Translational Brain Tumor Program, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
J Magn Reson Imaging. 2010 Mar;31(3):538-48. doi: 10.1002/jmri.22068.
To present comprehensive examinations of the assumptions made in functional diffusion map (fDM) analyses and provide a biological basis for fDM classification.
Sixty-nine patients with gliomas were enrolled in this study. To determine the sensitivity of apparent diffusion coefficients (ADCs) to cellularity, cell density from stereotactic biopsy specimens was correlated with preoperative ADC maps. For definition of ADC thresholds used for fDMs, the 95% confidence intervals (CI) for changes in voxel-wise ADC measurements in normal appearing tissue was analyzed. The sensitivity and specificity to progressing disease was examined using both radiographic and neurological criteria.
Results support the hypothesis that ADC is inversely proportional to cell density with a sensitivity of 1.01 x 10(-7) [mm(2)/s]/[nuclei/mm(2)]. The 95% CI for white matter = 0.25 x 10(-3) mm(2)/s, gray matter = 0.31 x 10(-3) mm(2)/s, a mixture of white and gray matter = 0.40 x 10(-3) mm(2)/s, and a mixture of white matter, gray matter, and cerebrospinal fluid = 0.75 x 10(-3) mm(2)/s. Application of these measurements as ADC thresholds produce varying levels of sensitivity and specificity to disease progression, which were all significantly better than chance.
This study suggests fDMs are valid biomarkers for brain tumor cellularity.
全面检查功能扩散映射（fDM）分析中所做的假设，并为 fDM 分类提供生物学依据。
本研究纳入 69 例脑胶质瘤患者。为了确定表观扩散系数（ADC）对细胞密度的敏感性，对立体定向活检标本中的细胞密度与术前 ADC 图进行了相关性分析。为了确定用于 fDM 的 ADC 阈值，分析了正常组织中体素 ADC 测量值变化的 95%置信区间（CI）。使用影像学和神经学标准检查了疾病进展的敏感性和特异性。
结果支持 ADC 与细胞密度成反比的假设，其敏感性为 1.01 x 10(-7) [mm(2)/s]/[nuclei/mm(2)]。95%CI 为白质= 0.25 x 10(-3) mm(2)/s，灰质= 0.31 x 10(-3) mm(2)/s，白质和灰质混合物= 0.40 x 10(-3) mm(2)/s，白质、灰质和脑脊液混合物= 0.75 x 10(-3) mm(2)/s。这些测量值作为 ADC 阈值的应用产生了不同水平的疾病进展敏感性和特异性，均明显优于随机水平。
本研究表明 fDM 是脑肿瘤细胞密度的有效生物标志物。
