High sensitivity of asymmetric 18F-THK5351 PET abnormality in patients with corticobasal syndrome

Abstract

Corticobasal syndrome (CBS) is characterized by symptoms related to the asymmetric involvement of the cerebral cortex and basal ganglia. However, early detection of asymmetric imaging abnormalities can be challenging. Previous studies reported asymmetric 18F-THK5351 PET abnormalities in CBS patients, but the sensitivity for detecting such abnormalities in larger patient samples, including early-stage cases, remains unclear. Patients clinically diagnosed with CBS were recruited. All patients displayed asymmetric symptoms in the cerebral cortex and basal ganglia. Asymmetric THK5351 PET abnormalities were determined through visual assessment. Brain MRI, perfusion SPECT, and dopamine transporter (DAT) SPECT results were retrospectively reviewed. The 15 patients had a median age of 72 years (59–86 years) and a disease duration of 2 years (0.5–7 years). Four patients met the probable and 11 met the possible CBS criteria according to Armstrong criteria at the time of PET examination. All patients, including early-stage cases, exhibited asymmetric tracer uptake contralateral to their symptom-dominant side in the cerebral cortex/subcortical white matter and striatum (100%). The sensitivity for detecting asymmetric imaging abnormalities contralateral to the symptom-dominant side was 86.7% for brain MRI, 81.8% for perfusion SPECT, and 90% for DAT SPECT. White matter volume reduction was observed in the subcortical region of the precentral gyrus with increased THK5351 uptake, occurring significantly more frequently than gray matter volume reduction. THK5351 PET may be a sensitive imaging technique for detecting asymmetric CBS pathologies, including those in early stages.

Clinical application of MAO‐B PET using 18F‐THK5351 in neurological disorders

“…18 F-THK5351 images exhibit intense uptake, especially in the right side of basal ganglia and cortical areas, suggesting that 18 F-THK5351 starts to accumulate even during the early stage of CBS. 25 Additionally, follow-up 18 F-THK5351 PET examinations may enable monitoring of the progression of astrogliosis in CBS. 27 Progressive supranuclear palsy PSP is a four-repeat tauopathy with various clinical phenotypes such as Richardson syndrome (PSP-RS), parkinsonism variant, and cerebellar ataxia variant.…”

“…A typical case of CBS exhibits asymmetric 18 F-THK5351 uptake in the basal ganglia and cortical areas. 25 A typical case of PSP exhibits intense 18 F-THK5351 uptake in the midbrain. 34 18 F-THK5351 uptake seems to increase around the striatum and pons in MSA.…”

“…18 F-THK5351 uptake asymmetrically increases in lesions corresponding to cortical and extrapyramidal motor symptoms. [25][26][27][28] A patient with CBS usually exhibits one-sided dominant cortical and parkinsonian symptoms, and its opposite side dominant increase in cortical and striatal uptake of 18 F-THK5351, likely reflecting ongoing astrogliosis. 18 F-THK5351 images in a patient with the early stage of CBS, who complained of progressive difficulty in using the left hand for a year, are displayed in Figure 5.…”

“…We focus on the cortical areas and basal ganglia in 18 F‐THK5351 images because the main symptom comes from cortical signs, such as apraxia and aphasia, and extrapyramidal motor signs, such as rigidity and tremor. 18 F‐THK5351 uptake asymmetrically increases in lesions corresponding to cortical and extrapyramidal motor symptoms 25–28 . A patient with CBS usually exhibits one‐sided dominant cortical and parkinsonian symptoms, and its opposite side dominant increase in cortical and striatal uptake of 18 F‐THK5351, likely reflecting ongoing astrogliosis.…”

“…Neurological examination showed limb apraxia and left‐sided dominant parkinsonian symptoms. 18 F‐THK5351 images exhibit intense uptake, especially in the right side of basal ganglia and cortical areas, suggesting that 18 F‐THK5351 starts to accumulate even during the early stage of CBS 25 . Additionally, follow‐up 18 F‐THK5351 PET examinations may enable monitoring of the progression of astrogliosis in CBS 27 …”