Subscribe to RSS
DOI: 10.1055/s-0029-1246587
Detection of cerebral microbleeds with dual echo T2*-weighted imaging at 7.0 Tesla MRI
Purpose: Increasing interest in microbleeds had led to numerous studies addressing the prevalence and clinical relevance of these lesions. However, the detection of microbleeds differs between studies, due to differences in image protocols and field strengths. A technique for accurate detection of microbleeds is needed. The purpose of our study was to assess the detection of cerebral microbleeds with dual echo T2*-weighted imaging at 7.0 Tesla magnetic resonance imaging (MRI).
Materials and Methods: Ten participants (8 men, 2 women, mean age 54 years) with vascular disease or vascular risk factors were included. Dual echo T2*-weighted scans (echo time: 2.5ms and 15.0ms) were made for all participants at 7.0 Tesla MRI. The number of visible microbleeds and the diameter of the microbleeds were recorded for both echo times. Microbleeds were evaluated on minimal intensity projections (minIP) images of both echoes.
Results: In total 104 microbleeds were detected, 88 (84.6%) were visible on the first echo and 102 (98.0%) on the second. The microbleeds on the first echo were significantly smaller than on the second echo (figure 1). On the first echo image microbleeds could be distinguished from veins and ferritin containing tissue, like the basal ganglia (figure 2).
Conclusion: T2*-weighted imaging at two echo times enables the detection of microbleeds by combining the large contrast between the microbleeds and the surrounding tissue at the first echo time and the larger size of the microbleeds at the second echo time.
Figure 1: The minimal intensity projection (minIP) of the first echo on the left shows a smaller microbleed than the minIP of the second echo on the right (arrows)
Figure 2: The microbleed is clearly visible on the first echo image (left), but it is hardly detectable on the second echo image (right)