Annals of Indian Academy of Neurology
EDITORIAL COMMENTARY
Year
: 2021  |  Volume : 24  |  Issue : 4  |  Page : 468-

Evaluation of multiple system atrophy subtypes with FDG-PET


Kurt Jellinger 
 Institute of Clinical Neurobiology, Vienna, Austria

Correspondence Address:
Dr. Kurt Jellinger
Institute of Clinical Neurobiology Alberichgasse 5/13, A-1150 Vienna
Austria




How to cite this article:
Jellinger K. Evaluation of multiple system atrophy subtypes with FDG-PET.Ann Indian Acad Neurol 2021;24:468-468


How to cite this URL:
Jellinger K. Evaluation of multiple system atrophy subtypes with FDG-PET. Ann Indian Acad Neurol [serial online] 2021 [cited 2021 Oct 19 ];24:468-468
Available from: https://www.annalsofian.org/text.asp?2021/24/4/468/326234


Full Text



Sir,

Seniaray N, et al. Recently analysed the functional spectrum of multiple system atrophy (MSA) using 18F-FDG PET/CT and 99mTc TRODAT-1 SPECT in 67 patients with clinically diagnosed MSA (29 MSA-P, 25 MSA-C and 13 mixed subtypes).[1] While dopamine transporter (DAT) imaging with TRODAT-1 SPECT cannot distinguish between MSA, PD, DLB and PSP and cannot differentiate MSA-P from PD and MSA-C, subtypes show characteristic patterns of FDG uptake on PET scan: MSA-P subjects showed diffuse hypometabolism in putamen-pallidum with relative sparing of the caudate nuclei, while in MSA-C patients hypometabolism was seen in cerebellum and brainstem. In mixed subtypes, variable hypometabolism in basal ganglia, cerebellum and brainstem was associated with that in fronto-parietal regions. Thus, FDG-PET may help in differentiating the subtypes of MSA in the presence of overlapping syndromes.

Targeting postsynaptic dopaminergic function using [123I] FP-CIT SPECT does not differentiate PD from MSA (both showing normal or increased signal),[2] DAT imaging showed more prominent and earlier DAT loss in anterior caudate and ventral putamen in MSA,[3] although normal DAT imaging does not exclude MSA.[4] In autopsy-confirmed cases, a greater asymmetry of striatal binding was seen in MSA than in PD,[5] but it is highly correlated with substantia nigra cell loss.[6] 18F-DOPA-PET showed more widespread basal ganglia dysfunction in MSA than in PD without evidence of early compensatory increase in DOPA uptake.[7] The above FDG-PET data confirm previous studies showing different patterns of decreased glucose metabolism between MSA-P and PD with a positive predictive value of 95%,[8],[9] while MSA-related patterns of metabolic topographies discriminated between normal, MSA, PSP and PD, and correlate with standard ratings of clinical stages and motor symptoms in MSA.[10] Moreover, they show further possibilities in differentiating the various subtypes of MSA. In conclusion, 18F-FDG PET provides a new basis for the differentiation of MSA-P and MSA-C,[11] reflecting distinct clinical features of MSA.[12] Future neuroimaging studies, such as Tau-PET will enlarge the diagnostic spectrum of MSA, its functional subtypes and its differentiation from other parkinsonian syndromes.

Acknowledgement

The author thanks Erich Mitter-Ferstl, PhD, for secretarial work.

References

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