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.

Systematic review and meta-analysis.

PubMed, EMBASE, Web of Science and PsycINFO (January 1990–27 January 2025), plus reference list screening and targeted manual searches.

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.

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.

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.

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.

CRD42024510241.

The utility of brain MRI in dementia diagnosis offers critical insights into structural brain changes, such as hippocampal and thalamic atrophy, which are hallmark features of Alzheimer’s disease and Alzheimer’s disease-related dementias . However, its use, especially in low- and middle-income countries (LMICs), is affected by limited accessibility. This protocol outlines a systematic review and meta-analysis to assess the diagnostic utility, feasibility and challenges of integrating brain MRI for dementia diagnosis in LMICs.

The review follows Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols with a priori eligibility criteria and is registered in PROSPERO. Searches (from inception to September 2025) will be run in MEDLINE/PubMed, EMBASE, Web of Science and PsycINFO, with supplementary bibliography screening. Adults ≥50 years in LMIC settings undergoing brain MRI for dementia evaluation will be eligible. Data will be synthesised narratively and, where appropriate, via random-effects meta-analysis with planned subgroup analyses by MRI approach (qualitative vs quantitative), magnet strength, sequence availability and reference standard. Screening and data extraction are planned for 1 November to 30 December 2025.

Ethical approval was obtained from the Makerere University School of Medicine Research and Ethics Committee (Mak-SOMREC; Ref Mak-SOMREC-2022-337). For verification, contact the SOMREC Administrator at rresearch9@gmail.com. Departmental contact: Dr Geoffrey Erem, Head, Department of Radiology, Makerere University College of Health Sciences (dreremgeoffrey@gmail.com). Only published data will be used, with no new patient contact. Findings will be disseminated via peer-reviewed publication, conference presentations and policy briefs (and, where feasible, mainstream media) to inform clinical practice and training in LMICs.

CRD42024510241.