丘脑代谢低下是 1 型神经纤维瘤病 (NF1) 患者使用 F-18 氟脱氧葡萄糖 (FDG) 进行脑部 PET 检查时一致发现的结果。然而，这种代谢改变的病理生理学尚不清楚。我们假设这可能是继发于 NF1 特征的外周神经鞘瘤 (PNST) 对丘脑的外周输入的干扰。为了检验这一假设，我们研究了丘脑 FDG 摄取与 PNST 的数量、体积和定位之间的关系。这项回顾性研究包括 22 名接受全身 FDG-PET 治疗的成年 NF1 患者（41% 女性，36.2 ± 13.0 岁） /对比增强 CT 检查疑似 PNST 恶变以及 22 名性别和年龄匹配的对照。大脑 FDG 摄取量按体素比例缩放至小脑灰质中的个体中位摄取量。使用左右对称解剖丘脑面罩测定丘脑 FDG 摄取的双侧平均和左右不对称性。在对比增强 CT 中手动分割 PNST。与对照组相比，NF1 患者丘脑 FDG 摄取量减少了 2.0 个标准差 (p < .0005)。左右不对称性增加了 1.3 个标准差 (p = .013)。 PNST ≥ 3 次的 NF1 患者的丘脑代谢低下程度高于 PNST ≤ 2 次的患者（2.6 与 1.6 标准差，p = .032）。椎旁/椎旁 PNST 的发生和平均 PNST 体积对丘脑 FDG 摄取的影响未达到统计显着性（p = .098 和 p = .189）。丘脑 FDG 摄取的左右不对称与 PNST 负担的左右不对称无关 (p = .658)。这项研究提供了 NF1 丘脑代谢低下左右不对称的第一个证据，并且它可能是由 NF1- 介导的相关外周肿瘤。© 2023 作者。 《神经影像杂志》由 Wiley periodicals LLC 代表美国神经影像学会出版。

Thalamic hypometabolism is a consistent finding in brain PET with F-18 fluorodeoxyglucose (FDG) in patients with neurofibromatosis type 1 (NF1). However, the pathophysiology of this metabolic alteration is unknown. We hypothesized that it might be secondary to disturbance of peripheral input to the thalamus by NF1-characteristic peripheral nerve sheath tumors (PNSTs). To test this hypothesis, we investigated the relationship between thalamic FDG uptake and the number, volume, and localization of PNSTs.This retrospective study included 22 adult NF1 patients (41% women, 36.2 ± 13.0 years) referred to whole-body FDG-PET/contrast-enhanced CT for suspected malignant transformation of PNSTs and 22 sex- and age-matched controls. Brain FDG uptake was scaled voxelwise to the individual median uptake in cerebellar gray matter. Bilateral mean and left-right asymmetry of thalamic FDG uptake were determined using a left-right symmetric anatomical thalamus mask. PNSTs were manually segmented in contrast-enhanced CT.Thalamic FDG uptake was reduced in NF1 patients by 2.0 standard deviations (p < .0005) compared to controls. Left-right asymmetry was increased by 1.3 standard deviations (p = .013). Thalamic hypometabolism was higher in NF1 patients with ≥3 PNSTs than in patients with ≤2 PNSTs (2.6 vs. 1.6 standard deviations, p = .032). The impact of the occurrence of paraspinal/paravertebral PNSTs and of the mean PNST volume on thalamic FDG uptake did not reach statistical significance (p = .098 and p = .189). Left-right asymmetry of thalamic FDG uptake was not associated with left-right asymmetry of PNST burden (p = .658).This study provides first evidence of left-right asymmetry of thalamic hypometabolism in NF1 and that it might be mediated by NF1-associated peripheral tumors.© 2023 The Authors. Journal of Neuroimaging published by Wiley Periodicals LLC on behalf of American Society of Neuroimaging.