Study on the etiological relations of tissue damage to the enlargement of periarteriolar spaces observed in MRI brain images.

2003 Fiscal Year Final Research Report Summary

• Project/Area Number: 14570884
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Radiation science
• Research Institution: Kanazawa Medical University
• Principal Investigator: IWAI Kunimitsu Kanazawa Medical University, Department of Medicine, assistant professor, 医学部, 助教授 (40243274)
• Co-Investigator(Kenkyū-buntansha): MATSUMOTO Masayuki Kanazawa Medical University, Department of Medicine, professor, 医学部, 教授 (50028677) ; MURAI Hirosi Kanazawa Medical University, Department of Medicine, assistant, 医学部, 助手 (50367471)
• Project Period (FY): 2002 – 2003
• Keywords: MRI-T2 weighted brain images / the spotty high intensity regions / atheroscrelotic risk factors / basal nuclei / gliosis / perivascular spaces / subcortical ischemic lesions / DCOM signal

Research Abstract

(Objective) By traditional diagnostic criteria for the asymptomatic cerebrovascular disorders the spotty high intensity regions on the MRI-T2 weighted brain images have been devided into two categories according to their sizes. The high intensity regions less than 3mm in diameter are diagsized as enlargement of the perivascular tissue and those more than 3mm in diameter are diagnized as the infracted areas. However, our recent study has demonstrated that the spotty high intensity regions of less than 3mm in diameter also have been made by tissue damages. In this study we investigated the relationship between the spotty high intensity regions on the MRI-T2 weighted brain images and atheroscrelotic risk factors.
(Methods) In the 129 subjects (mean age: 69.4±3.3) diagnized as healthy in the brain dock the number of spotty high intensity DICOM signals of between 1mm and 3mm in diameter in both the basal nuclei and white matter were calculated in MRI-T2 weighted brain images by means of the analyzing software : VOX-BASE. Moreover, association with hypertension, hypercholesterolemia, diabetes mellitus and obesity were investigated.
(Results) The number of spotty high intensity signals were recognized more in the>65 age-group than <65 age-group. In basal nuclei they were significantly related to hypertension and diabetes. In white matter they were significantly related to hypertension, hypercholesterolemia, and diabetes. In <65 age-group, age, sex or obesity was not related to the number of signals.
(Discussion) This study demonstrated the spotty high intensity regions less than 3mm in diameter on the MRI-T2 weighted brain images were related to the atherosclerotic risk factors. Our hypothesis is that the enlarged and clearized perivascular spaces is the gliosis. By tissue damage as ischemia the cerebrospinal fluid is oozed into the extracellular spaces in the brain tissue and pooled in the perivascular spaces. Therefore, the enlarged perivascular spaces have the same intensity as the cerebrospinal fluid in MRI-T2 weighted brain images. Thus, the spotty high intensity regions may become a sensitive index of the asymptomatic arteriosclerosis.