New Patterns of Magnetic Resonance Images in High-Grade Glioma Patients Treated with Bevacizumab (Avastin^®)

Objectives: To identify new magnetic resonance imaging (MRI) patterns in patients with high-grade glioma treated with bevacizumab (Avastin^®). Methods: The retrospective study was approved by the institutional review board. An extended case series of 27 patients (19 men, 8 women) with age range of 22–76 years and an average age 52 years were studied by 1.5T/3T MRI (Siemens scanner Erlangen, Germany). Protocol included axial T1-wi spin echo (SE), axial T2-wi fast SE, three-dimensional fluid-attenuated inversion recovery (3D FLAIR), axial diffusion tensor imaging, axial T2-wi gradient echo (GE), dynamic-susceptibility contrast T2-perfusion, axial T1-wi post-gadolinium (Gd) (0.2 ml/kg of body weight) and 3D T1-wi (weighted) GE post-Gd. Evaluation comprised oedema or low-grade tumour infiltration using FLAIR sequences, perfusion using relative cerebral blood volume (rCBV) and enhancement using T1-wi post-medium contrast images. Results: At baseline, the study included 27 patients, of which 14 patients were excluded and 13 patients analysed. One patient under treatment showed persistent hyperperfusion, three mixed perfusion, six hypoperfusion and three normal perfusion. FLAIR sequences were used in oedema analysis. When treated, 10 patients showed decrease in perilesional oedema, 1 showed increase in perilesional oedema and 2 had stability in perilesionnal oedema. Lesion enhancement was analysed using axial T1-wi SE post-Gd images; 12 patients showed decrease and 1 patient showed stability in lesion enhancement. Conclusions: Bevacizumab (Avastin) alters the process of angiogenesis resulting in different perfusion patterns in patients with disease progression that must be known in order to avoid erroneous interpretation.