Can a brain aneurysm or narrowing of the arteries show up on a MRI with contrast or with out?

Many times. These studies have limited resolution and can miss abnormalities. Mra is better than MRI as it shows the blood vessels better and is useful for screening. Even mra is limited resolution and can miss lesions smaller than 2-3mm. For high suspicion a catheter angiogram is the best study.
Large aneurysms. I have been taught that aneurysms greater than about 5 mm (about 1/4 inch) are visible on brain MRI with or without contrast. The contrast helps to make one more sure it is an aneurysm, not some other structure. The better image of the blood vessels is a mra, (magnetic resonance angiogram) with or without contrast. It is the same experience as a MRI but the computer outlines blood vessels.

Related Questions

Can a small brain aneurysm show up on a MRI with contrast? (I didn't get an MRA)

Yes. Usually CT alone will show brain aneurysm. MRI without contast is added if CT is negative but suspicion is high for aneurysm. Though MRA visualizes blood vessels it is not the diagnostic test of choice for cerebral aneurysm. Read more...

Can a brain aneurysm show on MRI with contrast?

Only if large enough. MRI with contrast has a resolution limit of about 5 mm, depending on the field strength of the magnet & the spin sequence performed (resolution of time-of-flight MRI or TOF-MRI is even worse). The "gold standard" for an aneurysm is a fluoroscopic angiogram of the brain, which only interventional neurologists or radiologists perform 4 (1) known stroke or (2) genetics. Use HealthTap Prime to discuss. Read more...

Can a small brain aneurysm show on an MRI with contrast (iodine)? I didn't get an MRA and have been getting pain on left side I'm scared

Yes. MRI will show an aneurysm. Your headaches could be due to other reason. If you got an MRI done already a physician is already involved so go back to your physician so they can further investigate the cause of your headaches. Read more...