Boers A M, Zijlstra I A, Gathier C S, van den Berg R, Slump C H, Marquering H A, Majoie C B
From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.) Biomedical Engineering and Physics (A.M.B., H.A.M.), Academic Medical Center, Amsterdam, the Netherlands Institute of Technical Medicine (A.M.B.)
From the Departments of Radiology (A.M.B., I.A.Z., R.v.d.B., H.A.M., C.B.M.).
AJNR Am J Neuroradiol. 2014 Dec;35(12):2279-86. doi: 10.3174/ajnr.A4042. Epub 2014 Aug 7.
Quantification of blood after SAH on initial NCCT is an important radiologic measure to predict patient outcome and guide treatment decisions. In current scales, hemorrhage volume and density are not accounted for. The purpose of this study was to develop and validate a fully automatic method for SAH volume and density quantification.
The automatic method is based on a relative density increase due to the presence of blood from different brain structures in NCCT. The method incorporates density variation due to partial volume effect, beam-hardening, and patient-specific characteristics. For validation, automatic volume and density measurements were compared with manual delineation on NCCT images of 30 patients by 2 radiologists. The agreement with the manual reference was compared with interobserver agreement by using the intraclass correlation coefficient and Bland-Altman analysis for volume and density.
The automatic measurement successfully segmented the hemorrhage of all 30 patients and showed high correlation with the manual reference standard for hemorrhage volume (intraclass correlation coefficient = 0.98 [95% CI, 0.96-0.99]) and hemorrhage density (intraclass correlation coefficient = 0.80 [95% CI, 0.62-0.90]) compared with intraclass correlation coefficient = 0.97 (95% CI, 0.77-0.99) and 0.98 (95% CI, 0.89-0.99) for manual interobserver agreement. Mean SAH volume and density were, respectively, 39.3 ± 31.5 mL and 62.2 ± 5.9 Hounsfield units for automatic measurement versus 39.7 ± 32.8 mL and 61.4 ± 7.3 Hounsfield units for manual measurement. The accuracy of the automatic method was excellent, with limits of agreement of -12.9-12.1 mL and -7.6-9.2 Hounsfield units.
The automatic volume and density quantification is very accurate compared with manual assessment. As such, it has the potential to provide important determinants in clinical practice and research.
在首次非增强计算机断层扫描（NCCT）上对蛛网膜下腔出血（SAH）后的血量进行量化是预测患者预后和指导治疗决策的一项重要影像学指标。在当前的量表中，未考虑出血体积和密度。本研究的目的是开发并验证一种用于SAH体积和密度量化的全自动方法。
该自动方法基于NCCT中不同脑结构因血液存在而导致的相对密度增加。该方法纳入了因部分容积效应、线束硬化和患者特定特征引起的密度变化。为进行验证，由两名放射科医生将自动体积和密度测量结果与30例患者的NCCT图像上的手动勾勒结果进行比较。使用组内相关系数以及针对体积和密度的Bland-Altman分析，将与手动参考标准的一致性与观察者间的一致性进行比较。
自动测量成功分割了所有30例患者的出血区域，与手动参考标准相比，出血体积（组内相关系数=0.98[95%CI，0.96 - 0.99]）和出血密度（组内相关系数=0.80[95%CI，0.62 - 0.90]）显示出高度相关性，而手动观察者间一致性的组内相关系数分别为0.97（95%CI，0.77 - 0.99）和0.98（95%CI，0.89 - 0.99）。自动测量的平均SAH体积和密度分别为39.3±31.5 mL和62.2±5.9亨氏单位，而手动测量分别为39.7±32.8 mL和61.4±7.3亨氏单位。自动方法的准确性极佳，一致性界限为-12.9至12.1 mL和-7.6至9.2亨氏单位。
与手动评估相比，自动体积和密度量化非常准确。因此，它有可能在临床实践和研究中提供重要的决定因素。
