Detection of Cerebral Microbleeds in MR Images Using a Single-Stage Triplanar Ensemble Detection Network (TPE-Det)

Abstract

Background: Cerebral microbleeds (CMBs) are microscopic brain hemorrhages with implications for various diseases. Automated detection of CMBs is a challenging task due to their wide distribution throughout the brain, small size, and visual similarity to their mimics. For this reason, most of the previously proposed methods have been accomplished through two distinct stages, which may lead to difficulties in integrating them into clinical workflows.

Purpose: To develop a clinically feasible end-to-end CMBs detection network with a single-stage structure utilizing 3D information. This study proposes triplanar ensemble detection network (TPE-Det), ensembling 2D convolutional neural networks (CNNs) based detection networks on axial, sagittal, and coronal planes.

Study type: Retrospective.

Subjects: Two datasets (DS1 and DS2) were used: 1) 116 patients with 367 CMBs and 12 patients without CMBs for training, validation, and testing (70.39 ± 9.30 years, 68 women, 60 men, DS1); 2) 58 subjects with 148 microbleeds and 21 subjects without CMBs only for testing (76.13 ± 7.89 years, 47 women, 32 men, DS2).

Field strength/sequence: A 3 T field strength and 3D GRE sequence scan for SWI reconstructions.

Assessment: The sensitivity, FP_avg (false-positive per subject), and precision measures were computed and analyzed with statistical analysis.

Statistical tests: A paired t-test was performed to investigate the improvement of detection performance by the suggested ensembling technique in this study. A P value < 0.05 was considered significant.

Results: The proposed TPE-Det detected CMBs on the DS1 testing set with a sensitivity of 96.05% and an FP_avg of 0.88, presenting statistically significant improvement. Even when the testing on DS2 was performed without retraining, the proposed model provided a sensitivity of 85.03% and an FP_avg of 0.55. The precision was significantly higher than the other models.

Data conclusion: The ensembling of multidimensional networks significantly improves precision, suggesting that this new approach could increase the benefits of detecting lesions in the clinic.

Evidence level: 1 TECHNICAL EFFICACY: Stage 2.

Keywords: CNNs; EfficientDet; cerebral microbleeds; computer-aided detection; deep learning; susceptibility-weighted imaging.