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Published on: May 31, 2024
Automated detection of cerebral microbleeds on T2*-weighted MRI
Anthony G Chesebro1, Erica Amarante1, Patrick J Lao1
1Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Vagelos College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Abstract:
Cerebral microbleeds, observed as small, spherical hypointense regions on gradient echo (GRE) or susceptibility weighted (SWI) magnetic resonance imaging (MRI) sequences, reflect small hemorrhagic infarcts, and are associated with conditions such as vascular dementia, small vessel disease, cerebral amyloid angiopathy, and Alzheimer's disease. The current gold standard for detecting and rating cerebral microbleeds in a research context is visual inspection by trained raters, a process that is both time consuming and subject to poor reliability. We present here a novel method to automate microbleed detection on GRE and SWI images. We demonstrate in a community-based cohort of older adults that the method is highly sensitive (greater than 92% of all microbleeds accurately detected) across both modalities, with reasonable precision (fewer than 20 and 10 false positives per scan on GRE and SWI, respectively). We also demonstrate that the algorithm can be used to identify microbleeds over longitudinal scans with a higher level of sensitivity than visual ratings (50% of longitudinal microbleeds correctly labeled by the algorithm, while manual ratings was 30% or lower). Further, the algorithm identifies the anatomical localization of microbleeds based on brain atlases, and greatly reduces time spent completing visual ratings (43% reduction in visual rating time). Our automatic microbleed detection instrument is ideal for implementation in large-scale studies that include cross-sectional and longitudinal scanning, as well as being capable of performing well across multiple commonly used MRI modalities.
Insights
This study introduces an automated method for detecting cerebral microbleeds using MRI scans. The novel algorithm significantly improves detection accuracy and efficiency compared to manual visual inspection, aiding in large-scale research.
Area of Science:
- Neuroimaging
- Medical image analysis
- Neurology
Background:
- Cerebral microbleeds (CMBs) are indicative of neurological conditions like Alzheimer's disease and vascular dementia.
- Current detection via visual inspection of MRI is time-consuming and unreliable.
- Standard MRI sequences for CMB detection include gradient echo (GRE) and susceptibility weighted (SWI).
Purpose of the Study:
- To develop and validate a novel automated method for detecting cerebral microbleeds on GRE and SWI MRI sequences.
- To compare the performance of the automated method against manual visual inspection in a community-based cohort of older adults.
- To assess the algorithm's utility for longitudinal studies and anatomical localization of microbleeds.
Main Methods:
- Development of an automated algorithm for microbleed detection on GRE and SWI MRI.
- Validation in a community-based cohort of older adults.
- Comparison of automated detection sensitivity, precision, and time efficiency against trained raters.
Main Results:
- The automated method achieved high sensitivity (>92%) and reasonable precision (<20 false positives/scan on GRE, <10 on SWI).
- Longitudinal analysis showed higher sensitivity for the algorithm (50%) compared to manual ratings (≤30%).
- The algorithm reduced visual rating time by 43% and provided anatomical localization of microbleeds.
Conclusions:
- The automated microbleed detection method is highly sensitive and precise across GRE and SWI MRI modalities.
- This tool enhances the efficiency and reliability of microbleed detection, particularly for large-scale longitudinal studies.
- The algorithm's ability to localize microbleeds and reduce manual effort makes it ideal for clinical research.

