Department of Neurology, Mayo Clinic, Rochester, MN, 55905, USA.
Department of Radiology, Mayo Clinic, Rochester, MN, 55905, USA.
J Neurol. 2024 Sep;271(9):6264-6273. doi: 10.1007/s00415-024-12583-y. Epub 2024 Aug 1.
FTLD-FET is a newly described subtype of frontotemporal lobar degeneration (FTLD characterized by pathologic inclusions of FET proteins: fused in sarcoma (FUS), Ewing sarcoma, and TATA-binding protein-associated factor 2N (TAF15)). Severe caudate volume loss on MRI has been linked to FTLD-FUS, yet glucose hypometabolism in FTLD-FET has not been studied. We assessed [F] fluorodeoxyglucose PET (FDG-PET) hypometabolism in FTLD-FET subtypes and compared metabolism to FTLD-tau and FTLD-TDP.
We retrospectively reviewed medical records of 26 autopsied FTLD patients (six FTLD-FET, ten FTLD-Tau, and ten FTLD-TDP) who had completed antemortem FDG-PET. We evaluated five regions, caudate nucleus, medial frontal cortex, lateral frontal cortex, and medial temporal using a 0-3 visual rating scale and validated our findings quantitatively using CORTEX-ID suite Z scores.
Of the six FTLD-FET cases (three females) with median age at onset = 36, three were atypical FTLD-U (aFTLD-U) and three were neuronal intermediate filament inclusion disease (NIFID). bvFTD was the most common presentation. Four of the six FTLD cases (3 aFTLD-U + 1 NIFID) showed prominent caudate hypometabolism relatively early in the disease course. FTLD-tau and FTLD-TDP did not show early prominent caudate hypometabolism. Hypometabolism in medial and lateral temporal cortex was associated with FTLD-TDP, while FTLD-tau had normal-minimal regional metabolism.
Prominent caudate hypometabolism, especially early in the disease course, appears to be a hallmark feature of the aFTLD-U subtype of FTLD-FET. Assessing caudate and temporal hypometabolism on FDG-PET will help to differentiate FTLD-FET from FTLD-tau and FTLD-TDP.
FTLD-FET 是一种新描述的额颞叶变性（FTLD）亚型，其特征为 FET 蛋白包涵体：融合肉瘤（FUS）、尤因肉瘤和 TATA 结合蛋白相关因子 2N（TAF15）。MRI 上严重尾状核体积丢失与 FTLD-FUS 有关，但 FTLD-FET 的葡萄糖代谢低下尚未研究。我们评估了 FTLD-FET 亚型的 [F]氟脱氧葡萄糖正电子发射断层扫描（FDG-PET）代谢低下，并将代谢与 FTLD-τ和 FTLD-TDP 进行了比较。
我们回顾性分析了 26 例尸检 FTLD 患者（6 例 FTLD-FET、10 例 FTLD-τ和 10 例 FTLD-TDP）的病历，这些患者均完成了 FDG-PET 检查。我们使用 0-3 视觉评分量表评估了尾状核、内侧额叶皮质、外侧额叶皮质和内侧颞叶五个区域，并使用 CORTEX-ID 套件 Z 分数对我们的发现进行了定量评估。
6 例 FTLD-FET 病例（3 例女性）的中位发病年龄为 36 岁，其中 3 例为非典型额颞叶痴呆（aFTLD-U），3 例为神经元中间丝包涵体病（NIFID）。bvFTD 是最常见的表现形式。6 例 FTLD 病例中有 4 例（3 例 aFTLD-U+1 例 NIFID）在疾病早期表现出明显的尾状核代谢低下。FTLD-τ和 FTLD-TDP 没有早期明显的尾状核代谢低下。内侧和外侧颞叶皮质的代谢低下与 FTLD-TDP 有关，而 FTLD-τ的区域代谢正常或轻度减少。
明显的尾状核代谢低下，尤其是在疾病早期，似乎是 FTLD-FET 的 aFTLD-U 亚型的一个特征。评估 FDG-PET 上的尾状核和颞叶代谢低下将有助于将 FTLD-FET 与 FTLD-τ和 FTLD-TDP 区分开来。
