Figure 1.

Radiological follow-up of GBM tumors treated with oncolytic virotherapy. (A) Patient 1 was diagnosed with GBM in 7/05 and underwent total surgical resection in 8/05. OV therapy was initiated in 5/06 and given for 3.5 years, after which patient remained with NED for 6.0 years. Recurrence in the left parietal lobe appeared on sagittal T1 contrast-enhanced images in 6/15 (left). The patient improved clinically after renewing OV alone. Five months thereafter, lesion shrinkage was observed (right). (B) Patient 2 was diagnosed with GBM in 10/10, underwent surgical resection and chemoradiotherapy. Relapse occurred (12/11) in the right frontal lobe (left image top row, T1 contrast enhanced images), with clinical deterioration. OV therapy was initiated. Follow-up imaging showed shrinkage until disappearance of the pathological enhancement. Concurrent to OV therapy and shrinkage, multiple scattered FLAIR hyperintense foci (with and without enhancement) were seen (bottom row, FLAIR images, yellow circle), possibly an immune-mediated response. (C) Patient 3 was diagnosed with a right temporal lesion (1/11; left image, T1 post contrast), underwent surgical resection and chemoradiotherapy, and no residual tumor mass was seen (9/11). Relapse occurred (6/12; red arrow), and following a second resection, OV therapy was initiated. The patient has no residual tumor (7/15; right image) and has remained with no radiological or clinical evidence of disease. (D) Patient 4 was diagnosed with GBM (10/15) and underwent resection and chemoradiotherapy. Following relapse in the surgical bed (5/16; yellow arrow, left image of T1 contrast enhanced images), OV was initiated. The focus of pathological enhancement decreased in size until disappearance (1/17). Concurrent PET-MRI images (bottom row) showed hypermetabolic activity even while Gd enhancement was decreasing.