Review Article

PET and SPECT Imaging of ALS: An Educational Review

Table 3

Summary of chemical structure of neuroinflammation targeting PET probes along with their application to ALS imaging.

PET radiotracerChemical name and structureApplication in ALSReferences

[11C]PBR28[11C]PBR28 (aryloxianilide)
N-acetyl-N-(2ā€“[11C]methoxybenzyl)-2-phenoxy-5-pyridinamine
Increased uptake in motor regions and the precentral gyrus in ALS patients as compared with controls and the lung, spine, and brain (primarily the hindbrain) in mouse models.[49ā€“52]

[11C]PK11195N-(sec-butyl)-1-(2-chlorophenyl)-N-(methyl-11C)isoquinoline-3-carboxamide
Several regions with increased uptake, including the motor cortex, frontal lobe, thalamus, occipital lobe, temporal lobe, pons, sensorimotor cortex, and cerebellum when compared to controls.[55, 56]

[18F]DPA714N,N-diethyl-2-(2-(4-(2-(fluoro-18F)ethoxy)phenyl)-5,7-dimethylpyrazolo[1,5-a]pyrimidin-3-yl)acetamide
Increased primary motor cortex uptake in humans and increased brainstem uptake in mice models.[52, 57]

[11C](l)-deprenyl-D2 or [11C]DED(R)-N-(methyl-11C)-N-(1-phenylpropan-2-yl)prop-2-yn-1-amine-1,1-d2
Increased uptake in pons and white matter, decreased uptake in parietal and temporal areas when compared to controls.[59]

[18F]THK5351(R)-1-(fluoro-18F)-3-((2-(6-(methylamino)pyridin-3-yl)quinolin-6-yl)oxy)propan-2-ol
Multiple regions with increased uptake, such as the precentral gyri, motor cortex, and temporal lobes. Sample size is limited.[60, 62]

[11C]KD2N-((1s,3s)-adamantan-1-yl)-8-(methoxy-11C)-4-oxo-1-pentyl-1,4-dihydroquinoline-3-carboxamide
Demonstrated specific uptake in ALS postmortem spinal cord tissue.[64]

[18F]RS-126N-((1s,3s)-adamantan-1-yl)-1-(2-(2-(fluoro-18F)ethoxy)ethyl)-8-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxamide
No specific binding to CB2 receptors in ALS postmortem spinal tissue.[63]

[11C]RS-0281-(2-Ethoxyethyl)-N-((1r,3r)-3-hydroxyadamantan-1-yl)-8-(methoxy-11C)-4-oxo-1,4-dihydroquinoline-3-carboxamide
Increased and specific binding to ALS postmortem spinal tissue compared to control tissue.[63]