Chapter 2 - Detectionof cerebral microbleeds

Summary

Of the metals that are commonly present in the human brain, it is considered that only iron in the form of ferritin and hemosiderin is present in sufficient quantities and appropriate oxidation state to be visualized by magnetic resonance imaging (MRI). Histology has shown that cerebral microbleeds (CMBs) contain hemosiderin deposits, a paramagnetic substance. In attempts to quantify the actual susceptibility distribution, many different models have been proposed, which relate measurable MRI effects to the underlying susceptibility distribution. However, for the detection of CMBs it is probably sufficient to use qualitative techniques with a high sensitivity to magnetic field inhomogeneities to provide information on the location and approximate size of the CMB. This chapter describes some possible technical developments to discriminate between some of the different origins of signal loss. The introduction of higher-field scanners and the development of new sequences can provide increased sensitivity for the detection of CMBs.