MRI Question — What Can an MRI Without Contrast Show That an MRI With Contrast Cannot?

[Lisa88]

Hi Dr. Ancill,

Thanks for joining us.
Your work with the brain is intriguing.
Wonder if you may be able to answer the following question:

What can an MRI without contrast show that an MRI with contrast cannot? I always thought the one with contrast was the most specific. Thanks.

Background to this question:
I have no symptoms of MS or other except for tinnitus. Tinnitus was induced Nov 2013 through intransal topical lidocaine solution during a menstrual migraine.

Spring 2014, I had an MRI without contrast done. Then two weeks later an MRI with contrast with the same company/radiologist.

The first one without contrast read:
There is a nonspecific 8 mm T2/FLAIR hyperintense focus within the centrum semiovale of the left frontal lobe with 2 adjacent 2 mm T2/FLAIR foci immediately posteriorly. Cerebral hemispheres are otherwise unremarkable.

The second MRI with contrast read:
The previously identified T2/FLAIR ... are not seen on post contrast sequence.

The advice for both read:
Clinical correlation is advised to exclude chronic small vessel ischemic disease, vasculitis, postinfectious or postinflammatory demyelinating processes or lesions.

One doctor noted this could have been a machine malfunction with the non contrast. Really don't want to have to have another MRI done with tinnitus.
Do I have to worry about this, if the MRI with contrast came up clear?

Thanks.
Lisa

 

[Dr. Ancill]

Ultimately, MRIs are cameras and can only 'see' to the limit of their resolution which is a few millimetres. I have no idea how intranasal lidocaine could (1) cause tinnitus or (2) be related to nonspecific lesions in the left frontal lobe. Now, I am a Canadian, so the US medical system is a mystery to me - I would advise that you get a recognized neuroradiologist to look at the data and get an independent 2nd opinion. I cannot comment on possible diagnoses and it would be improper to speculate. I can say that the older you are, the more likely it is to find these nonspecific signals in the brain and it likely means nothing at all. I would also advise that you discuss your concerns with your own doctors - on any forum, you never know what someone will tell you.