High Grade tumor vs stroke. Utility of PET and MRI corregistration

Sometimes, the clinical presentation of a brain tumour mimics that of stroke or viceversa. In these cases it is useful to evaluate follow-up with MR. The coregistration of PET and MR images improves the diagnostic performance of both techniques. In the area of interest, FDG uptake of any degree, with reference to the adjacent brain tissue uptake, should be considered suggestive of tumor if it corresponds to brain injury in MR, even when the FDG uptake is equal to or lower than that of the normal cerebral cortex. We present a case in which coregistration of images from both techniques contributed to the differential diagnosis of stroke and high-grade glioma, whole-body PET/CT ruled out metastatic etiology, and the results led to surgery.