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unenhanced MRI in lieu of ct/pet scans

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Posted 10/19/2016 12:08 PM (GMT 0)
I was shocked to read this:

http://www.urotoday.com/recent-abstracts/urologic-oncology/prostate-cancer/91804-unenhanced-whole-body-mri-versus-pet-ct-for-the-detection-of-prostate-cancer-metastases-after-primary-treatment.html

Mel
Posted 10/19/2016 2:15 PM (GMT 0)
www.urotoday.com/recent-abstracts/urologic-oncology/prostate-cancer/91804-unenhanced-whole-body-mri-versus-pet-ct-for-the-detection-of-prostate-cancer-metastases-after-primary-treatment.html

Post Edited (Wings of Eagles) : 10/19/2016 8:19:37 AM (GMT-6)

Posted 10/19/2016 3:50 PM (GMT 0)
Wings:

Thanks for making the link clickable!

Based on this article, why do the radiation scans?

Mel
Posted 10/19/2016 4:29 PM (GMT 0)
Unenhanced body MRI?...DWI Mri?? Confused!
Posted 10/19/2016 5:01 PM (GMT 0)

Darie said...
Unenhanced body MRI?...DWI Mri?? Confused!


I'll take a stab at helping clarify, Darie. Not sure how far back to go, but I'll jump in here...

Conventional MRIs use a "contrast" agent (injected/consumed) to "enhance" the image problem areas...radiologists often take images with and without contrast to examine the differences, but tests of MRI without the use of contrast agents are not necessarily less accurate and helpful than those with contrast. Contrast agents used in MRI with contrast are also subjects of potential risk to the patient...so "unenhanced" MRIs do not add incremental risk.

DW-MRI (or DWI-MRI) stands for "diffusion weighting," and examines the diffusion of water in the body...the water effectively acts as the contrast. Water molecule diffusion patterns can reveal details about tissue architecture, either normal or in a diseased state and can be utilized for the detection and characterization of malignant tumors.

If you've heard of multiParametric-MRI, or mp-MRI, you may know that DW-MRI is one of the components of mp-MRI. DW-MRI for prostate cancer mets has been under study for over a decade and is now "emerging" for clinical use. It has the advantage over PET/CT (currently used to look for PC mets) of being non-radioactive, takes less time (10 mins versus several hours, and the equipment is less expensive).
Posted 10/19/2016 5:06 PM (GMT 0)
This would appear to be HUGE NEWS.

Am I missing something?

Mel
Posted 10/19/2016 5:24 PM (GMT 0)
Thanks JackH.
I had 2 MRIs which found nothing both in my pelvis &bones 2 wks before my 68Ga PSMA PETCT.At a PSA of <0.3 PSMA
found 2 lesions!..now I know that this is a different stuff...not found in my area.
Posted 10/19/2016 5:38 PM (GMT 0)

Darie said...
I had 2 MRIs which found nothing...

DW-MRIs?




compiler said...
This would appear to be HUGE NEWS.

Am I missing something?

Science is the slow march of accumulating evidence. (https://www.healingwell.com/community/default.aspx?f=35&m=3674693&p=5)

You can find decade-old papers covering the emergence of this. Both have been done side-by-side for a while. There are pluses and minues to both, but...
Posted 10/19/2016 6:04 PM (GMT 0)
conventional 1.5T MRI.
Posted 10/19/2016 6:22 PM (GMT 0)
Mel -
Why were you shocked?
Posted 10/19/2016 6:32 PM (GMT 0)
I had a mp-MRI in a 3T MRI for staging during my initial work-up. Of course I had to ask for a copy of the scan, which they gave me on a DVD. It's quite interesting to look at those scans, looking at the different images to see the tumor area. They use the different parameters mostly to exclude certain gland features that could be possibly mistaken for tumors. For instance, areas that look darker in one scan, and lighter in another are more indicative. Many things show up in only one or the other and can thus be excluded, things like BPH areas, artifacts from biopsies, and so on.

It's also obvious that it takes a lot of training to really understand those scans. Those people can see details within things I can't even identify! As hard as I've looked at the scan images, I still can't see where the "neurovascular bundles" are, that they say are involved in my PCa. The bulging appearance of the gland's left side indicating extracapsular extension is pretty obvious, but lots of other things are not.
Posted 10/19/2016 8:54 PM (GMT 0)
TA:

Is this not suggesting that scans like the C11 or PSMA scans are now obsolete?

That's why I think I am missing something here.

(I thought the MRIs and Pet/Ct scans complemented each other)

Mel
Posted 10/19/2016 10:04 PM (GMT 0)
I reviewed the article again...I didn't see the word "obsolete" in the article, or anything closely resembling it, anywhere.

Nothing "shocking," either. Not a single exclamation point was used. The sky is not falling and no, the election is not "rigged" either.
Posted 10/19/2016 11:29 PM (GMT 0)
Just a thought.
Howard Sandler presented at PCRI this year, none of the scans today is the best scan. The older glucose based PET-scan is still quite capable of detecting a cancer spread when other newer scans do not. And vice versa. Getting a C11 and/or an F18 or whatever might miss cancers the glucose based PET scan can still find. Howard presented series of various scans within the same individuals. Each scan had areas where that scan was superior and each one also have areas where it was inferior. Improvements are happening quickly but to say "I got a C11 and that's the best scan" is probably not necessarily true. Same with other newer scans. In fact when a scan comes up negative that only opens the door for other scans as PSA keeps rising. And if the original less expensive glucose PET scan has not been performed, it may be reasonable to start right there before going on toe more expensive scans. Especially if you have pay for it yourself.

Keep in mind, it is quite possible that the results of all scans have not been proven to necessarily change the standard of care in the patient. If metastatic lesions can be found that can be hit with radiation that's one aspect. But not all distant lesions can be treated with radiation and not all that can be need to be.

Scans have been an interesting topic here since I arrived 10 years ago. Combidex, PET, you name it. The science is getting better on scans. But even today a standard Xray can detect abnormalities that could indicate cancer. Even indicate prostate cancer as a possibility. But should it change the approach to therapy? In some cases it can be. And in some cases it can be an assumption that finding small lesions and radiating them can be over treatment.

More trials needed please...
Posted 10/19/2016 11:36 PM (GMT 0)
JackH:

Glad you didn't see the word "obsolete." Now reread my post. I indicated that the information might SUGGEST that PET/CT scans are obsolete.

Tony -- yeah, all scans are imperfect, with various limitations. I find the idea that one can do an MRI to be intriguing because of the lack of radiation harm from MRIs, especially if one has to do many of them over time.

Mel
Posted 10/19/2016 11:41 PM (GMT 0)
Nope - it does not suggest that at all. It just says that for 152 patients who were scanned after failing RP (with PSA incr>1.2) or failing RT (with PSA incr >2), that a whole-body mpMRI was about as good as a F18 Choline PET/CT at detecting metastases. (I would imagine the cost of a full-body mpMRI would be as high if not higher than a PET/CT) This has nothing whatever to do with C11 or PSMA PETs.

The new combined PET/MRI scanners now becoming available are more accurate than the conventional PET/CT scanners.
Posted 10/20/2016 12:07 AM (GMT 0)
Yep. Figured I was reading too much into this

Mel
Posted 10/20/2016 5:42 PM (GMT 0)

Tall Allen said...
Nope - it does not suggest that at all. It just says that for 152 patients who were scanned after failing RP (with PSA incr>1.2) or failing RT (with PSA incr >2), that a whole-body mpMRI was about as good as a F18 Choline PET/CT at detecting metastases. (I would imagine the cost of a full-body mpMRI would be as high if not higher than a PET/CT) This has nothing whatever to do with C11 or PSMA PETs.

The new combined PET/MRI scanners now becoming available are more accurate than the conventional PET/CT scanners.


TA, are there any papers about using the combo scanners for prostate cancer? Just curious. I'm sure my insurance wouldn't cover one if needed some day anyway. They don't even acknowledge the C11 Choline PET scan for prostate cancer; experimental, they say.
Posted 10/20/2016 6:38 PM (GMT 0)
There have been several studies, and there are a few clinical trials. See these, for example:

Combined PET/MRI Improves Diagnostic Accuracy in Patients with Prostate Cancer: A Prospective Diagnostic Trial

Comparison of hybrid 68Ga-PSMA PET/MRI and 68Ga-PSMA PET/CT in the evaluation of lymph node and bone metastases of prostate cancer

You can check with UMich to see if they have plans of acquiring one. I imagine they are very expensive. I've heard of them at Washington U (St Louis), MSK, UCSF, Stanford, & Johns Hopkins - there are probably a few more out there at major cancer centers.

The only advanced PET indicators approved by the FDA are C-11 Choline and fluciclovine. Medicare will probably cover those, but private insurance may or may not. Sometimes they will cover it if it is part of a clinical trial.
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