Tumor growth analysis by magnetic resonance imaging of the C6 glioblastoma model with prospects for the assessment of magnetohyperthermia therapy.

OBJECTIVE The objective was to establish a pattern of tumor growth of the C6 model of glioblastoma multiform in Wistar rats via magnetic resonance imaging (MRI) for the subsequent verification of tumor volume reduction due to magnetic hyperthermia therapy. METHODS Young male Wistar rats weighing between 250 and 300 g were used for the C6 model. After the rats were anesthetized (55 mg/ kg ketamine and 11 mg/kg xylazine), C6 lineage tumorigenic cells suspended in culture medium (10(5) cells in 10 microl) were stereotaxically injected into the right frontal cortex (bregma coordinates: 2.0 mm anteroposterior, 3.0 mm laterolateral, and 2.5 mm depth) of the rats using a Hamilton syringe. For the control group, the rats were injected with culture medium without cells. MRI scans were performed at 14, 21, and 28 d after the injection using a 2.0 T MRI scanner (Bruker BioSpec, Germany). The animals were anesthetized with 55 mg/kg ketamine and 11 mg/kg xylazine before being examined. Coronal multilayers were acquired using a standard spin echo sequence with the following parameters: repetition/echo time = 4.000 ms/67.1 ms, field of view = 3.50, matrix = 192, slice thickness = 0.4 mm, and slice separation = 0 mm. RESULTS The MRI analysis enabled a clear visualization of the tumor mass, and it was possible to establish the tumor volume parameters on the various days that were examined. The volume at 14 d after induction was 13.7 +/- 2.5 mm3. On days 21 and 28, the tumor volumes were 31.7 +/- 6.5 mm3 and 122.1 +/- 11.8 mm3, respectively. CONCLUSION These results demonstrated that it is possible to evaluate the C6 model tumor volume in rats, which will allow for the future implementation and verification of magnetic hyperthermia therapy.