Denise Pavao (asker) Feb 18, 2018:

I've been waiting to hear from my niece who is an MRI tech. She just sent me the following explanation:
The diffusion sequence is a two part scan with half the scan running the diffusion and the other half running the ADS portion. They are usually used in comparison not only to visualize a stroke but the diffusion and ADC used together can tell how long ago a stroke happened. If its bright on the diffusion and dark on the ADC it means it's a recent stroke. If it's bright on diffusion but in comparison that same spot is bright on the ADC then it could mean its a non recent stroke, or from a little while ago, or that the tissue could be presenting as something other than a stroke. So those sequences are used to compare against each other.

So Liz, I think "in comparison," as you suggested in the first place, is probably the best translation here. I'll try to add an image in References to show the bright Diffusion sequence compared to the dark ADC sequence.

Denise Pavao (asker) Feb 18, 2018:

Here's a nice reference:

This same pattern of change can be observed in the diffusion-weighted MR imaging appearance of ischemic human brain tissue during the evolution of acute stroke: Hyperintense signal is seen with reduced ADC values from approximately 30 minutes to 5 days after the onset of symptoms

http://pubs.rsna.org/doi/full/10.1148/rg.26si065501

Denise Pavao (asker) Feb 17, 2018:

Thanks Liz - this looks promising!

liz askew Feb 17, 2018:

https://radiopaedia.org/articles/cortical-laminar-necrosis
Unfortunately both terms are often used inappropriately for a broader range of ischaemic events which result in areas of cortical T1 intrinsic hyperintensity, ... Although early cytotoxic oedema***8 causes high signal seen on DWI with corresponding low apparent diffusion coefficient (ADC)**** values in the affected cortex, and ...

liz askew Feb 17, 2018:

Please ignore below.
See:
https://books.google.co.uk/books?isbn=1469887134
Matthew Omojola, ‎Mauricio Castillo - 2014 - ‎Medical
Axial DWI through the upper centrum semiovale showing patchy bilateral almost symmetrical frontoparietal ***cortical hyperintensity with corresponding ADC hyperintensity*** in Figure 492 (arrows). Figures 493 and 494. Axial FLAIR and T2WI, respectively, through same level confirm cortical patchy hyperintensity with mild ...

liz askew Feb 17, 2018:

Yes,this is what I mean,
in comparison to

un hypersignal cortical et sous cortical hémisphèrique droit

Denise Pavao (asker) Feb 15, 2018:

@Liz: I'm wondering if they mean the decreased ADC is in comparison to (so perhaps doesn't match) the hyperintensity on diffusion.... Off to check it out...

Denise Pavao (asker) Feb 13, 2018:

Hi Liz. I do have decreased apparent diffusion coefficient, but there's really nothing "above," which is why I was looking for something other that "in comparision." The patient had an MRI due to a wake-up stroke, and there is no indication that he ever had a previous MRI.

liz askew Feb 13, 2018:

in comparison

liz askew Feb 13, 2018:

Decreased apparent diffusion coefficient