Recurrent brain tumor versus radiation necrosis; can dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging differentiate?

Abstract

Background: Assessment of treatment response in patients with a brain tumor is paramount, as true tumor recurrence and radiation necrosis are similar looking on conventional MRI. Purpose: To evaluate the role of dynamic susceptibility contrast (DSC) perfusion magnetic resonance imaging in the differentiation between recurrent brain tumors and radiation necrosis. Material and Methods: Twenty patients with a history of operated primary brain tumors and postoperative radiotherapy with or without chemotherapy were enrolled in this prospective study having conventional MRI findings of enhancing lesion suspicious of being recurrence or radiation necrosis. All patients were examined by DSC-perfusion MRI. Definitive diagnosis was reached through either subsequent surgical biopsy or follow up over 6-12 months. Results: Fifteen patients (75%) were diagnosed as tumor recurrence and 5 patients as radiation necrosis (25%). The relative cerebral blood volume (rCBV) and relative peak height (rPH) were significantly higher (P < 0.05) in recurrent tumors than in radiation necrosis lesions. The rCBV and rPH thresholds in differentiating between them were 1.8 and 1.22 respectively with 87%, 93% sensitivity and 100% specificity for each respectively. Conclusions: DSC-perfusion MRI is a valuable non-invasive tool besides conventional MRI whenever available to differentiate between radiation injury changes and tumor recurrence. Keywords: Dynamic susceptibility contrast, MR perfusion, Recurrent brain tumors, Cerebral blood volume, Peak height