Molecular imaging of cerebral water flow with a new concept of AQP4

2016 Fiscal Year Final Research Report

• Project/Area Number: 15K15453
• Research Category: Grant-in-Aid for Challenging Exploratory Research
• Allocation Type: Multi-year Fund
• Research Field: Radiation science
• Research Institution: University of Fukui
• Principal Investigator: Okazawa Hidehiko 福井大学, 高エネルギー医学研究センター, 教授 (50360813)
• Co-Investigator(Renkei-kenkyūsha): NORIKI SAKONN 福井大学, 学術研究院医学系部門, 准教授 (40397287) ; KIMURA HIROHIKO 福井大学, 学術研究院医学系部門, 教授 (10242596)
• Research Collaborator: HAYASHI TAKUYA 理化学研究所
• Project Period (FY): 2015-04-01 – 2017-03-31
• Keywords: 脳内水動態 / ミクロオートラジオグラフィー / アクアポリン / コンパートメント解析 / O-15ポジトロンCT (PET) / MRI-ASL

Outline of Final Research Achievements

A new molecular imaging method for evaluation of water flow in the brain was developed based on a new concept of a water channel, aquaporin 4 (AQP4). AQP4 is a subtype of aquaporin and is expressed in the podocyte of astrocyte at the blood brain barrier. O-15 labeled water is used for PET measurement of cerebral blood flow (CBF). Plasma water is also used for MRI imaging with the arterial spin labeling (ASL) method. These techniques are used based on an assumption that water molecules are transported into the brain by passive diffusion, but the concept of the water PET and ASL-MRI should be altered if the AQP4 or other channels are responsible for the water transport. This study aimed to confirm the water kinetics in the brain tissue, and apply it to the calculation of CBF imaging using PET or MRI. The technique of micro-autoradiography was applied to the microscopic observation using H-3 labeled water, and the concept was applied for precise CBF image calculation using PET.

Free Research Field

核医学