Related Experiment Video
Updated: Jan 13, 2026
Hybrid PET/MRI Imaging of Alzheimer's Disease Based on 18F-AV-1451
Published on: April 18, 2025
Simultaneous multiple post-labelling delay ASL MRI and [18F]FDG PET in a mixed memory clinic population and healthy
Otto M Henriksen1, Oriol P Calvo2,3,4, Frederik J Bruun2
1Department of Clinical Physiology and Nuclear Medicine, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark. otto.moelby.henriksen.01@regionh.dk.
Purpose:
To assess the quantitative and visual concordance of multiple post-labelling delay (multi-PLD) arterial spin labelling (ASL) MRI cerebral blood flow (CBF) measurements and [18F]-fluoro-deoxyglucose (FDG) PET in a mixed memory clinic population.
Methods:
Hybrid [18F]FDG PET/MRI including multi-PLD pseudo continuous ASL from 96 memory clinic patients and 38 elderly controls were analysed along with ASL data from 12 healthy young volunteers. ASL image interpretability, concordance with [18F]FDG PET, and value of Z-score maps were rated visually. Regional associations of CBF with [18F]FDG uptake ratio (SUVr) were investigated by univariate regression and mixed linear models. Also influences of age, disease stage and vascular pathology on ASL interpretability and concordance, and whole cortex spatial coefficient of variation (sCOV) were analysed.
Results:
ASL CBF maps were non-comparable to [18F]FDG PET, i.e. uninterpretable or discordant, in 53% of patients, 37% of elderly controls, and 8% of young controls. Only 14% of patient ASL MRI scans were concordant with [18F]FDG PET. Z-score maps were mainly of value in partially concordant scans. Increasing sCOV was strongly associated both with disease severity and with decreasing ASL interpretability and concordance, and allowed for identification of uninterpretable scans with 95% sensitivity and 90% specificity. Whole cortex CBF and [18F]FDG SUVr values showed similar distribution across groups, but low to moderate regional associations.
Conclusions:
Multi-PLD ASL provided quantitative CBF measurements correlating with disease severity, but poor image quality and low regional concordance in head-to-head comparison with [18F]FDG PET imaging restricts the clinical use in memory clinic patients.
Insights
Multiple post-labelling delay (multi-PLD) arterial spin labelling (ASL) MRI for cerebral blood flow (CBF) showed poor image quality and low concordance with FDG PET in memory clinic patients. This limits the clinical utility of ASL MRI in this population.
Area of Science:
- Neuroimaging
- Medical Physics
- Radiology
Background:
- Arterial spin labelling (ASL) MRI measures cerebral blood flow (CBF).
- Hybrid [18F]FDG PET/MRI allows simultaneous imaging.
- Assessing concordance between ASL and FDG PET is crucial for clinical application in memory disorders.
Purpose of the Study:
- To evaluate the quantitative and visual agreement between multi-PLD ASL MRI CBF and [18F]FDG PET.
- To assess ASL MRI interpretability and concordance in a mixed memory clinic population.
Main Methods:
- Hybrid [18F]FDG PET/MRI with multi-PLD pseudo continuous ASL was performed on 96 memory clinic patients, 38 elderly controls, and 12 young controls.
- ASL image interpretability, concordance with [18F]FDG PET, and Z-score map utility were visually assessed.
- Regional associations between CBF and [18F]FDG uptake ratio (SUVr) were analyzed using regression models.
Main Results:
- ASL CBF maps were uninterpretable or discordant in 53% of patients and 37% of elderly controls.
- Only 14% of patient ASL MRI scans showed concordance with [18F]FDG PET.
- Increased spatial coefficient of variation (sCOV) correlated with disease severity and predicted uninterpretable scans.
Conclusions:
- Multi-PLD ASL provides CBF measurements that correlate with disease severity.
- Poor ASL image quality and low regional concordance with [18F]FDG PET limit its clinical use in memory clinic patients.
- Further optimization of ASL techniques is needed for reliable application in neurodegenerative disease assessment.
