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Short-term Reproducibility (short-term + reproducibility)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

ANALYSIS OF SHORT-TERM REPRODUCIBILITY OF ARTERIAL VASOREACTIVITY BY PULSE-WAVE ANALYSIS AFTER PHARMACOLOGICAL CHALLENGE

CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 1 2009
Biju Paul
SUMMARY 1Pulse-wave analysis (PWA) is an established method to assess arterial wave reflections and arterial vasoreactivity in humans. A high short-term reproducibility of baseline augmentation index (AIx) has been reported. However, the short-term reproducibility of AIx changes following pharmacological challenge with either inhaled salbutamol (endothelium-dependent vasodilatation) or sublingual glyceryl trinitrate (GTN; endothelium-independent vasodilatation), using appropriate statistical methods, is largely unknown. 2Baseline AIx and GTN- and salbutamol-mediated changes in AIx (all corrected for a heart rate of 75 b.p.m.) were measured on two separate occasions, 1 h apart, in 22 healthy controls (mean (±SD) age 52.0 ± 13.4 years) and 11 elderly patients with chronic heart failure (CHF; 73.1 ± 8.7 years). Reproducibility was assessed by measuring intraclass correlation coefficients (ICC), coefficients of variation (CV) and Bland,Altman plots. 3Baseline AIx showed good short-term reproducibility with high ICC in both the control and CHF groups (0.90 and 0.87, respectively). In contrast, in the control and CHF groups, the ICC of GTN- (0.58 and 0.17, respectively) and salbutamol-mediated (0.18 and 0.04, respectively) changes in AIx were substantially low. The CV was relatively low for baseline AIx in control and CHF groups (25.0 and 22.5%, respectively), but not for GTN- (22.3 and 59.8%, respectively) or salbutamol-mediated (45.1 and 184.0%, respectively) changes in AIx. Bland,Altman analysis revealed poor reproducibility, with limits of agreement beyond either +15% or ,15% for changes in AIx after GTN and salbutamol for both control and CHF groups. The changes in blood pressure and heart rate following pharmacological challenge were similar between the two measurements. 4The poor reproducibility of changes in AIx following pharmacological challenge questions the use of this method in acute studies. [source]

Reproducibility of black blood dynamic contrast-enhanced magnetic resonance imaging in aortic plaques of atherosclerotic rabbits

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 1 2010
Claudia Calcagno MD
Abstract Purpose: To investigate the short-term reproducibility of black-blood dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in atherosclerotic rabbits to evaluate the potential of this technique to be a reliable readout of plaque progression and/or regression upon therapeutic intervention. Materials and Methods: Atherosclerotic rabbits were imaged at baseline and 24 hours later with DCE-MRI on a 1.5T MRI system. DCE-MRI images were analyzed by calculating the area under the signal intensity versus time curve (AUC). Intraclass correlation coefficients (ICCs) were used to evaluate interscan, intraobserver, and interobserver reproducibility. In addition, the test,retest coefficient of variation (CoV) was evaluated. Results: Statistical analyses showed excellent interscan, intraobserver, and interobserver agreement. All ICCs were greater than 0.75, P < 0.01 indicating excellent agreement between measurements. Conclusion: Experimental results show good interscan and excellent intra- and interobserver reproducibility, suggesting that DCE-MRI could be used in preclinical settings as a read-out for novel therapeutic interventions for atherosclerosis. This preliminary work encourages investigating the reproducibility of DCE-MRI also in clinical settings, where it could be used for monitoring high-risk patients and in longitudinal clinical drug trials. J. Magn. Reson. Imaging 2010;32:191,198. © 2010 Wiley-Liss, Inc. [source]

2322: Reproducibility of retinal vessel hemoglobin oxygenation saturation in healthy subjects

ACTA OPHTHALMOLOGICA, Issue 2010
M LASTA
Purpose Only recently systems for the measurement of hemoglobin oxygenation saturation in retinal vessels became commercially available. In the present study a fundus camera equipped with a dual wavelength transmission filter and a CCD camera was used (Imedos, Jena, Germany). Two monochromatic fundus images at 548 and 610 nm were recorded simultaneously and the oxygen saturation (SaO2) was calculated based on the optical density ratio. Methods A study on test/retest, short-term and day-to-day reproducibility of the technique was done in 14 healthy subjects. To assess test/retest variability fundus images were taken at each measurement cycle. To assess short-term reproducibility 2 such cycles of 3 fundus images were done within 15 minutes. Finally, this cycle of measurements was done on the next day to assess day-to-day reproducibility. Data were evaluated separately for retinal branch arteries and branch veins. The reproducibility was calculated using the standard deviation (SD) of the measurements. Results In retinal branch veins the SaO2 was 49±9% (range 32-69%, 38 vessels) and in retinal branch arteries 91±8% (range 77-112%, 40 vessels). The test/retest SD was 5.4±3.7% in retinal veins and 3.0±2.3% in retinal arteries. The short term SD was 4.7±3.7% in retinal veins and 2.9±2.1% in retinal arteries. The day-to-day SD was 6.2±4.1% in retinal veins and 4.0±2.8% in retinal arteries. Conclusion Our data indicate that the test/retest, short-term and day-to-day reproducibility of the technique is acceptable. Hence, the system may be adequate to follow oxygen saturation during disease processes. The data obtained in retinal branch arteries indicates, however, that the validity of measurements requires further studies. [source]