Biomedical Engineering, Bahcesehir University, Istanbul, Turkey.
Comput Med Imaging Graph. 2012 Sep;36(6):464-73. doi: 10.1016/j.compmedimag.2012.03.006. Epub 2012 May 31.
Quantification of structural changes in the human brain is important to elicit resemblances and differences between pathological and normal aging. Identification of dementia, associated with loss of cognitive ability beyond normal aging, and especially converters--the subgroup of individuals at risk for developing dementia--has recently gained importance. For this purpose atrophy markers have been explored and their effectiveness has been evaluated both cross-sectionally and longitudinally. However, more research is needed to understand the dynamics of atrophy markers at different disease stages, which requires temporal analysis of local along with global changes. Unfortunately, most of the longitudinal neuroimaging data available in the clinical settings is acquired at largely varying time intervals. In the light of the above, this study presents a novel methodology to process longitudinal neuroimaging data acquired incompletely and at different time intervals, and explores complementary nature of local and global brain volume changes in identifying dementia. Results on the OASIS database demonstrate discriminative power of global atrophy in hippocampus (as early as two years after the first visit) for identifying demented cases, and local volume shrinkage of thalamus proper (as early as three years after the first visit) for differentiating converters.
量化人类大脑的结构变化对于揭示病理性衰老和正常衰老之间的相似和差异非常重要。最近，人们越来越关注痴呆症的识别，痴呆症是指认知能力下降超出正常衰老范围，特别是易转换者——即有发展为痴呆症风险的亚组人群。为此，人们已经探索了萎缩标志物，并对其进行了横断面和纵向评估。然而，为了了解不同疾病阶段萎缩标志物的动态变化，需要对局部和整体变化进行时间分析，这需要更多的研究。不幸的是，临床环境中可用的大多数纵向神经影像学数据都是在很大的时间间隔内采集的。鉴于上述情况，本研究提出了一种新的方法来处理不完全和不同时间间隔采集的纵向神经影像学数据，并探讨了局部和整体脑容量变化在识别痴呆症方面的互补性。在 OASIS 数据库上的结果表明，在首次就诊后两年，海马体的整体萎缩（global atrophy）就具有识别痴呆病例的区分能力，而在首次就诊后三年，丘脑（thalamus）的局部体积收缩（local volume shrinkage）就具有区分易转换者的能力。
