胎生期ヒト脳，特にsecond trimesterの時期におけるMRIに関する研究

Abstract

Magnetic resonance (MR) images were compared with histological and anatomical observations in 31 fetuses ranging from 10 to 25 weeks gestation to study the relationship between MR images and the development of the neopallium during the second trimester. T1 weighted MR images and T2 weighted MR images taken within 8 hours after delivery were compared with H. E. stained histological slices. On T1 weighted MR images after 18 weeks gestation, the neopallium consisted of four layers which appeared as areas of high, relatively high, low and high signal intensity, respectively, from the ventricular side to the brain surface. These layers corresponded to the ventricular zone, the subventricular zone, the intermediate zone and the cortical plate respectively. On T2 weighted images, these areas appeared only as three layers of low, relatively low and high signal intensity, respectively, from the ventricular side, and the most lateral layer was not distinct from the adjacent layer. Beyond 14 weeks gestation, the ganglionic eminence showed almost the same signal intensity as the ventricular zone. The visualization of the primary fissures by MR images was compared with reported anatomical studies in all fetuses, and with anatomical sections from 18 fetuses. These studies revealed little variation in the time of the first appearance of primary fissures, except that there was a few weeks delay on MR imaging (MRI) of mesially located fissures. Thus MRI was confirmed to be useful in estimating the development of the fetal brain on the basis of imaging of the laminal structures of the neopallium and the appearance of primary fissures.