Pathologic correlates of incidental MRI white matter signal hyperintensities
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F Fazekas1, R Kleinert, H Offenbacher
1Department of Neurology, Karl-Franzens University, Graz, Austria.
Abstract:
We related the histopathologic changes associated with incidental white matter signal hyperintensities on MRIs from 11 elderly patients (age range, 52 to 82 years) to a descriptive classification for such abnormalities. Punctate, early confluent, and confluent white matter hyperintensities corresponded to increasing severity of ischemic tissue damage, ranging from mild perivascular alterations to large areas with variable loss of fibers, multiple small cavitations, and marked arteriolosclerosis. Microcystic infarcts and patchy rarefaction of myelin were also characteristic for irregular periventricular high signal intensity. Hyperintense periventricular caps and a smooth halo, however, were of nonischemic origin and constituted areas of demyelination associated with subependymal gliosis and discontinuity of the ependymal lining. Based on these findings, our classification appears to reflect both the different etiologies and severities of incidental MRI signal abnormalities, if it is modified to treat irregular periventricular and confluent deep white matter hyperintensities together.
Insights
This study links MRI white matter signal abnormalities in elderly patients to histopathologic changes. Findings help classify these common brain findings by severity and cause.
Area of Science:
- Neurology
- Neuroimaging
- Pathology
Background:
- White matter signal hyperintensities are common incidental findings on MRI in elderly individuals.
- Understanding the histopathologic basis of these abnormalities is crucial for accurate interpretation.
Purpose of the Study:
- To correlate histopathologic changes with a descriptive classification of white matter signal hyperintensities observed on MRI.
- To evaluate the utility of a classification system for differentiating etiologies and severities of these MRI findings.
Main Methods:
- Histopathologic examination of brain tissue from 11 elderly patients with incidental white matter signal hyperintensities on MRI.
- Correlation of observed histopathologic changes with specific MRI signal abnormality patterns (punctate, confluent, periventricular).
Main Results:
- Punctate, early confluent, and confluent hyperintensities correlated with increasing ischemic damage severity.
- Irregular periventricular hyperintensities showed microcystic infarcts and myelin rarefaction.
- Nonischemic demyelination, gliosis, and ependymal changes were associated with hyperintense periventricular caps and halos.
Conclusions:
- The proposed classification system reflects different etiologies and severities of incidental MRI white matter abnormalities.
- Modification to group irregular periventricular and confluent deep white matter hyperintensities together may enhance classification accuracy.