The cerebellar glucose metabolism in moyamoya vasculopathy and its correlation with neurocognitive performance after cerebral revascularization surgery: a [¹⁸F]FDG PET study

The vascular cognitive impairment (VCI) is quite common in moyamoya vasculopathy (MMV). However, the abnormality of cerebellar glucose metabolism in MMV and its relationship with patients’ neurocognitive performance were few reported.

In this study, we aimed to investigate the relationship between neurocognitive performance and cerebellar glucose metabolism. Furthermore, the cerebellar glucose metabolism changes after combined revascularization surgery were also researched.

We retrospectively analyzed the 2-[¹⁸F]fluoro-2-deoxy-D-glucose positron emission tomography ([¹⁸F]FDG PET) images and their neuropsychological scales in 93 eligible MMV patients by comparing their cerebellar standardized uptake values ratio (SUVR) and metabolic covariant network (MCN) among different neurocognitive groups. Then, forty-two MMV patients with VCI who underwent combined revascularization surgery were prospectively observed. According to their neuropsychological performance at 6-month follow-up, these patients were assigned to cognitive improved group (n = 22) and non-improved group (n = 20). The cerebellar SUVR and MCN changes were also analyzed.

SUVR of right Lobule VI/Crus II/VIII decreased when cognitive impairment progression (P < 0.05, Least-Significant Difference [LSD] post hoc analysis). The cerebellar glucose metabolic pattern can be divided into two parts, in which the cerebellar posterior lobe was positively related to patients’ neurocognitive performance, while the vermis and anterior lobe showed negative relationship with the neurocognitions (P < 0.001). Further MCN analysis expound that the degree of right Lobule VI/Crus II/VIII displayed decreased tendency as cognitive impairment worsened (P < 0.05, LSD post hoc analysis). After revascularization surgery, the SUVR of right cerebellar posterior lobe significantly promoted in improved group (P < 0.001). Besides, we also witnessed the SUVR improvement in left cerebral hemisphere, thalamus, and red nucleus (P < 0.001). The MCN analysis revealed that the posterior connective strength improvement among right Lobule VI and several cerebral regions significantly correlated with memory and executive screening (MES) score (P < 0.001, false discovery rate corrected).

We found that the hypometabolism of cerebellar posterior lobe, especially in the right Lobule VI, was associated with MMV patients’ neuropsychological performance, while the anterior lobe and vermis showed opposites tendencies. Combined revascularization surgery improved the posterior cerebellar metabolism and was associated with favorable neurocognitive outcomes, which might be related to the activation of cortico-rubral-cerebellar pathway.