Longitudinal brain and skeletal muscle FDG-PET changes in people with stiff person syndrome spectrum disorders
Samantha Roman1, Yujie Wang3, Mohammad Sadaghiani2, Scott Newsome1
1Johns Hopkins Hospital, 2Nuclear Medicine, Johns Hopkins Hospital, 3UW Northwest
Objective:
To describe changes in fluorodeoxyglucose positron emission tomography (FDG-PET) findings in the brain and muscles of individuals with stiff person syndrome spectrum disorders (SPSD) longitudinally.
Background:
SPSD includes multiple clinical phenotypes that rarely can be paraneoplastic in origin. An FDG-PET scan is frequently obtained as part of the malignancy work-up, and abnormal metabolic activity unrelated to malignancy has been shown to occur in both the brain and skeletal muscles of patients with SPSD. However, it is unclear if such findings persist or change over time.
Design/Methods:
A retrospective study was performed of patients with SPSD who were seen at Johns Hopkins SPS Center from 2009 to March 2022, with at least two FDG-PET studies in the medical record with source images of sufficient quality for comparison. Quantitative data was extracted from dedicated brain FDG-PET scans using NeuroQ™, which calculates Z-scores of 47 brain regions compared to healthy controls. Body FDG-PET scans will be reviewed qualitatively by a blinded nuclear medicine radiologist to detect the presence and pattern of hypermetabolism in skeletal muscle. Patients’ clinical characteristics, including type of treatment, will be correlated with PET data.
Results:
Out of 98 SPSD patients who underwent an FDG-PET scan, 10 were identified that met inclusion criteria. Median age at time of SPSD onset was 51±15.8 years, 60% were males, and 60% were black. Mean duration from symptom onset to first FDG-PET scan was 0.78±0.62 years. The majority of patients had SPS-plus phenotype. All patients were seropositive for an SPSD-associated antibody and received an immune therapy. Preliminary data demonstrate that all patients had at least 1 region of dysmetabolism on initial brain scan, and at least 3 regions on follow-up.
Conclusions:
We will present longitudinal metabolic changes in brain and body FDG-PET scans of patients with SPSD, and determine if any changes observed are associated with clinical characteristics.