Sanelli Pina C, Nicola Gregory, Tsiouris Apostolos J, Ougorets Igor, Knight Charles, Frommer Bruce, Veronelli Steve, Zimmerman Robert D
Department of Radiology, New York Presbyterian Hospital, Weill Medical College of Cornell University, 520 E 70th St., Starr 630, New York, NY 10021, USA.
AJR Am J Roentgenol. 2007 Jan;188(1):213-8. doi: 10.2214/ajr.05.2188.
The purpose of this study was to assess interobserver and intraobserver variability in evaluation of the reproducibility of quantitative data obtained in semiautomated postprocessing of CT perfusion data sets by observers of different levels of skill and experience and in fully automated postprocessing.
Twenty CT perfusion data sets were postprocessed by a neuroradiologist using an automated postprocessing program and by five observers (neuroradiology attending, neurology attending, radiology resident, senior and junior CT technologists) who received a brief training session in use of software for semiautomated postprocessing. For assessment of intraobserver variability, each observer repeated postprocessing of 10 CT perfusion data sets. Standard regions of interest were placed on identical locations for each observer's cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) maps of three brain regions: an ischemia-infarct region, normal cortical gray matter, and white matter.
The variability in mean quantitative values of CBF, CBV, and MTT was 2.5-9.5% among all observers. Greater variability (20.4%) was introduced with the automated program. High correlation was found among all possible pairings of observers (r = 0.87-0.99). Low correlation was observed between automated postprocessing and postprocessing by all observers. Intraobserver variability in quantitative CT perfusion data ranged from 0.29% to 10.8%. High intraobserver correlation (r = 0.91-0.99) was found for the observers.
Quantitative CBF, CBV, and MTT data obtained from postprocessing of CT perfusion data sets are reproducible among observers with varying levels of skill and experience. Observer interaction with the software is an important component for correct identification of user-defined parameters. Establishing a uniform and standard postprocessing technique is essential for maintaining good reproducibility.
本研究旨在评估不同技能和经验水平的观察者在半自动后处理CT灌注数据集及全自动后处理过程中，对所获得定量数据可重复性评估的观察者间和观察者内变异性。
一名神经放射科医生使用自动后处理程序对20个CT灌注数据集进行后处理，另外五名观察者（神经放射科主治医师、神经内科主治医师、放射科住院医师、资深和初级CT技师）接受了使用半自动后处理软件的简短培训课程后进行后处理。为评估观察者内变异性，每位观察者对10个CT灌注数据集重复进行后处理。在每位观察者的三个脑区（缺血梗死区、正常皮质灰质和白质）的脑血流量（CBF）、脑血容量（CBV）和平均通过时间（MTT）图的相同位置放置标准感兴趣区。
所有观察者之间CBF、CBV和MTT平均定量值的变异性为2.5 - 9.5%。自动程序引入了更大的变异性（20.4%）。观察者的所有可能配对之间均发现高度相关性（r = 0.87 - 0.99）。自动后处理与所有观察者的后处理之间观察到低相关性。CT灌注定量数据的观察者内变异性范围为0.29%至10.8%。观察者之间发现高度的观察者内相关性（r = 0.91 - 0.99）。
从CT灌注数据集后处理获得的定量CBF、CBV和MTT数据在不同技能和经验水平的观察者之间具有可重复性。观察者与软件的交互是正确识别用户定义参数的重要组成部分。建立统一和标准的后处理技术对于保持良好的可重复性至关重要。
