Mra/venogram says everything is normal but says there is a fetal right posterior cerebral artery there is hypoplastic left transverse dural venous sinus. what do these mean? are they risk factors for brain problems?

According to my reading both of these are not uncommon.or serious anatomic variants in brain circulation. These should pose no problems for you but a neurosurgeon and the interpreting radiologist can advise you further.

The reported findings are consistent with congenital vascular variants, and are not markers of acute or chronic disorders. I presume the imaging was done to exclude venous thrombosis, but you do not mention indication. Do discuss the results with your doctor to decide the next steps.