To investigate the mechanism of crossed cerebellar diaschisis(CCD) induced by supratentorial tumors and the characteristics of ¹⁸F-FDG PET/CT imaging.

Eighty-six patients with supratentorial tumors who underwent ¹⁸F-FDG PET/CT whole-body imaging from January 2017 to June 2021 were retrospectively analyzed.Placement, number, size, SUVmax, CT values, relationship with basal ganglia, edema, and cerebellar asymmetry index (AI) were observed and recorded.The imaging differences between patients with CCD and patients without CCD were compared, and the correlations between SUVmax, maximum diameter and cerebellar AI were analyzed.SPSS 21.0 software was used for statistical analysis.Chi-square test, independent sample t-test and Pearson correlation analysis were used for data statistics.

Among the 86 patients, 14 were patients with CCD and 72 were patients without CCD.The incidence of CCD was 16.3%.There were statistically significant differences in whether the primary lesions involved the basal ganglia region between patients with CCD and patients without CCD (χ²=7.637, P=0.006). The cerebellar AI ((0.27±0.09), (0.05±0.02), t=6.847, P=0.003)and maximum diameter of primary lesions((3.98±1.09)cm, (2.36±1.61)cm, t=2.011, P=0.040) in patients with CCD were both larger than those in patients without CCD.There was a significant positive correlation between cerebellar AI and the maximum diameter of primary lesions in patients with CCD (r=0.375 P=0.028).

¹⁸F-FDG PET/CT imaging can assist in the diagnosis of crossed cerebellar diaschisis.The primary lesion of supratentorial tumor involving the basal ganglia is more likely to cause crossed cerebellar diaschisis, and the size of the primary lesion is correlated with cerebellar AI.

Supratentorial tumor; Crossed cerebellar diaschisis; PET; CT; ¹⁸F-FDG