3D micro-CT imaging of the postmortem brain

Magnetic resonance microscopy (mu MRI) is becoming an important tool for non-destructive analysis of fixed brain tissue. However, unlike MRI, X-ray computed tomography (CT) scans show little native soft tissue contrast. In this paper, we explored the use of contrast enhanced (brains immersion stained in iodinated CT contrast media) micro-CT (mu CT) for high resolution 3D imaging of fixed normal and pathological brains, compared to mu MRI and standard histopathology. An optimum iodine concentration of 0.27 M resulted in excellent contrast between gray and white matter in normal brain and a wide range of anatomical structures were identified. In glioma bearing mouse brains, there was clear deliniation of tumor margin which closely matched that seen on histopathology sections. mu CT tumor volume was strongly correlated with histopathology volume. Our data suggests that mu CT image contrast in the immersion-stained brains is related to axonal density and myelin content. Compared to traditional histopathology, our mu CT approach is relatively rapid and less labor intensive. In addition, compared to mu MRI, mu CT is robust and requires much lower equipment and maintenance costs. For simple measurements, such as tumor volume and non-destructive postmortem brain screening, mu CT may prove to be a valuable alternative to standard histopathology or mu MRI. 2008 Elsevier B.V. All rights reserved.