Sloping Shoulders Sign: A Practical Radiological Sign for the Differentiation of Alzheimer’s Disease and Argyrophilic Grain Disease

Article type: Research Article

Authors: Sakurai, Keita^{a; *} | Iwase, Tamaki^{b; *} | Kaneda, Daita^c | Uchida, Yuto^d | Inui, Shohei^e | Morimoto, Satoru^f | Kimura, Yasuyuki^g | Kato, Takashi^a | Nihashi, Takashi^a | Ito, Kengo^a | Hashizume, Yoshio^c

Affiliations: [a] Department of Radiology, National Center for Geriatrics and Gerontology, Obu, Aichi, Japan | [b] Department of Neurology, Nagoya City Koseiin Medical Welfare Center, Nagoya, Aichi, Japan | [c] Choju Medical Institute, Fukushimura Hospital, Fukushima, Japan | [d] Department of Neurology, Nagoya City University Graduate School of Medical Sciences, Nagoya, Aichi, Japan | [e] Department of Radiology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan | [f] Department of Physiology, School of Medicine, Keio University, Tokyo, Japan | [g] Department of Clinical and Experimental Neuroimaging, National Center for Geriatrics and Gerontology, Obu, 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: [email protected], ORCID ID: 0000-0002-8849-7335; Tamaki Iwase, MD, PhD, Department of Neurology, Nagoya City Koseiin Medical Welfare Center, Nagoya, Aichi, Japan. E-mail: [email protected].

Abstract: Background:Although hippocampal atrophy is a well-known imaging biomarker of Alzheimer’s disease (AD), this finding is not useful to differentiate AD from argyrophilic grain disease (AGD) which is a common AD mimicker presenting with similar amnestic symptoms and medial temporal atrophy. Instead, we propose use of the “sloping shoulders sign”, defined as a distinct configuration of the bilateral hippocampal heads showing lateral and downward slopes on axial magnetic resonance imaging (MRI). Objective:We investigated the diagnostic utility of the “sloping shoulders sign” as a simple radiological discriminator of AD from AGD. Methods:Using axial and coronal three-dimensional MRI, our newly proposed “sloping shoulders sign”, other quantitative indices including the axial hippocampal head angle (AHHA), and well-known medial temporal atrophy (MTA) score were evaluated in pathologically-proven 24 AD and 11 AGD patients. Results:Detection rate of the “sloping shoulders sign” was significantly higher in all AD groups (83%; 20/24) and AD with Braak neurofibrillary tangle V/VI stage subgroup (88%; 15/17) than in AGD patients (18% – 2/11; p < 0.001 and p < 0.001, respectively). In contrast to the MTA score, this sign as well as AHHA demonstrated higher diagnostic performance and reproducibility, especially to differentiate all AD patients from AGD ones (accuracies of 71.4% , 82.9% and 82.9%; Cohen’s kappa of 0.70 and 0.81, and intraclass correlation coefficient of 0.96, respectively). Conclusion:The “sloping shoulders sign” is useful to differentiate advanced-stage AD from AGD. Its simplicity and reproducibility based on visual inspection using axial MRI make it suitable for routine clinical practice.

Keywords: Alzheimer’s disease, argyrophilic grain disease, hippocampus, magnetic resonance imaging, sloping shoulders sign

DOI: 10.3233/JAD-210638

Journal: Journal of Alzheimer's Disease, vol. 84, no. 4, pp. 1719-1727, 2021