Is it possible to have DWI negative despite high T2?

Hi doctor,

I want to know about the vertebral artery dissection. I had a traumatic brain injury (TBI) (with neck trauma too), no loss of consciousness, no amnesia. The computed tomography (CT) was negative. The magnetic resonance (MR) showed T2 hyperintensity in the right lateral medulla (no diffusion-weighted imaging (DWI) was performed). After few days, the MR showed the same even with contrast, DWI negative (is it not weird, DWI negative despite high T2?). In the same month, magnetic resonance angiography (MRA) showed the right vertebral artery very hypoplastic and completely occluded in the intracranial part. The computed tomography angiography (CTA) showed the right vertebral artery in the same situation. What I think is vertebral artery dissection and ischemia in the lateral medulla. For two reasons. 1) vertebral artery blockage can lead to ischemia in the lateral medulla (specifically the intracranial blockage, which I have); 2) Why is DWI negative if T2 is high? I guess because of high active diffusion control adenylate cyclase (ADC), and why is ADC high? What doctors told me: It is nothing to worry about. I do not know if they think my right vertebral artery has always been this way because my posterior cerebral arteries arise mainly from carotids.