Purpose: To evaluate the performance of computer-aided traumatic cerebral microbleed detection (CAD) with and without human interference.
Methods and Materials: 33 adult patients admitted to our emergency department with moderate or severe TBI (mean age 33 years, 21 males) underwent a standardized trauma 3T MRI-protocol at 28 weeks. The microbleeds in their SWI-scans were annotated by an expert. A CAD system was developed, based on this training set. Six experts, blind to the CAD-results, annotated a subset of ten patients. In two experiments, we compared the performance of the CAD system to each of these six experts, using the majority voting results of the other five experts as the reference standard for the calculation of performance characteristics (paired t-test). In the first experiment, the performance of fully automatic microbleed detection was assessed. In the second experiment, one expert removed CAD-annotations she considered false positives from the automatically detected microbleeds, and briefly screened the CAD-annotated SWI-scans to complete the dataset with missed definite microbleeds.
Results: Fully manual evaluation took one hour per patient with an average sensitivity of 77% (SD 12.4%). The sensitivity of fully automatic detection of candidate microbleeds was 89% (SD 0.8%). Evaluation of the CAD results by an expert took 13 minutes per patient with a sensitivity of 93% (SD 1.0%) (p < 0.05 versus fully manual evaluation).
Conclusion: This CAD system allows detecting more microbleeds in a reduced reading time. This may facilitate the execution of otherwise too time-consuming large studies on the clinical relevance of microbleeds.