Hi David,
Technically the behavior for Philips (old) MR Image Storage is slightly more complex. Per:
https://www.vuiis.vanderbilt.edu/~welcheb/manuals/R3.2.1/DICOM_Conformance_Statement_US.pdf
We have:
[...]
Rescale Slope 0028,1053 DS ALWAYS AUTO When a value is present and not 1, then this value shall be used in the scaling calculation for the correct Window setting.
[...]
I have seen cases (Achieva) such that:
$ gdcmdump MR0001.dcm | grep -1 Rescale
(0028,1051) DS [16.88 ] # 6,1-n Window Width
(0028,1053) DS [1.0 ] # 4,1 Rescale Slope
(0028,2110) CS [00] # 2,1 Lossy Image Compression
--
(fffe,e000) na (Item with undefined length)
(0028,1052) DS [0.0 ] # 4,1 Rescale Intercept
(0028,1053) DS [2.487424] # 8,1 Rescale Slope
(0028,1054) LO [normalized] # 10,1 Rescale Type
(2001,0010) LO [Philips Imaging DD 001] # 22,1 Private Creator
--
(2005,1406) SS 0 # 2,1 ?
(2005,1409) DS [0.0 ] # 4,1 Rescale Intercept Philips
(2005,140a) DS [2.48742368742368] # 16,1 Rescale Slope Philips
(2005,140b) LO [normalized] # 10,1 Rescale Type Philips
(2005,140e) SQ (Sequence with undefined length) # u/l,1 ?
The Philips private attributes Rescale Slope/Intercept seems to be consistent when one choose to use the Real World Value Mapping Sequence display path (C.7.6.16.2.11.1.1):
$ gdcmdump MR0001.dcm | grep -A 3 Real
(0040,9096) SQ (Sequence with undefined length) # u/l,1 Real World Value Mapping Sequence
(fffe,e000) na (Item with undefined length)
(0040,9224) FD 0 # 8,1 Real World Value Intercept
(0040,9225) FD 2.48742 # 8,1 Real World Value Slope
(fffe,e00d)
(fffe,e0dd)
(2001,0010) LO [Philips Imaging DD 001] # 22,1 Private Creator
So I suspect (old) MR Image Storage from Philips have always the public Rescale Slope set to 1 nowadays. Thus Real World Value Mapping Sequence information should be used to scale the stored pixel before processing and/or display.
The values for Real World Value Intercept/Slope are identical across all Series I've seen so far, so this is less messy than with some PET Image Storage with changing Rescale Slope/Intercept.