Search Results
precision of STP measured using an optical refractometer and IgG concentration measured using RID in neonatal calf serum by evaluating the amount of variance produced by each test. We hypothesized that STP measured using an optical refractometer would
locomotion have been correlated with observed lameness and altered PVF and VI. 4–6 Limiting variance improves data quality and aids in interpretation of gait analysis results. Variance in GRF values can be affected by dog body weight and conformation
population of dogs in which SI may be unreliable, GRF data need to be normalized to account for the variation among individual dogs to minimize variance when groups of dogs are compared. It is common to normalize GRF data on the basis of body weight, but this
Abstract
Objective—To determine interoperator variance in shunt fraction calculation.
Design—Case series.
Sample Population—101 transrectal portoscintigraphic studies.
Procedure—Results of dynamic portoscintigraphic studies were reviewed by 4 radiologists without knowledge of signalment, history, or medical profile. Results were judged to be negative or positive on the basis of the dynamic scan. Composite images were formulated, and hand-drawn regions of interest were determined for the heart and liver. Time-activity curves were generated, time-zero points were selected, curves were integrated during a 10-second interval, and shunt fractions were calculated.
Results—Radiologists were in agreement regarding positive versus negative results for 99 of 101 studies. Interoperator variance in shunt fraction calculation ranged from 0.4 to 59.6%. For 51 studies with positive results, variance ranged from 2.5 to 59.6% (mean ± SD, 22.8 ± 14.5%); differences among reviewers were significant. For 48 studies with negative results, variance in shunt fraction ranged from 0.4 to 25.9% (mean, 5.3 ± 5.8%); significant differences among reviewers were not detected. Shunt fraction calculations were not exactly reproducible among radiologists in 94 and 100% of studies with negative or positive results, respectively.
Conclusions and Clinical Relevance—Results suggest that shunt fraction values are not reproducible among operators. Range in variability was greater in studies with positive results. This factor may be of particular clinical importance in reassessment of patients after incomplete shunt ligation. (J Am Vet Med Assoc 2001;218:1116–1119)
influence GRFs. 7–11 Normalization of GRFs to body weight and the use of narrow velocity ranges (± 0.3 m/s) with controlled acceleration (± 0.5 m/s 2 ) have been recommended to minimize data variance, as determined on the basis of studies 9,10,12 in small
interpretive criteria for humans. Data analysis —Statistical software e was used to perform all statistical analyses, including descriptive statistics. A nested ANOVA was used to analyze field data to determine the composition of the variance for 3 (isolate
contribution of each repeated measure to data variance was calculated. Results were considered significant at P < 0.05. Results Of the 27 horses included in the study, 13 were geldings and 14 were mares. Horses ranged from 5 to 31 years of age (mean
prospective study reported here was to compare the within-subject variance for CO in healthy anesthetized adult horses when measured by 4 thermodilution protocols (injection of physiologic saline solution chilled to < 5 °C at volumes of 1 mL/15 kg, 1 mL/25 kg
scan was considered a separate event for this analysis. For evaluation of within-patient variance, dogs with multiple CT scans were included only when the same positioning for each CT event was used. Statistical analysis Results for the LEP were
observer (FCS), who was unaware of results from previous measurement trials. Intraobserver variability was determined via calculation of the coefficient of variance determined for 6 measurements for each variable measured in CT images of 1 dog with hind
