Not all age-related white matter hyperintensities are the same: a magnetization transfer imaging study

Area of Science:

• Neuroimaging
• Radiology
• Neurology

Background:

• Age-related white matter hyperintensities (WMH) are common findings in neuroimaging.
• Histologic heterogeneity of WMH is presumed but not well-characterized.
• Understanding WMH heterogeneity is crucial for comprehending their causes and consequences.

Purpose of the Study:

• To investigate if presumed histologic heterogeneity of age-related white matter hyperintensities (WMH) is reflected in quantitative magnetization transfer imaging (MTI) measures.
• To compare MTI measures between different subtypes of WMH.

Main Methods:

• 56 subjects with WMH from the PROSPER study were analyzed.
• WMH were classified as periventricular WMH (PVWMH) and deep WMH (DWMH).
• PVWMH were further subclassified as irregular or smooth based on border appearance. Mean magnetization transfer ratio (MTR) was assessed for different WMH types.

Main Results:

• Mean MTR of PVWMH was lower than that of DWMH.
• Frontal PVWMH exhibited lower MTR than occipital PVWMH.
• Frontal PVWMH more frequently presented smooth borders and low signal intensity on T1-weighted images compared to occipital PVWMH.

Conclusions:

• Age-related WMH display heterogeneity detectable by quantitative MTI, despite similar T2-weighted imaging appearance.
• Considering WMH heterogeneity in etiology and tissue destruction severity enhances understanding of their impact.
• MTI provides valuable insights into the microstructural differences within WMH.