Filippi M, Horsfield M A, Rovaris M, Yousry T, Rocca M A, Baratti C, Bressi S, Comi G
Department of Neurology, Scientific Institute Ospedale San Raffaele, University of Milan, Italy.
AJNR Am J Neuroradiol. 1998 Feb;19(2):239-44.
Our goal was to evaluate the intraobserver and interobserver reproducibility of measurements of brain lesion load in multiple sclerosis (MS) by using two proposed acquisition schemes.
Three-millimeter-thick conventional spin-echo (CSE) and fast fluid-attenuated inversion-recovery (FLAIR) sequences were obtained and the lesions segmented using a semiautomated technique based on local thresholding to calculate intraobserver and interobserver reproducibility. These were compared with images obtained from two separate MR units in which 5-mm CSE sequences were obtained and segmented by using the local thresholding technique and also by manual outlining.
The intraobserver coefficient of variation was 4.0% (95% confidence interval [CI], 3.0% to 4.5%) for the 5-mm CSE sequence measured with manual outlining, 3.1% (95% CI, 2.5% to 3.2%) and 5.1% (95% CI, 4.1% to 5.6%) for the two sets of 5-mm CSE sequences measured using the local thresholding technique, 5.7% (95% CI, 3.9% to 6.6%) for the 3-mm CSE sequence, and 2.6% (95% CI, 2.1% to 2.7%) for the fast FLAIR sequence. The interobserver coefficient of variation was 7.1% (95% CI, 4.9% to 8.7%) and 8.3% (95% CI, 6.4% to 9.6%) for the two sets of 5-mm CSE sequences, 7.3% (95% CI, 4.7% to 9.1%) for the 3-mm CSE sequence, and 2.9% (95% CI, 2.3% to 3.3%) for the fast FLAIR sequence. The intraobserver and interobserver reproducibility of measurements obtained with the fast FLAIR technique was significantly better than those obtained with the other techniques.
Our data indicate that the intraobserver and interobserver variability in quantifying MS lesions can be reduced significantly with the use of fast FLAIR sequences, while no significant improvement is gained by reducing the section thickness from 5 mm to 3 mm.
我们的目标是通过使用两种提议的采集方案，评估多发性硬化症（MS）脑病变负荷测量的观察者内和观察者间的可重复性。
获取3毫米厚的传统自旋回波（CSE）和快速液体衰减反转恢复（FLAIR）序列，并使用基于局部阈值的半自动技术对病变进行分割，以计算观察者内和观察者间的可重复性。将这些结果与从两个独立的磁共振单元获得的图像进行比较，在这两个单元中获取了5毫米的CSE序列，并使用局部阈值技术以及手动勾勒轮廓的方法进行分割。
对于使用手动勾勒轮廓测量的5毫米CSE序列，观察者内变异系数为4.0%（95%置信区间[CI]，3.0%至4.5%）；对于使用局部阈值技术测量的两组5毫米CSE序列，变异系数分别为3.1%（95%CI，2.5%至3.2%）和5.1%（95%CI，4.1%至5.6%）；3毫米CSE序列的变异系数为5.7%（95%CI，3.9%至6.6%）；快速FLAIR序列的变异系数为2.6%（95%CI，2.1%至2.7%）。对于两组5毫米CSE序列，观察者间变异系数分别为7.1%（95%CI，4.9%至8.7%）和8.3%（95%CI，6.4%至9.6%）；3毫米CSE序列的变异系数为7.3%（95%CI，4.7%至9.1%）；快速FLAIR序列的变异系数为2.9%（95%CI，2.3%至3.3%）。快速FLAIR技术获得的测量结果的观察者内和观察者间可重复性明显优于其他技术。
我们的数据表明，使用快速FLAIR序列可显著降低MS病变量化中观察者内和观察者间的变异性，而将层厚从5毫米减小到3毫米并未带来显著改善。
