Department of Radiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55902, USA.
Department of Neurology, Mayo Clinic, 200 First Street SW, Rochester, MN 55902, USA.
Neuroimage Clin. 2020;28:102481. doi: 10.1016/j.nicl.2020.102481. Epub 2020 Oct 28.
Disproportionately enlarged subarachnoid space hydrocephalus (DESH), characterized by ventriculomegaly, high convexity/midline tight sulci, and enlarged sylvian fissures on brain MRI has been increasingly recognized as a distinct diagnostic imaging entity that falls within the larger category of idiopathic normal pressure hydrocephalus. Normal pressure hydrocephalus has been previously characterized as a CSF dynamics disorder based on abnormalities on nuclear medicine cisternography: radiotracer in the lateral ventricles and absent or delayed ascent of radiotracer over the cerebral convexity. The purpose of this work was to evaluate for differences in nuclear medicine cisternography between patients with vs without DESH and thereby provide support for the concept that DESH is a structural imaging marker of a CSF dynamics disorder. The study included 102 patients (mean age 71 years, range 46-86, 38 females), 58 patients with cisternogram performed to evaluate suspected normal pressure hydrocephalus (mean age 73 years, range 46-86 years, 24 female) and 44 patients evaluated for headache (mean age 68 years, range 60-82 years, 14 female). All patients had an MRI of the brain performed within 13 months of the cisternogram. Cisternogram imaging, typically acquired at 0.5, 1, 2, 4, and 24 h post injection, was evaluated for the time at which radiotracer reached the basal cisterns, presence of persistent radiotracer in the lateral ventricles, time radiotracer first entered the lateral ventricles, presence of radiotracer over the cerebral convexity, and time at which radiotracer was first visualized over the cerebral convexity. MRI features of ventriculomegaly (defined as Evans' index ≥ 0.3) and high convexity tight sulci (HCTS) were recorded. Based on the MRI features, patients were grouped according to presence or absence of DESH (ventriculomegaly and HCTS). Those without DESH were separated into groups of ventriculomegaly alone, HCTS alone, and neither ventriculomegaly nor HCTS. Cisternogram metrics were compared between MR-defined groups. Patients with DESH showed a higher frequency of radiotracer in the lateral ventricles and delayed or absent ascent over the cerebral convexity compared to those without DESH, higher frequency of ventricular radioactivity vs those with HCTS alone, and shorter time to ventricular radioactivity compared to those with ventriculomegaly alone. Patients with ventriculomegaly or HCTS alone had a higher frequency of radiotracer in the lateral ventricles and delayed ascent of radiotracer over the cerebral convexity compared to those with neither ventriculomegaly nor HCTS. These findings support DESH and the individual components of ventriculomegaly and HCTS as markers of disordered CSF dynamics.
不成比例扩大的蛛网膜下腔脑积水 (DESH) 以脑室扩大、凸面高/中线紧张沟和扩大的大脑外侧裂为特征，在脑 MRI 上已越来越被认为是一种独特的诊断影像学实体，属于特发性正常压力脑积水的更大类别。正常压力性脑积水以前被认为是一种基于核医学脑池造影异常的脑脊液动力学障碍：放射性示踪剂在侧脑室，而放射性示踪剂在大脑凸面不存在或延迟上升。这项工作的目的是评估 DESH 患者与无 DESH 患者之间核医学脑池造影的差异，从而为 DESH 是脑脊液动力学障碍的结构影像学标志物这一概念提供支持。该研究纳入了 102 名患者（平均年龄 71 岁，范围 46-86 岁，38 名女性），58 名患者行脑池造影以评估可疑正常压力性脑积水（平均年龄 73 岁，范围 46-86 岁，24 名女性），44 名患者因头痛而评估（平均年龄 68 岁，范围 60-82 岁，14 名女性）。所有患者均在脑池造影后 13 个月内进行了脑 MRI 检查。脑池造影成像通常在注射后 0.5、1、2、4 和 24 小时获得，评估放射性示踪剂到达基底池的时间、侧脑室中持续存在放射性示踪剂的时间、放射性示踪剂首次进入侧脑室的时间、放射性示踪剂在大脑凸面的存在时间以及放射性示踪剂首次在大脑凸面可见的时间。记录了脑室扩大（定义为 Evans 指数≥0.3）和凸面紧张沟（HCTS）的 MRI 特征。根据 MRI 特征，根据是否存在 DESH（脑室扩大和 HCTS）对患者进行分组。无 DESH 的患者分为脑室扩大组、HCTS 组和脑室扩大及 HCTS 均无组。比较了脑池造影指标在 MRI 定义组之间的差异。与无 DESH 的患者相比，DESH 患者的侧脑室中放射性示踪剂的频率更高，大脑凸面放射性示踪剂的上升延迟或不存在，脑室放射性示踪剂的频率高于 HCTS 组，脑室放射性示踪剂的时间短于脑室单独扩大组。单独脑室扩大或 HCTS 的患者的侧脑室中放射性示踪剂的频率更高，大脑凸面放射性示踪剂的上升延迟。与既无脑室扩大也无 HCTS 的患者相比，单独脑室扩大或 HCTS 的患者的侧脑室中放射性示踪剂的频率更高，大脑凸面放射性示踪剂的上升延迟。这些发现支持 DESH 以及脑室扩大和 HCTS 作为脑脊液动力学障碍标志物的各个组成部分。
