Progression of Emphysema in a 12-month Hyperpolarized 3He-MRI Study: Lacunarity Analysis Provided a More Sensitive Measure than Standard ADC Analysis
Progression of Emphysema in a 12-month Hyperpolarized 3He-MRI Study: Lacunarity Analysis Provided a More Sensitive Measure than Standard ADC Analysis
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DOI：
10.1016/j.acra.2008.12.017
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发表时间：
2009-06-01
影响因子：
4.8
通讯作者：
Akeson, Per
中科院分区：
文献类型：
--
作者：
Diaz, Sandra;Casselbrant, Ingrid;Akeson, Per
理论基础和目标。吸入性超极化氦-3磁共振(MR)成像用于测量肺气肿患者的肺泡大小。这项研究的目的是验证He-3MR图像可以用来开发肺气肿进展的生物标记物的假设。12名健康对照组和18名肺气肿患者(8名现吸烟者，10名戒烟者)在基线、6个月和12个月时进行了成像。另外9名α-1抗胰蛋白酶缺乏的受试者(4名有肺气肿，6名没有症状)也在基线和6个月时进行了成像。每个受试者都接受了两种肺容量的成像：功能残气量(FRC)和功能残气量加总肺活量的15%。从全肺冠状图像计算表观弥散系数(ADC)的平均值和标准差，并与肺功能测试结果进行相关分析。从2×2×2到6×6×6个体素的数据中检验和计算空隙假设，并计算平均值。在6个月或12个月期间，任何受试者的两个肺体积的平均ADC值都没有变化。FRC和残余量在12个月内增加，表明空气滞留。仅在吸烟者6个月和12个月时，在FRC收集的图像的空洞增加(分别为P=.063和P=.023)。根据含氦肺的MR图像计算的平均ADC值不够敏感，无法检测12个月内的变化。然而，空隙捕捉到了图像中更多的空间信息，并检测到吸烟者的肺气肿进展。
Rationale and Objectives. Inhaled hyperpolarized He-3 magnetic resonance (MR) imaging has been used to measure alveolar size in patients with emphysema. The aim of this study was to test the hypothesis that He-3 MR images could be used to develop a biomarker of emphysema progression.Materials and Methods. Twelve healthy controls and 18 patients with emphysema (eight current smokers, 10 ex-smokers) were imaged at baseline and 6 and 12 months. An additional nine subjects with alpha-1 antitrypsin deficiency (four with emphysema, six without symptoms) were also imaged at baseline and at 6 months. Each subject was imaged at two lung volumes: functional residual capacity (FRC) and FRC plus 15% of total lung capacity. Means and standard deviations of apparent diffusion coefficients (ADCs) were calculated from coronal images of the entire lung and correlated with pulmonary function test results. The lacunarity hypothesis was tested and calculated from the data using a range of 2 x 2 x 2 to 6 x 6 x 6 voxels, and the average was calculated.Results. There was no change in the mean ADC at either lung volume in any subject over the 6- or 12-month period. FRC and residual volume increased over the 12 months, suggesting air trapping. The lacunarity of images collected at FRC increased at 6 and 12 months in smokers only (P = .063 and P = .023, respectively).Conclusions. The mean ADC calculated from MR images of the lungs with helium was not sufficiently sensitive to detect changes over a 12-month period. However, lacunarity captured more of the spatial information in the images and detected emphysema progress in the smokers.