issue with lesion dectected in cerebellum

[tib-sim]

Hello, I compared old hand lesion drawings and automated lesion drawing. LINDA seems to draw lesions in the cerebellum that does not exist for a couple of my subjects. I am not sure what it is causing this issue. The automated lesion drawings is in red, while the hand lesion drawing is in blue on one relevant example. The scans are quite old for most of them (2004 - 2006) so I don't know if something in the scan could cause the issue (I am sharing the T1w as well).

[dorianps]

Hi Simon,

Not sure what is causing it, but LINDA relies heavily on asymmetries. Also, it runs multiple iterative registrations to the template, and things can go wrong there, too. It was not trained with any cerebellar lesion, so it is just something during processing. So I would not spend much time on it unless you are interested on exactly what causes it for methodological reasons. In that case you could look at the features produced, registrations, etc.

I would just ignore them and remove that cluster from the mask, it should be easy on itksnap, and it's good that this is happening on just few subjects with old data.

Dorian

On Fri, Dec 22, 2023, 5:14 PM Simon Thibault @.***> wrote:

Hello, I compared old hand lesion drawings and automated lesion drawing. LINDA seems to draw lesions in the cerebellum that does not exist for a couple of my subjects. I am not sure what it is causing this issue. The automated lesion drawings is in red, while the hand lesion drawing is in blue on one relevant example. The scans are quite old for most of them (2004 - 2006) so I don't know if something in the scan could cause the issue (I am sharing the T1w as well). image.png (view on web) https://github.com/dorianps/LINDA/assets/67144860/8974eec3-9ac3-4f59-bd2b-acaf619c3f4f image.png (view on web) https://github.com/dorianps/LINDA/assets/67144860/c60459a1-303a-4e1d-8497-acdcc0dc89c1

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[tib-sim]

Thanks for the recommandation. I will do that. What do you think also about small cortical lesions (less than 10 voxels) that LINDA may detect sometimes and that are apart of the bigger lesion. Do you think this could be an image artefact as well in some cases? Is it worth asking a neurologist checking LINDA lesion drawings and manually correct the lesions if needed?

[dorianps]

No, I would never use LINDA drawings as a basis to suspect lesions. It may only be useful to make you look somewhere and if you suspect a lesion from what you see, then you can ask a radiologist. By itself LINDA is a dumb tool with no clinical value. It was created only to help drawing lesions more quickly. It also fails more often on small lesions than larger ones. So LINDA should be the elf that does some work, but you should always check carefully if it draws the lesion the way you would have drawn it yourself. All segmentations should be manually QCed at minimum and, if necessary, edited.

On Sat, Dec 23, 2023, 11:11 AM Simon Thibault @.***> wrote:

Thanks for the recommandation. I will do that. What do you think also about small cortical lesions (less than 10 voxels) that LINDA may detect sometimes and that are apart of the bigger lesion. Do you think this could be an image artefact as well in some cases? Is it worth asking a neurologist checking LINDA lesion drawings and manually correct the lesions if needed?

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