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Updated: Jan 16, 2026
Assessing Cortical Cerebral Microinfarcts on High Resolution MR Images
Published on: November 20, 2015
Comparative Diagnostic and Prognostic Performance of SWI and T2-Weighted MRI in Cerebral Microbleed Detection
Rachel Tan1,2,3, Kevin J Spring1,2,4,5,6, Murray Killingsworth1,2,3,4,7
1Global Health Neurology Lab, Sydney, NSW 2150, Australia.
Abstract:
Background and Objectives: Cerebral microbleeds (CMBs) are increasingly being considered as potential biomarkers of small vessel disease and cerebral vulnerability, particularly in patients with acute ischemic stroke (AIS). Accurate detection is crucial for prognosis and therapeutic decision-making, yet the relative utility of susceptibility-weighted imaging (SWI) versus T2*-weighted imaging (T2*) remains uncertain. Materials and Methods: We conducted a systematic review and meta-analysis (SPOT-CMB, Susceptibility-weighted imaging and Prognostic Outcomes in Acute Stroke-Cerebral Microbleeds study) of 80 studies involving 28,383 AIS patients. Pooled prevalence of CMBs was estimated across imaging modalities (SWI, T2*, and both), and stratified analyses examined variation by demographic, clinical, and imaging parameters. Meta-analytic odds ratios assessed associations between CMB presence and key outcomes: symptomatic intracerebral hemorrhage (sICH), hemorrhagic transformation (HT), and poor functional outcome (modified Rankin Scale score 3-6) at 90 days. Diagnostic performance was assessed using summary receiver operating characteristic curves. Results: Pooled CMB prevalence was higher with SWI (36%; 95% CI 31-41) than T2* (25%; 95% CI 22-28). CMB presence was associated with increased odds of sICH (OR 2.22; 95% CI 1.56-3.16), HT (OR 1.33; 95% CI 1.01-1.75), and poor 90-day outcome (OR 1.61; 95% CI 1.39-1.86). However, prognostic performance was modest, with low sensitivity (e.g., AUC for sICH: 0.29) and low diagnostic odds ratios. SWI outperformed T2* in detection but offered limited prognostic gain. Access to SWI remains limited in many settings, posing challenges for global implementation. Conclusions: SWI detects CMBs more frequently than T2* in AIS patients and shows stronger associations with adverse outcomes, supporting its value for risk stratification. However, prognostic accuracy remains limited, and our GRADE appraisal indicated only moderate certainty for functional outcomes, with lower certainty for diagnostic accuracy due to heterogeneity and imprecision. These findings highlight the clinical utility of SWI but underscore the need for standardized imaging protocols and high-quality prospective studies.
Insights
Susceptibility-weighted imaging (SWI) detects more cerebral microbleeds (CMBs) in acute ischemic stroke (AIS) patients than T2*-weighted imaging (T2*), showing stronger links to adverse outcomes. However, prognostic accuracy remains limited, highlighting the need for standardized protocols.
Area of Science:
- Neurology
- Radiology
- Biomarkers
Background:
- Cerebral microbleeds (CMBs) are key indicators of small vessel disease and brain vulnerability in acute ischemic stroke (AIS).
- Accurate CMB detection is vital for prognosis and treatment decisions in AIS patients.
- The comparative effectiveness of susceptibility-weighted imaging (SWI) and T2*-weighted imaging (T2*) for CMB detection and prognostic value is not fully established.
Purpose of the Study:
- To systematically review and meta-analyze the prevalence and prognostic implications of CMBs detected by SWI and T2* in AIS patients.
- To compare the diagnostic performance of SWI and T2* in identifying CMBs.
- To assess the association between CMBs and key adverse outcomes following AIS.
Main Methods:
- A systematic review and meta-analysis (SPOT-CMB study) of 80 studies involving 28,383 AIS patients.
- Pooled prevalence of CMBs was calculated for SWI, T2*, and combined modalities.
- Meta-analytic odds ratios and receiver operating characteristic curves were used to evaluate associations with symptomatic intracerebral hemorrhage, hemorrhagic transformation, and poor functional outcome, as well as diagnostic performance.
Main Results:
- Pooled CMB prevalence was higher with SWI (36%) compared to T2* (25%).
- CMB presence correlated with increased odds of symptomatic intracerebral hemorrhage (OR 2.22), hemorrhagic transformation (OR 1.33), and poor 90-day functional outcome (OR 1.61).
- SWI demonstrated superior detection but limited prognostic gain; diagnostic performance metrics were modest.
Conclusions:
- SWI is more sensitive than T2* for detecting CMBs in AIS patients and shows stronger associations with adverse outcomes, supporting its role in risk stratification.
- Despite clinical utility, the prognostic accuracy of CMB detection remains limited, with moderate certainty for functional outcomes and lower certainty for diagnostic accuracy.
- Challenges in global implementation exist due to limited SWI availability, emphasizing the need for standardized protocols and further high-quality research.
