What is difference between dicomdisp vs dicominfo?

Good afternoon, I am trying to access data within a dicom rt file. When I use dicomdisp the data I am interested is shown but when dicominfo is called on this file, the data is not displayed. What are the differences between a function call of dicomdisp and dicominfo that would cause this data loss?

Answer 1

[Julianna Mather]

What you're seeing here is the hierarchical nature of DICOM files. The "FluenceMapSeqeuence" struct in the dicominfo output contains the fields you want. (You can see this in the output of dicomdisp in the non-zero values of the "Level" column.)

In your example, you'd want to write something like this:

metadata = dicominfo('c:\file.dcm');
metadata.FluenceMapSequence.Item_1.FluenceDataScale

I hope this helps.

Answer 2

[Walter Roberson]

One difference is that dicomdisp() is for displaying only, but dicominfo() returns the information as a structure and so is for program use.

Some of the information returned by dicominfo does not get displayed by default because what is being returned is a struct array and the default display of struct arrays give summaries of the content if the content is more than a fairly small size. To see that information you would need to store the resulting struct and ask to display a particular field of it.

[Kevin Fallon]

Thanks Walter for your input. I think an example might be in order here. I am attaching an example code.

An Example:

So to store the struct, that would be:

 data_dicom=dicominfo('file.dcm');

and to access a element of the struct would be

 ssd = data_dicom.RadiationMachineSSD

which would have ssd = 1000 from data below.

dicomdisp Result:

File: 'C:\file.dcm' (73412 bytes)
Read on an IEEE little-endian machine.
File begins with group 0002 metadata at byte 132.
Transfer syntax: 1.2.840.10008.1.2.1 (Explicit VR Little Endian).
DICOM Information object: 1.2.840.10008.5.1.4.1.1.481.1 (RT Image Storage).

Location Level     Tag     VR       Size         Name                             Data                                               
----------------------------------------------------------------------------------------------------

0001092    0   (3002,0020) SH          0 bytes - RadiationMachineName             [] 
0001100    0   (3002,0022) DS          0 bytes - RadiationMachineSAD              [] 
0001108    0   (3002,0024) DS          4 bytes - RadiationMachineSSD              [1000] 
0001120    0   (3002,0026) DS          4 bytes - RTImageSID                       [1000] 
0001132    0   (3002,0040) SQ         48 bytes - FluenceMapSequence                
0001144    1   (FFFE,E000) UN         40 bytes - Item                              
0001152    2   (3002,0041) CS          8 bytes - FluenceDataSource                [MEASURED] 
0001168    2   (3002,0042) DS         16 bytes - FluenceDataScale                 [6.65966666666667] 
0001192    0   (300A,00B3) CS          0 bytes - PrimaryDosimeterUnit             [] 
0001200    0   (7FE0,0010) OW      72200 bytes - PixelData                        []

dicominfo Result:

Filename: 'C:\file.dcm'
         
              RadiationMachineName: ''
               RadiationMachineSAD: []
               RadiationMachineSSD: 1000
                        RTImageSID: 1000
                FluenceMapSequence: [1x1 struct]
              PrimaryDosimeterUnit: ''

The data I want to access is FluenceDataScale which is in the dicomdisp but not dicominfo. I shortened output to relevant data I am interested in.

I dont know why this information is not available in dicominfo. That why I was asking if, besides displaying, that something else is going on here.

[Walter Roberson]

Sorry, this is beyond my experience.

[Kevin Fallon]

Thanks for your time Walter. Have a great day.

[robbie hakeem]

This was very helpful. Do You know how I can read multiple control points ?

[mohd akmal masud]

Hi all,

I want to extract the RescaleSlope value from dicominfo for each slice. But i have 135 slice images. This is my code to extract RescaleSlope. But still failed. I JUST CAN EXTRACT ONE BY ONE ONLY.

P = zeros(256, 256, 135);

for K = 1 : 135

petname = sprintf('PET_I1001_PT%03d.dcm', K);

P(:,:,K) = dicominfo(petname);

end

info=dicominfo(P(:,:,K));

[r,c,slice] = findND (info.RescaleSlope);

Anyone who can help me solve this problem???

[Walter Roberson]

Do not keep posting the same question. You already created https://www.mathworks.com/matlabcentral/answers/383405-extract-rescale-slope-value