Metabolic alterations in the visual pathway of retinitis pigmentosa rats: A longitudinal multimodal magnetic resonance imaging study with histopathological validation

Because retinitis pigmentosa (RP) has been shown to cause degenerative changes in the entire visual pathway, there is an urgent need to perform longitudinal assessments of RP-induced degeneration and identify imaging protocols to detect this degeneration as early as possible. In this study, we assessed a transgenic rat model of RP by using complementary noninvasive magnetic resonance imaging techniques, namely, proton magnetic resonance spectroscopy (¹H-MRS), to investigate the metabolic changes in RP. Our study demonstrated decreased concentrations and ratios to creatine (Cr) of N-acetylaspartate (NAA), glutamate (Glu), γ-aminobutyric acid (GABA), and taurine (Tau), whereas myo-inositol (Ins) and choline (Cho) were increased in the visual cortex of Royal College of Surgeons (RCS) rats compared with control rats (p < 0.05). Furthermore, with the progression of RP, the concentrations of NAA, Glu, GABA, and Tau, and the ratios of GABA/Cr and Tau/Cr significantly decreased over time, whereas the concentrations of Ins and Cho and the ratio of Ins/Cr significantly increased over time (p < 0.05). In addition, in RCS rats, NAA/Cr decreased significantly from 3 to 4 months postnatal (p < 0.001), and Cho/Cr increased significantly from 4 to 5 months postnatal (p = 0.005). Meanwhile, the ¹H-MRS indicators in 5-month postnatal RCS rats could be confirmed by immunohistochemical staining. In conclusion, with the progression of RP, the metabolic alterations in the visual cortex indicated progressive reprogramming with the decrease of neurons and axons, accompanied by the proliferation of gliocytes.     

51例颅内生殖细胞瘤的薄层增强MR及临床特征分析

目的:探讨颅内生殖细胞瘤薄层增强 MR及临床特征，以提高诊断准确性。方法:回顾性分析 51例颅内生殖细胞瘤薄层增强 MR及临床资料。按部位分为 A组(鞍区 +松果体区)17例、B组(侧脑室周围) 22例、C组(基底节 +丘脑区)12例。对三组患者的影像特征及临床资料(包括年龄、性别、形状、生长方式、边界、强化方式、强化程度、椒盐征、伴囊变)进行比较分析。结果:三组的年龄分别为:A组(18.24±4.74)岁， B组(21.68±7.89)岁， C组(19.92±10.61)岁，差异无统计学意义( P=0.395)。性别男 /女比例分别为: A组(9/8)，B组(18/4)，C组(12/0)，P=0.010。形状(团块状 /不规则状)比例分别为:A组(16/1)，B组(22/0)，C组(0/12)，P<0.001。生长方式(肿块型 /蔓延型)比例分别为: A组(17/0)，B组(0/22)，C组(12/0)，P<0.001。边界(清楚 /不清楚)比例分别为: A组(16/1)，B组(20/2)，C组(9/3)， P=0.254。强化方式(均匀 /不均匀)比例分别为: A组(14/3)，B组(9/13)，C组(2/12)，P=0.001。强化程度(轻度 /明显)比例分别为: A组(16/1)，B组(19/3)，C组(11/1)，P=0.708。椒盐征(有 /无)比例分别为: A组(10/7)，B组(13/9)， C组(5/7)，P=0.574。伴囊变(有 /无)比例分别为:A组(7/10)，B组(18/4)，C组(8/4)，P=0.031。三组的性别、形状、生长方式、强化方式、伴囊变比例差异有统计学意义( P<0.05)，三组的边界、强化程度、椒盐征差异无统计学意义 (P>0.05)。结论:颅内生殖细胞瘤患者的性别、病变形状、生长方式、强化方式、伴囊变表现具有部位特征性，患者的年龄、病变边界、强化程度、椒盐征不同部位具有共同性，熟悉颅内生殖细胞瘤的 MR及临床特征，可以提高诊断准确性。     

胰腺导管腺癌CT、MR相关研究进展

胰腺导管腺癌（pancreatic ductal adenocarcinoma，PDAC）是最常见的胰腺恶性肿瘤，其恶性程度高，患者生存率低。CT、MR是PDAC诊断最常用的影像检查，其不仅可以帮助PDAC进行诊断、鉴别，还能通过特殊序列来提供相应功能参数。此外，影像组学可以挖掘更多的影像信息供临床医生分析、预测患者术后生存率。CT、MR对于PDAC临床治疗具有重要的指导意义，故本文对PDAC相关CT、MR进展进行综述。