Sensitivity of Axumin vs Specificity of MRI

[alephnull]

Does anyone know or know where I can find out the sensitivity of Axumin scans and also the specificity of MRI (specific to PCa).

And then how to compare them.

What it comes down to is, why would an MRI rule out an Axumin scan. And by rule out I mean, declare the Axumin results false positive because of the MRI

[Ahk1]

This is a good question. I was thinking about. I can’t answer but waiting to see how others who have more experience answer this question. Thanks for posting

[Tall_Allen]

This may help:

pcnrv.blogspot.com/2016/12/...

If they are unable to find a lesion where the Axumin scan says it should be, a false positive may be suspected. PETs don't have good resolution, which is why CTs are always taken at the same time. There is a Siemens machine that does both PET and MRI at the same time.

[alephnull in reply to Tall_Allen]

Thanks Allen!

By chance do you know if there is a chart like the one on your blog for MRIs based on PSA level?

[Tall_Allen in reply to alephnull]

MRI is not based on PSA level

[alephnull in reply to Tall_Allen]

I know, but like a CT or Bone scan are MRIs less likely to find mets when PSA is relatively low, say under 2.0.

It seems like someone would have done a study, but maybe not.

[Tall_Allen in reply to alephnull]

The role of MRI or CT is complementary to the pet scan

[alephnull in reply to Tall_Allen]

Yes, I know they are complementary.

But, certainly someone has compared MRI results to PSA. Just as they have with CTs and Bone scans and PET scans.

In my case, my PSA was all of 1.40 when I had the AXUMIN PET scan.

MRI was done just two weeks later, so the PSA was higher but not sure how much higher, probably about 2.0 (going by my PSADT)

[Tall_Allen in reply to alephnull]

MRI detects changes in the tissue of metastases. It is irrelevant how much PSA that met puts out. Certainly bigger metastases put out more PSA than smaller metastases on the average. MRI is useless for metastases smaller than about 4 mm unless special indicators are used. It is size and tissue changes rather than PSA that is more important for mri.

[alephnull in reply to Tall_Allen]

"MRI is useless for metastases smaller than about 4 mm unless special indicators are used. "

Thanks Allen!! This is the kind of info I'm looking for.

My test results didn't mention size, but implies very small. (I realize how darn small 4mm is, less than half a centimeter.

"Focal uptake in the L3 vertebral body suspicious for a solitary metastasis"

Maybe just maybe the PET saw it, but it was just too darn small for the MRI to see.

I know some may think I'm making something out of very little, but because I just turned castrate resistant, I'm looking for answers.

Thanks very much!!!

[cesanon]

I was told thar either PET or MRI is better for soft tissue and the other is better bone.

[cesanon]

"There is a Siemens machine that does both PET and MRI at the same time."

I went looking for one of those and I couldn't find any place associated with a prostate cancer practice that was using it for prostate cancer scans.

Does anyone know of any prostate cancer practices that make use of Pet/MRI scans from the Siemens machine?

[rscic]

Axumin® = fluciclovine

I am not sure if this will be helpful but it compares some of the different imaging types:

practicalradonc.org/article...