<prompt> A patient presented with a 4 cm tumour in the left pariental lobe for which he underwent surgery and radiotherapy. After 2 months, he presented with headache and vomiting. Which of the following would best characterize the lesion in this patient?:Gd-enhanced MRI99T-HNIPAO SPECT brainDigital subtraction angiography with dual source CT scan18EDG PET Scan  <response>: D i.e. 18FDG PET Scan - 18 FDG-PET scan detects cerebral metabolism and is used for tumor grading, estimation of prognosis, localization of optimal biopsy site most malignant areas show maximum F18 fluoro-deoxy-glucose uptake, assessment of response to therapy and detection of recurrence versus radionecrosisQ in brain tumor. 99mTcHMPAO-SPECT Scan detects uptake distribution of lipophilic radio pharmaceutical 99mTcHMPAO across functioning BBB propoional to cerebral blood flow with no redistribution. It is indicated in acute cerebral infarct imaging before evidence of CTMRI pathology and gives positive finding with in 1 hr of event, stroke shows flip flop phenomenon ie decreased aerial, equal capillary, and increased perfusionactivity in venous phase secondary to slow washout and late arrival of blood collaterals, dementia, seizure and blood brain barrier study. 