Hasegawa Tomohito, Nakajo Masanori, Gohara Misaki, Kamimura Kiyohisa, Nakano Tsubasa, Kamizono Junki, Takumi Koji, Ejima Fumitaka, Pahn Gregor, Langzam Eran, Nakanosono Ryota, Yamagishi Ryoji, Kanzaki Fumiko, Yoshiura Takashi
Department of Radiology, Kagoshima University Graduate School of Medical and Dental Sciences, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan.
Philips GmbH Market DACH, Röntgenstr. 22, 22335 Hamburg, Germany.
Tomography. 2025 Aug 25;11(9):95. doi: 10.3390/tomography11090095.
Few studies have reported in vivo measurements of electron density (ED) and effective atomic number (Z) in normal brain tissue. To address this gap, dual-energy computed tomography (DECT)-derived ED and Z maps were used to characterize normal-appearing adult brain tissues, evaluate age-related changes, and investigate correlations with myelin partial volume (V) from synthetic magnetic resonance imaging (MRI). Thirty patients were retrospectively analyzed. The conventional computed tomography (CT) value (CT), ED, Z, and V were measured in the normal-appearing gray matter (GM) and white matter (WM) regions of interest. V and DECT-derived parameters were compared between WM and GM. Correlations between V and DECT parameters and between age and DECT parameters were analyzed. V was significantly greater in WM than in GM, whereas CT, ED, and Z were significantly lower in WM than in GM (all < 0.001). Z exhibited a stronger negative correlation with V (ρ = -0.756) than CT (ρ = -0.705) or ED (ρ = -0.491). ED exhibited weak to moderate negative correlations with age in nine of the 14 regions. In contrast, Z exhibited weak to moderate positive correlations with age in nine of the 14 regions. CT exhibited negligible to insignificant correlations with age: This study revealed distinct GM-WM differences in ED and Z along with opposing age-related changes in these quantities. Therefore, myelin may have substantially contributed to the lower Z observed in WM, which underlies the GM-WM contrast observed on non-contrast-enhanced CT.
很少有研究报告正常脑组织中电子密度（ED）和有效原子序数（Z）的体内测量值。为了填补这一空白，采用双能计算机断层扫描（DECT）得出的ED和Z图来表征外观正常的成人大脑组织，评估与年龄相关的变化，并研究其与合成磁共振成像（MRI）中髓鞘部分体积（V）的相关性。对30例患者进行了回顾性分析。在外观正常的灰质（GM）和白质（WM）感兴趣区域测量传统计算机断层扫描（CT）值（CT）、ED、Z和V。比较了WM和GM之间的V和DECT衍生参数。分析了V与DECT参数之间以及年龄与DECT参数之间的相关性。WM中的V显著大于GM，而WM中的CT、ED和Z显著低于GM（均P<0.001）。与CT（ρ=-0.705）或ED（ρ=-0.491）相比，Z与V的负相关性更强（ρ=-0.756）。在14个区域中的9个区域，ED与年龄呈弱至中度负相关。相比之下，在14个区域中的9个区域，Z与年龄呈弱至中度正相关。CT与年龄的相关性可忽略不计或不显著：本研究揭示了ED和Z在GM-WM之间存在明显差异，以及这些量与年龄相关的相反变化。因此，髓鞘可能是导致WM中观察到较低Z值的主要原因，这也是在非增强CT上观察到GM-WM对比度的基础。
