Can Medial Temporal Impairment Be an Imaging Red Flag for Neurodegeneration in Disproportionately Enlarged Subarachnoid Space Hydrocephalus?

Article type: Research Article

Authors: Sakurai, Keita^{a; *} | Kaneda, Daita^b | Uchida, Yuto^c | Inui, Shohei^d | Bundo, Masahiko^e | Akagi, Akio^f | Nihashi, Takashi^a | Kimura, Yasuyuki^e | Kato, Takashi^a | Ito, Kengo^a | Ohashi, Wataru^g | Hashizume, Yoshio^b

Affiliations: [a] Department of Radiology, National Center for Geriatrics and Gerontology, Aichi, Japan | [b] Choju Medical Institute, Fukushimura Hospital, Aichi, Japan | [c] Department of Neurology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Japan | [d] Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan | [e] Department of Clinical and Experimental Neuroimaging, National Center for Geriatrics and Gerontology, Aichi, Japan | [f] Department of Neuropathology, Institute for Medical Science of Aging, Aichi Medical University, Aichi, Japan | [g] Division of Biostatistics, Clinical Research Center, Aichi Medical University Hospital, Aichi, Japan

Correspondence: [*] Correspondence to: Keita Sakurai, MD, PhD, Department of Radiology, National Center for Geriatrics and Gerontology, 7-430 Morioka-cho, Obu, 474-8511, Aichi, Japan. Tel.: +81 52 46 2311; E-mail: ksak666@yahoo.co.jp.; ORCID ID: 0000-0002-8849-7335

Abstract: Background:The differentiation of idiopathic normal pressure hydrocephalus (iNPH) from neurodegenerative diseases such as Alzheimer’s disease (AD) and dementia with Lewy bodies (DLB) is often challenging because of their non-specific symptoms. Therefore, various neuroradiological markers other than ventriculomegaly have been proposed. Despite the utility of disproportionately enlarged subarachnoid-space hydrocephalus (DESH) for the appropriate selection of shunt surgery candidates, the specificity and neuropathology of this finding have not been sufficiently evaluated. Objective:Investigation of the clinicopathological features and comparison of the neuroradiological findings between DESH with postmortem neuropathological diagnoses (pDESH) and clinically-diagnosed iNPH (ciNPH) patients are the main purposes of this study. Method:In addition to the retrospective evaluation of clinicopathological information, quantitative, semiquantitative, and qualitative magnetic resonance imaging (MRI) indices were compared between pathologically-investigated 10 patients with pDESH and 10 patients with ciNPH Results:Excluding one patient with multiple cerebral infarctions, the postmortem neuropathological diagnoses of the pathologically-investigated patients were mainly neurodegenerative diseases (five AD, one DLB with AD pathologies, one DLB, one argyrophilic grain disease, and one Huntington’s disease). In addition to the common neuroradiological features Conclusion:Hippocampal atrophy and deformation with temporal horn enlargement seem to be characteristic neuroradiological findings of long-standing severely demented patients with DESH and neurodegenerative diseases, mainly advanced-stage AD.

Keywords: Disproportionately enlarged subarachnoid-space hydrocephalus, hippocampal atrophy, hippocampal deformation, idiopathic normal pressure hydrocephalus, magnetic resonance imaging, temporal horn enlargement

DOI: 10.3233/JAD-210535

Journal: Journal of Alzheimer's Disease, vol. 83, no. 3, pp. 1199-1209, 2021