Detection of Neuronal Loss in Alzheimer Disease Using Magnetization Transfer MR Imaging

目的：应用高分辨率磁化转移（MT）、快速自旋回波（FSE）和快速短反转-时间反转-恢复（FSTIR）技术评估早期阿尔茨海默病（AD）患者海马和内嗅皮质神经元丢失的相关变化。方法：采用1.5特斯拉超导磁共振扫描仪（Signal Horizon Lx， GEMS）对15例早期AD患者和10例年龄匹配的正常志愿者进行前瞻性检查。我们使用的脉冲序列是原始优化的FSTIR 4000/120/36 （TR/Tl/Teff）序列，以及单层和多层采集的质子密度加权（PDW） FSE 1000/24 （TR/Teeff）序列。在每种情况下，通过乳状体获得4 mm厚的冠状图像，视场为17cm，零插值的512x512矩阵。分别测量海马、内嗅皮质、扣带回、颞上回、尾状核、深部白质和脑脊液的信号强度。在FSTIR图像上手动确定测量区域，其中灰质/白质对比度显著。每个结构的MT比（MTR）由单层/多层PDW-FSE图像的信号强度计算，并通过尾状核的MTR归一化。结果：在所有病例中，在FSTIR图像的指导下，测量区域很容易确定。AD患者海马和内嗅皮层的MTRs均低于对照组，差异有统计学意义，而其他结构的MTRs无显著变化。结论：采用单层/多层PDW-FSE结合优化后的FSTIR技术，成功测量了海马和内嗅皮层的MTRs。阿尔茨海默病早期海马和内嗅皮层的MTRs下降，表明这种变化与神经元丢失有关。使用高分辨率FSE/FSTIR图像进行MT测量可能有助于在明显萎缩发生之前早期诊断AD。少

Purpose: To evaluate changes related to the neuronal loss of the hippocampus and the entorhinal cortex in patients with early Alzheimer disease (AD) using high-resolution magnetization-transfer (MT) fast spin-echo (FSE), and fast short inversion-time inversion-recovery (FSTIR) techniques. Methods: Fifteen patients with AD including early stages and ten age-matched normal volunteers were prospectively examined by a 1.5 Tesla superconductive MR scanner (Signal Horizon Lx, GEMS). The pulse sequences we used were FSTIR 4000/120/36 (TR/Tl/Teff) sequence with original optimizations, and proton-density weighted (PDW) FSE 1000/24 (TR/Teeff) sequence with single and multislice acquisitions. In each case, 4 mm thick coronal images through mamillary bodies were obtained with a 17cm field of view and zero-interpolated 512x512 matrices. Signal intensities of the hippocampus, entorhinal cortex, cingulate gyrus, superior temporal gyrus, caudate nucleus, deep white matter, and CSF were measured in sin … More gle-slice and multislice PDW-FSE images. Measurement areas were manually determined on FSTIR images in which gray/white matter contrast was remarkable. The MT ratio (MTR) in each structure was calculated from signal intensities obtained on single/multislice PDW-FSE images, and was normalized by MTR in the caudate nucleus.Results: In all of the cases, measurement areas were readily determined with guidance of FSTIR images. MTRs of the hippocampus and the entorhinal cortex in patients with AD were lower than the control group with statistical significance, whereas those of the other structures indicated no significant alterations.Conclusion: We successfully measured MTRs of the hippocampus and the entorhinal cortex by a combination of single/multislice PDW-FSE and optimized FSTIR techniques. MTRs in the hippocampus and the entorhinal cortex were decreased in early AD, suggesting changes related to the neuronal loss. MT measurements using high-resolution FSE/FSTIR images may help early diagnosis of AD before visible atrophy occurs. Less