(contributed by David Clunie; followup on April 30, 2015 QIICR bi-weekly meeting)

One publicly available example is at:

[ftp://medical.nema.org/MEDICAL/Dicom/DataSets/WG16/Philips/EnhancedMR/Brain/]

Look in Series 801; there is a DWI with B values of 0 and

I.e., each frame has an
{{{
(0x0018,0x9117) MRDiffusionSequence
}}}
with either:
{{{
(0x0018,0x9087) DiffusionBValue = 0
(0x0018,0x9075) DiffusionDirectionality = NONE
}}}
or
{{{
(0x0018,0x9087) DiffusionBValue = 1000
(0x0018,0x9075) DiffusionDirectionality = ISOTROPIC
}}}
Note also that the type of (inherent) contrast is specified too; in the:
{{{
(0x0018,0x9226) MRImageFrameTypeSequence
}}}
you will find:
{{{
(0x0008,0x9209) AcquisitionContrast = DIFFUSION
}}}


Another publicly available set of samples can be found at:

[ftp://ftp.ihe.net/Connectathon/samples/RAD-profiles/DIFF_samples/]

but these are less useful as a reference since:

- the Philips images do not contain useful pixel data

- the Hitachi images have a lot of issues with respect to the functional
   group encoding (try validating them), but do have pixel data

I also have some of Philips diffusion images that have directionality
encoded;
these are from an IHE test set, are are of a phantom, so are not restricted
in their use, but I don't think there is a public URL for them. Anyway, you
can get them from:

[https://www.dropbox.com/s/hg42y1v15bfevyl/emr_diff_perf_profiles_2010.zip]

and can perhaps copy them to somewhere permanent and publicly accessible
(and share the link with the QIN folks who were asking about this too).

The image with the directionality contains for the non B0 frames, in
{{{
(0x0018,0x9117) MRDiffusionSequence
}}}
the attributes:
{{{
(0x0018,0x9087) DiffusionBValue = 800
(0x0018,0x9075) DiffusionDirectionality = DIRECTIONAL
(0x0018,0x9076) DiffusionGradientDirectionSequence
}}}
and in turn {{{DiffusionGradientDirectionSequence}}} contains:
{{{
(0x0018,0x9089) DiffusionGradientOrientation = -1\0\0
}}}
or
{{{
(0x0018,0x9089) DiffusionGradientOrientation = 0\-1\0
}}}
or
{{{
(0x0018,0x9089) DiffusionGradientOrientation = 0\0\1
}}}

PS. You can find the corresponding "singe frame" ("legacy") style images
for the first case at:


[ftp://medical.nema.org/MEDICAL/Dicom/DataSets/WG16/Philips/ClassicSingleFrame/Brain/]