American Journal of Neuroradiology 27:912-918, April 2006
© 2006 American Society of Neuroradiology
BRAIN
Hippocampal Cerebrospinal Fluid Spaces on MR Imaging: Relationship to Aging and Alzheimer Disease
a Department of Psychiatry, New York University School of Medicine, New York, NY
b State Institute for Basic Research in Developmental Disabilities, Staten Island, NY
c Nathan Kline Institute, Orangeburg, NY
d Department of Radiology, QiLu Hospital of Shandong University, Shandong, China
e Department of Neuroradiology, TianTan Hospital, Beijing, China
Address correspondence to Dr. Mony J. de Leon, Center for Brain Health, MHL400, New York University School of Medicine, 560 First Ave, New York, NY 10016
BACKGROUND AND PURPOSE: Perihippocampal fissures (PHFs) and hippocampal sulcus residual cavities (HSCs) are common findings in the MR imaging examination of the hippocampus in aging and Alzheimer disease (AD); however, little is known about how to distinguish them or their relative clinical relevance. We hypothesized that prominence of the HSC, unlike PHF, is not significantly influenced by the hippocampal atrophy related to aging or AD.
METHODS: We studied and evaluated these hippocampal CSF spaces on MR imaging scans from 130 normal control (NC) subjects (2090 years of age) and 27 AD patients.
RESULTS: HSC is poorly correlated with age and is not related to the magnitude of hippocampal atrophy. There is no significant difference of HSCs between AD and age-matched NCs, but in the extremely high HSCs group (top 20%), 91% of cases are NC. PHFs, on the other hand, are strongly correlated with age and are valuable in the diagnosis of AD. Location and communication with ambient cistern is the key to distinguish HSC from PHF.
CONCLUSION: Identifying hippocampal atrophy (enlarged PHF) may be particularly challenging in the presence of HSC. Distinguishing among the CSF spaces in hippocampus may help in the radiologic evaluation of hippocampal atrophy. Patients with extremely high HSCs (>8.4) can be excluded from AD risk with 93% specificity.