Comprehensive functional evaluation of the spectrum of multi-system atrophy with 18F-FDG PET/CT and 99mTc TRODAT-1 SPECT: 5 Year's experience from a tertiary care center

• Main Authors: Nikhil Seniaray, Ritu Verma, Rajeev Ranjan, Ethel Belho, Harsh Mahajan
• Format: Article
• Language: English
• Published: Wolters Kluwer Medknow Publications 2021-01-01
• Series: Annals of Indian Academy of Neurology
• Subjects: 18f-fdg pet/ct; 99mtc trodat-1 spect; multisystem atrophy
• Online Access: http://www.annalsofian.org/article.asp?issn=0972-2327;year=2021;volume=24;issue=4;spage=490;epage=494;aulast=Seniaray
• ISSN: 0972-2327; 1998-3549

Aim: To elucidate the patterns of characteristic hypometabolism on 18F- fluorodeoxyglucose( 18F-FDG) positron emission tomography/computed tomography (PET/CT) in multisystem atrophy (MSA) and their correlation with the patterns of uptake on dopamine transporter imaging with 99mTc TRODAT-1 SPECT. Material and Methods: A retrospective analysis of 67 patients with clinically diagnosed MSA was performed. All the subjects underwent 99mTc TRODAT-1 SPECT and 18F-FDG PET/CT scanning on two separate days. The 99mTc-TRODAT-1 scans were analyzed visually for asymmetry and rostro-caudal gradient. The FDG uptake patterns were recorded, and areas of hypometabolism that were two standard deviations from the mean were considered abnormal. Results: All the subjects had an abnormal pattern of FDG uptake on PET scan, both on a visual inspection and semiquantitative analysis. In MSA-P subjects (n = 29), diffuse predominant hypometabolism of the globus pallidus-putamen complex was noted, with relative sparing of the caudate nuclei. In MSA-C subjects (n = 25), characteristic hypometabolism was noted in the cerebellum and brainstem. In mixed subtypes (n = 13), variable involvement of the basal ganglia, cerebellum, and brainstem was noted with frontoparietal hypometabolism. A statistically significant difference between MSA-P and MSA-C for gradient reduction and asymmetry with gradient reduction was observed. Conclusion: Dopamine transporter imaging with 99mTc TRODAT-1 SPECT not only helps in confirmation of parkinsonian disorders but also demonstrates varying patterns of distribution in different subtypes of MSA. Characteristic patterns of hypometabolism in 18F-FDG PET may help in the differentiation of the subtypes of MSA in the presence of clinically overlapping symptoms.