appropriate IOD for GE Signa screensaves

[Richard Lanyon]

I'm currently in the process of converting a lot of old MR images in
Signa 5.x format into DICOM, for which I'm using David Clunie's
"gentodc".

This is fine in most cases, except when it comes to what GE calls
"screensaves", i.e. screen captures/screen grabs from the scanner
console. As these are just screen grabs, they don't have all the
information required to create a valid DICOM MR image: I've run the
output of gentodc through CTN's dcm_verify, for example, and it
complains that 0018,0091 (Echo Train Length) is missing from the
MRImageModule.

I thought about converting these files to Secondary Capture instead of
MR images, which makes a certain amount of sense, except for one
further complication. This is that the original Signa files contain
bitmap overlays - in fact two separate overlays, one for text and one
for graphics - and the Secondary Capture IOD doesn't seem to allow
overlays. So can anyone suggest the best way of representing these
files in DICOM? In case it makes any difference, the overlay bitmaps
are not stored in with the pixel data of the original files - the Signa
files have separate sections specifically to store the bitmaps for the
text and graphical overlaps.

Thanks,

Richard

[Mathieu Malaterre]

Richard,

0018,0091 (Echo Train Length) is Type 2:

http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0091)

HTH
Mathieu

[Richard Lanyon]

Mathieu Malaterre wrote:
> Richard Lanyon wrote:

> > As these are just screen grabs, they don't have all the
> > information required to create a valid DICOM MR image: I've run the
> > output of gentodc through CTN's dcm_verify, for example, and it
> > complains that 0018,0091 (Echo Train Length) is missing from the
> > MRImageModule.

> 0018,0091 (Echo Train Length) is Type 2:

Yes, you're right, but I don't think that's the only problem with these
files. The full output of dciodvfy on a DICOM file converted from a
Signa screensave is:

Error - Value invalid for this VR - (0x0002,0x0012) UI Implementation
Class UID UI [0] = <0.0.0.0> - Nothing but zero components
Error - Value invalid for this VR - (0x0008,0x0014) UI Instance Creator
UID UI [0] = <0.0.0.0> - Nothing but zero components
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [0] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [1] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [2] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [3] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [4] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0035) DS Image
Orientation DS [5] = <nan> - Character invalid for this VR = 'n'
(0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [0] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [1] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [2] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [3] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [4] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Value invalid for this VR - (0x0020,0x0037) DS Image
Orientation (Patient) DS [5] = <nan> - Character invalid for this VR =
'n' (0x6e)
Error - Dicom dataset contains invalid data values for Value
Representations
MRImage
Warning - Unrecognized defined term <UNKNOWNUNKNOWN> for attribute
<Patient Position>
Warning - Optional Type 2C Conditional Element=<PatientOrientation>
Module=<GeneralImage>
Error - Unrecognized enumerated value <UNKNOWN> for attribute <MR
Acquisition Type>
Error - Missing attribute Type 2 Required Element=<EchoTrainLength>
Module=<MRImage>
Warning - Optional Type 2C Conditional Element=<InversionTime>
Module=<MRImage>

Some of those may be fixable, but the lack of position/orientation
information looks more difficult.