(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://drive.google.com/open?id=0BzGsmNN8MvZqcG5oSllNMEw5VDA&authuser=0]

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/]