unknown cause of stroke like symptoms

[kcbobe]

My fahter is 74.  Two days ago, at 6:00 PM he had a dizzy spell.  He shook it off and a few minutes later he was having a hard time walking straight.  From their his right fingers and toes started tingling.  My mother took him to the ER and they ran some tests.  The conducted a CT scan to look for signs of a stroke.  The CT scan was completed by 7:00 PM and it came back clear.  Hestarted feeling better until 9:00 PM when his right arm started going numb and the tingling in his right foot came back and his speach became slurred.  The ER continued to watch him and and at 5:00 AM the next morning decided to transfer him to a large hospital in Kansas City.  The medical team in KC ran tests and scheduled an MRI.  At 6:30 PM they cnducted the MRI.  The following morning, he felt a little better however his speach was still slurred and he was complaining about sharp pins and needles in his right arm, right hand and his right foot.  He had feeling in those extremities but had no control and he couldn't walk.  :Ater that day, the neurologist came in after reading the MRI. The MRI showed no signs of a stroke and no damage to the brain.  The nuerologist simply said he had symptoms of a stroke but the MRI didn't conclusively show anything.  He simply said they would treat it as a stroke because he didn;t have any answers as to what was really going on.  Lather that night, my dad stated that the pins and needles were getting worse in his hand and feet as well as up his right arm.  His speach really started getting worse and his also started complaining about double vision.  The double vision only occured when he was laying on his back.  When he raised his head the double vision would go away.   At that time I asked the nurse to call the neurologist.  The nuerologist orderd another MRI.  The second MRI came back clean again showing no signs of a stroke.  The neurologist stated that he had never seen anything like this and is at a loss.  So my question is where do we go from here?  There has to be something they are not seeing because he still has stroke like symptoms.  Any help or advice would be greatly appreciated..  

[Londres70]

I see you have done your homework already.  

Follow up with the Neurologist and see what he/she thinks.  

[kcbobe]

I'm unsure if the CT and MRI utilized had contrast. I've reseached various scans and I will ask the Neurologist what type of MRI was given.  Based off my research, it appears that a diffusion weighted MRI or a perfusion-weighted image would provide a more detailed picture.

[Londres70]

It is possible to have a stroke and a negative MRI.  In some patients, it can take some time for radiologic evidence to show and/or the infarct could be very small that it is getting missed.  

Was the CT and MRI with contrast?