Filippi M, Horsfield M A, Bressi S, Martinelli V, Baratti C, Reganati P, Campi A, Miller D H, Comi G
Department of Neurology, Scientific Institute Ospedale San Raffaele, University of Milan, Italy.
Brain. 1995 Dec;118 ( Pt 6):1593-600. doi: 10.1093/brain/118.6.1593.
The measurement of MRI lesion load in multiple sclerosis is increasingly being used to evaluate the natural history of the disease and to monitor the efficacy of treatments. If, as might occur in multicentre studies, lesion load is measured by several observers in different patients or by the same observer in serial scans, it would be necessary to utilize a technique which provides results with high inter- and intra-observer agreements. This study was performed to evaluate the intra- and inter-observer agreement of semi-automated lesion volume measurement using thresholding, and to compare them with those obtained using an arbitrary scoring system (ASS) and a quantitative manual tracing method (MTM). Brain MRIs were obtained for 20 clinically definite multiple sclerosis patients and were evaluated independently by three observers. The median intra- and inter-observer agreements were, respectively, 88.5% (range 69.0-96.8%) and 79.0% (range 73.3-98.3%) using the ASS, 95.0% (range 85.1-99.4%) and 93.4% (range 77.3-98.3%) for the MTM, 96.3% (range 94.2-98.9%) and 93.7% (range 83.8-98.3%) for the semi-automated technique. The intra- and inter-observer agreements for the semi-automated technique increased to 98.5% (range 96.3-99.8%) and 96.1% (range 90.5-98.6%) when a consensus in the choice of threshold for lesion segmentation was reached. The intra- and inter-observer agreements were significantly greater for the semi-automated method compared with both the arbitrary scoring and the MTMs. The intra-observer variability for the semi-automated technique was significantly lower (P < 0.0001) than the inter-observer variability obtained using the same technique. These data indicate that it is possible to obtain high intra- and inter-observer agreements using a semi-automatic thresholding technique to quantify lesion volumes in multiple sclerosis. The technique may prove useful in multicentre studies, in which a single observer is still preferable.
在多发性硬化症中，磁共振成像（MRI）病灶负荷的测量越来越多地用于评估疾病的自然史和监测治疗效果。在多中心研究中可能会出现这种情况，即由不同的观察者对不同患者的病灶负荷进行测量，或者由同一观察者对连续扫描的结果进行测量，此时就需要采用一种能够提供观察者间和观察者内高度一致性结果的技术。本研究旨在评估使用阈值法进行半自动病灶体积测量时观察者内和观察者间的一致性，并将其与使用任意评分系统（ASS）和定量手动追踪法（MTM）所获得的一致性进行比较。对20例临床确诊的多发性硬化症患者进行脑部MRI检查，并由三名观察者独立评估。使用ASS时，观察者内和观察者间的中位数一致性分别为88.5%（范围69.0 - 96.8%）和79.0%（范围73.3 - 98.3%）；MTM分别为95.0%（范围85.1 - 99.4%）和93.4%（范围77.3 - 98.3%）；半自动技术分别为96.3%（范围94.2 - 98.9%）和93.7%（范围83.8 - 98.3%）。当在病灶分割阈值的选择上达成共识时，半自动技术的观察者内和观察者间一致性分别提高到98.5%（范围96.3 - 99.8%）和96.1%（范围90.5 - 98.6%）。与任意评分法和MTM相比，半自动方法的观察者内和观察者间一致性显著更高。半自动技术的观察者内变异性显著低于（P < 0.0001）使用相同技术获得的观察者间变异性。这些数据表明，使用半自动阈值技术来量化多发性硬化症的病灶体积可以获得较高的观察者内和观察者间一致性。该技术在多中心研究中可能会被证明是有用的，在这类研究中，单个观察者仍然是更可取的。
