Measurement of the Stratum Radiatum/Lacunosum-Moleculare (SRLM)

© Springer-Verlag Berlin Heidelberg 2014.Alzheimer disease (AD) at an early stage is characterized by a synaptic loss and atrophy in the apical layer of the CA1 part of the hippocampus, the stratum radiatum and stratum lacunosum-moleculare (SRLM). It was shown in vivo that patients with mild AD exhibit a reduced thickness of the SRLM. We propose a new approach to measure SRLM thickness in coronal brain sections. It is based on the interpolated contour of the manually segmented SRLM and its medial axis. We automatically compute the axis by combining Voronoi diagrams and methods from graph analysis. While existing measurement approaches require a mental segmentation of the SRLM and a repeated local estimate of its center, we obviate the latter. We evaluate our approach based on coronal T2∗-weighted 7T MR images of 27 subjects.