Assessment of muscle function using hybrid PET/MRI: comparison of 18F-FDG PET and T2-weighted MRI for quantifying muscle activation in human subjects

Abstract

PurposeThe aim of this study was to determine the relationship between relative glucose uptake and MRI T 2 changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans.MethodsTen young healthy recreationally active men (age 21 – 28 years) were injected with 18F-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 with 18F-FDG PET/MRI and muscle groups were evaluated for increases in 18F-FDG uptake and MRI T 2 values.ResultsA significant linear correlation between 18F-FDG uptake and changes in muscle T 2 (R 2 = 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 between 18F-FDG uptake and changes in muscle T 2 did not vary among subjects.ConclusionThis is the first assessment of skeletal muscle activation using hybrid PET/MRI and the first study to demonstrate a high correlation between 18F-FDG uptake and changes in muscle T 2 with physical exercise. Accordingly, it seems that changes in muscle T 2 may 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.

In situ macrophage phenotypic transition is affected by altered cellular composition prior to acute sterile muscle injury

“…; Haddock et al . ), FDG uptake in resting muscles is minimal and thus in our experiments day 0 served as the baseline, allowing us to follow the metabolic changes in the muscle, as the result of CTX injury, and exclude the contribution of skeletal muscle activity. By the quantitative analysis of the decay‐corrected 18 F‐FDG PET images we found significant differences in the mean standardized uptake value (SUV) of the indicated TA muscle tissues 50 min after tracer injection and at various time points (day 0–8) post‐CTX injury (Fig.…”

“…In order to make sure that muscle metabolism was not interfering with our labelling, PET-MRI experiments were always performed during the light cycle in which the activity of the mice is minimal and thus muscles are considered as being at rest. In addition, in various exercise physiology studies (Tashiro et al 1999;Kemppainen et al 2002;Slimani et al 2006;Haddock et al 2017), FDG uptake in resting muscles is minimal and thus in our experiments day 0 served as the baseline, allowing us to follow the metabolic changes in the muscle, as the result of CTX injury, and exclude the contribution of skeletal muscle activity. By the quantitative analysis of the decay-corrected 18 F-FDG PET images we found significant differences in the mean standardized uptake value (SUV) of the indicated TA muscle tissues 50 min after tracer injection and at various time points (day 0-8) post-CTX injury (Fig.…”

Applications of PET‐MRI in musculoskeletal disease

“…PET‐MRI has been applied to study muscle activation . FDG PET, which measures glucose uptake and is thus sensitive to muscle metabolism and activity, was used as a reference standard to study the relationship between T 2 relaxation time changes and glucose uptake in skeletal muscle after exercise.…”

“…PET-MRI has been applied to study muscle activation. 144 FDG PET, which measures glucose uptake and is thus sensitive to muscle metabolism and activity, was used as a reference standard to study the relationship between T 2 relaxation time changes and glucose uptake in skeletal muscle after exercise. Simultaneous acquisition of PET and MRI data allowed for analysis of the two quantitative measures following the same exercise paradigm on the same time course, which would not have been possible with sequential scanning.…”

MRI of the Intrinsic Muscles of the Hand

“…1,2 The intrinsic muscles of the hand have not received much attention in the radiologic literature, despite their importance in moving the hand. [3][4][5][6][7] Prospective studies on magnetic resonance (MR) imaging of the intrinsic muscles of the hand are rare, especially with a focus on new imaging techniques. [6][7][8] However, similar to the other skeletal muscles, the intrinsic muscles of the hand can be affected by many conditions with resultant alterations in MR signal intensity or morphology (e.g., with congenital abnormalities, inflammation, infection, trauma, neurologic disorders, and neoplastic conditions).…”