Texture analysis in non-contrast enhanced CT: Impact of malignancy on texture in apparently disease-free areas of the liver
Texture analysis in non-contrast enhanced CT: Impact of malignancy on texture in apparently disease-free areas of the liver
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DOI：
10.1016/j.ejrad.2007.12.005
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发表时间：
2009-04-01
影响因子：
3.3
通讯作者：
Chatwin, Chris R.
中科院分区：
文献类型：
--
作者：
Ganeshan, Balaji;Miles, Kenneth A.;Chatwin, Chris R.
目的：为了确定结直肠癌患者肝外和肝内恶性肿瘤的存在是否会改变非增强CT图像的纹理分析，材料和方法：在三组结直肠癌患者中评估非增强CT的肝脏衰减和纹理：（A）15例无恶性肿瘤的对照;（B）9例肝外恶性肿瘤但无肝脏受累的患者;（C）8例肝转移患者。感兴趣区域仅在明显正常的肝组织区域上手动构建，不包括主要血管和肝内脂肪区域，否则可能会改变CT纹理，而不管是否存在恶性肿瘤。在未过滤图像上分析纹理，并在带通图像过滤后突出显示不同空间频率下的图像特征（精细：2像素/1.68 mm宽，中等：6像素/5.04 mm宽，粗糙：12像素/10.08 mm宽）。在两个不同的空间频率的特征对图像的相对贡献表示为滤波器比率（细/中，细/粗和中/粗）。纹理被量化为平均灰度强度、熵和均匀性。纹理在未过滤的图像上没有改变，而在图像过滤后的相对纹理分析发现，与无肿瘤患者相比，肝转移患者的肝脏明显无病区域的细到中等纹理比率存在差异（熵，p = 0.0257）和肝外疾病患者（均匀性，p = 0.0143）。肝脏CT平扫的相对纹理分析可以显示明显病变的变化，肝脏的自由区域，以前需要更复杂的灌注测量进行检测。(C)2007爱思唯尔爱尔兰有限公司保留所有权利。
Objectives: To determine whether texture analysis of non-contrast enhanced computed tomography (CT) images in apparently disease-free areas of the liver is altered by the presence of extra- and intra-hepatic malignancy in colorectal cancer patients.Materials and methods: Hepatic attenuation and texture were assessed from non-contrast enhanced CT in three groups of colorectal cancer patients: (A) 15 controls with no malignancy; (B) nine patients with extra-hepatic malignancy but no liver involvement; (C) eight patients with hepatic metastases. Regions of interest were manually constructed only over apparently normal areas of liver tissue excluding major blood vessels and areas of intra-hepatic fat, which may otherwise alter CT texture irrespective of the presence of malignancy. Texture was analysed on unfiltered images and following band-pass image filtration to highlight image features at different spatial frequencies (fine: 2 pixels/1.68 mm in width, medium: 6 pixels/5.04 mm and coarse: 12 pixels/10.08 mm). The relative contributions made to the image by features at two different spatial frequencies were expressed as filter ratios (fine/medium, fine/coarse and medium/coarse). Texture was quantified as mean grey-level intensity, entropy and uniformity.Results: Texture was not altered on unfiltered images whereas relative texture analysis following image filtration identified differences in fine to medium texture ratios in apparently disease-free areas of the liver in patients with hepatic metastases as compared to patients with no tumour (entropy, p = 0.0257) and patients with extra-hepatic disease (uniformity, p = 0.0143).Conclusions: Relative texture analysis of unenhanced hepatic CT can reveal changes in apparently disease-free areas of the liver that have previously required more complex perfusion measurements for detection. (C) 2007 Elsevier Ireland Ltd. All rights reserved.