Sometimes with the higher intensity mris. However a combination PET MRI will show inflammatory areas in PLS and sometimes in PALS. I don’t think they have decided why yet but I suspect LMND PALS may be less likely. There is a study now looking for those inflammations in the spinal cord of PALS perhaps to see if lmnd PALS show more there
when I was diagnosed my mri had "white spots". Sorry I can't remember exactly what the terminology was, but the mri notes did say"images suggest als if there was clinical weakness "
which there was in my right foot at the time.