Is MRI of brain necessary after Pet ct scan - 1263357

Hello,

Since the brain routinely "lights up" on a PET scan, it is not a good method for detecting brain mets. The CT portion of the scan does a better job, although an MRI is more sensitive and is generally preferred. As Dr. West has stated:

“There is little to no question that head MRIs are superior to CT scans in detecting brain metastases. MRI scans detect a greater number of lesions and defines the location more readily, and they are also better at detecting spread to the meninges, the lining around the brain (and spinal cord).” – http://cancergrace.org/lung/2007/04/05/intro-to-brain-mets/

Whether your husband "needs" a brain MRI may depend on the context. At diagnosis, a brain MRI is routinely ordered, but most oncologists do not use them for follow-up surveillance. The GRACE faculty is in general agreement on this practice:

Dr. Weiss has said:

“I typically acquire an MRI at diagnosis, then again if symptoms suggest. Some oncologist obtain more regular MRIs. I have no objection to this, but am not convinced that it improves actual patient outcomes compared to having a low threshold to get MRI once symptoms develop.” – http://cancergrace.org/lung/topic/should-brain-mri-be-done-even-in-abse…

And in the next reply, Dr. Aggarwal concurred: “I agree with Dr. Weiss. I obtain MRI brain if symptoms (headache, blurry vision, uncontrolled nausea, seizures etc.) develop, after getting a baseline scan.”

Dr. West also agreed, stating: “I follow the same approach. It is not the standard of care at this time to do surveillance brain MRI scans after diagnosis in people with advanced NSCLC who don’t have evidence of brain involvement at their initial work-up.”

JimC
Forum moderator

Unless the brain was to be included, normal PET/CT would be from eye to thigh.
Take care, Judy

CT is usually preferred for imaging of the lung, especially after the initial workup. As Dr. Weiss has said:

"Each of these modalities have different utility. MRI of the chest tends to be most useful only for certain very specific questions. PET/CT gives functional imaging about how much sugar a tumor takes up, and by proxy, how metabolically active it is; this can be helpful in discerning if an area seen on CT is really tumor and in finding small areas of disease not evident on CT alone. However, with known cancer, "plain" CT can often be more helpful than PET/CT because the images are higher resolution and there is IV contrast, better delineating vessels and nodes." - http://cancergrace.org/forums/index.php?topic=3424.msg20414#msg20414

And Dr. West has said that PET/CT "casts a very wide net for abnormal areas around the body (typically covering “eyes to thighs”, which is where you’d find almost all cancers that would spread to the lungs)." - http://cancergrace.org/topic/metastatic#post-1255514 (The reverse is also true, almost all cancers which spread from the lung would appear in the "eyes to thighs" area).

JimC
Forum moderator

Risk of radiation from CT is not a realistic concern compared with the risk of the cancer. Honestly, the risk of driving to the cancer clinic is probably far greater than the risk of radiation from the CT (which is not to say we should be alarmist about the risk of driving to the clinic, but just to say that it's not rational to get worked up about the risk of a CT scan if crossing the street poses a 10-fold greater risk). Imaging-related issues would only be a realistic concern from MANY, MANY CT scans over MANY years of follow up.

-Dr. West