were 33% and 96%, respectively. In sample II, the observation was repeated in 48 patients. The Kappa coefficient was 0.56, whereas the proportion of positive agreement was 67% and the proportion of negative agreement was 91%. CONCLUSIONS: The reproducibility of Lasègue's sign in routine general practice seems to be low, but may be similar to the reproducibility observed in hospital settings in selected patients who have a high chance of low back pain owing to a specific disease.

Adult↗

PubMed2000

Accuracy, concordance, and reproducibility of histologic diagnosis in cutaneous T-cell lymphoma: an EORTC Cutaneous Lymphoma Project Group Study. European Organization for Research and Treatment of Cancer.

OBJECTIVE: To assess the level of observer variability in the histologic identification of cutaneous T-cell lymphoma (CTCL) and its discrimination from diseases with similar histologic features. DESIGN: Cutaneous T-cell lymphoma specimens and randomly mixed controls were evaluated twice by 3 examiners. SETTINGS: The European Organization for Research and Treatment of Cancer (EORTC) Cutaneous Lymphoma Project Group. PATIENTS: The study was conducted with histologic specimens from 32 patients with mycosis fungoides (MF). In addition, 13 specimens of spongiotic, lichenoid, or psoriasiform simulators of MF were blindly and randomly mixed with the CTCL specimens as controls. MAIN OUTCOME MEASURES: To evaluate the accuracy and concordance among and individual reproducibility of raters of histologic diagnoses. RESULTS: Overall, the concordance among raters was fair to moderate (range, 0.283-0.562; weighted overall kappa, 0.412). Individual reproducibility of examiners ranged from moderate to almost perfect (range, 0.473-0.896; weighted overall kappa, 0.709) and was not significantly different for the definite lymphoma (range, 0.551-0.921; overall kappa, 0.802) and nonlymphoma (range, 0.368-0.950; overall kappa, 0.793) categories. Accuracy was similarly variable among raters: sensitivity ranged from 49.3% to 78.1% (overall kappa, 0.654), and specificity (control series) ranged from 46.2% to 69.2% (overall kappa, 0.595). Adding the diagnoses of probable lymphoma to those of definite lymphoma, sensitivity ranged between 73.5% and 84.9%. Although for each examiner there was a trend toward a lower sensitivity in the detection of early lesions compared with later lesions, the difference in sensitivity between the 2 groups was not statistically significant. CONCLUSIONS: The levels of concordance and reproducibility found in this investigation were similar to those obtained with comparable studies in the most varied fields of pathology, confirming that the identification of CTCL for our observers did not cause particular problems. Our findings also revealed that pitfalls in CTCL identification are not only limited to early lymphomatous lesions, as commonly postulated.

Biopsy↗

PubMed1995

Reproducibility and responsiveness of the VF-14. An index of functional impairment in patients with cataracts.

OBJECTIVES: To assess the test-retest reliability and responsiveness of the VF-14, which is an index of functional impairment in patient with cataracts. DESIGN: Observational longitudinal study. Patients were enrolled prior to undergoing their first cataract surgery between July 15 and December 15, 1991, and they were followed up for 1 year after surgery. SETTING: Patients were recruited from 72 ophthalmologists' practices in three US cities. PATIENTS: Five hundred fifty-two patients who had undergone a surgical procedure in only one eye by the 4-month postoperative follow-up (responsiveness analyses) and a subset of these (n = 426) who had not subsequently undergone surgery for the second eye by the 12-month postoperative follow-up (reproducibility analyses). MAIN OUTCOME MEASURES: Two health status measures (the VF-14 and the Sickness Impact Profile, two global measures of a patient's trouble and satisfaction with his or her vision, and best corrected visual acuity in each eye. RESULTS: The VF-14 is highly reproducible, with an intraclass correlation coefficient of .79 when patient-rated criteria are used to define stable patients. The intraclass correlation coefficient was lower (.57 to .71) when various measures of visual acuity were used to define stable patients. The VF-14 is also about three times more responsive to a change in vision than the Sickness Impact Profile, which is a generic health status measure (effect size of approximately 1.00 vs 0.30). Estimates of the responsiveness of the VF-14 and the Sickness Impact Profile were not associated with preoperative visual acuity in the operated on or better eye. Responsiveness of the VF-14, however, was higher in patients with greater self-rated trouble with vision preoperatively. CONCLUSIONS: The VF-14 was reproducible in stable patients during an 8-month period, and it was more responsive to clinically significant changes in vision than was a generic health status measure (ie, the Sickness Impact Profile).

Aged↗

PubMed1998

Is the short insulin tolerance test safe and reproducible?

The short insulin tolerance test (SITT) is described as a simple method to measure insulin sensitivity. To investigate the safety and reproducibility of the SITT, 16 healthy volunteers underwent two SITTs within 1 week. Intravenous insulin (0.05 U kg(-1) body weight) was injected into an antecubital vein. Blood samples were collected from the contralateral antecubital vein. The insulin-induced glucose disposal rate (Kitt) was calculated from the slope of the regression line of the logarithm of blood glucose against time during the first 3-15 min. Plasma glucose concentrations fell below 2.8 mmol l(-1) in 4 of the 32 tests and below 2.2 mmol I(-1) in 1 of these 4. Five subjects had mild hypoglycaemic symptoms, three of whom had plasma glucose concentrations below 2.8 mmol l(-1) in at least one SITT. The mean Kitt was 4.2% min(-1) (range 0.8-8.4) for the first test and 3.4% min(-1) (range 0.1-6.8) for the second test. The mean within-subject coefficient of variation was 30.7%. We conclude that SITT should be applied with caution especially on insulin sensitive subjects and has poor reproducibility using 0.05 U kg(-1) body weight of insulin injection, venous sampling, uncontrolled physical activity and uncontrolled dietary composition. Whether 0.1 U kg(-1) body weight of insulin injection and arterialized venous blood sampling as in the original description of this test can improve the reproducibility of the SITT needs further investigation.

Adult↗

PubMed1999

Reproducibility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for replicate bacterial culture analysis.

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to demonstrate the reproducibility of bacterial spectra collected on different days. The reproducibility of analysis by MALDI-MS of intact Escherichia coli and Bacillus atrophaeus is presented as a replicate culture study in which spectra were collected on ten different occasions over a three-month period and by two different operators. The analysis resulted in the detection of specific biomarkers in the m/z 2000-20 000 range. Some of the peaks in the Escherichia coli spectra are identified by comparison with other published work. All of the spectra obtained are reproducible over the course of the experiment, but operator variability does exist. The Escherichia coli spectra show operator variability while the Bacillus atrophaeus spectra do not. This work demonstrates the utility of MALDI in obtaining consistent spectra from bacteria over a period of time.

Bacillus↗

PubMed1997

Reproducibility study of cervical cytopathology in Mexico: a need for regulation and professional accreditation.

Due to the high rate of false negative results in diagnosis of cervical cytopathology, in many countries its practice has been transformed through the application of several interventions aimed at medical regulation to improve diagnostic accuracy. Diagnostic reproducibility of gynecological cytopathology was evaluated in a series of 20 cytology specimens [Papanicolaou (Pap)] and 20 cervical biopsy. (CB) studies in different clinical stages, during 1994. The observation unit consisted of 30 pathologists who observed 2 groups of 20 Pap and 20 CB specimens. The standard was a cytopathologist certified by the Pathological Anatomy Council of Mexico. Intraclass reproducibility in gynecological cytopathology is low in Mexico. In a group analysis, concordance increased as clinical status of the cervical lesion increased. For moderate dysplasia, concordance in Pap was kappa = 0.04, compared to 0.23 in CB. Concordance of diagnosis of invasive cancer was 0.29 for Pap and 0.64 for CB. Using weighted kappa at the individual level for all possible diagnoses, concordance varied from 0.29 to 0.59 for Pap, and 0.42 to 0.65 for CB. The problem of reproducibility in cervical cytopathology in Mexico emphasizes the need for continuing education, uniform diagnostic criteria, and the advantages of a single operational classification-possibly the Bethesda System-since current classification systems are obsolete.

Accreditation↗

PubMed1996

Reproducibility of erythrocyte polyamine measurements and correlation with plasma micronutrients in an antioxidant vitamin intervention study.

Erythrocyte polyamine measurements have been previously investigated as candidate biomarkers for hyperproliferation and recently as a potential intermediate endpoint in clinical chemoprevention trials with difluoromethylornithine, an inhibitor of polyamine biosynthesis. This study was performed to determine the reproducibility of erythrocyte polyamine measurements and their possible correlation with plasma micronutrients in seven healthy adults in an antioxidant vitamin intervention study. As part of this cross-over intervention study, three subjects took beta-carotene (31.4 mg/day) plus D-alpha-tocopherol acetate (720 IU/day) supplements during the first 3 months and four subjects took the supplements during the second 3 months. Heparinized blood samples were collected at baseline and every month over total 6 months for simultaneous determination of erythrocyte polyamines and plasma micronutrients by the high-performance liquid chromatographic method. For all the measures of erythrocyte polyamines the intraindividual variation was smaller than that between subjects, and three or four measurements required to accurately characterize long-term erythrocyte polyamines for an individual. The intra-class correlations were moderately high for all erythrocyte polyamine measurements, indicating a good reproducibility for intra-individual erythrocyte polyamine measurements. Based on monthly values, significant inverse correlations were found between erythrocyte spermidine and the plasma levels of retinol (r = -0.50) and lutein (r = -0.52). There were also significant inverse associations between erythrocyte spermine and plasma levels of alpha-tocopherol (r = -0.29), lutein (r = -0.44), lycopene (r = -0.29), beta-cryptoxanthin (r = -0.30), and total carotenoids (r = -0.29). The effects of supplementation upon the associations between erythrocyte polyamines and plasma nutrient levels were additionally addressed. The results indicate an acceptable longitudinal reproducibility of erythrocyte polyamine measurements, support the hypothesis that erythrocyte polyamine measurements may be correlated with plasma levels of certain nutrients, and suggest a further biomarker application in cancer prevention trials involving dietary modifications or specific relevant micronutrients.

Adult↗

PubMed1997

Maximal inspiratory pressure and inspiratory muscle endurance time in asthmatic children: reproducibility and relationship with pulmonary function tests.

Respiratory muscle strength, assessed by maximal inspiratory mouth pressure (PImax), and endurance, assessed as the length of time a subject could breathe against inspiratory resistance with a target mouth pressure > or = 70% of PI,max (Tlim), were measured in 20 symptomless asthmatic children, in order to assess the reproducibility of such measurements and their relationship to traditional pulmonary function tests or tests of bronchial hyperresponsiveness. After recording lung volumes and bronchial response to methacholine, PI,max and Tlim were measured twice in the same morning, with a 30-minute interval between each experimental trial. Mean (+/-SD) values of PI,max were 72.2 +/- 20.6 cmH2O in the first and 75.8 +/- 22.9 cmH2O in the second trial. Tlim was 154 +/- 65 and 164 +/- 66 seconds in the first and in the second trial respectively. A lack of agreement between different measurements was seen for both PI,max and Tlim. The coefficient of repeatability was 24.8 for PI,max and 92.3 for Tlim. A significant correlation between age and PI,max as well as between body mass index and PI,max were shown; no similar correlation was found for Tlim. No correlation was found between PI,max and Tlim in either of the two successive runs or between either PI,max or Tlim and lung volumes or bronchial response to methacholine. Our study shows that at this time the reproducibility of PI,max or Tlim in children with asthma in remission seems to be poor, although PI,max has a better reproducibility than Tlim. A standardized procedure to measure PI,max, should be obtainable in the near future. This would improve its clinical usefulness since PI,max is the only noninvasive test to assess respiratory muscle strength that can identify subjects at risk to develop respiratory muscle fatigue during an acute asthmatic attack.

Adolescent↗

PubMed1998

Determinants of reproducibility of lung function tests in children aged 7 to 10 years.

Lung function (LF) tests are part of many investigations in childhood lung disease. However, individual reproducibility of LF will confound between-subject differences. At the same time, increased LF variability has been linked to respiratory disease. In a sample of 598 children, two LF tests, separated by a 5-min interval, were recorded, and reliability (Rel) of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and maximal expiratory flow at 50% of FVC (MEF50) was determined. Rel was also assessed in children trained and untrained in the performance of LF. To investigate determinants of reproducibility for FEV1, the absolute difference between two repeated tests was calculated. Whenever this difference was > 120 ml, a child was considered to demonstrate excessive variability (poor reproducibility) in FEV1. For volume parameters coefficients of reliability (Crel) were found to be better than for MEF50 (FEV1: 0.96; FVC: 0.94, MEF50: 0.91). In untrained children Crel for FEV1 was only 0.91, but it was increased in subsequent visits (0.98, 0.97, and 0.97 at the second, third, and fourth tests, respectively). Excessive variability in FEV1 was observed in 10% of children and was related to the presence of wheeze [odds ratio (OR) 6.31; 95% confidence interval (CI) 1.78-22.4), shortness of breath (OR 3.14; 95% CI 1.00-9.93), a diagnosis of asthma (OR 6.25; 95% CI 1.76-22.1), and bronchial hyperresponsiveness (OR 4.30; 95% CI 2.07-8.94). We conclude that increased variability of LF is likely to be present in young children not accustomed to the testing procedure and in children with respiratory symptoms. Therefore, before guidelines for LF testing are applied, children should be trained to perform the tests and we should be cautious in the interpretation of test results in children who present with symptoms.

Child↗

PubMed1997

Pressure transmission ratio reproducibility in stress continent and stress incontinent women.

Our objective was to determine the effect of cough strength on pressure transmission ratios and establish quantitative and qualitative intra-observer test-retest reproducibility of pressure transmission ratios calculated from dynamic urethral pressure profilometry. The study included 242 consecutive urodynamic evaluations on women without pelvic organ prolapse. Dynamic urethral pressure profiles were performed in duplicate with coughs of different intensities. The analysis included pressure transmission ratios from the proximal 3 urethral quartiles (Q1 through Q3) and the mean pressure transmission ratio calculated from these quartiles. The final diagnoses were stratified into genuine stress incontinence, 135 (56%), and stress continence, 107 (44%). Correlations were strong for pressure transmission ratios from the first versus the second dynamic urethral pressure profile (K = 0.712 for mean). While the variation in cough intensity between hard and soft coughs averaged 30 cm H2O (P < 0.001), correlation's were equally strong between hard and soft cough pressure transmission ratios (K = 0.712 for mean). When mean pressure transmission ratios were stratified into below 90% and at least 90% categories, 83.5% of subjects had test-retest concordance (K = 0.671). Concordance rates were less for stress continent subjects (80.0%; K = 0.527) than for genuine stress incontinence subjects (86.4%; K = 0.679). Pressure transmission ratios appear to have reasonable quantitative and qualitative reproducibility which is unaffected by cough strength. The degree of individual variability limits the utility of pressure transmission ratios to diagnose genuine stress incontinence independent of other, equally variable clinical and urodynamic parameters, but this measure is sufficiently reproducible to be useful in characterizing stress sphincteric function in population studies.

Aged↗

PubMed2000

Parameters affecting reproducibility in capillary electrophoresis.

It is well known that poor quantitative reproducibility substantially limits the practical implementation of capillary electrophoresis (CE) separations in chemical analysis. The principal sources of variance in observed peak areas are irreproducible flow rate, which influences on-column detector response, and inconsistent injection volume or amount. An overview of studies by researchers to address the reproducibility issue will be presented. In addition, current efforts in our laboratory to assess sources of quantitative variance for separations of dansylated amino acids using an automated CE system are presented and related when appropriate to the body of existing knowledge on this important topic. A comparison of different injection methods (hydrostatic vs. electrokinetic) and approaches (e.g., high vs. low pressure), the effect of random changes in electroosmotic flow (EOF) due to air bubbles in the CE capillary, and choice of certain peak integration parameters in terms of peak area reproducibility are presented. Under optimum conditions relative standard deviation (RSD) values in raw peak area are typically 2.0%. With nonoptimum conditions (e.g., with air bubbles in capillary), RSD values can substantially degrade. However, normalizing with retention times, internal standards, or observed electrophoretic current produces RSD values in a range of 1.4-2.3%.

Amino Acids↗

PubMed1999

Intersubject variability and intrasubject reproducibility of the bereitschaftspotential.

We assessed the intersubject variability and intrasubject reproducibility of the bereitschaftspotential (BP). Twenty healthy volunteers performed extensions of their wrist in a self-paced manner every 5-10 seconds. A surface electromyography (EMG) electrode was attached to the wrist extensor group of the dominant hand to record at least 100 wrist movements, and electroencephalography electrodes were placed over the scalp. Trials were performed at baseline, 15 minutes, 4 hours, and 4 weeks. Measures derived from the BP included area 1 (-2000 to -650 msec), area 2 (-650-0 msec), total area (area 1 + area 2), amplitude at -650 msec, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec (trigger). Our findings revealed different variability/reproducibility depending on the particular BP measure being analyzed. Using intraclass correlation coefficient (ICC) and concordance correlation coefficient (CCC) as measures of intrasubject reproducibility, area 2, amplitude at peak negativity prior to EMG onset, and amplitude at 0 msec produced the best values. We conclude that in studies that attempt to quantify BP changes before and after an intervention in the same group of subjects, the most reproducible BP measures are those pertaining to the late BP component.

Adolescent↗

PubMed1991

Reproducibility and temporal stability of ADP-induced platelet aggregation: comparison of the anticoagulants sodium citrate and D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone.

We compared the reproducibility and temporal stability of ADP-induced aggregation of platelet-rich plasma anticoagulated with citrate or with D-phenylalanyl-L-prolyl-L-arginyl-chloromethyl ketone (PPACK), a thrombin inhibitor. Citrate- or PPACK-platelet-rich plasma (PRP) was stored at room temperature in capped plastic tubes or in plastic syringes from which all air was expelled. At intervals over 1-5 hr after venipuncture, platelet aggregation was induced by 1-1.5 microM ADP. Initially, the aggregation of PPACK-PRP was nearly twice that of citrate-PRP. The response of PPACK-PRP stored in the syringe remained essentially constant over the interval of study, in contrast to the responses of the other samples which declined with time. The improved stability of the response obtained from samples anticoagulated with PPACK was due to the absence of citrate, since PRP containing both citrate and PPACK became less responsive over time in a manner similar to PRP which contained only citrate. Anticoagulation with PPACK rather than citrate results in a more reproducible and stable aggregation response and more closely reproduces the in vivo environment of the platelet.

Adenosine Diphosphate↗

PubMed1992

Accuracy and reproducibility of visual coronary stenosis estimates using information from multiple observers.

The reliability of visual estimation of severity of coronary artery stenosis may be improved using data from multiple independent observers. Data were collected from the results of a video format examination used on an experimental basis in 1987 by the American Board of Internal Medicine to test 61 candidates for certification in cardiovascular diseases. Twenty arteriographic cases were presented in a standardized format. Each artery was viewed in multiple projections including angled views. Each view was shown in both real time and slow motion, and each case was seen twice in its entirety. The observers rated stenosis severity on a four-point scale ranging from 1-4. A two-way repeated measures analysis of variance was performed on the tabulated results, yielding variance components for the arteriographic data (signal), the differences among observers, and the observer by case interaction (both considered noise). These components then allowed calculation of 68 and 95% confidence intervals, the signal-to-noise ratio, and the reproducibility coefficient for any number of observers. When a single observer was considered, reproducibility was low, with 95% confidence intervals of +/- 0.9 points, corresponding to approximately +/- 22% diameter stenosis. However, when data of three observers were averaged, the 95% confidence interval decreased to +/- 0.52 points (13% stenosis), signal-to-noise ratio rose to 12.2, and reproducibility coefficient was 0.92. Relatively small increments in these values were noted when data from a fourth or fifth observer were added. In comparison to a computer-assisted quantitative method, 86% accuracy was found for the results of averaged subjective determinations of stenosis severity.(ABSTRACT TRUNCATED AT 250 WORDS)

Constriction, Pathologic↗