Classification and characterization of periventricular and deep white matter hyperintensities on MRI: A study in older adults

• Published in: NeuroImage (Orlando, Fla.) Fla.), 2018-04, Vol.170, p.174-181
• Main Authors: Griffanti, Ludovica, Jenkinson, Mark, Suri, Sana, Zsoldos, Enikő, Mahmood, Abda, Filippini, Nicola, Sexton, Claire E, Topiwala, Anya, Allan, Charlotte, Kivimäki, Mika, Singh-Manoux, Archana, Ebmeier, Klaus P., Mackay, Clare E., Zamboni, Giovanna
• Format: Article
• Language: English
• Subjects: Age; Age Factors; Aged; Aging; Aging - pathology; Blood pressure; Body Mass Index; Brain research; Cardiovascular diseases; Classification; Cognitive ability; Cognitive Dysfunction - diagnostic imaging; Cognitive Dysfunction - pathology; Cohort Studies; Female; Humans; Hypertension - diagnostic imaging; Hypertension - pathology; Leukoaraiosis - classification; Leukoaraiosis - diagnostic imaging; Leukoaraiosis - pathology; Magnetic resonance imaging; Male; Medical imaging; Middle Aged; Neuroimaging - methods; NMR; Nuclear magnetic resonance; Older people; Psychiatry; Risk factors; Studies; Substantia alba
• ISSN: 1053-8119; 1095-9572
• DOI: 10.1016/j.neuroimage.2017.03.024

White matter hyperintensities (WMH) are frequently divided into periventricular (PWMH) and deep (DWMH), and the two classes have been associated with different cognitive, microstructural, and clinical correlates. However, although this distinction is widely used in visual ratings scales, how to best anatomically define the two classes is still disputed. In fact, the methods used to define PWMH and DWMH vary significantly between studies, making results difficult to compare. The purpose of this study was twofold: first, to compare four current criteria used to define PWMH and DWMH in a cohort of healthy older adults (mean age: 69.58 ± 5.33 years) by quantifying possible differences in terms of estimated volumes; second, to explore associations between the two WMH sub-classes with cognition, tissue microstructure and cardiovascular risk factors, analysing the impact of different criteria on the specific associations. Our results suggest that the classification criterion used for the definition of PWMH and DWMH should not be considered a major obstacle for the comparison of different studies. We observed that higher PWMH load is associated with reduced cognitive function, higher mean arterial pressure and age. Higher DWMH load is associated with higher body mass index. PWMH have lower fractional anisotropy than DWMH, which also have more heterogeneous microstructure. These findings support the hypothesis that PWMH and DWMH are different entities and that their distinction can provide useful information about healthy and pathological aging processes. •Classification criteria for periventricular/deep white matter hyperintensities are compared.•The definition of PWMH and DWMH is not a major obstacle for study comparison.•PWMH and DWMH have different functional, microstructural and clinical correlates.•10mm distance rule gave best separation in terms of associations with the tested factors.