A Pilot Study on Clinical and Neuroimaging Characteristics of Chinese Posterior Cortical Atrophy: Comparison with Typical Alzheimer's Disease.

Xiao-Dan Wang,Li Cai,Yong Ji,Hui Lu,Shuling Liu,Shuo Gao,Tong Han,Zhihong Shi,Yuying Zhou,Shuai Liu,Xinping Wang,Ying Wang

doi:10.1371/journal.pone.0134956

Abstract

Posterior cortical atrophy (PCA) is a clinicoradiologic neurodegenerative syndrome characterized by predominant impairment of higher visual functions. Neuroimaging and neuropathological studies show that PCA is probably an atypical presentation of Alzheimer’s disease. However, in China PCA has rarely been studied and remains largely unknown. Our study therefore aimed to analyze the clinical manifestations and patterns of cerebral atrophy, amyloid beta deposition and regional glucose metabolism in Chinese PCA patients, comparing them directly with those of typical Alzheimer’s disease (TAD). Seven PCA patients, 6 TAD patients and 5 controls underwent neuropsychological assessment, MRI scan, 11C-PIB PET scan and 18F-FDG PET scan. Cerebral atrophy including ventricular enlargement, posterior atrophy and medial temporal lobe atrophy were evaluated with MRI. The uptake of 11C-PIB was quantified at the voxel level using the standardized uptake value ratio. Comparisons of regional cerebral glucose metabolism were calculated with statistical parametric mapping. PCA patients showed significant impairment on visuospatial function in neuropsychological assessment. And PCA patients showed more severe posterior atrophy and less severe left medial temporal lobe atrophy compared with TAD patients. The data from 11C-PIB PET scanning showed that amyloid beta deposition in PCA was comparable to TAD. Moreover, in PCA the results from 18F-FDG PET scanning revealed significant hypometabolism in the temporoparietooccipital region and identified specific hypometabolism in the right occipital lobe, compared with TAD. Our study thus provides a preliminary view of PCA in Chinese patients. A further study with a larger number of subjects would be recommended to confirm these findings.

Highlights

Posterior cortical atrophy (PCA) is a clinicoradiologic neurodegenerative syndrome characterized clinically by predominant impairment of higher visual functions [1]
The present study explored for the first time the clinical manifestations, cerebral atrophy, cerebral Aβ deposition and glucose metabolism of Chinese PCA patients, and compared them with those of typical Alzheimer’s disease (TAD) patients
PCA patients showed more posterior atrophy (PA) and less left medial temporal lobe atrophy (MTA) compared with TAD patients

Summary

Introduction

Posterior cortical atrophy (PCA) is a clinicoradiologic neurodegenerative syndrome characterized clinically by predominant impairment of higher visual functions [1]. The diagnosis of PCA depends on demonstrating the core clinical features of the condition, and is further supported by neuroimaging and neuropathological evidence [11]. Studies of regional cerebral glucose metabolism using 18F-fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG PET) have shown significant hypometabolism in the occipital, parietal and posterior temporal cortices compared to healthy controls, and in the region of the frontal eye fields as well [12, 13]. A recent study of PCA patients has shown an area of syndrome-specific hypometabolism in the inferioroccipitotemporal cortex, compared to TAD patients, and in the right lateral temporooccipital cortex, compared to patients with dementia with Lewy bodies [14]. Cerebrospinal fluid biomarkers of AD such as protein tau, phosphorylated tau and amyloid beta 1–42 (Aβ1–42) are recognized as being supportive features in the diagnosis of PCA [16, 17]

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Results

Conclusion