Accuracy of resonance frequency analysis by third generation Osstell® / Precisión del análisis de frecuencia de resonancia mediante Osstell® de tercera generación

The Resonance Frequency Analysis by Osstell® is used in the assessment of primary and secondary implant stability. The aim of this study was to determine its accuracy as a method of testing, checking its repeatability and reproducibility. A pilot study was performed whereby implants were placed in a cow rib to compare several ISQ measurements with the same SmartPeg transducer (repeatability), or with different SmartPegs (reproducibility). Statistical analysis of the data showed a high correlation of the ISQ values obtained in both assays, which suggests that Osstell®analysis can provide high repeatability and reproducibility.

El análisis de frecuencia de resonancia (AFR) por Osstell® se utiliza en la evaluación de la estabilidad primaria y secundaria del implante. El objetivo del presente estudio fue establecer la precisión del AFR mediante Osstell©, como método de prueba empleado en la determinación de la estabilidad implantaria. Se realizó un estudio experimental in vitro, en el que se colocaron implantes en una costilla de vaca y compararon diferentes mediciones del coeficiente de estabilidad del implante (ISQ) obtenidas sobre estos implantes con un mismo transductor SmartPeg (repetibilidad) o con diferentes SmartPegs (reproductibilidad). El análisis estadístico de los datos mostró una elevada correlación de los ISQ obtenidos en ambos ensayos, lo cual sugiere una reproductibilidad y repetibilidad elevada del análisis mediante Osstell.

Evaluación del sistema de medición en la fabricación de gel de hidróxido de aluminio / Evaluation of the measurement system analysis in the aluminum hydroxide gel production

Introducción: el estudio de repetibilidad y reproducibilidad se basa en la cuantificación experimental de la contribución del sistema de medición a la variabilidad total observada, y determina si este es aceptable o no. Objetivo: evaluar el sistema de medición en la fabricación de gel de hidróxido de aluminio mediante el estudio de repetibilidad y reproducibilidad. Métodos: el estudio de repetibilidad y reproducibilidad se desarrolló a través de un experimento factorial balanceado de efecto aleatorio. Se tomaron 10 muestras (partes) del producto terminado, de un lote de producción, las que se midieron dos veces por tres operadores seleccionados aleatoriamente. Las mediciones se realizaron en el Laboratorio de Investigación de Medilip (nivel de confianza: α= 0,05; 95 por ciento). Se aplicó el método ANOVA cruzado. El procesamiento de los datos se realizó utilizando el paquete estadístico Minitab 16. Resultados: según los índices Cg y Cgk (estudio tipo I), se comprobó que el sistema de medición fue aceptable. Con el estudio de repetibilidad y reproducibilidad se determinó que el factor que contribuye en mayor cuantía resultó el denominado partes (96,85 por ciento) y que la contribución de la variabilidad del sistema de medición (3,15 por ciento) fue aceptable, así como el porcentaje de la varianza del estudio con respecto a la varianza total (17,75 por ciento). Conclusiones: el estudio de repetibilidad y reproducibilidad identifica al factor parte como el de mayor contribución a la variabilidad total y que el sistema de medición es adecuado, lo cual está avalado por los índices reconocidos internacionalmente, por lo que se recomenda tomar acciones para mejorar el desempeño(AU)

Introduction: the repeatability and reproducibility study is based on experimental quantitation of the measurement system contribution to the total observed variability, and is aimed at determining whether this system is acceptable. Objective: to evaluate the measurement system in aluminum hydroxide gel production process through the repeatability and reproducibility study. Methods: this study was carried out through a balanced factorial experiment of random effect. Ten finished product samples from a production batch were measured twice by three randomly selected operators. The measurements were made in the Medilip research laboratory (Cross ANOVA method. Confidence level α= 0.05; 95 percent). The statistical package Minitab 16 served to process relevant data. Results: according to Cg and Cgk (type I Study) indexes, the measurement system was acceptable. The repeatability and reproducibility study determined that the main contributing factor was parts (98.85 percent) and that the measurement system variability (3.15) was also allowable as well as the percentage of the study variance with regard to the total variance (17.75 percent). Conclusions: the repeatability and reproducibility study identifies the factor called parts as the one largely contributing to the total variability and determines that the measurement system is adequate, which is endorsed by international set standards, so it is recommended to take actions to improve its performance(AU)

Repeatability and reproducibility of TonoLab rebound tonometer in DBA/2J mice / 中华实验眼科杂志

Background Reliable intraocular pressure (IOP) measurement is essential in glaucomatous study.TonoLab is a newly designed tonometer for small animals,however,its repeatability and reproducibility remains unknown.Objective This study aimed to evaluate the repeatability and reproducibility of TonoLab rebound tonometer in DBA/2J mice.Methods Intraocular pressure was measured in both eyes of 63 DBA/2J mice aged 7 months under systemic anesthesia with TonoLab rebound tonometer.IOP of each eye was measured for 3 times by two observers independently and consecutively using TonoLab rebound tonometer,and the data were obtained in single blind method.Within standard deviation (Sw),interclass correlation coefficient (ICC),within coefficient of variation (CVw) and corresponding 95％ confidence interval (CI) were calculated to evaluate the repeatability of measuring result from single observer,and Bland-Altman method was used to assess the agreement between two observers.The abnormal data which affected repeatability was analyzed.Results Among the 126 eyes,105 eyes showed the normal IOP with mean value (12.98 ± 1.05) mmHg from observer 1 and (12.41 ±0.92) mmHg from observer 2.Ocular hypertension was found in 21 eyes with mean value (27.76 ± 1.95) mmHg and (27.49 ± 1.28) mmHg for observer 1 and observer 2 respectively.Sw,ICC and CVw for observer 1/observer 2 were 1.34/1.11 mmHg,0.90/0.92,8.24％/7.42％ in normal eyes and 2.21/1.49 mmHg,0.89/0.95,6.97％/4.82％ in hypertensive eyes.The average bias between two measuring values from different observers was 0.60 mmHg in the normal eyes (95％ CI:-5.20-6.30 mmHg) and 0.30 mmHg in the hypertensive eyes (95％ CI:-7.30-7.80 mmHg).Conclusions TonoLab rebound tonometer can offer a good intraobserver repeatability in both normal and hypertensive eyes in mice,but the agreement between two observers is outside an acceptable level.So we consider IOP in mice obtained by TonoLab rebound tonometer is reliable and accurate from a single observer.

Repeatability and reproducibility of macular thickness profiles of intra-retinal layers determined by an automated algorithm with RTVue100 OCT / 中华实验眼科杂志

Background Evaluation of intra-retinal layer thickness plays an important role in the diagnosis and monitor of various eye diseases,and spectral domain optical coherence tomography (OCT) is a frequently used tool.Software analysis method was used to measure the retinal thickness in previous study,but the study on the reliability of automatic layered software is lack.Objective This study was to evaluate the repeatability and reproducibility of thickness profile measurement of intra-retinal layers determined by an automated algorithm applied to OCT images from RTVue100 OCT instrument.Methods In this prospective cross-sectional study,retinal thickness images at 6 mm around fovea were obtained from 18 right eyes of 18 normal subjects with RTVue100 OCT instrument.The retinal images were segmented into retinal nerve fiber layer (RNFL),ganglion cell layer and inner plexiform layer(GCL+IPL),inner nuclear layer (INL),outer plexiform layer (OPL),outer nuclear layer (ONL),inner segment (IS),outer segment (OS) and retinal pigment epithelial (RPE) layer using automated algorithm method.Then Matlab software was used to analyze the measuring outcome.Interclass correlation coefficient (ICC) and coefficients of reproducibility (COR) were calculated from the results of two-time examination by the same examiner to evaluate the repeatability and from the results of two different examiners to assess the reproducibility.Written informed consent was obtained from each subject prior to any medical procedure.Results The entire retinal thickness measured by RTVue-OCT was (303.22± 14.10) μm in the horizontal meridian and (306.68 ± 13.32) μm in the vertical meridian,with the maximum values of retinal thickness in the GCL+ IPL and ONL.Whether in the horizontal meridian or in the vertical meridian,the ICC and COR were ＜0.60 in the OPL,IS and OS;while those in the RNFL,GCL+IPL,INL,ONL and RPE layer were ＞0.70.Conclusions RTVue OCT with automated algorithm is a useful and reliable approach to the measurement of intra-retinal layer thickness.Automated segmentation can offer accurate and repeatable thickness profile of OCT retinal image.This method may improve the diagnosis and monitoring of retinal diseases.