Objective: The mesocoelic recess (MCR) is found in the brain of human embryos and fetuses. The mesocoelic recess seems to be functionally related to the subcommissural organ that is one of neurosecretory organs involved in osmoregulation on the basis of data from other species. Subsequently, recent speculation as to the importance of the subcommissural organ in the development of congenital hydrocephalus has been raised. Yet unlike other mammals, MCR is known to be a vestigial structure in the adult human brain. Here, we performed the in vivo imaging identification of this space to investigate functional and clinical correlations.
Methods: We studied adult human brains using a 7.0-T magnetic resonance imaging (MRI). Twenty healthy individuals aged 22 to 30 years were selected, and they were all volunteers. The parasagittal images through the intercommissural line were examined. We determined the type of shape of the MCR; a triangular C shape was classified as type 1, and a trapezoidal concave shape was classified as type 2.
Results: In 14 brains, the recesses were radiologically demonstrated just rostral to the tectal plate of the midbrain and covered the ventral aspect of the posterior commissure and pointed the opening into the aqueduct. The average size of the circumference of the MCR measured from the end point of the C-shaped cup was 6.82 mm.
Conclusions: This study on the anatomy of the MCR of adult brains in vivo is the first of its kind, thanks to the availability of 7.0-T MRI because it has been barely discernible even in autopsy specimens as well as in radiology owing to the resolution limit of the currently available imaging system. The current study raises awareness of the MCR, an important but little-known anatomic structure in adult human brain. This visualization of MCR in human in vivo with ultrahigh-field MRI will certainly provide us important clues including the functional information of MCR, a mystery of modern neurological science.
From the *Department of Pathology, Gil Medical Center, †Neuroscience Research Institute, Gachon University of Medicine and Science, Incheon; ‡Department of Pathology, Seoul National University College of Medicine, Seoul; Departments of §Neurosurgery, and ∥Radiology, Gil Medical Center, Gachon University of Medicine and Science, Seoul, Korea.
Received for publication December 27, 2010; accepted March 11, 2011.
Reprints: Zang-Hee Cho, PhD, Neuroscience Research Institute, Gachon University of Medicine and Science 1198 Guwol-dong, Namdong-gu, Incheon, 405-760 Korea (e-mail: firstname.lastname@example.org).
This research was supported by a grant from System Development for 7.0-T MRI and in vivo Human Image Program funded by the Ministry of Education, Science and Technology, Republic of Korea.