The first awake simultaneous PET-MR study of an adult with fragile X syndrome: A case report

Abstract Introduction: Fragile X syndrome (FXS) is a debilitating neurogenetic disorder that can result in a multitude of impairments in cognition, memory, and learning. Case Presentation: a 25-year-old male with FXS participated in this study. The participant obtained scores in the non-spectrum range on the Autism Diagnostic Observation Scale and obtained an full scale IQ score of 57 (Verbal IQ = 23 and Nonverbal IQ = 34) on the Stanford-Binet Intelligence Scales (SB-5). On the Vineland Adaptive Behavior Scales, 2nd Edition (VABS-2) he obtained a composite score of 66. Pre-scan serum cortisol reactivity was 16.45 mcg/dL. Following a [18F]flumazenil (5mCi) intravenous bolus injection, the participant was scanned without sedation on a hybrid PET-MR system (Signa, GE Healthcare, Waukesha, WI) for 60 mins. List mode PET data, structural and diffusion MRI (DWI), and MR spectroscopy (MRS) were acquired simultaneously. Quantitative PET and DWI measures were extracted from 83 pre-defined regions of interest. MRS data was collected from two 20 cc voxels (thalamus and dorsolateral prefrontal cortex). Conclusion: This is the first study to investigate neuromolecular behavior in FXS without the use of sedation using PET-MR. Mapping the neuromolecular differences in FXS can lead to targeted treatments that can significantly improve quality of life for families and individuals with intellectual disabilities.