JNNP: Nerve protrusion density explains the weighted/T2 weighted ratio of multiple hardened corties

The ratio between the T1 weighted (T1w) and T2 weighted (T2w) sequences (T1w/T2w ratio) is thought to improve myelin sensitivity and specificity.
, however, studies evaluating the tissue pathology basis of multiple sclerosis (MS) have found contradictory results.
study showed a lower T1w/T2w ratio between the demyelinated corted and the normal corted, but did not study the density of synapses.
in another study, the T1 weighted/T2w ratio was associated with dendruples, but not myelin density;
myelin and neurodetic density affect the T1w/T2w ratio.
because of the T1w/T2w ratio, which comes from the usual sequences and seems sensitive to cortical damage, pathological validation is necessary before it is widely used.
In this autopsy MRI/histopathology study, this paper evaluated the normal appearance and demyelination of non-nervous system control groups (nNC) and MS patients (PwMS) to determine whether myelin and/or neurodegeneration density was associated with the T1w/T2w ratio.
the following sequences are obtained from the 3TMRI scan: 3D FLAR of the vector bit, 3D T1w fast gradient echo of the vector bit, and spin echo of the axis bit T2w.
T1w/T2w ratio was obtained through an internal pipeline adapted from Ganzetti et al.
field correction (SPM12) was performed using the machine's 3D T1w and T2w sequences.
to calibrate the unsket image using the lowest and highest intensity peak adjustment strength histograms of the upper eye and tima masks in the T1w and T2w images.
T2w sequence is recorded on the T1w image and the T1w/T2w ratio is calculated.
from 3D T1w images, gray mass (GM) and WM diagrams (SPM12) are established.
threshold of the GM chart is 0.5 to limit part of the volume.
mri collection, the brain is cut into 10mm-thick crown slices.
tissue blocks are taken from the frontal lobes up and down, buckled back to the front and rear corties, the upper temporal back and the lower lobes of the top lobes (.
immune staining of myelin (antiprotein lipoprotein) and neurodegeneration (Bielschowsky silver dyeing) with a continuous 10 m thick slice, cortical lesions (CLs) are classified according to their cortical position.
areas of interest (ROI) that affect the normal corties and demyelinated corties include the entire cortique width.
on a 3D T1w sequence, the MRI area corresponding to the tissue block is manually identified.
manually defines 5 ROIs corresponding to normal appearance and demyelination cortitis, including the entire cortique width.
the average T1w/T2w ratio of normal and demyelinated corted roi is calculated using the T1w/T2w ratio graph.
15 cases of PWM (female - 10; medium (IQR): age : 63.0 (23.4) years old; course of illness : 32.0 (18.0) years old; PMD - 480 (75) minutes; 3 cases of one Period sex MS, 12 phase II sex MS) and 10 age matching, gender and PMD matching nNC (female s 5 cases, medium (IQR) age s 73.0 (6.8) years old; PMD s 613 (304) minutes).
PwMS has a higher WM LV (Estimated Average (SE): MS=48.6 (6.0), nNC=8.0 (7.5) mm; p=0.001 ) and a lower WM T1w/T2w ratio (MS=2.235 (0.111); nNC=2.543 (0.124);p=0.021).
T1w/T2w ratio of the total GM (MS=1.348 (0.028); nNC=1.437 (0.035);p=0.074) and leather There was no significant difference between PwMS and nNC in quality (MS=1.354 (0.077); nNC=1.440 (0.080);p=0.083).
56 organizational blocks from nNC and 49 from PwMS.
found 26 CLs: I.3/26 (11.5%), II.1/26 (3.9%), III.22/26 (84.6%)in PwMS tissue blocks at 24/49 (51%).
compared to nNC, the MS normal cortique T1w/T2w ratio and protrusion density are lower (p≤0.045), while the MS demyelinated cortline T1w/T2w ratio, myelin and protrusion density are lower (p≤0.001).
the T1w/T2w ratio of MS normal appearance and demyelination cortology is significantly lower than nNC, and the T1w/T2w ratio of MS demyelination cortology is significantly lower than that of disease-free cortology.
, however, the correlation between the T1w/T2w ratio and myelin density was not statistically significant.
the nerve protrusion density of the MS cortique is significantly lower than nNC, especially the demyelinated cortique, and is consistent with recent studies, which show a significant positive correlation with the T1w/T2w ratio.
differences in supply, MRI, and histopathological analysis, as well as the correlation between neurodetic and myelin density (r=0.58, p-lt;0.001) may explain the differences between studies.
, however, this correlation suggests that, in addition to myelin, synth density also contributes to the T1w/T2w ratio.
limitations of the study, MRI scanning uses sequence optimization parameters, and T2w images are resampled as 3D T1w sequences, and all cortical layers are analyzed due to limited spatial resolution.
this paper only studies the conductive PwMS, but different processes affect the T1w/T2w ratio during the disease.
small samples can explain that PwMS and nNC did not have significant T1w/T2w ratio differences throughout the GM and cortivity, nor did there are significant correlations between neurodetrusion density and NNC's T1 weighted/T2 weighted ratio.
temperature differences may affect post-mortem quantitative indicators.
summary, although demyelination and neurodetic loss both occur in the MS cortique, the T1 weighted/T2 weighted ratio appears to reflect cortological dendrients better than myelin density.
Preziosa P, Bouman PM, Kiljan S, et al Neurite density explains cortical T1-weighted/T2-weighted ratio in multiple sclerosisjournal of Neurology, Neurosurgery and Psychic Publishers online First: 12 January 2021. doi: 10.1136/jnnp-2020-324391MedSci Original Source: MedSci Original Copyright Notice: All text, images and audio and video materials on this website that indicate "Source: Met Medical" or "Source: MedSci Original" are owned by Mets Medicine and are not authorized to be reproduced by any media, website or individual. Source: Mays Medicine.
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