Image saved as DICOM doesn't match original

Dear all,

I am a medical student postprocessing DICOM images, and wish to save the resulting image (I_blended) back into DICOM format. However, when I use the following:

>>dicomwrite(I_blended, 'I_blended_DICOM')

The resulting DICOM file 'I_blended_DICOM' is different than 'I_blended' in multiple ways:

1. The image of 'I_blended_DICOM' is very, very bright (the values are either 0 or 65535, while 'I_blended' as a range of numbers)
2. 'I_blended' is a 512*512 double, while 'I_blended_DICOM' is 512*512 uint16
3. I am unable to adjust the window/contrast level of 'I_blended_DICOM' in my DICOM viewer, unlike other DICOM images.

I also tried to copy the metadata from an existing DICOM into my save:

>> metadata = dicominfo('IM20');
>> dicomwrite=(I_blended, 'I_blended_DICOM', metadata);

But the resulting 'I_blended_DICOM' is the same as I just described.

Please help! Thank you so much.

Answer 1

[Walter Roberson]

As an experiment, how about

dicomwrite=(I_blended, 'I_blended_DICOM', metadata, 'CreateMode', 'Copy');

However, I doubt this will more than one of your difficulties.

The documentation for dicomread() says that the input images are always uint8, uint16 or int16. Never double. The data you read in with dicomread could not have been double but you are trying to write out double and expect it to be the same. The postings I find, some with the same difficulty about value conversions, say that you should convert your data to uint16() before trying to dicomwrite it. If that requires rescaling it, then rescale it before doing the uint16()

[Brian]

Converting it to int16 does the magic! Thank you so much!