RT Journal Article
SR Electronic
T1 MR Imaging of Normal Perivascular Space Expansion at Midbrain
JF American Journal of Neuroradiology
JO Am. J. Neuroradiol.
FD American Society of Neuroradiology
SP 566
OP 571
VO 26
IS 3
A1 Saeki, Naokatsu
A1 Sato, Motoki
A1 Kubota, Motoo
A1 Uchino, Yoshio
A1 Murai, Hisayuki
A1 Nagai, Yuichiro
A1 Ishikura, Hiroshi
A1 Nomura, Seitaro
A1 Matsuura, Iichiro
A1 Yamaura, Akira
YR 2005
UL http://www.ajnr.org/content/26/3/566.abstract
AB BACKGROUND AND PURPOSE: A previous investigation of the MR imaging findings in the midbrain reported expanded perivascular (PV) spaces in only the ponto-mesencepalic junction (PMJ) in 20% of healthy subjects, whereas pathologically expanding PV spaces have been reported at the mesencephalo-diencephalic junction (MDJ) as multi-lobulated, cystic lesions with signal intensity compatible with that of CSF that cause aqueductal stenosis. To clarify the anatomical distinctions between normally expanded and pathologically expanding PV spaces, we defined their distribution in the normal midbrain by using high-spatial-resolution MR imaging.METHODS: Heavily T2-weighted MR imaging was performed in 115 adult subjects with neurologic complaints without cerebral disease. Histologic studies were performed from two normal midbrain blocks.RESULTS: Expanded PV spaces were visible at the PMJ in 87% of subjects and at the MDJ in 63% of subjects. On axial images, ovoid or linear lesions with signal intensity compatible to CSF were present behind the cerebral peduncle at both the PMJ and MDJ. These areas varied from less than 1 mm to 5 mm (maximum diameter on coronal sections). Histologic studies confirmed the distribution of expanded PV spaces, as noted on MR images.CONCLUSION: This study, by using high-spatial-resolution MR imaging, revealed that expanded PV spaces were visible at the PMJ and MDJ. Our finding of expanded PV spaces normally present at the MDJ may be related to pathologically expanding PV spaces, which should be kept in mind as a differential diagnosis for intraparenchymal cystic lesions in the midbrain with signal intensity compatible to CSF.