RT Journal Article SR Electronic T1 Cerebral 18F-FDG PET/CT Metabolism as Diagnostic Signature for Central Nervous System Toxicity After Immune Checkpoint Blockade Cancer Treatment JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1129 OP 1136 DO 10.2967/jnumed.123.267025 VO 65 IS 7 A1 Ma, Yifei A1 Zeng, Jiling A1 Ding, Fadian A1 Xu, Yiwei A1 Wang, Youlong A1 Zhong, Guanqing A1 Liu, Nianqi A1 Wang, Yanqi A1 Li, Yiming A1 Chen, Shuqin A1 Wei, Xiaolong A1 Zhu, Pengfei A1 Jian, Guangmin A1 Niu, Yu Si A1 Fu, Guangzhen A1 Liu, Cantong A1 Li, Guiqiang A1 Zhou, Xiaotong A1 Zhang, Ao A1 Weng, Shangeng YR 2024 UL http://jnm.snmjournals.org/content/65/7/1129.abstract AB Our aim was to investigate probable biomarkers specific to immune-related central nervous system toxicity (CNST) in cancer patients treated with immune checkpoint inhibitors (ICI) by analysis of 18F-FDG PET/CT images. Methods: Cancer patients receiving ICI treatment were enrolled in a multicenter observational study that analyzed regional metabolic changes before and during CNST onset from January 2020 to February 2022. In 1:1 propensity score–matched pairs, the regional SUVmean of each bilateral brain lobe of CNST patients (CNST+) was compared with that of patients who had central nervous system infections (CNSIs) and patients without CNST or CNSI (CNST−). In a validation cohort, patients were recruited from February 2022 to July 2023 and followed up for 24 wk after the start of ICI. Early changes in regional SUVmean at 5–6 wk after therapy initiation were evaluated for ability to predict later CNST onset. Results: Of 6,395 ICI-treated patients, 2,387 underwent prognostic 18F-FDG PET/CT and 125 of the scanned patients had CNST (median time from ICI treatment to onset, 9 wk; quartile range, 2–23 wk). Regional 18F-FDG PET/CT SUVmean changes were higher in CNST+ than in CNST− patients (117 patient pairs) but were lower than in CNSI patients (50 pairs). Differentiating analysis reached an area under the curve (AUC) of 0.83 (95% CI, 0.78–0.88) for CNST+ versus CNST− and of 0.80 (95% CI, 0.72–0.89) for CNST+ versus CNSI. Changes in SUVmean were also higher before CNST onset than for CNST− (60 pairs; AUC, 0.74; 95% CI, 0.66–0.83). In a validation cohort of 2,878 patients, preonset changes in SUVmean reached an AUC of 0.86 (95% CI, 0.79–0.94) in predicting later CNST incidence. Conclusion: Brain regional hypermetabolism could be detected during and before CNST clinical onset. CNST may be a distinct pathologic entity versus brain infections defined by 18F-FDG PET/CT brain scans. Regional SUV differences may be translated into early diagnostic tools based on moderate differentiating accuracy in our study.