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Correlations between histopathologic white matter changes and proton MR relaxation times in dementia
Abstract:
Our previous studies have shown that incomplete white matter infarctions are common in senile dementia of the Alzheimer type. To visualize and interpret these changes on magnetic resonance imaging (MRI), knowledge of MR relaxation times associated with this histopathology is important. The proton MR relaxation times T1 and T2 were determined in vitro for 3 groups of specimens. Fifty specimens of normal and incompletely infarcted white matter from 21 patients with senile dementia and 38 normal and pathologic white matter specimens from 19 elderly cases with infarcts were analyzed. The specimens were evaluated for infarct type, grade of incomplete infarction, and the proportion of old complete or incomplete infarction versus normal tissue in each sample. The incomplete infarct had longer relaxation times than normal white matter, with prolongation of T1 and T2 being proportional to the severity of the tissue changes. Old complete infarcts had longer relaxation times than both normal white matter and incomplete infarctions. These differences in relaxation times, reflecting various degrees of tissue damage, are important for the interpretation of MR images in vivo. Visualization of incomplete infarctions is essential for an in vivo diagnosis of these frequent and sometimes extensive changes.
Insights
Incomplete white matter infarctions in Alzheimer's disease show longer MRI relaxation times (T1 and T2) than normal tissue. These changes correlate with disease severity, aiding in diagnosis.
Area of Science:
- Neuroimaging
- Neuropathology
- Biophysics
Background:
- Incomplete white matter infarctions are prevalent in Alzheimer's disease.
- Understanding magnetic resonance imaging (MRI) relaxation times is crucial for interpreting these neuropathological changes.
- Proton magnetic resonance (MR) relaxation times (T1 and T2) are key biophysical parameters.
Purpose of the Study:
- To determine the in vitro proton MR relaxation times (T1 and T2) for normal white matter, incomplete infarctions, and old complete infarcts.
- To correlate these relaxation times with the severity of histopathological changes.
- To assess the utility of these findings for in vivo MRI interpretation in Alzheimer's disease.
Main Methods:
- In vitro determination of T1 and T2 relaxation times for white matter specimens.
- Analysis of 50 specimens from 21 Alzheimer's patients and 38 specimens from 19 elderly individuals with infarcts.
- Histopathological evaluation of infarct type, severity, and proportion of normal versus infarcted tissue.
Main Results:
- Incomplete infarcts exhibited significantly longer T1 and T2 relaxation times compared to normal white matter.
- The prolongation of T1 and T2 was directly proportional to the severity of incomplete infarction.
- Old complete infarcts demonstrated longer relaxation times than both normal white matter and incomplete infarctions.
Conclusions:
- Distinct MR relaxation times are associated with varying degrees of white matter damage in Alzheimer's disease.
- These findings are vital for accurate in vivo MRI interpretation of white matter infarctions.
- Improved visualization and diagnosis of incomplete infarctions are possible through understanding these MR properties.