RT Journal Article
SR Electronic
T1 Laminar analysis of the cortical T1/T2-weighted ratio at 7T
JF Neurology - Neuroimmunology Neuroinflammation
JO Neurol Neuroimmunol Neuroinflamm
FD Lippincott Williams & Wilkins
SP e900
DO 10.1212/NXI.0000000000000900
VO 7
IS 6
A1 Maria Petracca
A1 Mohamed M. El Mendili
A1 Matteo Moro
A1 Sirio Cocozza
A1 Kornelius Podranski
A1 Lazar Fleysher
A1 Matilde Inglese
YR 2020
UL http://nn.neurology.org/content/7/6/e900.abstract
AB 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.CL=cortical lesion; GM=gray matter; HC=healthy control; MPRAGE=Magnetization-Prepared Rapid Acquisition of Gradient Echo; PMS=progressive MS; RRMS=relapsing-remitting MS; SPACE=Sampling Perfection with Application optimized Contrasts using different flip angle Evolution; WM=white matter