Neuro-vascular Region Of Lateral Skull Base: Imageo-anatomic Study By Multi-slice CT And High Field MR

Part I: Neuro-vascular region of lateral skull base: anatomic study on dissectionsPurpose: To observe and analysis the neuro-vascular region of lateral skull base by morphologic anatomy, including location, morphology, size and neighbor structures.Materials and methods: Twenty skull specimens were observed and analyzed . Three completed cadaveric heads were dissected and the cranial nerves and blood vessels in this region were reserved. Anatomic analysis was performed.Results: 1 The internal carotid artery (ICA) arrived petrol bone and begun the petrol segment. The ICA canal was divided into vertical segment, horizon segment and genial segment. The horizon segment end at the internal aperture and run upwards into the cavernous sinus. 2 The jugular foramen (JF) located at the posterior part of petro-occipital fissure of posterior fosse. Its external part was bigger than the internal part with irregular shape. There were glosso-pharyngeal meatus and vagus meatus in the JF entrance. The contents within the JF included the glossopharyngeal nerves, the inferior petrol sinus, the vagus nerves, the accessory nerves, the posterior meningeal artery and the jugular bulb, which arranged from anterior to posterior. 3 The facial nerve was the longest cranial nerve, which run in the canal, and was divided into the pons cerebella angle segment (PCA), the internal acoustic canal segment (IAC), labyrinth segment, tympanic segment, mastoid segment and extra-temporal segment. 4 The hypoglossal nerve leaves from the anterior lateral sulcus and run into the hypoglossal canal. Besides of the nerves, there were hypoglossal vein plexus and the hypoglossal artery in the canal. The hypoglossary nerves located between the vagus accessory nerves, the jugular and ICA.Part II: Neuro-vascular region of lateral skull base: anatomic study on thin dissectionPurpose: To do further anatomic study by collodion embedding processMaterials and methods: Five formalin fixed (10%) adult cadaveric heads were selected, 4 male, 1 female. All specimens were performed CT and MR scanning. Three cadaveric heads were dissected by thin-slice collodion embedding process, 2 in axial plane, 1 in coronal plane. 1 mm slice thickness,no gap.Results: The morphology of the lateral skull base was various, such as configuration and size. Affected by the characteristics of human body, the mostly structures run along the direction of up to down, some of them go left to right, or in reverse order. Compared to the axial plane, the coronal plane was better to display the anatomic relationship in the region. The axial and coronal plane both were important to integrate the anatomic section study.Part III: Neuro-vascular region of lateral skull base:imageo-anatomic study by multi-slice CT and high field MRPurpose: According to CT and MR images, to do further imageo-anatomic study.1.Petrol segment and canal of ICA: imageo-anatomic studyMaterials and methods: Five formalin fixed (10%) adult cadaveric heads were performed with CT and MR examinations. Twenty healthy volunteers were scanned by 1.5T MR unit (Marconi, Eclipse). Twenty cases without skull base history were done CT contrast examinations. CT scanning was accomplished by multi-slice CT (GE, Lighspeed QX/i), with spiral and HQ mode. All 20 volunteers were scanned MR sequences as SE TiWI, FSE T2WI and RF-FAST (Radio-Frequency Fourier Acquired Steady-state) in axial plane, and SE TiWI and RF-FAST in coronal plane.Results: Compared to the axial plane, the ICA canal was better displayed on the bone window CT images in coronal plane.(1) On CT images at the level of the outer aperture of hypoglossary canal, the ICA canal existed and tended to disappear. It was advised to be as the imaging level of outer aperture of ICA canal.(2) On RF-FAST images, the ICA course could be revealed clearly.(3) The nerve within canal couldn't be distinguished on CT or MR images.(4) The whole petrol segment could be optimal shown on an oblique plane, whichwasllS0 to the mid-sagittal plane( 1...