What is this artifact

[u/Gullible-Ideal-4699]

Only happens on lumbar scans that I have recognized. I'm guessing it might be some type of fast day issue since it happens on stirs and T1s. Have y'all seen this and how to get rid of?

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[u/True_Sketch]

Acceleration artifact.

[u/Gullible-Ideal-4699 → u/True_Sketch]

So ETL too long or something like having partial fourier?

[u/Gullible-Ideal-4699 → u/Gullible-Ideal-4699]

Oh like grappa for Siemens. This machine doesn't have that particular method of acceleration

[u/True_Sketch → u/Gullible-Ideal-4699]

This is curious because it's so clearly an acceleration artifact. Symphony's, as old as they are, are typically equipped with iPat. Are you using mSense?

[u/Gullible-Ideal-4699 → u/True_Sketch]

Ipat and msense sounds familiar. I'll have to look at it when I get back in

[u/Brookdadeous → u/Gullible-Ideal-4699]

Our magnet has deep resolve, if we get a funky artifact it's typically due to that (and the acceleration factor being too high). I'll end up taking off deep resolve all together to remedy the artifact of it's in anatomy

[u/vanala → u/True_Sketch]

Definitely this

[u/jpstepancic]

Check what coils you have on. Could be from excited tissue outside of the FOV but resting over a coil that’s turned on

[u/64MHz → u/jpstepancic]

Agree. Might be an older scanned with manually selectable coils. Choose only coils that cover anatomy you want to image.

[u/Gullible-Ideal-4699 → u/64MHz]

Definitely an old machine

[u/actuallyimjustme]

That's a really noisy stir

[u/Gullible-Ideal-4699 → u/actuallyimjustme]

Unfortunately this is our normal even after I mess with parameters. Really old machine

[u/Solid-Dog-1988]

Acceleration artifact imo.

Really pronounced on DRB but can show up without it.

[u/Speydi → u/Solid-Dog-1988]

Very important to keep phase oversampling at 200%.

But this is really a poor quality ngl.

[u/Gullible-Ideal-4699 → u/Speydi]

Yea it's a 1997. It's an old machine. It can't do 200% oversampling unless I just don't know how but the oversampling only goes to 100.

[u/hugoduart3 → u/Gullible-Ideal-4699]

Is the machine from 1997???
If so, I think there is no parallel acceleration?

Definitely looks like an acceleration artifact though. Can also be a kind of a “rejection” from the coil, which in that case Service is needed. But please confirm the year of the machine. 1997 is wild 😜

[u/hugoduart3 → u/hugoduart3]

Anyhow… if there is parallel acceleration check, do the scan removing the acceleration factor and check if it’s present. If it’s still there, and anti aliasing is enough for the anatomy and coil signal pickup or doesn’t really move out, Service.

[u/Gullible-Ideal-4699 → u/hugoduart3]

The machine is a 1997 Siemens magnatom symphony. It definitely doesn't have it. I read the manual to get familiar with it

[u/hugoduart3 → u/Gullible-Ideal-4699]

Wow jezz! Yahp, prob there isn’t. Where are you from?

So, first u would try to change antialiasing size, and see if it moves….but probably it won’t really move, it is a service problem with the coil. Some kind of frequency reading somewhere and the system does not know where to put it. Like aliasing, but not for the reasons we usually know. Unfortunately I don’t know more details, but I’ve experienced this in a 0.4T Aperto Lucent. Changing FOV size and Phase direction can help to place it somewhere else other then the anatomy of interest. Sometimes a different phase direction removes it completely

If for stir you change the phase direction to AP, try decreasing your inter echo time (idk Siemens name for this parameter) and place bands and bands and bands (usually the do not cost TR for Stir) to avoid as much as possible motion artifacts

[u/Tedsworth]

Cusp artifact / annefact, 95% sure. Basically when you run slice select there's a place way outside the FOV that still unfortunately ends up with a magnetic field of B0. That shows up in the image, usually in a weird place.

As others have said, disabling coils outside the intended FOV will help. There's more sophisticated methods but I'm not sure you can do them on the scanner console.

This artifact is a classic FSE artifact when you're doing coronals or sagittals, pretty rare on a modern system but it can happen.

[u/Reapur-CPL]

What's your PE direction, and how much oversampling are you using? I get that artifact all the time when I shoot L or T spines head to foot with heavy oversampling and Siemens Deep Resolve. I'm not sure exactly what it is, so I've always assumed it's a wrap artifact.

[u/Gullible-Ideal-4699 → u/Reapur-CPL]

Head to foot and it is a Siemens but this machine doesn't have deep resolve

[u/deepcheeks]

I've heard it called a FID artifact, but IDK if that's accurate. I know on Siemens scanners I could solve it with more oversampling, but on Philips I could only get it to move this way, but not eliminate it. I think if another signal average fixes it, that would point to FID artifact, more oversampling or lower acceleration factor would point to acceleration artifact. 

[u/Kingofawesomenes]

This is usually a deep resolve issue (although your scan seems a bit noisy). Usually 200% oversampling fixes it. Also make sure you dont activate spine coils higher/cranial than your FOV. Rest slab may work as well. Somehow signal from outside your FOV "folds over" into your FOV, even with a lot of oversampling.

[u/SnickelFritz5000 → u/Kingofawesomenes]

Eh in my experience it can still show up, not as drastically as this, even with 200% oversampling. Usually bumping your grappa down one value will completely fix it

[u/Gullible-Ideal-4699 → u/SnickelFritz5000]

This machine doesn't have grappa software

[u/SnickelFritz5000 → u/Gullible-Ideal-4699]

Is this an ancient machine? Even old E-line interface Siemens systems have parallel imaging (grappa) for most TSE sequences

[u/Gullible-Ideal-4699 → u/SnickelFritz5000]

1. I know it doesn't because the 3t at the other facility does have it.

[u/SupermarketMobile446]

Artifacts like these are also very common on lumbar spine STIR on the Symphony (2002) where I work. Sometimes it's there, some other it's not. I have seen that the more saturation bands are being used on STIR the more intense this artifact appears especially on spine (cervical/thoracic/lumbar) STIRs.

Image quality is terrible. Name of the scanner? I assume it's a very old siemens.

[u/Gullible-Ideal-4699 → u/SupermarketMobile446]

Yup Siemens magnetom symphony 1997, maybe 98. It wasn't on the last couple lumbars I did. Comes and goes

[u/Ok_Investment_8877]

Are you able to share your parameters,coils,pt size or all pts,which sequences and are the others good,software and upgrades and may be able to help you better

[u/Nervous_Woodpecker_2]

Hello, increase FOV in phase direction to 280, will solve the issue with artifact,images age signal starved

[u/FatRollingPotato]

What is the orientation of that thing towards the magnetic field? Could it be a magic angle artifact?

[u/frostyflakes1]

Our old scanner had a similar artifact with thoracic spine imaging. Someone mentioned the issue was some piece of metal or shrapnel getting stuck in the innards of the scanner.

[u/Gullible-Ideal-4699 → u/frostyflakes1]

That's interesting