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At least 199 records · Page 11Linked to original sources
PubMed2004

Evaluation of the reproducibility of the GHRH plus GHRP-6 test of growth hormone reserve in adults.

BACKGROUND: The diagnosis of GH deficiency (GHD) is controversial, relying on GH secretion elicited by the provocative tests of GH reserve. However, the performance of most of the tests in use have not been evaluated rigorously. The repeatability of a test is a prerequisite before evaluating its diagnostic capability. OBJECTIVE: The combined administration of GH-releasing hormone (GHRH) and GH-releasing hexapeptide (GHRP-6) is an efficacious test of GH reserve in adults, and the target of this work was to evaluate its reproducibility. METHODS: Seventeen healthy subjects were challenged with GHRH plus GHRP-6 (1 micro g/kg i.v.). All subjects underwent four tests on different days separated by at least 2 months. GH peaks were evaluated by several mathematical analyses of reproducibility. RESULTS: As a group, the subjects showed high reproducibility after the four tests, with GH peaks of 46.0 +/- 5.1; 48.4 +/- 6.4; 50.1 +/- 5.4 and 52.9 +/- 5.8 micro g/l, respectively (1 micro g/l = 3 mU/l). Individually analysed, the reproducibility was good, and the regression analysis showed a correlation between tests 1 and 2 of R = 0.729, P < 0.0009, between tests 1 and 3 of R = 0.710, P < 0.001, and between tests 1 and 4 of R = 0.683, P < 0.002. Under mathematical analysis, the multiple correlation coefficient analysis, analysis of variance (anova) with repeated measurements, repeatability index, the simplest coefficient of variation and the intraclass correlation coefficient (ICC) all unambiguously showed that the GHRH + GHRP-6 test was reproducible. Furthermore, the repeated tests did not alter the biochemical diagnosis of the subjects, with absence of false-positive values. CONCLUSIONS: The GHRH + GHRP-6 test of GH reserve is reproducible in adult subjects.

Adult↗
PubMed2002

Reproducibility of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those with pregnancy-induced hypertension.

OBJECTIVE: To assess the inter- and intraobserver reproducibilities of pulsed Doppler measurements of the maternal renal circulation in normal pregnancies and those affected by pregnancy-induced hypertension. MATERIALS AND METHODS: Color and pulsed Doppler ultrasound was used to measure acceleration time and resistance index in the renal segmental and interlobar arteries. For the investigation of interobserver reproducibility, two sonographers performed measurements blindly in six normal pregnant women and 14 women with pregnancy-induced hypertension between 28 and 36 weeks' gestation. A second group of 10 patients between 30 and 35 weeks' gestation were examined by one sonographer to assess the level of intraobserver reproducibility of measurements. For each patient in this group, the flow waveform was measured three times in succession. Calculations of the intraclass correlation coefficient Ri were used to determine the level of reproducibility. RESULTS: The interobserver Ri and intraobserver Ri for acceleration time in the segmental artery were 0.95 and 0.96 and for the interlobar artery they were 0.97 and 0.98, respectively. For the resistance index, these values were 0.01 and 0.01 in the segmental artery and 0.52 and 0.29 in the interlobar artery. CONCLUSION: Both the inter- and intraobserver reproducibility of acceleration time measurements in the renal segmental and interlobar arteries were clinically acceptable but the equivalent reproducibilities of resistance index measurements were poor.

Adult↗
PubMed2002

Reproducibility of three-dimensional ultrasound endometrial volume measurements in patients with postmenopausal bleeding.

OBJECTIVE: To evaluate the reproducibility of transvaginal three-dimensional (3D) endometrial volume measurement in patients with postmenopausal bleeding and to compare the reproducibility of this technique to that of two-dimensional (2D) endometrial thickness measurement. METHODS: In a prospective, blinded study, transvaginal ultrasound examinations were performed in 51 consecutive patients with postmenopausal bleeding. Three-dimensional volume and 2D thickness measurements were made and intraobserver and interobserver reproducibility of each technique were assessed. RESULTS: The intraobserver correlation of 3D endometrial volume measurement of the first observer was 0.97 and that of the second observer was 0.99. Thus, mean intraobserver correlation was 0.98. The mean interobserver correlation was 0.95 (0.95 vs. 0.96). There was no significant difference in reproducibility at different volume cut-offs. The mean intra- and interobserver correlation of endometrium volume measurements for five patients with endometrial carcinoma did not differ significantly from that for patients without carcinoma (0.98, 0.98 vs. 0.98, 0.95). The intraobserver correlation of 2D endometrial thickness measurements from the first observer was 0.71 and that from second observer 0.87. Thus, mean intraobserver correlation of the endometrial thickness measurements was 0.79. The mean interobserver correlation was 0.76 (0.84 vs. 0.70). CONCLUSIONS: Endometrial volume and thickness measurements by 3D and 2D ultrasound, respectively, show good reproducibility but the reproducibility of 3D ultrasound is better.

Double-Blind Method↗
PubMed2002

Quantitative transvaginal two- and three-dimensional sonography of the ovaries: reproducibility of antral follicle counts.

OBJECTIVE: To assess the intra- and interobserver reproducibilities in addition to the between-method reliability of antral follicle counts using two (2D)- and three (3D)-dimensional transvaginal sonography (TVS). METHODS: Two groups of women with regular menstrual cycles were studied. One group consisted of healthy volunteers with proven fertility and the other group consisted of patients visiting the general infertility clinic. In each woman, 2D or 3D TVS was performed in the early follicular phase (day 2, 3 or 4) of the menstrual cycle to measure the number of antral follicles (2-10 mm). RESULTS: Intraobserver reproducibility was calculated from follicle counts using 3D TVS in 41 women. The intraclass correlation coefficient was 0.99 and the 95% coverage interval of the difference (CID) was -3.2 to +3.2. Interobserver reproducibility was assessed from both 2D (n = 37) and 3D (n = 49) TVS-based follicle counts. An interclass correlation coefficient of 0.98 was found for both methods. The 95% CID was -5.0 to +4.1 for 2D and -5.6 to +5.7 for 3D measurements. The latter CID appeared to increase in the higher range of counts. Finally, the degree of agreement between 2D and 3D TVS counts (n = 76) was characterized by a 95% CID of -5.3 to +8.3. This coverage interval widened when higher numbers of follicles were counted. With the exception of the between-method analysis, kappa values indicated overall that follicle counts will hardly change from one category to another when repeatedly carried out. CONCLUSIONS: Determination of antral follicle numbers by both 2D and 3D TVS is adequate with regard to the intra- and interobserver reproducibility. The between-method reproducibility of follicle counts measured both by 2D and 3D ultrasound is moderate. When higher follicle counts are observed both interobserver and between-method reproducibilities tend to decline. If used in categorical classifications, ultrasound-based follicle counts appear to have a high level of agreement between and within observers.

Female↗
PubMed2002

Reproducibility of sequential head-up tilt testing in patients with recent syncope, normal ECG and no structural heart disease.

AIMS: To assess the reproducibility of the response to sequential head-up tilt tests. METHODS AND RESULTS: A head-up tilt test was performed early after syncope in 127 patients with a normal ECG and no structural heart disease. Patients with a positive response (82 patients) were randomized to two (1 week and 2 weeks later) or one (2 weeks later) additional head-up tilt tests, and patients with a negative response (45 patients) were randomized to a second head-up tilt test 1 or 2 weeks after the first. The reproducibility of a positive response in the second head-up tilt test was 80% after 1 week and 53% after 2 weeks (P<0.01). Only 53% of the patients with a positive response to a first and second head-up tilt test had a positive response to a third (P=0.01). Intra-individual variation in the time to a positive response was wide. The reproducibility of the cardioinhibitory responses was very poor. Reproducibility of a negative response was 80%. CONCLUSIONS: In patients with recent syncope, the rate of positive responses decreases with sequential head-up tilt tests. Furthermore, the time to a positive response in different head-up tilt tests shows important intra-individual variations, and the reproducibility of the cardioinhibitory responses is very poor. In contrast, the reproducibility of the negative responses is high.

Adolescent↗
PubMed2002

Validity and reproducibility of histologic diagnosis and grading for adult soft-tissue sarcomas.

Soft-tissue sarcomas in adults show great variations in histologic type and grade. A valid and reproducible prognostication system is needed to select patients with soft-tissue sarcomas who could benefit from adjuvant chemotherapy. This study was conducted to assess the validity and reproducibility of diagnosis of the histologic type, MIB-1 grade, and mitosis grade, as well as of the 3 components of these grading systems. MIB-1 grade is a recently proposed grading system for predicting the prognosis of patients with adult soft-tissue sarcomas on the basis of 3 criteria (tumor differentiation, necrosis, and MIB-1 score) and replaces the mitotic count in the French system with MIB-1 immunohistochemical staining. Four surgical pathologists from 4 institutions who had experience in diagnostic soft-tissue tumor pathology reviewed 130 cases of soft-tissue sarcoma and independently determined histologic type and grade. The validity of histologic diagnosis was measured by sensitivity and specificity, and that of grading was measured by kappa statistics and percentage agreement with the diagnosis of the expert panel at the National Cancer Center, which was defined as a gold standard. Interobserver reproducibility was measured by kappa and by percentage agreement between the diagnoses of the 4 pathologists. The validity of the diagnosis of histologic type was high for synovial sarcoma, small round-cell sarcoma, and liposarcoma (sensitivity 89% to 100%; specificity, 98% to 100%) but low for malignant fibrous histiocytoma (MFH) and spindle-cell sarcoma (73% to 75%; 93% to 95%). For the grading, the validity of the MIB-1 grade was substantial (kappa = 0.68; agreement, 79%) and higher than that of the mitosis grade (0.54; 69%). The most valid component was tumor differentiation (kappa = 0.79), followed by tumor necrosis (0.66), MIB-1 score (0.59), and mitotic score (0.37). Interobserver reproducibility of histologic diagnosis was high for small round-cell sarcoma, synovial sarcoma, and liposarcoma (kappa = 0.92, 0.90, 0.87; percentage agreement = 99%, 97%, 96%, respectively); for grading, reproducibility was highest for tumor differentiation (0.78; 87%) and second highest for MIB-1 grade (0.68; 79%). We conclude that diagnosis of the type of soft-tissue sarcoma for synovial sarcoma, small round-cell sarcoma, and liposarcoma and the MIB-1 grading system based on tumor differentiation are highly valid and reproducible among Japanese pathologists who are familiar with the grading system, whereas re-evaluation of histologic criteria is essential for other histologic types such as MFH and spindle-cell sarcoma.

Antigens, Nuclear↗
PubMed2003

Reproducibility and validity of the secondary level School-Based Nutrition Monitoring student questionnaire.

OBJECTIVE: To evaluate the reproducibility and validity of the School-Based Nutrition Monitoring (SBNM) secondary level student questionnaire. DESIGN: Reproducibility was evaluated using a test-retest study design by administering the questionnaire on the same day (morning and afternoon, n=254) and, when appropriate, 9 to 14 days apart (n=259). Validity was assessed by comparing foods selected on the questionnaire with foods reported from a single 24-hour recall covering the same referent period (yesterday) in 209 students. SUBJECTS/SETTING: Eighth grade students in middle schools from central Texas were used: male and female, approximately 75% white, for the reproducibility study, with 15% Hispanic, 6% African American; for the validation study, approximately 38% white, 41% Hispanic, and 17% African American. STATISTICAL ANALYSIS: Spearman rank order correlation, kappa statistic, and percentage agreement were used for both reproducibility and the validation. RESULTS: For the reproducibility study, agreement for questions about food intake "yesterday" were 70% to 98%, with kappa statistics ranging from 0.54 to 0.93 and correlations between 0.66 and 0.97. Questions on recent physical activity had high agreement (66% to 89%) as did "usual" physical activity items, weight loss, and food selection behaviors. Nutrition knowledge items showed relatively weaker reliability: agreements ranged from 47% to 92%, with kappa statistics between 0.30 and 0.56. Attitude questions had weaker agreement (50% to 87%), kappa statistics (0.27 to 0.52), and correlations (0.33 to 0.63). For the validation study, correlation coefficients ranged from 0.32 for breads to 0.68 for milk and beans. Percentage agreement ranged from 38% for breads to 89% for gravy. APPLICATIONS/CONCLUSIONS: Most questions on the SBNM secondary questionnaire were found to have acceptable reproducibility, whereas validation of food choice behaviors showed results similar to or better than other dietary assessment instruments for this age group. This questionnaire is a useful epidemiologic tool for surveillance, assessing broad intervention effects among groups or providing needs assessment data on selected nutrition and physical activity-related constructs.

Adolescent↗
PubMedDate not supplied

Day-to-day reproducibility of mental stress-induced abnormal left ventricular function response in patients with coronary artery disease and its relationship to autonomic activation.

BACKGROUND: Mental stress (MS) results in left ventricular (LV) dysfunction in approximately half of the patients with symptomatic coronary artery disease (CAD) and is an adverse prognostic sign. The reproducibility of various MS tasks in inducing LV dysfunction and its relationship to autonomic activation in patients with CAD are not known. We studied the reproducibility on different days of 3 commonly used MS tasks on LV ejection fraction (LVEF), heart rate, blood pressure, and rate-pressure product and the relationship of reproducibility to autonomic activation as determined by heart rate variability in patients with chronic stable angina. METHODS AND RESULTS: Ten patients with CAD and exercise-induced ischemia who had abnormal LVEF responses to at least one MS task from a battery of MS tasks (mental arithmetic, anger recall, and color Stroop test) while undergoing continuous ambulatory Holter and LV function monitoring underwent a second MS testing 4 to 8 weeks later, with no change in clinical status or cardiac medications in the interim. Autonomic tone was determined from indexes of heart rate variability (high frequency [HF] for parasympathetic activity and low frequency [LF] and low frequency/high frequency ratio [LF/HF] for sympathetic activity). MS tasks resulted in a small increase in heart rate (P <.0001), a modest increase in systolic blood pressure (P <.0001) and the rate-pressure product (P <.0001), and a small but statistically significant increase in LF (P <.002) and LF/HF (P <.0001), but no change in HF compared with baseline. These changes were highly reproducible over the 2 studies. With a fall in LVEF of 5% or greater considered as indicative of an MS-positive task, anger recall was the most effective and reproducible MS task in inducing LV dysfunction. MS-positive tasks were associated with a greater increase in systolic blood pressure (P =.005). Anger recall resulted in a trend toward a higher increase in systolic blood pressure (P =.08) than the other MS tasks. In MS tasks with inconsistent LVEF responses in the 2 studies (LV dysfunction present in one study but not in the other), there was significant parasympathetic withdrawal (P =.02) in MS-negative tasks but no difference in sympathetic activation. On the other hand, in MS tasks with consistent LV dysfunction on both occasions, there was no difference in parasympathetic or sympathetic activation. MS-positive tasks were not accompanied by chest pain or ST depression. CONCLUSIONS: Of the commonly used MS tasks, anger recall produces LV dysfunction with the highest frequency and is the most reproducible task when retested 4 to 8 weeks later in patients with CAD. These data are relevant for planning studies of the effects of therapeutic interventions on MS-induced LV dysfunction.

Aged↗
PubMed2001

Interobserver and intraobserver reproducibility of peripheral blood and oxygen pressure measurements in the assessment of lower extremity arterial disease.

INTRODUCTION: Peripheral blood pressure measurements play a prominent role in the diagnosis and follow-up of patients with peripheral vascular diseases. Toe pressure of the hallux (TP1) and second toe (TP2) and transcutaneous oxygen pressure (TCPO2) measurements are becoming more important. The ankle/brachial pressure index (ABPI) is known to be a reliable parameter, but the toe pressure and TCPO2 are evaluated less thoroughly. Therefore, we evaluated the reproducibility of TP1, TP2, TCPO2, ABPI, ankle pressure (AP), and brachial pressure (BP). PATIENTS AND METHODS: In 54 patients with various stages of peripheral vascular disease, the intraobserver and interobserver reproducibility of BP, AP, ABPI, TP1, TP2, and TCPO2 was investigated by calculating the repeatability coefficient (RC) and the intraclass correlation coefficient (ICC) and by using Bland-Altman plots. RESULTS: The intraobserver and interobserver reproducibility at 1 day and after 1 week of BP, AP, ABPI, and TP1 was substantial and comparable (ICC range, 0.80-0.99), except for the BP after 1 week. The TP2 and TCPO2 were less reproducible (ICC range, 0.62-0.98). The interobserver RC of BP was 31 mm Hg; of AP, 44 mm Hg; of ABPI, 27%; of TP1, 41 mm Hg; of TP2, 67 mm Hg; and of TCPO2; 30 mm Hg. The difference plot showed that the observer variability was equally distributed across the range of pressure in all measurements. CONCLUSION: The BP, AP, ABPI, and TP1 have a substantial intraobserver and interobserver reproducibility, whereas TP2 and TCPO2 show worse reproducibility. Especially when low values (or values around a cutoff value) are measured, the RC should be taken into account, and repetition of the measurement is advocated.

Aged↗
PubMed2005

Application of TLC for confirmation and screening of pesticide residues in fruits, vegetables, and cereal grains: Part 2. Repeatability and reproducibility of Rf and MDQ values.

This paper illustrates the effect of major factors influencing the reproducibility of thin layer chromatography (TLC) separation and detection under largely differing environmental and laboratory conditions. The optimum conditions for reproducibility and detection sensitivity was obtained on 20 x 20 cm layer in the retention factor (Rf) range of 0.2-0.7 by applying the sample in spots of 3-4 mm diameter at 2 cm from the edge of the plate. The reproducibility rapidly decreased below Rf = 0.2. Above Rf = 0.2 the within-laboratory reproducibility of 219 pesticides obtained in ethyl acetate silica gel elution system by several laboratories was typically below 10%. The among-laboratories reproducibility of the average retention factors was generally below 12%. The minimum detectable quantities (MDQ) of 219 pesticide residues were determined with nine detection methods. The MDQ values largely varied depending on the mode of detection. Bioassay methods enabled the detection down to 0.1-10 ng, while 20-100 ng could be achieved with the chemical reagents. Higher MDQ values are also reported in order to assist the identification of compounds potentially present. The between-laboratories reproducibility of MDQ values was typically 1-5 MDQmin.

Chromatography, Thin Layer↗
PubMed2006

Evaluation of the reproducibility of lung motion probability distribution function (PDF) using dynamic MRI.

Treatment planning based on probability distribution function (PDF) of patient geometries has been shown a potential off-line strategy to incorporate organ motion, but the application of such approach highly depends upon the reproducibility of the PDF. In this paper, we investigated the dependences of the PDF reproducibility on the imaging acquisition parameters, specifically the scan time and the frame rate. Three healthy subjects underwent a continuous 5 min magnetic resonance (MR) scan in the sagittal plane with a frame rate of approximately 10 f s-1, and the experiments were repeated with an interval of 2 to 3 weeks. A total of nine pulmonary vessels from different lung regions (upper, middle and lower) were tracked and the dependences of their displacement PDF reproducibility were evaluated as a function of scan time and frame rate. As results, the PDF reproducibility error decreased with prolonged scans and appeared to approach equilibrium state in subjects 2 and 3 within the 5 min scan. The PDF accuracy increased in the power function with the increase of frame rate; however, the PDF reproducibility showed less sensitivity to frame rate presumably due to the randomness of breathing which dominates the effects. As the key component of the PDF-based treatment planning, the reproducibility of the PDF affects the dosimetric accuracy substantially. This study provides a reference for acquiring MR-based PDF of structures in the lung.

Artifacts↗
PubMed2006

Reproducibility of cerebral blood volume measurements by near infrared spectroscopy in 16 healthy elderly subjects.

Near infrared spectroscopy (NIRS) is a non-invasive method to monitor cerebral haemodynamics. Used either alone or in combination with other non-invasive methods such as transcranial Doppler sonography, this technique is well suited for use in cerebrovascular research in ageing. Reproducibility of NIRS, however, has only been determined in neonates and adults. We applied controlled desaturation (the O(2)-method) to measure the cerebral blood volume (CBV) with NIRS in 16 healthy subjects aged 65 to 88. This method uses deoxygenated haemoglobin (the concentration of which is manipulated by desaturation) as an intravascular tracer for NIRS. We determined repeatability (between tests interval: 2 min), short-term reproducibility (intervals of 20 and 40 min) and long-term reproducibility (interval > 2 weeks). We found a coefficient of variation (CV) of 12.5% for repeatability and a CV of 11.7% for short-term reproducibility. The CV for long-term reproducibility was 15%. We conclude that NIRS can reproducibly measure CBV in subjects aged 65 and older, using the O(2)-method. In this group of healthy subjects, this method was well tolerated.

Aged↗
PubMed2006

Reproducibility of soft tissue landmarks on three-dimensional facial scans.

This study evaluated the reproducibility of 24 soft tissue landmarks on six three-dimensional (3D) facial scans. The scans were taken on a DSP400 facial scanner and were viewed using a customized software program. Intraoperator data were obtained by one researcher placing the 24 landmarks on all six scans a total of 30 times. Thirty different orthodontists of varying experience were then asked to place all 24 landmarks on each of the six facial scans in order to establish interoperator reproducibility. The standard deviations (SDs) from the mean were calculated from the data for each individual landmark in the x-, y-, and z-axes. For the intraoperator data, 12 of the 24 landmarks were found to be reproducible to within a 1 mm SD for each plane of space. The interoperator data showed lower reproducibility with just two landmarks showing less than a 1 mm SD in all three planes of space. Familiarity with 3D facial scans and associated software programs is important in improving reproducibility. In addition, the landmarks investigated in this study included those not often used. It is suggested that landmarks showing poor reproducibility for both inter- and intraoperator data should be avoided, if at all possible, or at least used with caution.

Adult↗
PubMed1996

Reproducibility of the interpretation of hysterosalpingography in the diagnosis of tubal pathology.

The aim of the study was to estimate the inter- and intra-observer reproducibility of the interpretation of hysterosalpingography (HSG) in the diagnosis of tubal pathology, and associate reproducibility with diagnostic accuracy. Four observers evaluated 143 HSGs twice, on proximal tubal obstruction, distal tubal obstruction, hydrosalpinx and peritubal adhesions. Diagnostic laparoscopy with chromopertubation was considered to be the reference strategy. Reproducibility (inter- and intra-observer agreement) was expressed in terms of kappa-values. Accuracy was expressed in terms of sensitivity, specificity and likelihood ratios. kappa-values for reproducibility between observers were almost perfect for proximal obstruction, substantial for distal obstruction and hydrosalpinx, and moderate for adhesions. kappa-values for reproducibility within observers were almost perfect for proximal obstruction and substantial for distal obstruction, hydrosalpinx and adhesions. HSG had a high specificity for proximal obstruction, but a low sensitivity. Distal obstruction, absence of hydrosalpinx and adhesions had a poor accuracy. The likelihood ratio for the presence of hydrosalpinx was high. In conclusion, proximal tubal obstruction detected on HSG changes the pre-test probability of proximal tubal obstruction from 16 to 50%. Proximal tubal patency detected on HSG changes the pre-test probability of proximal tubal patency from 16 to 9%. It is unlikely that a lack of reproducibility of the interpretation of proximal tubal patency is responsible for the low sensitivity; alternative explanations are artefacts occurring while performing HSG or an imperfect reference strategy diagnostic laparoscopy. HSG is of limited use in diagnosing distal tubal obstruction and hydrosalpinx, and has no value in the detection of peritubal adhesions.

Fallopian Tube Diseases↗
PubMed2000

Pathologists' agreement with experts and reproducibility of breast ductal carcinoma-in-situ classification schemes.

Several histologic classifications for breast ductal carcinoma in situ (DCIS) have been proposed. This study assessed the diagnostic agreement and reproducibility of three DCIS classifications (Holland [HL], modified Lagios [LA], and Van Nuys [VN]) by comparing the interpretations of pathologists without expertise in breast pathology with those of three breast pathology experts, each a proponent of one classification. Seven nonexpert pathologists in New Hampshire and three experts evaluated 40 slides of DCIS according to the three classifications. Twenty slides were reinterpreted by each nonexpert pathologist. Diagnostic accuracy (nonexperts compared with experts) and reproducibility were evaluated using inter- and intrarater techniques (kappa statistic). Final DCIS grade and nuclear grade were reported most accurately among nonexpert pathologists using HL (kappa = 0.53 and 0.49, respectively) compared with LA and VN (kappa = 0.29 and 0.35, respectively, for both classifications). An intermediate DCIS grade was assessed most accurately using HL and LA, and a high grade (group 3) was assessed most accurately using VN. Diagnostic reproducibility was highest using HL (kappa = 0.49). The VN interpretation of necrosis (present or absent) was reported more accurately than the LA criteria (extensive, focal, or absent; kappa = 0.59 and 0.45, respectively), but reproducibility of each was comparable (kappa = 0.48 and 0.46, respectively). Intrarater agreement was high overall. Comparing all three classifications, final DCIS grade was reported best using HL. Nuclear grade (cytodifferentiation) using HL and the presence or absence of necrosis were the criteria diagnosed most accurately and reproducibly. Establishing one internationally approved set of interpretive definitions, with acceptable accuracy and reproducibility among both pathologists with and without expertise in breast pathology interpretation, will assist researchers in evaluating treatment effectiveness and characterizing the natural history of DCIS breast lesions.

Breast Neoplasms↗
PubMed1990

Reproducibility of food frequency measurements and inferences from a case-control study.

To investigate the relationship between the reproducibility of measurements of exposure from a frequency questionnaire and inferences from a case-control study, 229 patients were reinterviewed on the telephone an average of 6 weeks after the original interview. Several indices of agreement were computed. Information on smoking and use of alcohol and coffee was quite reproducible, as reflected by most measures of agreement, using grouped or continuous data. Frequency of meat, vegetable, and fruit intake had low reproducibility. For all variables, reproducibility was similar for cases and controls. Reproducibility of the exposure variables was a good predictor of the reproducibility of the relative odds (RO) obtained with the first and the repeat interviews. Lack of reliability of the exposure variable appeared to produce fluctuations in the ROs in either direction, even though the same degree of agreement was observed for cases and controls. This situation may partially explain discrepant findings between case-control studies of diet and chronic diseases.

Adult↗
PubMed1990

Reproducibility of radionuclide left ventricular ejection fraction in patients awaiting cardiac transplantation.

Radionuclide-derived left ventricular ejection fraction (LVEF) is used to assess LV systolic function, to follow trends in the natural history of dilated cardiomyopathy, and to prioritize patients waiting for cardiac transplantation. Reproducibility of LVEF at extremely low levels has not, however, been reported. To assess the reproducibility of radionuclide LVEF at levels below 0.30 EF U, 17 highly symptomatic patients (NYHA Class III/IV) with dilated cardiomyopathy were studied on two occasions, 72 hours apart. Sequential scans were analyzed by two independent observers. Mean LVEF was 0.18 +/- 0.06 U (scan 1) and 0.17 +/- 0.06 U (scan 2). Interoperator reproducibility (SD) was 0.03 U (R = 0.76), interscan reproducibility (SD) was 0.03 U (R = 0.62), and overall reproducibility (SD) was 0.04 U (R = 0.50). The interobserver variation of 0.03 (actually 0.027) was just over one half that seen in normal volunteers (variation 0.05, n = 29) studied previously in this department. A change of greater than or equal to 0.08 U (2SD) in either direction is highly likely to represent a real change in LV function in those with LVEF less than or equal to 0.30 units, compared with the change of at least 0.10 units required in those with normal LV function. Lower interobserver and interscan reproducibility should be taken into account when interpreting sequential scans in patients with severe LV dysfunction.

Adolescent↗
PubMed2002

Absolute quantification of cerebral blood flow with magnetic resonance, reproducibility of the method, and comparison with H2(15)O positron emission tomography.

While H2(15)O positron emission tomography (PET) is still the gold standard in the quantitative assessment of cerebral perfusion (rCBF), its technical challenge, limited availability, and radiation exposure are disadvantages of the method. Recent work demonstrated the feasibility of magnetic resonance (MR) for quantitative cerebral perfusion imaging. There remain open questions, however, especially regarding reproducibility. The main purpose of this study was to assess the accuracy and reproducibility of MR-derived flow values to those derived from H2(15)O PET. Positron emission tomography and MR perfusion imaging was performed in 20 healthy male volunteers, who were chronic smokers, on day 1 and day 3 of a 4-day hospitalization. Subjects were randomly assigned to one of two groups, each with 10 subjects. One group was allowed to smoke as usual during the hospitalization, while the other group stopped smoking from day 2. Positron emission tomography and MR images were coregistered and rCBF was determined in two regions of interest, defined over gray matter (gm) and white matter (wm), yielding rCBF(PET)gm, rCBF(MR)gm, rCBF(PET)wm, and rCBF(MR)wm. Bland-Altman analysis was used to investigate reproducibility by assessing the difference rCBFday3 - rCBFday1 in eight continual-smoker volunteers. The analysis showed a good reproducibility for PET, but not for MR. Mean +/- SD of the difference rCBFday3 - rCBFday1 in gray matter was 6.35 +/- 21.06 and 0.49 +/- 5.27 mL x min(-1) x 100 g(-1) for MR and PET, respectively; the corresponding values in white matter were 2.60 +/- 15.64 and -1.14 +/- 4.16 mL x min(-1) x 100 g(-1). The Bland-Altman analysis was also used to assess MRI and PET agreement comparing rCBF measured on day 1. The analysis demonstrated a reasonably good agreement of MR and PET in white matter (rCBF(PET)wm - rCBF(MR)wm; -0.09 +/- 7.23 mL x min(-1) x 100 g(-1)), while in gray matter a reasonable agreement was only achieved after removing vascular artifacts in the MR perfusion maps (rCBF(PET)gm - rCBF(MR)gm; -11.73 +/- 14.52 mL x min(-1) x 100 g(-1)). In line with prior work, these results demonstrate that reproducibility was overall considerably better for PET than for MR. Until reproducibility is improved and vascular artifacts are efficiently removed, MR is not suitable for reliable quantitative perfusion measurements.

Adult↗