MRI vs MRA which is right?

[josiegrossie]

I recently had an MRI done and the results showed that I had a 4mm in size aneuryusm. Then a few weeks after I had an MRA done and the results showed that there was no aneurysm. Which one is right? How can something that size show up on one and not the other? My neurosurgeon has had cases where the MRA was wrong and his patients did end up having one. Now I dont know the technical terms cause this is new to me but it is suppose to be in an area at the top of my head where two arteries come together and there is a little bridge in between them. The side views of the MRA arent 100% visible so they are going by the top view only is my understanding. They are thinking about doing the procedure where they go up into the groin but because there is a chance for a stroke they really dont want to and are giving me the all clear. I really don't know how to feel about this because the surgeon is putting all his faith in the radiologist. I shold be happy about this but am more confused, I just dont have a great feeling about this especially since I have had a family member die from one at age 45. I am 35.
Thanks

[josiegrossie]

Thanks, not exactly sure what all the terms mean but am glad to have gotten a reply to help me out. They never offered a CT scan just an artery procedure through the groin but felt it was too risky. I originaly had the first MRI because I had to do a routine hearing test at work which showed that I had loss of hearing in one ear and then a few weeks later they did another one and the results were the same. I also had been having a lot of dizziness and nausea for a couple years so they finally decided to do an MRI of my ears, ear canal etc... and when the results came back they said that they "saw a medium sized (4mm) aneurysm" said "it's not small but it's not big" so then they decided to do the MRA to look at actuall location and size and then nothing appeared but like I said the neurosurgen was not 100% convinced it wasn't there. I thought when I came out of that office I would have had a clear cut direction I would have to take but am more confused and nervous. I do have high blood pressure and high cholesterol (hereditay). I did her the surgeon say to the radiologist that he didn't go through the slices and wants him to double check them. Not a confident feeling. Thanks for you help.

[Christopher R Newey, DO]

Thanks for using the forum. I am happy to address your questions, and my answer will be based on the information you provided here. Please make sure you recognize that this forum is for educational purposes only, and it does not substitute for a formal office visit with a doctor.

Without the ability to examine and obtain a history, I can not tell you what the exact cause of the symptoms is. However I will try to provide you with some useful information.

Aneurysms can be noticed one modality and not another. This can be from several factors. One being the aneurysm is too small for detection (4mm is getting close to the cut off). The other being that the slices taken for the image does not slice directly through the aneurysm or lesion.

Another modality that can be used to assess for aneurysm (other than MRA and angiography) is CT-angiography (CTA). This is a CT scan taken after a dye is injected through a peripheral IV. If the aneurysm is seen clearly, it may not need angiography and can be monitored serially with CTA.

You should discuss your concerns and the options with your physician.

By the way, why did you have the MRI/A performed?

Thank you for this opportunity to answer your questions, I hope you find the information I have provided useful, good luck.