DICOM tag with missing VR loads inconsistently (Philips ScaleSlope)

I have two Philips mDixon datasets. In both, the VR for ScaleSlope is apparently missing:

(2005,100D) 00 A0 AA 44 # 1, 4

This should be read as a single value. In fact, dcminfo reads it correctly in one case: ScaleSlope = 1365, and incorrectly in the other: ScaleSlope = 0

160

170

68

Both times, I am using the same dictionary with the tag filled in (2005,100d) FL ScaleSlope 1.

1) What might cause one case to read correctly and the other not?

2) Is it possible to convert the string of 4 int8 numbers to a single 'single data type' number?

Many thanks,

Bogdan

Answer 1

[Walter Roberson]

A = uint8(sscanf('00 A0 AA 44', '%2x'))

A = 4×1

0 160 170 68

typecast(A, 'single')

ans = single 1365

(Thank you for mentioning your release -- that saved me from showing you code that would not work in your release)

[Bogdan Dzyubak]

Thanks so much! I was able to also salvage another dataset by converting '20 20' to int16 based on your example. Matlab has the most helpful Q&A!!!

If anyone also needs a python equivalent, it is:

import struct

if len(value) == 4:

value = struct.unpack('f',ds['2005','100d'].value)[0]

elif len(value) == 2:

value = struct.unpack('h',ds['2005','100d'].value)[0]

# For data type codes: https://pypi.org/project/rawutil/