使用数字体模评估 CT 和 MR 灌注分析软件的准确性和可靠性。
Accuracy and reliability assessment of CT and MR perfusion analysis software using a digital phantom.
机构信息
Division of Ultra-High Field MRI and Department of Radiology, Iwate Medical University, 19-1 Uchimaru, Morioka 020-8505, Japan.
出版信息
Radiology. 2013 Apr;267(1):201-11. doi: 10.1148/radiol.12112618. Epub 2012 Dec 6.
PURPOSE
To design a digital phantom data set for computed tomography (CT) perfusion and perfusion-weighted imaging on the basis of the widely accepted tracer kinetic theory in which the true values of cerebral blood flow (CBF), cerebral blood volume (CBV), mean transit time (MTT), and tracer arrival delay are known and to evaluate the accuracy and reliability of postprocessing programs using this digital phantom.
MATERIALS AND METHODS
A phantom data set was created by generating concentration-time curves reflecting true values for CBF (2.5-87.5 mL/100 g per minute), CBV (1.0-5.0 mL/100 g), MTT (3.4-24 seconds), and tracer delays (0-3.0 seconds). These curves were embedded in human brain images. The data were analyzed by using 13 algorithms each for CT and magnetic resonance (MR), including five commercial vendors and five academic programs. Accuracy was assessed by using the Pearson correlation coefficient (r) for true values. Delay-, MTT-, or CBV-dependent errors and correlations between time to maximum of residue function (Tmax) were also evaluated.
RESULTS
In CT, CBV was generally well reproduced (r > 0.9 in 12 algorithms), but not CBF and MTT (r > 0.9 in seven and four algorithms, respectively). In MR, good correlation (r > 0.9) was observed in one-half of commercial programs, while all academic algorithms showed good correlations for all parameters. Most algorithms had delay-dependent errors, especially for commercial software, as well as CBV dependency for CBF or MTT calculation and MTT dependency for CBV calculation. Correlation was good in Tmax except for one algorithm.
CONCLUSION
The digital phantom readily evaluated the accuracy and characteristics of the CT and MR perfusion analysis software. All commercial programs had delay-induced errors and/or insufficient correlations with true values, while academic programs for MR showed good correlations with true values.
SUPPLEMENTAL MATERIAL
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112618/-/DC1.
目的
基于被广泛接受的示踪动力学理论，设计一个用于 CT 灌注和灌注加权成像的数字体模数据集，其中脑血流量（CBF）、脑血容量（CBV）、平均通过时间（MTT）和示踪剂到达延迟的真实值是已知的，并评估使用该数字体模的后处理程序的准确性和可靠性。
材料和方法
通过生成反映 CBF（2.5-87.5 mL/100 g/分钟）、CBV（1.0-5.0 mL/100 g）、MTT（3.4-24 秒）和示踪剂延迟（0-3.0 秒）真实值的浓度-时间曲线来创建体模数据集。这些曲线被嵌入到人类大脑图像中。使用 13 种算法（包括 5 种商业供应商和 5 种学术程序）对数据进行分析。通过使用 Pearson 相关系数（r）评估真实值的准确性。还评估了延迟、MTT 或 CBV 依赖性误差以及残留函数（Tmax）最大值时间之间的相关性。
结果
在 CT 中，CBV 通常得到很好的再现（12 种算法中的 r>0.9），但 CBF 和 MTT 则不然（7 种和 4 种算法中的 r>0.9）。在 MR 中，一半的商业程序观察到良好的相关性（r>0.9），而所有学术算法都显示出所有参数的良好相关性。大多数算法具有与延迟相关的误差，特别是对于商业软件，以及 CBF 或 MTT 计算的 CBV 依赖性和 CBV 计算的 MTT 依赖性。Tmax 除了一个算法外相关性都很好。
结论
数字体模可以很好地评估 CT 和 MR 灌注分析软件的准确性和特性。所有商业程序都存在与延迟相关的误差和/或与真实值的相关性不足，而 MR 的学术程序则与真实值具有良好的相关性。
补充材料
http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12112618/-/DC1.
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