P1‐297: Effects of Age and Alzheimer's Disease on Hippocampal Subfields: Comparison Between Manual and Freesurfer Volumetry

Structural imaging of hippocampal subfields in healthy aging and Alzheimer’s disease

“…More precisely, doubts are cast upon the ability to distinguish (numerous) subfields using low-resolution images, but also about the boundaries of the parcellation scheme, which strongly differs from the majority of in vivo and imaging atlases. For instance, FreeSurfer 5.3's CA1 is the smallest subfield while CA2-3 is the biggest, which contrasts with histologic data showing the opposite (for discussion, see de Flores et al, 2015and Wisse et al, 2014a, Yuschevich et al, 2015. These specificities of the FreeSurfer 5.3 subfield segmentation package must be recognized when interpreting the abundance of results based on this broadly used but controversial method (see below).…”

“…The considered age range is also a source of heterogeneity between studies (Walhovd et al, 2011) as some studies evaluate the effect of age over the entire adult lifespan (Mueller et al, 2007(Mueller et al, , 2009Chételat et al, 2008 ;La Joie et al, 2010 ;Ziegler et al, 2010 ;Raz et al, 2014 ;de Flores et al, 2015 ;Pereira et al, 2014), while others only included elderly people (Wang et al, 2003(Wang et al, , 2006Frisoni et al, 2008 ;Apostolova et al, 2012 ;Wisse et al, 2014b ;Khan et al, 2014). This point is particularly important as the effect of age on brain structures is known to be non-linear, with a strong regional specificity in the dynamic of the effects (Sowell et al, 2003;.…”

“…This point is particularly important as the effect of age on brain structures is known to be non-linear, with a strong regional specificity in the dynamic of the effects (Sowell et al, 2003;. Moreover, most studies only investigated linear associations between age and subfield volumes, while quadratic or more complex models were used in only a few studies (Mueller et al, 2007;Ziegler et al, 2011;de Flores et al, 2015;Yang et al, 2013). Table 3 summarizes the main results from studies on the effect of age on subfield structure.…”

“…In some studies, abnormalities were also found in medial regions of the surface, mostly corresponding to the (pre)subiculum (Frisoni et al, , 2006Wang et al, 2006) or even in all subfields Chow et al, 2012Chow et al, , 2015. Using direct volumetry in AD patients, several studies reported significant atrophy in all, or almost all, investigated subfields (Adachi et al, 2003;Boutet et al, 2014;de Flores et al, 2015;Khan et al, 2014;La Joie et al, 2013;Li et al, 2013), the major atrophy being generally located in CA1 (La Joie et al, 2013;de Flores et al, 2015;Mueller et al, 2010). In a few studies, some subfields were (relatively) spared, namely CA3/DG (Mueller and Weiner, 2009; or CA2 (Wisse et al, 2014b).…”

Will PET Amyloid Imaging Lead to Overdiagnosis of Alzheimer Dementia?

“…There have been many efforts to use computer analysis to expand the diagnostic and prognostic data from MRI studies (30,31); however, these require nonroutine imaging sequences and advanced postprocessing not generally available outside of research studies. Furthermore, although many are proven effective at the sites where they are developed, dissemination of these advanced analytical techniques between institutions has proven challenging (32)(33)(34)(35). Like CSF measurements, sensitivity and specificity of hippocampal volume calculations have shown limited ability to predict who will convert from MCI to AD and are often combined with other biomarkers (36)(37)(38)(39)(40).…”