18F-FDG PET Reveals Voxel-Based Decreases in Brain Glucose Uptake After Chemotherapy in Leukemia Patients: A Retrospective Matched-Control Study

Chemotherapy-induced cognitive impairment is increasingly recognized in leukemia survivors. Its underlying neurobiologic correlations remain unclear. This study investigated voxel-based alterations in brain glucose metabolism after chemotherapy using high-resolution [¹⁸F]FDG PET/CT. Methods: This retrospective study included 100 adults with leukemia, both newly diagnosed and relapsed, who underwent [¹⁸F]FDG PET/CT brain imaging. Patients were grouped by chemotherapy exposure: recent (≤1 y), prior (>1 y), and none (chemotherapy-naïve controls). Brain metabolism was quantified using MIM software and normalized to reference regions. Statistical analysis included t tests and ANOVA, adjusted for age and sex. Results: Among 100 patients (49 recent, 22 prior, and 29 control), chemotherapy-exposed individuals showed significant metabolic alterations compared with controls. Decreased uptake was found in the posterior cingulate gyrus (1.33 vs. 1.36; P = 0.04), anterior orbital gyrus (1.05 vs. 1.11; P = 0.05), and thalami (1.19 vs. 1.24; P = 0.05). In patients aged 55 y or older, reduced metabolism was observed in the Rolandic operculum (1.12 vs. 1.19; P < 0.001) and inferior frontal gyrus (1.16 vs. 1.19; P = 0.05). Recent chemotherapy recipients showed increased metabolism in the fusiform gyrus (1.34 vs. 1.27; P = 0.04) and insula, whereas long-term survivors did not. Intrathecal chemotherapy was linked to reduced thalamic metabolism (1.11 vs. 1.15; P = 0.02). Conclusion: Chemotherapy is associated with voxel-based brain metabolic alterations, particularly in areas governing cognition and emotion. Effects are more pronounced in older adults and those receiving intrathecal treatment. These findings support research into metabolic imaging biomarkers for early detection and intervention in chemotherapy-induced cognitive impairment.