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), 59 patients with cisternogram performed to evaluate suspected normal pressure hydrocephalus (mean age 73 years, range 46-86 years, 24 female) and 41 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 hours 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积水 (DESH)，其特征是脑室扩大、高凸度/中线紧脑沟和脑 MRI 上的侧裂扩大，已越来越多地被认为是一种独特的诊断成像实体，属于特发性正常压力脑积水的较大类别。正常压力脑积水以前被定性为基于核医学脑池造影异常的脑脊液动力学障碍：侧脑室中的放射性示踪剂和大脑凸面上方的放射性示踪剂没有或延迟上升。这项工作的目的是评估有与没有 DESH 的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成像标志物的概念提供支持。该研究包括 102 名患者（平均年龄 71 岁，范围 46-86，38 名女性），59 名患者进行了脑池造影以评估疑似正常压力脑积水（平均年龄 73 岁，范围 46-86 岁，24 名女性）和 41 名接受评估的患者用于头痛（平均年龄 68 岁，范围 60-82 岁，14 名女性）。所有患者都在脑池造影后的 13 个月内进行了脑部 MRI。通常在注射后 0.5、1、2、4 和 24 小时采集的胸腔造影成像评估放射性示踪剂到达基底池的时间、侧脑室中持续存在的放射性示踪剂、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上的存在，以及放射性示踪剂首次在大脑凸面上可视化的时间。记录了脑室扩大（定义为埃文斯指数 > 0.3）和高凸度紧脑沟（HCTS）的 MRI 特征。根据 MRI 特征，根据存在或不存在 DESH（脑室扩大和 HCTS）对患者进行分组。那些没有 DESH 的人被分为单独的脑室扩大组、单独的 HCTS 组和既没有脑室扩大又没有 HCTS 的组。在 MR 定义的组之间比较了脑池图指标。与没有 DESH 的患者相比，有 DESH 的患者在侧脑室中的放射性示踪剂频率更高，大脑凸面上升延迟或没有上升，与单独使用 HCTS 的患者相比，心室放射性的频率更高，与脑室肥大的患者相比，出现心室放射性的时间更短独自的。与既没有脑室扩大也没有 HCTS 的患者相比，仅患有脑室扩大或 HCTS 的患者在侧脑室中的放射性示踪剂频率更高，并且放射性示踪剂在大脑凸面上的上升延迟。这些发现支持 DESH 和脑室扩大和 HCTS 的各个组成部分作为脑脊液动力学紊乱的标志物。