MR perfusion imaging, techniques and role in differentiating radiation necrosis and tumor recurrence

High grade brain tumours are treated with surgery, chemotherapy and radiation therapy and despite such aggressive treatment, can recur in a short span of time. MRI scan has been the conventional diagnostic modality to diagnose recurrence, although at times it becomes difficult for the neuroradiologists to differentiate between tumour recurrence and radiation necrosis. Herein lies the emergent need to explore the efficacy of functional imaging to assist in this diagnostic challenge. Recent studies have sought to do so with promising implications, which we have attempted to summarize in this review.