Role of Perfusion Computed Tomography (PCT) in the pre-operative grading of intra-axial brain tumors

Introduction. Conventional MR imaging provides important anatomic informations of brain tumors, but it proves to be insufficient to preoperatively determine the grade of the tumors. Contrast enhancement on MR imaging depicts areas of breakdown of blood-brain barrier, which is often associated with high-grade tumors. Contrast enhancement, however, is not always accurate in predicting the tumor grade. In fact, in highgrade gliomas with pathologic contrast enhancement, the enhancement may not reflect the areas of neovascularity and angiogenesis. Malignant brain tumors are characterized by neovascularity and increased angiogenic activity, with a higher proportion of immature and hyperpermeable vessels. Perfusion Computed Tomography (PCT) is a recently introduced technique, able to assess in vivo neoplastic Cerebral Blood Volume (CBV) and Permeability Surface (PS), parameters related to tumor neoangiogenesis. Objects. The aims of our study was to investigate the role of Perfusion Computed Tomography in the preoperative diagnosis of the grade of malignancy of intraaxial tumors.Materials and Methods. Between January 2012 and January 2013, we prospectively enrolled 21 consecutive patients (12 women – 9 men) admitted to the Neurosurgical Department of the University Hospital of Messina with a first diagnosis of intra-axial brain tumor at MRI. Pre-operative PCT was performed in all patients with CBV and PS calculation. Patients underwent surgery and PCT parameters were finally correlated to histological type and angiogenic markers (MVD and CD 34). Results and Conclusions. Histological examination showed 11 low-grade tumors (9 gliomas, 1 oligodendroglioma, 1 astrooligodendroglioma) and 10 high-grade tumors (9 gliomas, 1 rhabdoid tumor). An excellent correlation between PCT parameters and histological angiogenic markers was demonstrated. In conclusion, our experience confirms the important role of PCT in pre-operative grading of intra-axial brain tumors. PCT, in fact, appears to be an excellent technique, both for accuracy and speed, to obtain in vivo assessment of neoplastic grading, showing significant advantages compared to Perfusion-weighted magnetic resonance imaging (PWI).