Malik Prateek, Branson Helen, Yoon Grace, Shroff Manohar, Blaser Susan, Krishnan Pradeep
From the Department of Diagnostic Imaging (P.M., H.B., M.S., S.B., P.K.), The Hospital for Sick Children, Toronto, Canada.
Division of Clinical and Metabolic Genetics (G.Y.), The Hospital for Sick Children, Toronto, Canada.
AJNR Am J Neuroradiol. 2024 Oct 3;45(10):1578-1585. doi: 10.3174/ajnr.A8361.
The abnormalities of the long arm of chromosome 18 (18q) constitute a complex spectrum. We aimed to systematically analyze their MR imaging features. We hypothesized that there would be variable but recognizable white matter and structural patterns in this cohort.
In this retrospective cohort study, we included pediatric patients with a proved abnormality of 18q between 2000-2022. An age- and sex-matched control cohort was also constructed.
Thirty-six cases, median MR imaging age 19.6 months (4.3-59.3), satisfied our inclusion criteria. Most were female (25, 69%, F:M ratio 2.2:1). Fifty MR imaging studies were analyzed, and 35 (70%) had delayed myelination. Two independent readers scored brain myelination with excellent interrater reliability. Three recognizable evolving MR imaging patterns with distinct age distributions and improving myelination scores were identified: Pelizaeus-Merzbacher disease-like (9.9 months, 37), intermediate (22 months, 48), and washed-out pattern (113.6 months, 53). Etiologically, MRIs were analyzed across 3 subgroups: 18q deletion (34, 69%), trisomy 18 (10, 21%), and ring chromosome 18 (5, 10%). Ring chromosome 18 had the highest myelination lag (27, = .005) and multifocal white matter changes ( = .001). Trisomy 18 had smaller pons and cerebellar dimensions (anteposterior diameter pons, = .002; corpus callosum vermis, < .001; and transverse cerebellar diameter, = .04).
In this cohort of 18q chromosomal abnormalities, MR imaging revealed recognizable patterns correlating with improving brain myelination. Imaging findings appear to be on a continuum with more severe white matter abnormalities in ring chromosome 18 and greater prevalence of structural abnormalities of the pons and cerebellum in trisomy 18.
18号染色体长臂（18q）异常构成了一个复杂的谱系。我们旨在系统分析其磁共振成像（MR）特征。我们假设在这个队列中会有可变但可识别的白质和结构模式。
在这项回顾性队列研究中，我们纳入了2000年至2022年间经证实存在18q异常的儿科患者。还构建了一个年龄和性别匹配的对照队列。
36例患者符合我们的纳入标准，MR成像的中位年龄为19.6个月（4.3 - 59.3个月）。大多数为女性（25例，69%，女性与男性比例为2.2:1）。分析了50份MR成像研究，其中35份（70%）存在髓鞘形成延迟。两名独立阅片者对脑髓鞘形成进行评分，评分者间信度良好。确定了三种可识别的不断演变的MR成像模式，具有不同的年龄分布和改善的髓鞘形成评分：佩利措伊斯 - 默茨巴赫病样模式（9.9个月，37例）、中间模式（22个月，48例）和消退模式（113.6个月，53例）。从病因学角度，对MRI进行了三个亚组分析：18q缺失（34例，69%）、18三体（10例，21%）和18号环状染色体（5例，10%）。18号环状染色体的髓鞘形成延迟最严重（27例，P = 0.005）且多灶性白质改变最多（P = 0.001）。18三体患者脑桥和小脑尺寸较小（脑桥前后径，P = 0.002；胼胝体蚓部，P < 0.001；小脑横径，P = 0.04）。
在这个18q染色体异常队列中，MR成像显示出与脑髓鞘形成改善相关的可识别模式。成像结果似乎呈现出一个连续谱，18号环状染色体的白质异常更严重，18三体中脑桥和小脑结构异常的发生率更高。
