Can you determine from these scan sequences what this lesion is?
Technically no - although there are a number of features that are in keeping with glioblastoma (see teaching page at the end). Knowledge of other existing tumours may make metastases more likely, and other techniques using diffusion restriction can be useful.
Why do you think the patient had right sided weakness on examination?
The motor regions may have been affected by tumour spread or oedema, but it is worth remembering about the weakness patients can experience following a seizure (Todd's paresis).
Low signal from the centre of the lesion in keeping with necrosis or central haemorrhage. Avid enhancement and high signal around the periphery with high signal surrounding this in keeping with vasogenic oedema.