Question
Question Posted 02/07/26:
Hi, I previously asked how to locate raw Difffusion MRI scans from ADNI and someone replied that ADNI does not acquire specific DWI sequence and nly have DTI data! I was wondering how is that possible? There are many studies that use raw Diffusion MRI scans from ADNI.
Hi, I previously asked how to locate raw Difffusion MRI scans from ADNI and someone replied that ADNI does not acquire specific DWI sequence and nly have DTI data! I was wondering how is that possible? There are many studies that use raw Diffusion MRI scans from ADNI.
Response posted 02/07/26 by Rob Reid:
Hello, unfortunately "DWI" means different things in different contexts, and whoever answered your original question thought that by DWI vs. DTI you meant a short diffusion weighted scan (4 volumes, only enough to estimate MD), vs. one long enough to fit a diffusion tensor (at least 7 volumes). Although any diffusion weighted image can be abbreviated to DWI, and DTI is really a diffusion model, not a scan, it is very common to call short dMRI "DWI"s, and dMRIs long enough to fit a tensor "DTI". The former are used clinically to save time, e.g. when only a check for edema is needed.
ADNI has acquired "long" diffusion MRI scans since ADNI2, ranging from 33 volume b = 0 and 1000 s/mm^2 to 127 volume b = 0, 500, 1000, and 2000 s/mm^2 protocols, depending on the scanner manufacturer (ADNI2) or capability (ADNI3 and 4). LONI's Advanced Image Search called them DTIs (and by MRI meant other sequences, such as T1w and FLAIR, but not fMRI). Could you please try the new ARC builder? One of its goals is to make it easy for ADNI and SCAN users to get the data they want without needing to know the quirks of the old interface.
ADNI has acquired "long" diffusion MRI scans since ADNI2, ranging from 33 volume b = 0 and 1000 s/mm^2 to 127 volume b = 0, 500, 1000, and 2000 s/mm^2 protocols, depending on the scanner manufacturer (ADNI2) or capability (ADNI3 and 4). LONI's Advanced Image Search called them DTIs (and by MRI meant other sequences, such as T1w and FLAIR, but not fMRI). Could you please try the new ARC builder? One of its goals is to make it easy for ADNI and SCAN users to get the data they want without needing to know the quirks of the old interface.
Response posted 02/07/26 by Rob Reid:
OK,
1. log into IDA at https://ida.loni.usc.edu/home/projectPage.jsp?project=ADNI
1. Click on "Search & Download" at the top, select "ARC Builder".
1. Wait a bit, and then the page should refresh. I really recommend using the Video Tutorials linked near the top of the page, since me guess at what you want might not be correct.
2. Under Search/Tables/Images, select Key MRI. You might need to click again to make a column of 14 Variables slide out.
3. and Tables/Imaging Data/MR Image Acquisition/MRI3META
4. Go back to Key MRI and click on SERIES_TYPE. Scroll down to dMRI and click on the bar. The "Create a New Filter" button will jiggle. Click on it.
4. Click Create New Filter, deselect all values, and scroll down and click on dMRI. Click Done.
5. The AI should have made a cohort called "DWI Cohort Study". Go to the Downloads tab and select Images. Make sure the DWI Cohort Study is selected.
6. Unfortunately it still has a "Modality" split, with DTI being dMRI and MRI being...I'm not sure what - it only has 125 subjects instead of 1911.
At this point the files to be downloaded would be hundreds of GB, so I'm not going to follow through until the end. Hopefully this is enough to get you started.
5. In the "Create" box at the bottom, use the drop down to Create a new filter after untouched image cohort study, and click on New Filter.
1. log into IDA at https://ida.loni.usc.edu/home/projectPage.jsp?project=ADNI
1. Click on "Search & Download" at the top, select "ARC Builder".
1. Wait a bit, and then the page should refresh. I really recommend using the Video Tutorials linked near the top of the page, since me guess at what you want might not be correct.
2. Under Search/Tables/Images, select Key MRI. You might need to click again to make a column of 14 Variables slide out.
3. and Tables/Imaging Data/MR Image Acquisition/MRI3META
4. Go back to Key MRI and click on SERIES_TYPE. Scroll down to dMRI and click on the bar. The "Create a New Filter" button will jiggle. Click on it.
4. Click Create New Filter, deselect all values, and scroll down and click on dMRI. Click Done.
5. The AI should have made a cohort called "DWI Cohort Study". Go to the Downloads tab and select Images. Make sure the DWI Cohort Study is selected.
6. Unfortunately it still has a "Modality" split, with DTI being dMRI and MRI being...I'm not sure what - it only has 125 subjects instead of 1911.
At this point the files to be downloaded would be hundreds of GB, so I'm not going to follow through until the end. Hopefully this is enough to get you started.
5. In the "Create" box at the bottom, use the drop down to Create a new filter after untouched image cohort study, and click on New Filter.
