What question did this study set out to answer?

To synthesize the prevalence and patterns of brain MRI abnormalities in adults with suspected dementia in LMICs.

April 4, 2026Open Access

Utilisation of brain MRI for the diagnosis of dementia in low and middle-income countries: systematic review and meta-analysis

Q: What does this research mean for the field?

Brain MRI frequently identifies dementia-relevant pathology, typically presenting as mixed neurodegenerative-vascular patterns, in adults with suspected or confirmed dementia in low- and middle-income countries, with a pooled prevalence of 58%. Novelty: ClaimNovelty.SYNTHESIS. Consensus alignment: ConsensusAlignment.NEUTRAL.

Key Points

To synthesize the prevalence and patterns of brain MRI abnormalities in adults with suspected dementia in LMICs.
Conducted a systematic review and meta-analysis of observational studies.
Included studies from PubMed, EMBASE, Web of Science, and PsycINFO published since January 1990.
Extracted data on MRI protocols and abnormalities in adults aged 50 and older with suspected dementia.
Included 39 studies from LMICs, with 23 studies contributing to the meta-analysis.
Found that 58% of participants had dementia-relevant MRI abnormalities.
Observed substantial heterogeneity among studies, indicating variability in findings.

Abstract

Objectives To synthesise the prevalence and patterns of dementia-relevant structural brain MRI abnormalities in adults with suspected or confirmed dementia in low- and middle-income countries (LMICs), and to summarise MRI protocols and the incremental diagnostic contribution of MRI beyond cognitive screening. Design Systematic review and meta-analysis. Data sources PubMed, EMBASE, Web of Science and PsycINFO (January 1990–27 January 2025), plus reference list screening and targeted manual searches. Eligibility criteria Observational or diagnostic-accuracy studies from World Bank-defined LMICs including adults (≥50 years) with suspected or confirmed dementia who underwent brain MRI as part of diagnostic evaluation. Data extraction and synthesis Two reviewers independently screened, extracted data and assessed risk of bias using ROBINS-I. Random-effects models pooled prevalence of dementia-relevant MRI abnormalities; diagnostic-accuracy outcomes were synthesised narratively due to heterogeneous reference standards and incomplete reporting. Results 39 LMIC studies were included; 23 studies (2513 participants) contributed to the meta-analysis. Dementia-relevant MRI abnormalities (defined as ≥1 clinically relevant structural abnormality per study definition) were present in 1248/2513 participants. The pooled prevalence of dementia-relevant MRI abnormalities was 58% (95% CI 43% to 72%), with substantial heterogeneity (I²=95%) and a wide prediction interval (8–96%), indicating marked between-study variability; this estimate should be interpreted as a descriptive summary of study-level proportions rather than a precise population parameter. Conclusions Brain MRI frequently demonstrates dementia-relevant pathology in LMIC clinical cohorts, usually with mixed neurodegenerative-vascular patterns. Structured visual ratings may add aetiologic specificity beyond cognitive screening, but pooled estimates should be interpreted as summaries of heterogeneous study-level findings rather than precise population parameters, given high heterogeneity and risk of bias. PROSPERO registration number CRD42024510241.

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