lesion phenotypes by PET (positron emission tomography)

[frodo]

Phenotyping of multiple sclerosis lesions according to innate immune cell activation using 18 kDa translocator protein-PET

https://academic.oup.com/braincomms/art ... ogin=false

Lesions under PET can be classified in three subtypes:

- (i) rim-active lesion: lesions with <5% active voxels in the core and at least 5% point higher proportion of active voxels at the rim compared to the core and lesions which have 5–20% active voxels in the core and at the same time at least double the proportion of active voxels at the rim;

- (ii) inactive lesions: lesions with no active voxels at the rim or in the core and

- (iii) overall-active lesions: lesions which do not fit into the other two categories (Fig. 1A and B).

The importance is that smouldering lesions, which appear on MRI because of their iron rim, can also be detected by PET by a reason completely different (because PET shows microglia).

Quotes:

"Taken together, there are now neuropathology-based, susceptibility MRI-based and TSPO-PET-based methods to quantify progression-associated smouldering inflammation in multiple sclerosis brain"

"Future studies will demonstrate how the different methods can be used in a complementary way to evaluate the dynamic innate inflammatory process contributing to neuroaxonal damage and disease progression. Accurate and dynamic in vivo assessment of progression-related innate immune system activation has potential to advance our understanding of the mechanisms related to disability accrual among multiple sclerosis patients. This has implications for predicting future disease course, for obtaining meaningful outcome markers and for selecting optimal patients when performing treatment trials of progressive multiple sclerosis"