Assessment of muscle function using hybrid PET/MRI: comparison of18F-FDG PET and T2-weighted MRI for quantifying muscle activation in human subjects.
OBJECTIVE
The aim of this study was to determine the relationship between relative glucose uptake and MRI T2changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans.


METHODS
Ten young healthy recreationally active men (age 21 - 28 years) were injected with18F-FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with18F-FDG PET/MRI and muscle groups were evaluated for increases in18F-FDG uptake and MRI T2values.


RESULTS
A significant linear correlation between18F-FDG uptake and changes in muscle T2(R2= 0.71) was found. for both small and large muscles and in voxel to voxel comparisons. Despite large intersubject differences in muscle recruitment, the linear correlation between18F-FDG uptake and changes in muscle T2did not vary among subjects.


CONCLUSIONS
This is the first assessment of skeletal muscle activation using hybrid PET/MRI and the first study to demonstrate a high correlation between18F-FDG uptake and changes in muscle T2with physical exercise. Accordingly, it seems that changes in muscle T2may be used as a surrogate marker for glucose uptake and lead to an improved insight into the metabolic changes that occur with muscle activation. Such knowledge may lead to improved treatment strategies in patients with neuromuscular pathologies such as stroke, spinal cord injuries and muscular dystrophies.
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark. bryan.haddock@regionh.dk.
Bryan
http://orcid.org/0000-0002-9721-4712
B
Haddock
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Søren
S
Holm
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Jákup M
JM
Poulsen
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Lotte H
LH
Enevoldsen
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Henrik B W
HB
Larsson
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Andreas
A
Kjær
Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
Charlotte
C
Suetta
D000328:Adult; D000818:Animals; D015444:Exercise; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D064847:Multimodal Imaging; D018482:Muscle, Skeletal / Q000000981:diagnostic imaging* / Q000502:physiology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
Exercise; Hybrid imaging; Muscle; PET/MRI; T 2