Intracranial stenosis interacts with amyloid positron emission tomography (PET) standard uptake value ratio (SUVR) to predict cognitive decline in a memory clinic cohort

Abstract

AbstractBackgroundIntracranial stenosis (ICS) is associated with cognitive impairment and dementia. However, data examining the effect of ICS and beta‐amyloid on cognitive decline are lacking. Thus, we aimed to investigate the effect of ICS on beta‐amyloid and their interaction on cognition in a memory clinic cohort.MethodsParticipants were recruited from the National University Hospital memory clinic in Singapore. Data was collected using a standardized questionnaire, physical examination and 3T MRI. ICS was defined as arterial narrowing that exceeded 50% of the luminal diameter in any of the intracranial vessels. Beta‐amyloid was measured using [11C]‐PiB‐PET global standardized uptake value ratio (SUVR). Cognition was assessed by neuropsychological testing.Results185 participants diagnosed with no cognitive impairment, cognitive impairment no dementia, or dementia were included. The mean age was 75.7 ± 7.3 years and 86 (46.5%) participants were male. A total of 17 (9.2%) participants had ICS and the mean SUVR was 1.4 ± 0.4. In adjusted models, ICS was not significantly associated with elevated SUVR in the overall population (β = ‐0.04; 95%CI = ‐0.24 – 0.16; p‐value = 0.69). In adjusted models, ICS had significant interaction with SUVR in global cognition (p = 0.043), attention (p = 0.024), visual memory (p = 0.019), and visuospatial function (p = 0.047). In patients with no ICS, SUVR was associated with worse cognitive scores, while in patients with ICS, SUVR was associated with better cognitive scores. This interaction remained significant for attention (β [No ICS]: ‐1.57 [95%CI: ‐2.50 to ‐0.63]; β [Yes ICS]: 1.42 [95%CI: ‐1.13 to 3.96]; p = 0.029) and visual memory (β [No ICS]: ‐1.57 [95%CI: ‐2.38 to ‐0.76]; β [Yes ICS]: 1.04 [95%CI: ‐1.17 to 3.24]; p = 0.028) even after further adjustment for ApoE and hippocampal volume.ConclusionIn patients with no ICS, beta‐amyloid was associated with worse cognition, while in patients with ICS, beta‐amyloid was associated with better cognition. This suggests that beta‐amyloid may have a protective effect against cognitive impairment in patients with ICS. Further studies are required to investigate this association and elucidate on the mechanistic pathway of the interaction between ICS and beta‐amyloid on cognition.