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Results for “Reproducibility”

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PubMed1993

[Measurement of cardiac output by CO2 rebreathing technique. A study of reproducibility in the normal subject; application to cardiac insufficiency].

A feasibility and reproducibility study of cardiac output measurement by CO2 rebreathing was performed in normal subjects and in patients with compensated cardiac failure. The measurements were performed at rest and at the second stage of the Bruce protocol in normal subjects (N = 12) with a good reproducibility (r = 0.81) after an interval of two days. In patients with stable cardiac failure (N = 17), the cardiac outputs were 9.4 +/- 3.9 l/min and 9.3 +/- 3.1 l/min by measuring the arterial pCO2 and end-expiratory CO2 compared with the theoretical value of 9.9 +/- 2 l/min. The non-invasive measurement of cardiac output by the CO2 rebreathing method was well tolerated by patients and is reliable and reproducible.

Adult↗

PubMed1993

Reproducibility of ambulatory intragastric pH monitoring.

Ambulatory 24-hour intragastric pH monitoring is nowadays the standard technique for assessing intragastric acidity. For (patho)physiological and pharmacological studies the method has to be sensitive and reproducible. Intragastric acidity was measured continuously by means of intragastric electrodes in the gastric corpus. In order to assess the reproducibility of the test, we repeated it test twice on separate days under standardized conditions in 8 healthy subjects. Subjects were fully ambulatory and no medication was administered. We found no significant difference between 24-hour median pH values during both study days [1.45 (range 1.20-1.90) and 1.40 (1.20-2.00), day 1 and 2, respectively]. There was a significant overall correlation between consecutive 30-min median pH values during 24 hours (r = 0.97, p < 0.0001). Over 24 hours and during the day the technique was able to detect consistent pH changes of > 0.1 pH units, but during the night only changes of > 0.3 pH units could be detected, due to nocturnal pH fluctuations in two subjects. This study shows that ambulatory 24-hour intragastric pH monitoring is reproducible and is able to detect small changes in gastric acidity.

Adult↗

PubMed1993

[Intra-individual reproducibility of tilt table studies in diagnosis of vasovagal syncope].

Neurally-induced syncope appears to be the underlying pathophysiologic mechanism in many patients with unexplained syncope. Diagnosis of vasovagal syncope, however, remains difficult and constitutes in many cases an exclusion diagnosis. The present study thus aimed to determine the yield of tilt-table testing in the work-up of patients with unexplained syncope and most importantly to examine the reproducibility of the results of this method. Twenty-four patients with a history of syncope and 11 healthy volunteers were examined on 2 days. In 10 patients, symptoms could be provoked during tilting, in 8 during both tests, in 2 only on one occasion. Only 1 of 11 volunteers developed presyncope during tilting which was not reproducible during the second test. These findings resulted in a sensitivity of 42% and a specificity of 91% for the protocol employed in this study. Overall reproducibility was 91% which suggests that this tilt-table protocol is suitable for evaluation of therapeutic interventions in patients with neurally-mediated syncope.

Adult↗

PubMedDate not supplied

Vaginal intraepithelial neoplasia. Reproducibility of pathologic diagnosis and correlation of smears and biopsies.

Masked slides of 124 vaginal smears and 70 corresponding biopsies obtained from 45 patients with a reported cytologic diagnosis of vaginal intraepithelial neoplasia (VAIN) were examined by two pathologists to assess the interobserver reproducibility and histopathologic correlation of cytopathologic diagnoses of VAIN. The cytopathologic diagnoses by the two pathologists were identical in 94 (76%) cases and matched the originally reported diagnosis in 45 (46%) cases. The histopathologic diagnoses by the two pathologists agreed in 47 (67%) cases and matched the originally reported diagnosis in 35 (55%). The consensus cytopathologic and histopathologic diagnoses rendered by the pathologists agreed within one grade in 49 (70%) cases. A consensus histopathologic diagnosis of VAIN 2 was rendered in only 1 (10%) of 10 cases in which the cytopathologic diagnosis was VAIN 2. These results suggest that the cytopathologic and histopathologic grading of VAIN is moderately reproducible. Because (1) combining VAIN 2 and 3 under the diagnosis of high grade squamous intraepithelial lesion provided a slight improvement in diagnostic reproducibility and cytopathologic-histopathologic correlation and (2) the cytopathologic diagnosis of VAIN 2 was employed rarely and rarely confirmed histopathologically, we advocate the use of the term high grade squamous intraepithelial lesion to designate VAIN 2 and 3.

Adult↗

PubMed1993

Validity and reproducibility of a self-administered dietary questionnaire in obese and non-obese subjects.

The validity and reproducibility of a self-administered dietary questionnaire has been tested with specific attention to differences between obese and non-obese subjects. To test the validity, the dietary questionnaire was compared with 4-day food records, 24-h energy expenditure (24EE) and nitrogen excretion in 45 obese and 19 non-obese men and women. Energy intake was 2% higher (non-significantly) from questionnaire than from food records in the non-obese, but 35% higher (P < 0.001) in the obese. Comparing energy intake from the questionnaire with estimated 24EE, the questionnaire gave 4% higher values in both the non-obese and obese, differences which were not significant. The reproducibility in the obese sample that completed the questionnaire twice was comparable to that observed in normal populations. These data suggest that it is possible to obtain information on obese subjects' dietary intake that is at least as valid and reproducible as that from normal weight individuals.

Adult↗

PubMed1993

Accuracy and reproducibility of precordial percussion and palpation for detecting increased left ventricular end-diastolic volume and mass. A comparison of physical findings and ultrafast computed tomography of the heart.

OBJECTIVE: To assess the accuracy and reproducibility of indirect definitive precordial percussion in detecting increased left ventricular end-diastolic volume (LVEDV), left ventricular mass (LVM), and left ventricular end-diastolic wall thickness (LVEDWT), and to compare it with palpation of the apical impulse. DESIGN: Descriptive study. SETTING: Hospitals and clinics of a university medical center. PATIENTS: Convenience sample of 103 patients (62 men and 41 women) referred for ultrafast computed tomography (CT) of the heart. INTERVENTIONS: Percussion dullness distance from the midsternal line in the left fourth through sixth intercostal spaces, distance of the apical impulse from the midsternal line, and apical impulse diameter in the left lateral decubitus position were measured on all patients. Measurements of LVEDV, LVM, and LVEDWT were taken using ultrafast CT of the heart. Investigators performing the physical diagnostic maneuvers were blinded to the clinical history and CT results, and investigators performing the CT scans were blinded to physical findings. RESULTS: Percussion dullness distance in the left fifth intercostal space was the best discriminator of LVEDV (receiver operating characteristic [ROC] area, 0.680; 95% confidence interval [CI], 0.547 to 0.813), and dullness distance in the left sixth intercostal space was the best discriminator of LVM and LVEDWT (ROC areas, 0.831, 95% CI, 0.674 to 0.988; and 0.849, 95% CI, 0.651 to 0.999, respectively). A percussion dullness distance of greater than 10.5 cm in the left fifth intercostal space detected increased LVEDV or LVM with a sensitivity of 91.3% (95% CI, 70.5% to 98.5%) and a specificity of 30.3% (95% CI, 19.9% to 43.0%). There was moderate concordance between investigators for percussion dullness distance (kappa, 0.57; 95% CI, 0.18 to 0.96). In patients in whom an impulse was palpated, an apical impulse diameter of greater than 3.0 cm in the left lateral decubitus detected increased LVEDV or LVM with a sensitivity of 100% (95% CI, 77.1% to 100%) and a specificity of 40% (95% CI, 23.2% to 59.3%). However, an impulse was palpable in only 53% of cases and showed only slight interobserver reproducibility (kappa, 0.18; 95% CI, 0.0 to 0.58). CONCLUSION: Indirect definitive percussion of the precordium is a sensitive and moderately reproducible maneuver for excluding cardiomegaly due to increased LVEDV or LVM. Although measurement of apical impulse diameter was also sensitive in excluding cardiomegaly, lack of a palpable impulse in many patients and low precision between physicians may limit its utility in clinical practice.

Cardiomegaly↗

PubMed1993

Confocal laser scanning ophthalmoscope. Reproducibility of optic nerve head topographic measurements with the confocal laser scanning ophthalmoscope.

BACKGROUND: Glaucoma is an optic neuropathy in which changes in the appearance of both the optic nerve head and the surrounding tissues are important in both diagnosing its presence and progression. Accurate methods to objectively document the appearance of the optic nerve are necessary. The confocal laser scanning ophthalmoscope (Zeiss) is a new prototype instrument that may have the capability to accurately perform this function. METHODS: The authors performed a prospective pilot study evaluating the ability of the confocal laser scanning ophthalmoscope to reproduce three-dimensional optic nerve images. Each retinal image contained 600,000 bytes of information. Thirty discrete images of the right optic nerves of 19 visually normal volunteers were obtained. Depth measurements were compared from the same 100 x 100 micron areas (neighborhoods). RESULTS: Image comparisons found the variability of depth measurements for the entire image were within 102 microns (95% confidence interval). Sixty percent of the depth measurements were reproducible within 100 microns. Variability of the depth measurements was greatest where the neuroretinal rim sloped at the edge of the optic cup and lowest in the peripapillary area. CONCLUSION: The confocal laser scanning ophthalmoscope has the potential to be a safe, rapid, and reproducible method of imaging ocular structures.

Adult↗

PubMed1993

Reproducibility of repeated measures of carbon-11-raclopride binding in the human brain.

Carbon-11-raclopride has been successfully utilized with PET to assess changes in endogenous dopamine concentration after pharmacological intervention in the living baboon brain. For similar studies to be done in humans, measurements of 11C-raclopride with no intervention need to be reproducible. In order to test the reproducibility (test-retest) of 11C-raclopride binding in the human brain, we performed repeated studies on two different days. Studies were done in five normal controls with no pharmacological intervention. Time-activity (%dose/cc) curves for 11C-raclopride in the basal ganglia (BG) and cerebellum (CBL) were highly reproducible with an average difference in peak uptake for repeated studies in the same individual of 4%. The BG to CBL ratio for the average activity concentration between 30 and 60 min showed differences that ranged from -7% to 8% between the repeated studies. Graphical analysis to obtain the distribution volume revealed intrasubject values that ranged from -9% to 7% for the ratio of the distribution volume in BG to that in CBL. These studies demonstrate that in order to use 11C-raclopride to measure an individual's change in relative dopamine concentration secondary to pharmacological or behavioral intervention, a change in striatal 11C-raclopride binding in excess of 10% is required.

Adult↗

PubMed1993

Reproducibility of the condylar reference position.

The reproducibility of the condylar reference position was examined at the pont of unstrained hinging movement of the mandible in subjects with TMJ symptoms and in asymptomatic subjects. Three different operators performed the procedure to detect interoperator variability. Each operator made five registrations using computerized axiography in the electronic mandibular position indicator mode. Data were evaluated by an analysis of variance using three factors: (1) repetitions of the single operator, (2) data from symptomatic versus asymptomatic patients, and (3) values of different operators. The results showed that none of these factors had a significant influence on reproducibility of the condylar reference position. High reproducibility was obtained in both symptomatic and asymptomatic groups. Measured values remained within +/- 0.1 mm in 58.6% and within +/- 0.2 mm in 24.3% of the registrations.

Adolescent↗

PubMed1993

[Reproducibility of the signal-averaged, high-pass filtered electrocardiogram].

In order to test the reproducibility of the signal-averaged electrocardiogram (SAECG) using Simson's method (high-pass filter cutoff frequency 25 Hz, orthogonal leads, recording of 133 s per lead), 121 patients were examined. In all patients, two signal-averaged ECGs were performed on the first day of the study immediately after each other, using identical electrode position. In a subgroup of 47 patients, the same procedure was repeated 3 days later. There was no difference between the mean values of conventionally calculated averaging parameters (heart rate, QRS-duration, root-mean-square voltage in the terminal 40 ms of the highly amplified and filtered QRS-complex [V40], the low amplitude signal duration under 40 microV in the terminal portion of the QRS-complex [LAS], total root-mean-square voltage of the QRS-complex), both with regard to immediate and short-term reproducibility. Thus, conventionally calculated averaging parameters are well reproducible.

Adolescent↗

PubMed1995

Reproducibility of computed tomography measurement of visceral adipose tissue area.

OBJECTIVE: The purpose of the current study is to examine the reproducibility of CT measurement of the cross-sectional area of abdominal adipose tissue. DESIGN: Sixteen healthy pre-menopausal women, ranging from lean to obese, underwent duplicate cross-sectional CT scans of the abdomen at the level of the 4th lumbar vertebral disc space. Subjects stood after the initial scan and were then re-positioned prior to repeat CT scanning. RESULTS: There was a high degree of reproducibility in measurement of overall cross-sectional adipose tissue (AT) and in the partitioning of this into subcutaneous and visceral AT. The excellent reproducibility is demonstrated by a high correlation between duplicate measurements (r = 0.99, P < 0.01), and by small precision errors; 1.2% of the mean value for total AT cross-sectional area, 1.9% for subcutaneous AT area, and 3.9% for visceral AT area. CONCLUSION: Measurement of abdominal AT area by cross-sectional CT scanning is not only an accurate determination of this adipose depot but can also be repeated with a high degree of precision.

Adipose Tissue↗

PubMed1995

Heterogeneity and reproducibility of microvessel counts in breast cancer.

BACKGROUND: Microvessel counting has proven to be of prognostic value in breast cancer, as shown in different retrospective studies. However, methodology has not been studied widely, and this must be done before the method can become clinically applicable. The aim of this study was to determine the degree of heterogeneity and reproducibility of microvessel counts (MC) in breast cancer. EXPERIMENTAL DESIGN: In 10 cases of breast cancer, the available blocks (2-4 blocks) containing invasive tumor parts were selected, and four sections (4 microns) were cut with interdistances of 100 microns. In each section, two or three invasive areas (0.5 x 0.5 cm) were demarcated. Microvessels, visualized by immunohistochemistry (CD31 Ab), were counted by one observer in 10 systematically selected fields of vision (400 x magnification). Furthermore, microvessels were counted in four fields with the highest microvessel density ("hot spots"). Coefficients of variation (CV) were calculated for the different sampling levels. RESULTS: Repeated MC yielded high intra- and interobserver reproducibility (correlation coefficients > 0.92). For the systematic counting method, CV between MC from different areas within one section was on average (17.1% (0.7-52.1). When comparing MC from corresponding areas in different sections from the same black, CV was on average 14.7% (0.5-41.9), and for MC from different blocks of the same tumor, CV was on average 25.8% (9.9-44.6). Nested ANOVA showed an approximately equal contribution to the total variance of the different sampling levels, except for the variation between sections (not significant). For the hot spot MC, CV for different sections from the same block was on average 11.1% (0.7-29.5) and for different blocks from the same tumor, 24.2% (5.7-54.9). Nested ANOVA showed that variation between different blocks from the same tumor contributed most to the total variance. CONCLUSIONS: There is a noteworthy heterogeneity in MC between different areas from the same section, between corresponding areas in different sections from the same block, and between different blocks from the same tumor. Consequently, one must carefully scan all the available tumor material in each case for the best hot spot. The hot spot approach is efficient and reproducible, but only a comparative prognostic evaluation can show whether it is clinically more useful than systematic counts.

Breast Neoplasms↗

PubMed1995

[Comparison and reproducibility of 4 methods of indirect blood pressure measurement in moderate hypertension].

UNLABELLED: The measurements and the reproducibility of ambulatory, home, clinic and repeated non ambulatory automatic blood pressure (BP) were compared in 16 patients (45 +/- 11 yrs) with mild untreated hypertension (BP: 164 +/- 12/101 +/- 6 mmHg at the selection visit); 26 +/- 19 days after this visit, each patient had two sets of BP measurements in 4 different ways taken 2 weeks apart under similar study conditions: daily ambulatory recordings (ABP), home self-measurement readings (over 5 days) (HBP), 2-minute repeated automatic BP measurements during the 20 minutes preceding the physician examination (RABP) and clinic BP (CBP) with a standard sphygmomanometer mercury column. The reproducibility was assessed by standard deviation of the differences (SDD). Decisions to treat the patients were made according to the results obtained by CBP (BP > 140/90 mmHg during the selection visit and the 2 study visits), by the first ABP (mean BP > 139/87 mmHg) and by the first week of HBP (mean BP > 127/83 mmHg) were compared; the outcome of these three procedures was then compared. RESULTS: [table: see text] CONCLUSION: Repeated automatic and clinic BP were higher than ambulatory and home BP. Reproducibility of ambulatory and home BP were comparable and better than clinic or repeated automatic BP. The percentage of decision to treat according to the results of clinic, home and ambulatory BP was comparable but they were not the same patients who were treated with the 3 methods.

Adult↗

PubMed1996

Reproducibility and physiological characteristics of 24-hour ambulatory esophangeal manometry/pH-metry.

OBJECTIVES: To assess the reproducibility and physiological characteristics of ambulatory esophageal manometry/pH-metry. METHODS: Ten healthy volunteers were studied on two separate occasions (2 wk apart) using the Synectics Microdigitrapper System. The pH recording failed in one subject; thus, pH data were analyzed in nine, and motility measurements in all 10 subjects. RESULTS: A high degree of reproducibility was established for the five pH and seven manometry variables assessed. Using the paired t test and Wilcoxon signed rank test to compare the two sets of data, all p values were >0.05. Narrow 95% confidence intervals containing the zero measures were also obtained on the differences of the data from both sessions for all variables. Better correlation coefficients were obtained for the motility parameters than for the pH parameters. As would be expected, reflux occurred more often in the upright than in the supine position. Furthermore, esophageal contractions were of higher amplitude and longer duration in the distal esophagus, and the frequency of propulsive contractions sequences was higher during meals and in the upright position than in the supine position. CONCLUSIONS: This study demonstrates the reproducibility of ambulatory esophageal manometry/pH-metry, suggesting that this technology may be useful in assessing the effect of pharmacological intervention on esophageal motor function.

Adult↗

PubMed1996

Reproducibility of iodine-123-beta-CIT SPECT brain measurement of dopamine transporters.

UNLABELLED: Iodine-123-beta-CIT has been used as a probe of monoamine transporters in human and nonhuman primates utilizing SPECT. To assess the utility of this tracer for measurement of striatal dopamine (DA) transporters in human disease, we studied the test/retest variability and reliability of SPECT measures obtained after bolus injection of [123I]beta-CIT 0-7 hr (Day 1) and 18-24 hr (Day 2) after administration. METHODS: For the Day 2 study, seven healthy humans (4 men, 3 women; aged 19-74 yr) participated in two [123I]beta-CIT SPECT scans separated by 7-14 days. Subjects were imaged at 18, 21 and 24 hr postinjection of 370 MBq (10 mCi) [123I]beta-CIT. Two outcome measures were evaluated: (a) the ratio of specific striatal (activity associated with DA transporter binding) to nondisplaceable uptake, also designated V"3 and (b) the total, specific striatal uptake (%SSU) expressed as a percentage of injected radiotracer dose. Test/retest variability associated with V"3 and total specific striatal uptakes were compared for scans acquired at 18, 21 and 24 hr with 24 hr only postinjection scans. For the Day 1 study, three of the subjects participated in two kinetic studies of [123I]beta-CIT uptake. A three-compartment model was used for determination of konBmax and binding potential (BP = Bmax/Kd) and the reproducibility of the measures assessed. RESULTS: In the Day 2 study, both outcome measures demonstrated excellent test/retest reproducibility with variability of V"3 = 6.8 +/- 6.8% and percent striatal uptake = 6.6 +/- 4.3% using data acquired from all time points. There were no significant differences in variability for the two outcome measures obtained. The intraclass correlation coefficient rho was 0.96 and 0.98 for V"3 and %SSU, respectively. Considering the 24 hr postinjection scans only, there was a nonsignificant trend toward lower test/retest variability for %SSU compared to V"3 (6.6 +/- 4.2% and 12.8 +/- 9.0%, respectively). The test/retest variability for the Day 1 kinetic modeling data showed marked differences depending on the fitting strategy and assumptions about the reversibility of [123I]beta-CIT in striatum. Using a model that assumed a low, fixed value for reversible striatal binding (k4) produced low variability (12 +/- 9%). CONCLUSION: These data suggest that SPECT imaging performed at either 0-7 hr or 18-24 hr after [123I]beta-CIT injection permits calculation of reliable and reproducible measures of dopamine transporters and supports the feasibility of using [123I]beta-CIT in serial evaluation of human neuropsychiatric disease.

Adult↗

PubMed1996

Validity and reproducibility of self-administered joint counts. A prospective longitudinal followup study in patients with rheumatoid arthritis.

OBJECTIVE: To investigate the reproducibility and validity of self-administered joint counts (JC), measuring tenderness, swelling and the combination of both, in a longitudinal study. METHODS: At the outpatient department a form self-administered by patients (SAI-form), was used to measure joint involvement. Concurrent joint examinations were performed by an assessor. The JC and scores for groups of joints by assessors were correlated with those by patients. As a retest the form was completed again by the patients within 10 days. Correlations between the JC measured by the test and retest were computed to investigate reproducibility. RESULTS: Correlations between test and retest were high (> 0.7). Correlations between JC and groups of joints measured by the assessors and by the patients were moderate (0.06). Correlations with other disease activity variables did not differ between assessors' and patients' joint examination scores. CONCLUSION: The patient-administered joint examination was reproducible; however, correlation with the assessors' joint examination was moderate. The value of the self-administered joint count needs further examination and cannot yet replace the assessor's joint examination.

Adult↗

PubMed1996

Reproducibility of the circadian blood pressure fall at night in healthy young volunteers.

The aim of this study was to evaluate the reproducibility of the circadian blood pressure (BP) change in normal healthy volunteers. The subjects were 32 healthy, young, normotensive volunteers who underwent 24 h ambulatory BP monitoring on two occasions, at least 4 weeks apart. Data were analysed using standard definitions of day and night (i.e. 07.00-22.00 for daytime and 22.00-07.00 for night time), event diaries to identify individual's day and night time and a time independent method (cusum analysis). Intraindividual variations of BP were assessed using the coefficient of variation (CV). The mean 24 h BP was very reproducible with a CV of 4.7%. Using the fixed definition of day and night, mean night time systolic blood pressure (SBP) was significantly reduced on the second visit compared to the first (P < 0.001). Using fixed times for day and night, day-night difference was poorly reproducible, with a CV of 52% for SBP and 59% for diastolic blood pressure (DBP), however this improved using diary based day-night to 40/41% and cusum analysis to 24.6/28.1%. We recommend that circadian BP changes are studied using individual definitions of day and night or time independent methods such as cusum analysis.

Adult↗

PubMed1996

Studies on the reproducibility of allergic contact dermatitis.

Diagnosis of allergic contact dermatitis depends upon the use of epicutaneous patch tests with suspected antigens. It has been claimed that the method is unreliable because of variability. Therefore, we have tested this by comparing responses to various forms of replicate, standardized challenge in nickel-sensitive subjects. Nickel-containing coins applied at 2-4 different sites on the back elicited similar responses in up to 95% of tests. Serial dilutions of nickel sulphate (NiSO4) applied, in duplicate, gave highly reproducible responses on the back. However, the forearm skin was clearly less responsive. Examination of the effect of the quantity of nickel-containing vehicle showed that, above a certain minimal level, this had no effect on the reproducibility of the responses. In conclusion, the immune system can give highly reproducible responses when presented with standard eliciting stimuli.

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