7T MRI allows detection of disturbed cortical lamination of the medial temporal lobe in patients with Alzheimer's disease

Using 7T T2⁎-weighted imaging, we scanned post-mortem hemispheres of Alzheimer patients and age-matched controls to describe the patterns of appearance of cortical lamination on T2*-weighted MRI in the medial temporal lobe and to assess the changes in Alzheimer patients versus controls. While controls showed a hypointense line of Baillarger in the majority of the cases, appearance of cortical lamination varied to a greater extent in the Alzheimer patients. Severely distorted cortical lamination was also observed in advanced stage Alzheimer patients and presented itself as a broad hypointense inhomogeneous band, covering a large part of the cortical width. Histology indicated that the changes in the appearance of visible cortical lamination were not only associated with myelin changes, but also with diffuse cortical iron alterations and depositions. Therefore, imaging cortical lamination alterations in Alzheimer patients using T2*-weighted MRI might provide new information on involved neuroanatomical structures in an advanced neurodegenerative stage.
Highlights • 7T T2*-weighted MRI of post-mortem hemispheres allows detection of cortical lamination features in the medial temporal lobe • AD patients show increased variation in the appearance of visible contrast patterns in the cortex. • Severely distorted cortical lamination is observed in a proportion of advanced stage AD patients, but not in controls. • Altered cortical contrast of AD patients reflects myelin-associated iron alterations and depositions on histology.