Mori Koichiro, Kurokawa Mariko, Harada Masafumi, Nakamichi Kazuo, Arai Hideo, Takao Masaki, Takaki Yasunobu, Miura Yoshiharu
Department of Radiology, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, 3-18-22 Honkomagome, Bunkyo-Ku, Tokyo, 113-8677, Japan.
Department of Radiology, The University of Tokyo, Tokyo, Japan.
Jpn J Radiol. 2025 Jul 21. doi: 10.1007/s11604-025-01837-y.
Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the central nervous system caused by JC virus (JCV) infection. PML affects patients with various underlying conditions, such as HIV/AIDS, hematological malignancies, organ transplants, autoimmune diseases, or multiple sclerosis particularly those receiving disease-modifying therapies. MRI plays a crucial role in diagnosis, demonstrating characteristic findings across multiple sequences, including T2-weighted imaging (T2WI)/fluid-attenuated inversion recovery (FLAIR), T1-weighted imaging (T1WI), diffusion-weighted imaging (DWI), and susceptibility-weighted imaging (SWI). Early stage markers first appear as a cluster of punctate high-signal areas in T2WI (the "punctate pattern") and later develop into a distribution of oval-shaped lesions of varying sizes, commonly referred to as the "milky way appearance." Lesions typically show T2WI/FLAIR hyperintensity, T1WI hypointensity, and DWI hyperintensity. Recent findings highlight the significance of SWI hypointensity as a potential early marker. The prognosis varies significantly depending on the underlying condition and timing of diagnosis, with mortality rates ranging from 20 to 90%. Early detection, particularly in asymptomatic stages, significantly improves survival rates, emphasizing the importance of regular MRI screening in high-risk patients. Diagnostic challenges include low JCV DNA levels in cerebrospinal fluid (CSF), particularly in early stages and drug-associated cases, necessitating ultrasensitive PCR testing. This review provides an overview of PML's imaging characteristics, with particular emphasis on early diagnostic features using MRI, with a detailed understanding of PML's imaging characteristics across various stages and clinical subtypes, aiming to improve patient outcomes through early detection and intervention.
进行性多灶性白质脑病（PML）是由JC病毒（JCV）感染引起的一种严重的中枢神经系统脱髓鞘疾病。PML影响患有各种基础疾病的患者，如艾滋病毒/艾滋病、血液系统恶性肿瘤、器官移植、自身免疫性疾病或多发性硬化症，特别是那些接受疾病修饰疗法的患者。MRI在诊断中起着至关重要的作用，在多个序列上显示出特征性表现，包括T2加权成像（T2WI）/液体衰减反转恢复序列（FLAIR）、T1加权成像（T1WI）、扩散加权成像（DWI）和磁敏感加权成像（SWI）。早期标志物首先在T2WI上表现为一簇点状高信号区（“点状模式”），随后发展为大小不一的椭圆形病灶分布，通常称为“银河外观”。病灶通常表现为T2WI/FLAIR高信号、T1WI低信号和DWI高信号。最近的研究结果强调了SWI低信号作为潜在早期标志物的重要性。预后因基础疾病和诊断时间的不同而有很大差异，死亡率在20%至90%之间。早期检测，尤其是在无症状阶段，可显著提高生存率，强调了对高危患者进行定期MRI筛查的重要性。诊断挑战包括脑脊液（CSF）中JCV DNA水平较低，特别是在早期和药物相关病例中，需要进行超灵敏PCR检测。本综述概述了PML的影像学特征，特别强调了使用MRI的早期诊断特征，详细了解PML在各个阶段和临床亚型的影像学特征，旨在通过早期检测和干预改善患者预后。
