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Updated: Dec 4, 2025
Assessing Cortical Cerebral Microinfarcts on High Resolution MR Images
Published on: November 20, 2015
Laminar analysis of the cortical T1/T2-weighted ratio at 7T
Maria Petracca1, Mohamed M El Mendili1, Matteo Moro1
1From the Department of Neurology (M.P., M.M.E.M., M.M., S.C., K.P., M.I.), Icahn School of Medicine at Mount Sinai, NY; Aix-Marseille Univ (M.M.E.M.), CNRS, CRMBM; APHM (M.M.E.M.), Hôpital de la Timone, CEMEREM, Marseille, France; Department of Informatics (M.M.), Bioengineering, Robotics and Systems Engineering (DIBRIS) and Machine Learning Genoa Center (MaLGa), University of Genoa; Department of Advanced Biomedical Sciences (S.C.), University of Naples "Federico II", Italy; Department of Radiology (L.F.), Icahn School of Medicine at Mount Sinai, NY; Department of Neurosciences, Rehabilitation, Ophthalmology, Genetics (M.I.), Maternal and Child Health (DINOGMI) and Center of Excellence for Biomedical Research, University of Genoa; and Ospedale Policlinico San Martino-IRCCS (M.I.), Genoa, Italy.
Objective:
In this observational study, we explored cortical structure as function of cortical depth through a laminar analysis of the T1/T2-weighted (T1w/T2w) ratio, which has been related to dendrite density in ex vivo brain tissue specimens of patients with MS.
Methods:
In 39 patients (22 relapsing-remitting, 13 female, age 41.1 ± 10.6 years; 17 progressive, 11 female, age 54.1 ± 9.9 years) and 21 healthy controls (8 female, , age 41.6 ± 10.6 years), we performed a voxel-wise analysis of T1w/T2w ratio maps from high-resolution 7T images from the subpial surface to the gray matter/white matter boundary. Six layers were sampled to ensure accuracy based on mean cortical thickness and image resolution.
Results:
At the voxel-wise comparison (p < 0.05, family wise error rate corrected), the whole MS group showed lower T1w/T2w ratio values than controls, both when considering the entire cortex and each individual layer, with peaks occurring in the fusiform, temporo-occipital, and superior and middle frontal cortex. In relapsing-remitting patients, differences in the T1w/T2w ratio were only identified in the subpial layer, with the peak occurring in the fusiform cortex, whereas results obtained in progressive patients mirrored the widespread damage found in the whole group.
Conclusions:
Laminar analysis of T1w/T2w ratio mapping confirms the presence of cortical damage in MS and shows a variable expression of intracortical damage according to the disease phenotype. Although in the relapsing-remitting stage, only the subpial layer appears susceptible to damage, in progressive patients, widespread cortical abnormalities can be observed, not only, as described before, with regard to myelin/iron concentration but, possibly, to other microstructural features.
