How to deal with DTI data and the problem of conversion from dicom to nii

Why do I get more than 100 images of nii every time I convert a file of dicom, should I deal with the all nii images to get the dti data? I am very confused about it,looking forward to your answer.Thank you.

first of all, it depends what sequence and what DCM to NII converter you are talking about. For example, converting diffusion data using dcm2niix software (which we recommend) would produce one nifti file per volume.

Okay,thank you very much,the DCM I convert is DTI imaging. could I show the process to you ? or could I use the DCM file directly through the SCT.

You cannot input DCM files into SCT. Only Nifti files are accepted. I suggest you go through the SCT course before diving into processing your own data. Many of your questions will be answered by the course. Please note that a Chinese version of the course is available.

thank you,I have learn a lot . I think I should chang it to 4d fsl version nii.

yes, the starting point of a diffusion MRI analysis is indeed a 4d nifti file.

dear jcohenedad , when I put the 4d nifti file into the SCT , It shows the :ERROR in Size of data (17) and size of bvecs (35) are not the same. Check your bvecs file. and ,what should I do for the data ??
If you have time ,please help me ,I will be very appreciative .
Thank you.

As the error message states, it looks like your bvecs file is not consistent with your input data. Apparently you only have 17 volumes in your DWI dataset, while your bvecs file is expecting 35 volumes.
If you send me your DCM i can give it a try,

okay,that is great , I will send you my DCM , Thank you a lot . TANG,_WING_KUN_WIP_DTI_thk7_breath-1_5_1.PAR (34.6 KB) TANG,_WING_KUN_WIP_DTI_thk7_breath-1_5_1.REC (3.2 MB)

These are Philips PAR data. As mentioned when running dcm2niix, PAR files are not actively supported, and dicm2nii is recommended instead.

I’ve tried converting your data with dicm2nii and it worked fine: (738.2 KB)

okay, thank you very much.

dear jcohenadad, thank you for your help , I have got the result . but I have a question, in the past, I used the matlab to deal with the dti , however I think the output data are different from the sct . I could not understand the meaning of the output data from the sct. could you tell me what is the fa and md , rd value from the output data ?



FA: Fractional Anisotropy
MD: Mean Diffusivity
RD: Radial Diffusivity

you can find more information in review articles about DTI, such as this one.

dear jcohenadad , the problem is the difference between matlab and sct, I don’t know which row is the data I want. this data are output of the matlab .

the problem is the difference between matlab and sct

I don’t know which software you are using in Matlab to process your diffusion MRI data, therefore I don’t know what difference you are referring to. Could you please be more specific as to what exactly you would like to quantify and compare?

okay, thank you for your patience. I am really grateful.

  1. I just put the my patient’s dti imaging to the dmri document , and the other documents stay the same that I downloaded from the course ,it it will affect the accuracy of my patient’s dti?
  2. after the output data came out , I don’t know which raw is the fa , md, ra value that I want.
  3. what value I want to get is the gray matter of my patient. but the output data shows the label region is white matter, if it means I should change the code of my script? if I should change , which line should I change? this is my (16.1 KB)
    that is all I want to ask . I wish you will not be confused. thank you very much.

I’m sorry but I don’t understand your question. Could you please rephrase?

Each row corresponds to a vertebral level. Depending on your research project, you might have specific hypotheses related to the vertebral level. You could also output a single value averaged across multiple levels, but again, it depends on your research project.

Use flag -l 52 instead of -l 51 from the function sct_extract_metric. All that is explained in the SCT course material, which I encourage you to follow.

dear jcohenadad , I just put the my patient’s dti imaging to the dmri document , and the other documents stay the same that I downloaded from the course ,it it will affect the accuracy of my patient’s dti?
it means only the imaging in dmri document is belong to my patient, the imanging in other document don’t belong to my patient. if it affects the accuracy of my patient’s dti in dmri document.
thank you .

i’m really sorry but i still don’t understand your question.

I want to explain , that I just put my patient’s dti imaging to the dmri document, and the other document is other patient’s(I don’t know who) imaging.( fmri, t1 ,t2 and so on). if I could get the right dti result of my patient?
my English is poor, please forgive me .