Evaluation of the standard deviation from duplicate results

Synek, Václav

doi:10.1007/s00769-008-0390-x

Cited by 51 publications

(44 citation statements)

References 4 publications

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“…Repeatability was expressed as the coefficient of variation (CoV) calculated by dividing the mean of the duplicate measurements by the standard deviation of these measurements [31]. The repeatability coefficient was expressed as 2.77 times the within-subject standard deviation [32].…”

Section: Discussionmentioning

confidence: 99%

Echocardiographic assessments of longitudinal left ventricular function in healthy English Springer spaniels

Dickson¹,

Shave

Rishniw³

et al. 2017

Journal of Veterinary Cardiology

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Section: Discussionmentioning

confidence: 99%

Echocardiographic assessments of longitudinal left ventricular function in healthy English Springer spaniels

Dickson¹,

Shave

Rishniw³

et al. 2017

Journal of Veterinary Cardiology

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“…To examine the linear proportionality of the estimated average particle speed

v

to the applied flow rate, a linear regression analysis of the estimated speed

v

versus the applied flow rate was performed. To quantify the agreement between the 2 measurement series, A and B, the coefficient of variation (

CV

) was calculated via

C V (%) = 100 \times \frac{SD}{Mean},

with

S D = \sqrt{(\sum_{i = 1}^{n} {false(x_{A, i} - x_{B, i} false)}^{2}) / 2 n}

italicMean = \sum_{i = 1}^{n} false(x_{A, i} + x_{B, i} false) / 2 n

, and the number

n

of estimate pairs

x_{1}

and

x_{2}

.…”

Section: Methodsmentioning

confidence: 99%

Assessment of intravoxel incoherent motion MRI with an artificial capillary network: analysis of biexponential and phase‐distribution models

Schneider

Gaaß

Ricke

et al. 2019

Magnetic Resonance in Med

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Purpose To systematically analyze intravoxel incoherent motion (IVIM) MRI in a perfusable capillary phantom closely matching the geometry of capillary beds in vivo and to compare the validity of the biexponential pseudo‐diffusion and the recently introduced phase‐distribution IVIM model. Methods IVIM‐MRI was performed at 12 different flow rates (0.2⋯2.4mL/italicmin) in a capillary phantom using 4 different DW‐MRI sequences (2 with monopolar and 2 with flow‐compensated diffusion‐gradient schemes, with up to 16 b values between 0 and 800s/mm2). Resulting parameters from the assessed IVIM models were compared to results from optical microscopy. Results The acquired data were best described by a static and a flowing compartment modeled by the phase‐distribution approach. The estimated signal fraction f of the flowing compartment stayed approximately constant over the applied flow rates, with an average of f=0.451±0.023 in excellent agreement with optical microscopy (f=0.454±0.002). The estimated average particle flow speeds v=0.25⋯2.7italicmm/s showed a highly significant linear correlation to the applied flow. The estimated capillary segment length of approximately 189um agreed well with optical microscopy measurements. Using the biexponential model, the signal fraction f was substantially underestimated and displayed a strong dependence on the applied flow rate. Conclusion The constructed phantom facilitated the detailed investigation of IVIM‐MRI methods. The results demonstrate that the phase‐distribution method is capable of accurately characterizing fluid flow inside a capillary network. Parameters estimated using the biexponential model, specifically the perfusion fraction f, showed a substantial bias because the model assumptions were not met by the underlying flow pattern.

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“…For each nerve site, we calculated mean CSA and the expert–trainee difference between CSA measurements. We also calculated the coefficient of variation of the repeated CSA measurements for each nerve site as (SD of the expert–trainee CSA differences / mean CSA) × 100% . To assess bias, we compared the expert versus trainee nerve CSA using a two‐tailed paired t test.…”

Section: Methodsmentioning

confidence: 99%

“…We also calculated the coefficient of variation of the repeated CSA measurements for each nerve site as (SD of the expert-trainee CSA differences / mean CSA) 3 100%. 9 To assess bias, we compared the expert versus trainee nerve CSA using a two-tailed paired t test. We compared expertnovice versus expert-experienced interrater CSA differences using a two-tailed t test for 2 samples of unequal variances.…”

Section: Methodsmentioning

confidence: 99%