In vivo micro-CT imaging of rat brain glioma: A comparison with 3 T MRI and histology

The aim of this study was to evaluate the potential of a novel micro-CT system to image in vivo the extent of tumor in a rat model of malignant glioma compared to 3 T magnetic resonance imaging (MRI) and histology. Fourteen animals underwent double dose contrast-enhanced imaging with micro-CT and 3 T MRI using a clinical machine at day 10 after stereotactic F98 glioma cell implantation. Calculation of the volume of the contrast-uptaking part of the tumor was done by manually outlining the tumor contours by two experienced neuroradiologists. The micro-CT- and MRI-derived tumor volumes were compared to histology as gold standard (hematoxylin and eosin staining and fluorescence staining). There was high interobserver reability regarding the tumor volumes (Crombach's α > 0.81). Also, there was good correlation of micro-CT- and high-field MRI-derived tumor volumes compared to histology: 72 ± 21 mm3 and 69 ± 23 mm3 compared to 81 ± 14 mm3, respectively (r > 0.76). Both the micro-CT- and MRI-derived tumor volumes were not significantly smaller compared to histology (P > 0.14). In conclusion, micro-CT allows in vivo imaging of the contrast-enhancing part of experimental gliomas with an accuracy comparable to high-field MRI.