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MRI investigations of white matter hyperintensity and structural abnormalities of brain in urban and rural cohorts of India
Author(s) -
Tiwari Vivek,
Kallur Kumar,
Rao Naren P,
Sivakumar Palanimuthu T,
Balakrishnan Aditi,
Ravindranath Vijayalakshmi
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.045687
Subject(s) - hyperintensity , cohort , fluid attenuated inversion recovery , medicine , white matter , cohort study , magnetic resonance imaging , brain aging , psychology , gerontology , radiology , disease
Background White‐matter degeneration appears as white‐matter‐hyperintensities (WMHs) on T2‐weighted FLAIR (T2w‐FLAIR) MRI. WMH load and alterations in hippocampal volume may serve as an imaging‐marker to identify brain‐health in aging and associated disorders. Here, we have investigated periventricular‐white‐matter‐hyperintensities (PVWMHs) and deep‐white‐matter‐hyperintensities (DWMHs) together with brain volumetric‐measurements in an urban‐cohort TATA longitudinal study on aging (TLSA) and a rural‐cohort Srinivaspura Aging, Neuro Senescence and COGnition study (SANSCOG) at the baseline visit of the longitudinal‐study. These study cohorts have distinct population characteristics: SANSCOG participants are recruited from the rural area Srinivaspura, whereas, those in TLSA are recruited from urban Bangalore. The study cohorts comprise of cognitively healthy individuals aged ≥45 years. Method MRI experiments were conducted on 3T whole‐body scanner. T2w‐FLAIR, 3D‐MPRAGE and DWI MR‐images were obtained. WMHs volume‐burden was measured using Fazekas grading on T2w‐FLAIR images. WMHs load and volumetric‐measures were stratified across three age‐groups, early (45‐54 years), intermediate (55‐64 years) and late (>65 years), for both cohorts. Result MRI analysis was performed across 117 subjects in the urban‐cohort (TLSA) and 84 from the rural‐cohort (SANSCOG) from the ongoing study. Prevalence of PVWMHs in the SANSCOG‐cohort was significantly higher (p<0.001) at the early age‐group (45‐54 years) compared to that of TLSA‐cohort. PVWMHs in SANSCOG was significantly higher across all the age‐groups, although PVWMHs in TLSA closely catched‐up at the late‐age group. This suggests that rural cohort had severe vascular abnormality at much earlier age while vascular health deteriorated with increasing age for the urban cohort. Prevalence of PVWMHs in SANSCOG‐cohort did not significantly change across age‐groups, while TLSA‐cohort showed significant increase with increasing age. Similarly, DWMH prevalence was also higher in the SANSCOG at the early age‐group but did not increase significantly with age. However, WMH‐load (Fazekas grading) with aging showed significant positive correlation, indicating that WMH volume‐burden increases with age for both cohorts. Gender based segregation showed that WMH‐prevalence was significantly higher for males (>55%) in both cohorts. Conclusion Increased WMHs prevalence at the early‐age in the rural‐cohort indicates occurrence of small vessel pathology of brain at much earlier age compared to the urban‐cohort. This may predispose the rural population towards aging associated disorders.