T1-magnetic resonance imaging (MRI) studies report early atrophy in the left anterior temporal lobe, especially the perirhinal cortex, in semantic variant primary progressive aphasia (svPPA). Improved segmentation protocols using high-resolution T2-MRI have enabled fine-grained medial temporal lobe (MTL) subregional measurements, which may provide novel information on the atrophy pattern and disease progression in svPPA. We aimed to investigate the MTL subregional atrophy pattern cross-sectionally and longitudinally in patients with svPPA as compared with controls and patients with Alzheimer's disease (AD). MTL subregional volumes were obtained using the Automated Segmentation for Hippocampal Subfields software from high-resolution T2-MRIs in 15 svPPA, 37 AD, and 23 healthy controls. All MTL volumes were corrected for intracranial volume and parahippocampal cortices for slice number. Longitudinal atrophy rates of all subregions were obtained using an unbiased deformation-based morphometry pipeline in 6 svPPA patients, 9 controls, and 12 AD patients. Cross-sectionally, significant volume loss was observed in svPPA compared with controls in the left MTL, right cornu ammonis 1 (CA1), Brodmann area (BA)35, and BA36 (subdivisions of the perirhinal cortex). Compared with AD patients, svPPA patients had significantly smaller left CA1, BA35, and left and right BA36 volumes. Longitudinally, svPPA patients had significantly greater atrophy rates of left and right BA36 than controls but not relative to AD patients. Fine-grained analysis of MTL atrophy patterns provides information about the evolution of atrophy in svPPA. These results indicate that MTL subregional measures might be useful markers to track disease progression or for clinical trials in svPPA.

中文翻译：

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语义变异原发性进行性失语症的横断面和纵向内侧颞叶亚区域萎缩模式

T1 磁共振成像 (MRI) 研究报告在语义变异原发性进行性失语症 (svPPA) 中左前颞叶，尤其是鼻周皮质的早期萎缩。使用高分辨率 T2-MRI 改进的分割协议使细粒度的内侧颞叶 (MTL) 亚区域测量成为可能，这可能提供有关 svPPA 萎缩模式和疾病进展的新信息。我们的目的是调查 svPPA 患者与对照组和阿尔茨海默病 (AD) 患者相比的横断面和纵向 MTL 亚区域萎缩模式。MTL 分区体积是使用海马子区域自动分割软件从 15 svPPA、37 AD 和 23 名健康对照中的高分辨率 T2-MRI 获得的。所有 MTL 体积都针对颅内体积和海马旁皮质切片数进行了校正。在 6 名 svPPA 患者、9 名对照组和 12 名 AD 患者中使用基于变形的无偏形态测量管道获得所有子区域的纵向萎缩率。从横截面上看，与左侧 MTL、右侧 cornu ammonis 1 (CA1)、Brodmann 区 (BA)35 和 BA36（鼻周皮质的细分）中的对照相比，svPPA 中观察到显着的体积损失。与 AD 患者相比，svPPA 患者的左 CA1、BA35 和左右 BA36 体积明显更小。纵向上，svPPA 患者的左右 BA36 萎缩率明显高于对照组，但与 AD 患者无关。MTL 萎缩模式的细粒度分析提供了有关 svPPA 萎缩演变的信息。