Laboratory of Neuro Imaging, Department of Neurology, UCLA School of Medicine, Los Angeles, California 90095-1769., USA.
Hum Brain Mapp. 2010 Apr;31(4):499-514. doi: 10.1002/hbm.20882.
A key question in designing MRI-based clinical trials is how the main magnetic field strength of the scanner affects the power to detect disease effects. In 110 subjects scanned longitudinally at both 3.0 and 1.5 T, including 24 patients with Alzheimer's Disease (AD) [74.8 +/- 9.2 years, MMSE: 22.6 +/- 2.0 at baseline], 51 individuals with mild cognitive impairment (MCI) [74.1 +/- 8.0 years, MMSE: 26.6 +/- 2.0], and 35 controls [75.9 +/- 4.6 years, MMSE: 29.3 +/- 0.8], we assessed whether higher-field MR imaging offers higher or lower power to detect longitudinal changes in the brain, using tensor-based morphometry (TBM) to reveal the location of progressive atrophy. As expected, at both field strengths, progressive atrophy was widespread in AD and more spatially restricted in MCI. Power analysis revealed that, to detect a 25% slowing of atrophy (with 80% power), 37 AD and 108 MCI subjects would be needed at 1.5 T versus 49 AD and 166 MCI subjects at 3 T; however, the increased power at 1.5 T was not statistically significant (alpha = 0.05) either for TBM, or for SIENA, a related method for computing volume loss rates. Analysis of cumulative distribution functions and false discovery rates showed that, at both field strengths, temporal lobe atrophy rates were correlated with interval decline in Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog), mini-mental status exam (MMSE), and Clinical Dementia Rating sum-of-boxes (CDR-SB) scores. Overall, 1.5 and 3 T scans did not significantly differ in their power to detect neurodegenerative changes over a year. Hum Brain Mapp, 2010. (c) 2009 Wiley-Liss, Inc.
在设计基于 MRI 的临床试验时，一个关键问题是扫描仪的主磁场强度如何影响检测疾病效果的能力。在 110 名纵向扫描的受试者中，包括 24 名阿尔茨海默病（AD）患者[74.8 +/- 9.2 岁，MMSE：基线时 22.6 +/- 2.0]、51 名轻度认知障碍（MCI）患者[74.1 +/- 8.0 岁，MMSE：26.6 +/- 2.0]和 35 名对照者[75.9 +/- 4.6 岁，MMSE：29.3 +/- 0.8]，我们评估了更高场强的 MR 成像是否提供了更高或更低的能力来检测大脑的纵向变化，使用张量基形态计量学（TBM）来揭示进行性萎缩的位置。正如预期的那样，在两种场强下，AD 患者的进行性萎缩广泛存在，而 MCI 患者的萎缩更具空间限制。功率分析显示，为了检测到 25%的萎缩速度减缓（80%的功率），在 1.5 T 下需要 37 名 AD 和 108 名 MCI 受试者，而在 3 T 下需要 49 名 AD 和 166 名 MCI 受试者；然而，在 TBM 或用于计算体积损失率的相关方法 SIENA 中，1.5 T 的增加功率都没有统计学意义（alpha = 0.05）。分析累积分布函数和假发现率显示，在两种场强下，颞叶萎缩率与阿尔茨海默病评估量表认知分量表（ADAS-cog）、简易精神状态检查（MMSE）和临床痴呆评定总和量表（CDR-SB）评分的间隔下降相关。总的来说，1.5 和 3 T 扫描在一年内检测神经退行性变化的能力没有显著差异。人脑映射，2010。（c）2009 年 Wiley-Liss，Inc.
