what does "high signal" mean?

[OperatingThetan]

I am reading the radiologist's report of a cervical spine MRI and it mentions "high signal in the lower cord". What does that mean and how can you tell its there from looking at the dicom images? I do not see any bright spots.

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[colbgw02]

You're probably not looking at the right sequence. Apart from that, my brain will melt if I try to explain what high signal means on the different sequences over the internet. Suffice it to say it's abnormal, and if you want to know what it might be then the easiest thing to do is check the impression section of the report.

 

[OperatingThetan]

The impression says "not confirmed in axial, likely artifact".

So you are saying it does not appear as a bright spot? I checked all the sequences and the tone is a smooth gray throughout the lower cord.

What type of pathology does "high signal" generally indicate in the lower cervical cord?

 

[colbgw02]

It would be helpful if I knew the nature of this "conversation". Are you a healthcare provider, a patient, or just a curious soul?

 

[OperatingThetan]

Brain and spine MRIs fascinate me. I managed to download a few anonymized DICOMs and their reports but could only match some of the more obvious abnormalities to their respective images, namely neophitic ridges, spondylosis, veinous angiomas, etc. The "high signal" indication baffles me because I do not see any change in the lower cord's brightness.

 

[colbgw02]

In that case...

I'll guess that it's T2WI, in which case the high signal is probably edema. Things that pop into my brain immediately are infection, underlying neoplasm, trauma, or a demyelinating disorder, but that list is by no means exhaustive. Given what the report said, it probably is just artifact. Without actually looking at the images or having another radiologist describe the findings, that's about the best I can do.

 

[Bart Clarridge]

The impression says "not confirmed in axial, likely artifact".

...

High signal should look relatively bright, but as they said it was not seen on axial images. Do you know that you have all of the images?

 

[tum]

Likely artifact means just that -- its likely an artifact. Sagittal images are usually reconstructions made based on axial images. If something shows up on the sagittal images that wasn't on axial slices, then sometimes it can be a computer based reconstruction artifact.

For example, on CT images, hepatic cysts of a certain caliber are considered unreliable imaging findings because of something called volume averaging.

 

[colbgw02]

Likely artifact means just that -- its likely an artifact. Sagittal images are usually reconstructions made based on axial images. If something shows up on the sagittal images that wasn't on axial slices, then sometimes it can be a computer based reconstruction artifact.

For example, on CT images, hepatic cysts of a certain caliber are considered unreliable imaging findings because of something called volume averaging.

Ummm...unless your magnet and software are vastly different from ours, then all MR sequences are acquired in their "true" planes - true axial, true sagittal, true coronal.

Also, with the widespread use of multislice CT scanners that obtain images helically, multiplanar reformations are extraordinarily useful. I don't find them as helpful as the transverse cuts, but I would hardly characterize them as "unreliable".

 

[tum]

Ummm...unless your magnet and software are vastly different from ours, then all MR sequences are acquired in their "true" planes - true axial, true sagittal, true coronal.

Also, with the widespread use of multislice CT scanners that obtain images helically, multiplanar reformations are extraordinarily useful. I don't find them as helpful as the transverse cuts, but I would hardly characterize them as "unreliable".

Whoops, brain fart sorry.