[Insight-developers] Re: [Insight-users] GDCM orientation issue....

[Mathieu Malaterre]

Simon Warfield wrote:
> Neil Weisenfeld wrote:
> 
>> Hi Mathieu,
>>
>> Thanks for your offer of help.  I ran my code in a debugger so I could 
>> trace through what's happening and here's the problem:
>>
>> One of our standard scan protocols is a dual-echo spin-echo sequence. 
>> This is delivered by the scanner typically as a DICOM dataset with 
>> every  odd slice being the early echo scan and every even slice being 
>> the late echo scan.  The current implementation of 
>> GDCMSeriesFileNames::GetInputFileNames does indeed attempt to sort 
>> based on ImagePositionPatient, but silently falls back to image 
>> number, as you  mentioned, if this fails.  In the case of our data, it 
>> fails because there are two slices at each position.
> 
> 
> It would be possible to order this type of data by first sorting on 
> ImagePositionPatient, and then for slices that have the same position 
> (which is perfectly legitimate) to sort based on EchoNumber (0018,0086).
> 
> Alternatively, perhaps the interface could allow the specification of a 
> particular EchoNumber and only files with a matching EchoNumber would be 
> read and sorted.

Exactly and therefore collecting images that have the same UID becomes 
just a new rule, which could be removed in case of very specific task. 
This is definitely on my TODO list.

Mathieu