Localization Study Of Gyri By Medullary Branches On Sagittal Section And MRI Image

Objective In order to provide reliable morphological basis and new way for MRI localization of cerebral local lesion and imaging study of brain functions, observing and studying cerebral medulla on 30 cranial sagittal sections and its MRI film, Then identified the corresponding gyri according to medullary pattern and its direction. According to this method, the cerebral lobe and gyri can be accurately described.Methods choosing 30 normal cadaver heads to scan in sagittal plane. MRI was performed on a 1. 5-T unit(G. E. signal Milwaukeee, WI) as Tl-weighted spin-echo series (parameters; TR/TE540/11) 5 24cm field of view? 6mm slice thickness; no intraslice gap,2Nex;and 320X 192 display matrix. The brain was obtained from the scanned cadaver heads, then painting different water-colors on the major gyri and fasten it with 20% glutin. To cut the brain slice in correspondence with MR scan with the brain knife on slice frame. Observing the medullary pattern and direction and localizing the corresponding gyri and sulci on sagittal section by the comparison of the MR images with serial sagittal sections of the brains.Results Through our studying, the rules of localizing gyrus through the pattern of medullary branches on the sagittal plane are described as follows:(1)Pre- and post-central gyri: On the central sagittal section, rabbit-tail sign is the key landmark of post-central gyrus. As the sections away from the medial, this sign disappear, and the rules of medullary branches' direction are more clearly. The medullary branches of pre-central gyrus appeared on the direction of about 12 o'clock and post-central gyrus on the half past 12 o 'clock. In addition to, the direction of medullary branches move anti-clockwise as the sections away from the medial. On the section cutting insula, central sulcus locate exactly 12 o'clock direction and outward is ultimately changeless. (2)Frontal lobe The medullary patterns on sagittal sections can be acted to identify superior and middle frontal gyri, when the medullary branches are all superior or middle frontal gyri, its branches are very clear. On the sections which contain superior and middle frontal gyri together, medullary branches are blur, especially signal of cortex predominate on MRI image. Inferior frontal sulcus is the landmark of middle and inferior frontal gyri. (3)Parietal lobe I-dentification of superior and inferior parietal lobe is equal to that of superior and middle frontal gyri. Another 2 o'clock direction can be acted as borderline of parietal lobe and occipital lobe. Supramarginal gyrus and angular gyrus can be found at the end of lateral sulcus and superior temporal sulcus respectively. Horseshoe sign is guideline for identifying supramarginal gyrus.(4)It is a reliable and accurate method to localize the gyri and lobes according to the pattern of medullary branches.(5)Using of the dial plate make the methods of localization more simple and accurately , To manipulate is easy also.