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At least 1,423 records · Page 79Linked to original sources

PubMed2000

Reproducibility and accuracy of gated SPECT for determination of left ventricular volumes and ejection fraction: experimental validation using MRI.

UNLABELLED: Quantitative gated SPECT (QGS) has been used for computation of left ventricular volumes and ejection fraction. This study evaluated, first, the effect of injected dose, time of imaging, and background activity on the reproducibility of QGS and, second, the accuracy of QGS, compared with cine MRI, for determining left ventricular volumes and ejection fractions in dogs with and without perfusion defects. METHODS: Sixteen dogs were subjected to either chronic occlusion of the circumflex artery (group I, no perfusion defect) or acute occlusion of the anterior descending coronary artery (group II, perfusion defect). Both groups underwent serial MRI and SPECT. RESULTS: ( QGS was very reproducible using the automated program (r = 0.99997). Correlation between left ventricular ejection fraction (LVEF) at 15 and 45 min was poor after the low-dose injection (r = 0.54; SE = 9%) and only fair after the high-dose injection (r = 0.77; SE = 5%). Correlation was poor in the presence of significant background activity (r = 0.36; SE = 12%). Correlation between QGS left ventricular volumes and MRI was good for group I (end-diastolic volume, r = 0.86; end-systolic volume, r = 0.81) and only fair for group II (end-diastolic volume, r = 0.66; end-systolic volume, r = 0.69). The overall LVEF correlation between QGS and MRI was poor (r = 0.51). QGS LVEF (mean +/- SD, 42% +/- 3%) overestimated MRI LVEF (29% +/- 2%). CONCLUSION: QGS provides a highly reproducible estimate of LVEF. However, QGS is affected by changes in background activity, time of imaging, and injected dose. In the presence of perfusion defects, QGS overestimated volume relative to MRI. The correlation between QGS- and MRI-derived LVEF was poor in this canine model.

Animals↗

PubMedDate not supplied

[Validity and reproducibility of a questionnaire on physical activity and non-activity for school children in Mexico City].

OBJECTIVE: To assess the validity and reproducibility of a self-reported questionnaire on physical activity and inactivity, developed for children aged 10-14 in Mexico City. MATERIAL AND METHODS: Between May and December 1996, a self-reported physical activity and inactivity questionnaire was developed and applied twice to a sample of 114 students aged 10 to 14, from a low and middle income population of Mexico City. The children's mothers completed the same questionnaire, and two 24-hour recalls of physical activity were used for comparison. Statistical analysis consisted of central tendency and dispersion measures and Pearson's correlation coefficient. RESULTS: Correlations between hours per day spent in physical activity and inactivity from the children's questionnaire and the 24-hour recall data, were 0.03 for moderate activity, 0.15 for vigorous activity, and 0.51 (p = 0.001) for watching television, adjusted by age, gender, town, and illness prior to the administration of the questionnaire. Compared to the 24-hour recall data, the questionnaire overestimated the time spent watching television, reading or participating in vigorous activity, and underestimated the time engaged in moderate activity. Statistically significant (p < 0.05) six-month reproducibility values were observed for watching television (r = 0.53), sleeping (r = 0.40), moderate (r = 0.38), and vigorous activity (r = 0.55). CONCLUSIONS: Among children of Mexico City aged 10-14, the questionnaire showed acceptable validity in estimating the time watching television, and acceptable reproducibility of the time watching television, vigorous and moderate activity.

Adolescent↗

PubMed2000

Reproducibility of body composition and body water spaces measurements in healthy elderly individuals.

BACKGROUND AND AIMS: The assessment of body composition and water spaces in elderly persons, especially in disease situations, would be a critical component of the nutritional and hydration management. Bioelectrical impedance analysis (BIA) is a validated bed-side technique for the estimate of total body (TBW) and extracellular (ECW) water. The aim of the present study was to address the reproducibility of estimates of TBW, ECW and fat-free mass (FFM) in healthy elderly individuals (n=24, 61 +/- 3.6 yrs). METHODS: Repeated measurements of weight, height, skinfold thickness, TBW and ECW (BIA) were obtained (in almost identical experimental conditions) on days 0, 14, 28 and 42. FFM and the hydration fraction of FFM (HF) were calculated with a three compartment model. RESULTS: Analysis of variance for repeated measurements showed that time did not explain a significant part of the variance in water spaces, FFM, and HF. Mean SDs for repeated measurements were well within 1 litre for water spaces, 1 kg for FFM and 1% for HF. CONCLUSIONS: We conclude that reproducible measurements of water spaces can be obtained with BIA, which could be used to monitor hydration changes. Given the small variability in HF, FFM, can be derived from BIA with good reproducibility.

Aging↗

PubMed2000

Nasal histamine challenge: a reproducible model of induced congestion measured by acoustic rhinometry.

We describe the development of a clinical model of nasal congestion using a fixed dose histamine challenge in normals. The objective was to use histamine to induce a similar degree of nasal congestion as a natural common cold (from unpublished data of 250 cold sufferers) and thus establish a rapid screening system for decongestant drug effects. Sixtynine normal subjects were challenged with histamine diphosphate (300 micrograms/nostril) on 2 visits. Thirtytwo subjects were identified showing reproducible baseline values (< 15%CV (coefficient of variation)) and adequate nasal congestion (minimum 20%) without excessive sneezing. Reproducibility was evaluated in them post challenge using acoustic rhinometry and rhinomanometry. Twentythree subjects showed a variation < 25%CV of nasal volume over multiple visits in a 5 month period. The average reduction in nasal volume and airflow 15 minutes post challenge was 32% and 41% respectively. Acoustic rhinometry values were less variable than rhinomanometry values. Negligible differences (< 2%) in histamine response over visits and similar correlation between measured values at first, second and last visits indicate that 2 visits are adequate to evaluate response reproducibility in a selected population. We conclude that it is feasible to develop a robust clinical model of nasal congestion using histamine.

Acoustics↗

PubMed2001

Reproducibility of an automatic quantitation of regional myocardial wall motion and systolic thickening on gated 99mTc-sestamibi myocardial SPECT.

UNLABELLED: We investigated the reproducibility of an automatic quantitative algorithm for measuring regional myocardial wall motion and systolic thickening. METHODS: 99mTc-sestamibi gated myocardial SPECT with dipyridamole stress was performed twice consecutively on 31 patients with known or suspected coronary artery disease, with the patients in the same position for each scan. With AutoQUANT software, segmental wall motion and systolic thickening were quantified automatically and expressed in millimeters and percentage increase, respectively, for 20 segments. Afterward, the correlation and agreement between repeated measurements were investigated, and the influences of wall location, perfusion grade, and partitioning of the myocardium on reproducibility were evaluated by ANOVA and t testing. RESULTS: High correlations (r = 0.95 for wall motion and 0.88 for systolic thickening) and good agreements (weighted kappa = 0.81 and 0.71, respectively) were obtained from repeated measurements on consecutive gated SPECT. Changes in wall location and perfusion grade did not cause significant differences between repeated measurements (P > 0.05 in ANOVA and t testing), but a change in partitioning did. On Bland-Altman analysis, 2 SDs for repeated wall motion and for systolic thickening were 2.0 mm and 20%, respectively. CONCLUSION: The automatic quantitative algorithm for myocardial SPECT provided by AutoQUANT software has good reproducibility under diverse conditions. A change of motion > 2.0 mm or a change of systolic thickening > 20% can be regarded as significant during a follow-up study using this software.

Adult↗

PubMedDate not supplied

[Reproducibility of spirometry in Mexican workers and international reference values].

OBJECTIVE: To describe spirometric function and adjustment to foreign prediction equations in Mexican workers claiming work related disability. MATERIAL AND METHODS: We reviewed 5771 spirometries done at the Mexican National Institute of Respiratory Diseases performed with equipment and methods proposed by the American Thoracic Society. With the spirometries we generated multiple regression equations separated for men and women based on age and height, compared to other in common use reported by Knudson and Hankinson in North America and by Quanjer in europeans. RESULTS: 80% of the tests were reproducible for FVC and FEV1 according to ATS, whereas 10% were reproducible for neither. Mean FVC in men was 12% above values reported by Quanjer, 22% above Knudson, 3% above Hankinson and 6% above Rodriguez-Reynaga, whereas similar values for women were 18%, 10%, 0% and 1%. Excluding obese and those who had less than 2 acceptable maneuvers, the numbers increase by 1-2%. FEV1 was also above predicted. CONCLUSIONS: Most workers requesting disability are able to generate a reproducible spirometry. However for the same gender, age and height, workers had a FEV1 and a FVC above normal values reported by Knudson and Quanjer and are more similar to those reported by Hankinson in Mexican-Americans. While a set of appropriate reference values are obtained, regression equations obtained from the studied group will generate less error in the evaluation of disability in mexican workers. The English version of this paper is available at: http://www.insp.mx/salud/index.html.

Age Factors↗

PubMed2001

[The Autocad system for planimetric study of the optic disc in glaucoma: technique and reproducibility study].

PURPOSE: To develop a lens planimetry technique for the optic disc using AutoCAD. To determine variability magnitude of the optic disc morphological measurements. METHODS: We employed AutoCAD R.14.0 Autodesk: image acquisition, contour delimitation by multiple lines fitting or ellipse adjustment, image sectorialization and measurements quantification (optic disc and excavation, vertical diameters, optic disc area, excavation area, neuroretinal sector area and Beta atrophy area). Intraimage or operator and interimage o total reproducibility was studied by coefficient of variability (CV) (n=10) in normal and myopic optic discs. RESULTS: This technique allows to obtain optic disc measurement in 5 to 10 minutes time. Total or interimage variability of measurements introduced by one observer presents CV range from 1.18-4.42. Operator or intraimage measurement presents CV range from 0.30-4.21. Optic disc contour delimitation by ellipse adjustment achieved better reproducibility results than multiple lines adjustment in all measurements. CONCLUSIONS: Computer assisted AutoCAD planimetry is an interactive method to analyse the optic disc, feasible to incorporate to clinical practice. Reproducibility results are comparable to other analyzers in quantification optic disc morphology. Ellipse adjustment improves results in optic disc contours delimitation.

Glaucoma↗

PubMed2001

Reproducibility and validity of a food-frequency questionnaire in assessing dietary intakes and food habits in epidemiological cancer studies in Argentina.

A Food-Frequency questionnaire (FFQ) is the method chosen for estimating dietary intake in epidemiological studies because it can provide valid and reliable estimates of usual intake in a variety of populations. Colorectal cancer is associated with diet but no information about validity and reproducibility of dietary exposure assessment is available in Argentina. The purpose of the study is to evaluate the validity and reproducibility of the FFQ used in assessing the relationship between dietary intake and colorectal cancer. Selected nutrient intake, measured by two interviewer-administered FFQs, was compared with average intake derived from using four 24 hour dietary recalls (DR) as the reference method, for 62 control subjects from Córdoba, Argentina. Pearson's product-moment and Spearman correlation coefficients were used. Nutrient intakes were adjusted for energy, sex and age using tertiles of residuals from regression models. Weighted and unweighted kappa statistics were calculated for both FFQs versus DR. The mean correlation coefficients between DR and FFQs were 0.74. Agreement measurement (Kappa) varied from 0.51 to 0.74 for FFQ1 vs. FFQ2 to between 0.71 and 0.87 for FFQ1 and FFQ2. This study demonstrates an acceptable validity and reproducibility for this FFQ. The pattern of the correlation coefficients found in the present study indicates that the FFQ can provide an acceptable assessment of long-term dietary intake in the Argentine population and in other Latin-american areas.

Age Factors↗

PubMed2001

Reproducibility and responsiveness of evaluative outcome measures. Theoretical considerations illustrated by an empirical example.

OBJECTIVE: This article outlines basic methods for quantifying reproducibility and responsiveness of evaluative outcome measures. METHODS: The background noise in stable patients provides the desired information to quantify the reproducibility. From this, the smallest real difference (SRD) for longitudinal differences can be derived. We propose to use the SRD to define responsiveness: from all patients who change according to an external criterion, we take the percentage that changes at least SRD on the outcome measure. A more complete picture of the responsiveness of the outcome measure arises when the receiver operating characteristic (ROC) is constructed, corresponding to all possible cut-off change scores. The proposed methods are illustrated with an empirical example. RESULTS: In the illustration the methods appeared to be very useful and complemented each other. We could evaluate whether the observed change score was larger than that expected due to chance. With the methods it was possible to evaluate both the ability of an instrument to detect change if there is a real change in health status (sensitivity to change) and the ability to detect absence of change if there is no real change (specificity to change). CONCLUSION: We presented the use of SRDs and ROC curves for quantifying reproducibility and responsiveness. We started with the basic notions and arrived at methods that are both understandable and useful.

Health Status Indicators↗

PubMed2002

Chest radiograph abnormalities associated with tuberculosis: reproducibility and yield of active cases.

SETTING: Tertiary care referral centre specialising in respiratory diseases. OBJECTIVES: Chest radiography is a major screening and diagnostic tool for tuberculosis (TB). We evaluated the reproducibility of a radiographic classification system for screening for active TB of immigration applicants to Canada. We also evaluated the validity of this classification system for detection of prevalent active TB among the screened applicants, as well as tuberculin-positive close contacts and symptomatic patients. METHODS: Reproducibility was assessed by re-reading a randomly selected 10% sample of screening chest films. Validity was estimated from the final clinical and microbiologic diagnosis of patients undergoing detailed clinical evaluation. RESULTS: Inter-reader agreement using five broad categories was moderate (kappas of 0.44-0.56), while intra-reader agreement was substantial (kappas of 0.59-0.72). After adjustment for age and patient group, the adjusted odds of active tuberculosis, relative to normal or minor findings or granulomas, for fibronodular changes was 10.2 (95% confidence interval [CI] 3.2-33), for mass or pleural effusion it was 11.6 (95%CI 3.6-37), and for parenchymal infiltrate it was 46.1 (95%CI 18-117). Among tuberculin-positive close contacts, the probability of active tuberculosis was more than 50% if the radiographs showed any mass, pleural disease, or parenchymal infiltrates. CONCLUSION: A simple classification of TB-related chest radiographic abnormalities into five broad categories had moderate to substantial reproducibility of readings, with reasonable validity.

Adolescent↗

PubMedDate not supplied

Reproducibility of retinal nerve fiber layer thickness measurements using scanning laser polarimetry in pseudophakic eyes.

OBJECTIVE: To assess the reproducibility of retinal nerve fiber layer measurements in pseudophakic normal and glaucomatous eyes using scanning laser polarimetry (GDx, Laser Diagnostic Technologies, Inc., San Diego, CA). PATIENTS AND METHODS: Normal and glaucomatous patients with polymethylmethacrylate posterior chamber intraocular lenses that satisfied entry criteria underwent imaging by two experienced operators. Eyes with posterior capsule opacification or vision less than 20/30 were excluded. Baseline images (mean pixel SD less than 8 mm) were obtained on 3 separate days within a 7-week period. Reproducibility, defined as the pooled within eye variance of these 3 measurements and the coefficient of variation for 12 retardation parameters generated by GDx software were calculated. RESULTS: Eighteen eyes (11 glaucoma, 7 normal) of 15 patients (7 female, 8 male) were enrolled (mean age 78 +/- 6 years). Among glaucomatous eyes, the average mean deviation and corrected pattern standard deviation using achromatic automated perimetry (Zeiss-Humphrey, Dublin, CA) was -3.8 +/- 1.5 dB (range, -1.89 to -5.04 dB) and 4.9 +/- 3.3 dB (range 0 to 11.05 dB), respectively. Coefficient of variation was 10% or less for all retardation parameters except ellipse modulation (20.2%) and neural network number (12.4%). Glaucomatous and normal eyes had similar variability for 8 of 12 (66.7%) retardation parameters. Inferior ratio, ellipse modulation, and superior ratio were significantly less variable in glaucomatous eyes (P = 0.007, 0.02, and 0.04 respectively) than normal eyes. Superior integral was more variable in glaucomatous eyes (P = 0.03). CONCLUSION: Retardation measurements may be obtained in pseudophakic eyes with acceptable reproducibility. Normal eyes and eyes with mild glaucomatous damage have similar variability for most retardation parameters.

Aged↗

PubMed2002

Reproducibility and validity of a short food questionnaire for the assessment of dietary habits.

BACKGROUND AND AIM: Dietary changes such as reducing the consumption of foods high in saturated fat, and increasing the daily intake of unsaturated fat, fibre and vitamins may have beneficial effects on long-term health. Accurate dietary information is essential for dietary counselling. Most of the methods used to examine an individual's diet (food records, diet interview, food frequency questionnaires) are too complicated and time-consuming for routine clinical use. There is a need for a fast and simple tool for food assessment. The aim of this study was to evaluate a short and simple food questionnaire for use in clinical practice that emphasises the intakes of fat, fibre, fruit and vegetables representative of the usual diet of an individual or group. METHODS AND RESULTS: A 15-item questionnaire was completed twice on the same day by 111 participants in order to study reproducibility, and its validity was checked by comparing the results with those of a 7-day food record for 101 subjects. The participants reported a positive attitude to the questionnaire. The reproducibility and validity studies comparing the sum scores of the questionnaire and food record gave correlation coefficients of respectively 0.95 and 0.73, thus indicating good agreement. The reproducibility study showed weighted Kappa coefficients ranging from 0.97 for milk and snacks to 0.75 for vegetables. In the validity assessment, the weighted Kappa coefficients ranged from 0.73 for butter and margarine to 0.14-0.25 for vegetables, fish and snacks, which is a less satisfactory result. The correlation coefficient between the sum score of the questionnaire and the percentage of dietary saturated fat was-0.59. CONCLUSIONS: This simple self-administered questionnaire allows for the rapid assessment of the constituents of the usual diet of an individual. It provides a good estimate of dietary fat and fibre but is less accurate in terms of the intake of vegetables, fish and snacks. It also offers an opportunity to discuss central points in the improvement of dietary habits and may be a useful health educational tool in clinical practice.

Adult↗

PubMed2002

Reproducibility of primary motor cortex somatotopy under controlled conditions.

BACKGROUND AND PURPOSE: The somatotopic organization of the contralateral primary motor cortex (M1) and its intra- and intersubject reproducibility has been the subject of many investigations and controversies. A potential explanation for a least some of the conflicting results could be the lack of movement control in the studies performed. The purpose of this study was to investigate these issues under controlled experimental conditions. METHODS: Functional MR imaging was performed in 12 healthy volunteers performing hand, finger, wrist, elbow, foot, and tongue movements. Two experimental sessions were separated by 2 weeks. Controlled conditions were achieved by means of a custom-designed arm and hand manipulandum providing standardization of the movements within and across subjects. RESULTS: The experiments revealed a clear large-scale somatotopy of the contralateral M1 with distinct subregions controlling the foot, arm, and tongue. Despite considerable overlap of the volumes, geometric centers of gravity (COGs) showed statistically significant differences in coordinates between the elbow, wrist, fingers, and hand. COGs showed a high degree of intra- and interindividual reproducibility, particularly for the upper limb movements, in contrast to the activation volumes that proved to be unreliable parameters, despite the controlled conditions. CONCLUSION: These findings support the existence of a gross-scale somatotopic organization yet also demonstrate a clear, fine-scale somatotopy of the within-arm representations. Furthermore, they reveal high reproducibility of the COGs when standardized conditions are applied. This observation highlights the need for movement control to allow for intra- and intersubject comparison.

Adult↗

PubMedDate not supplied

The reproducibility of the circadian BP rhythm in treated hypertensive patients with polycystic kidney disease and mild chronic renal impairment--a prospective ABPM study.

BACKGROUND: Diurnal BP rhythm is known to be abnormal (reduced BP fall with sleep) in chronic renal failure, dialysis and renal transplantation patients. In subjects with primary hypertension and with reduced diurnal BP fall with sleep there is consistent evidence of increased target-organ damage. However, the few studies that have addressed the reproducibility of diurnal rhythm in normal or hypertensive subjects have concluded that the BP fall with sleep is poorly reproducible. It is not known whether the same is true for patients with renal disease. METHODS: In 30 subjects with autosomal polycystic kidney disease (ADPKD), mild chronic renal failure and normal office BP levels on standardised anti-hypertensive treatment, ambulatory blood pressure monitoring (ABPM) was done three times over a twelve month period to assess the reproducibility of blood pressure fall with sleep. RESULTS: When comparing ABPM 2 with the ABPM 1 recording (3 months difference between measurements) only 43.3% of the patients maintained the initial dipping category (defined by quartiles of the ABPM 1 diurnal BP distribution). The same proportion of subjects had a similar dipping category, when ABPM 3 was compared to ABPM 1 (9 months difference between measurements), but a large (24%) subset of patients had dramatic shifts in their amplitude in nocturnal BP fall, significantly greater than those recorded after a shorter inter-measurement interval. Equally important, our study reveals the fact that, with time, there is no tendency to decrease circadian variation: a similar proportion (a quarter to one third) of patients increased or decreased their amplitude in nocturnal BP fall, at 3 and 9 months. When several ABPM measurements are repeated for the same patients, the repeatability is even worse, since only 36.6% of our study population maintained the initial dipping category across all three ABPM determinations (ABPM 1 and ABPM 2 and ABPM 3). CONCLUSIONS: There is a widespread abnormality in diurnal BP rhythm in ADPKD patients with renal impairment, but the extent of this abnormality varies considerably over time. It is too simplistic to assume that, having arbitrarily categorised subjects into "dippers" or "non-dippers", these labels will always be valid. Thus, it would be unwise to extrapolate the impact of a single baseline circadian BP profile on organ target end points.

Antihypertensive Agents↗

PubMed2003

Standardized, reproducible, high resolution global measurements of T1 relaxation metrics in cases of multiple sclerosis.

BACKGROUND AND PURPOSE: We herein present a methodology for standardized and clinically applicable measurement of T1 relaxation maps with high resolution and volumetric coverage by using the commercially available 3D spoiled gradient-echo sequence. The reproducibility of the T1 metrics derived from these maps and their sensitivity to distinguish between control participants and patients with multiple sclerosis are evaluated. METHODS: Axial view 3D RF spoiled data sets with two flip angles were acquired at 1.5 T to generate the T1 maps, with all other imaging parameters (27/6 ms [TR/TE]; field of view, 180 x 240 x 186 mm(3); matrix, 192 x 256 x 124) kept identical between the two acquisitions. T1 maps were collected from 20 normal control participants and 32 patients with multiple sclerosis. An automated and operator-independent method was developed to segment the relaxation maps and define T1 metrics. RESULTS: We showed that the metrics derived from these maps to represent tissue characteristics were highly reproducible (coefficient of variation, approximately 1% to 4%) and were significantly different between normal control participants and patients with multiple sclerosis (P <.001) for the small cohort of patients in this study. CONCLUSION: The commercially accessible 3D spoiled gradient-echo sequence can be used to generate T1 relaxation maps with high resolution and volumetric coverage. The metrics derived from the relaxation maps are reproducible and have been shown to be sensitive to qualitative and quantitative differences between subgroups of patients with multiple sclerosis and control participants, with strong statistical significance. The use of a commercially available sequence enables the standardization and comparison of T1 metrics across different multiple sclerosis centers.

Artifacts↗

PubMed2003

Reproducibility and reliability of pressure flow parameters in women.

OBJECTIVE: The aim of this study was to evaluate the intra- and inter-rater reliability of pressure flow parameters in women. DESIGN: A prospective study. SETTING: Tertiary referral unit in a London teaching hospital. POPULATION: Urodynamic traces of 621 women were studied to assess the reproducibility and reliability of pressure flow parameters. METHODS: Women with lower urinary tract symptoms were studied prospectively. Opening detrusor pressure (ODP), detrusor pressure at maximum flow rate P(detQ(max)), maximum flow rate (Q(max)) and closure detrusor pressure (CDP) were measured by the same observer twice, one week apart. Pressure flows were compared using different media for filling (saline and contrast). All parameters were also measured in nine women from multiple voids during ambulatory urodynamics to assess their reproducibility and finally were remeasured by a second observer. RESULTS: There was good intra-observer agreement for all pressure flow parameters except detrusor pressure at maximum flow rate and good inter-observer agreement for opening detrusor pressure, closure detrusor pressure and detrusor pressure at maximum flow rate. There was no significant difference between parameters using saline or contrast (P > 0.05, independent samples t test). CONCLUSION: Pressure flow parameters appear to be reproducible and consistent urodynamic measurements in women.

Adult↗

PubMed1992

[Reproducibility of the measurement of humeral artery diameter, velocity of carotido-femoral pulse wave and digital pulse wave in normal subjects].

The aim of this study was to assess the intra-observer reproducibility at short and medium term of three non-invasive methods of arterial measurement: in the same day eight volunteers underwent five successive measurements of brachial artery diameter by two dimensional pulsed Doppler of the carotido-femoral pulse wave velocity by a piezoelectric transducer. The measurements were repeated three times at two weeks' interval. The short term (same day) and medium term (after several weeks) reproducibility of the first two methods of measurement was good: 4.69 +/- 2.37%/4.24 +/- 1.90% and 4.09 +/- 1.16%/5.02 +/- 1.71% respectively for brachial artery diameter and carotido-femoral pulse wave velocity. The reproducibility of the method of measuring digital pulse wave velocity was 10.64 +/- 3.50%/11.62 +/- 4.25%, confirming the greater variability of this parameter. Our results with these noninvasive techniques indicate that they may be used to study the arterial system and could be clinically useful in the surveillance of hypertensive patients.

Adult↗

PubMed1992

A reproducible porcine vertebral fracture for biomechanical testing of spinal fixation devices.

To evaluate vertebral fracture fixation devices in the laboratory, it is necessary to produce identical and unstable fractures either in anatomic specimen or animal models. Consistent achievement of this goal has not been reported in the literature. This report presents a technique for the study of reproducibility for a particular vertebral fracture model. A precise anterior defect was created in a vertebra of each specimen drawn from a homogeneous population of mature sow spines. The spines were loaded to failure. Fracture reproducibility was shown by measurement of load and displacement, and confirmed by roentgenographic evaluation. The technique is easily applied to human specimens. Because there is a plethora of fracture fixation devices based on hooks, wires, or, more recently, plates and pedicle screws, the reliability of comparative testing of these devices in the laboratory requires an appropriate and reproducible fracture.

Animals↗