A Control Study Of Thin-slice Radioanatomic And Cross-sectional Anatomy About Jugular Foramen Area

Jugular foramen is a important bony channel of skullbase with irregular forms in posterior cranial fossa,which lccates between occipital bone and petrous bone ,under the iternal auditory canal , upward the foramen magnum,on the bilateral of clival. Ordinarily it is divided into two parts by temporal process and occipital process,the anterior neural parts is smaller, with inferior petrosal sinus pouring into it and Glossopharyngeal Nerve,Vagus Nerve and Accessory Nerve crossing,the posterior va scular parts is larger,with internal jugular vein passing through. The region of jugular foramen is adjacent to carotid canal,vertical section of facial nerve,ampulla of posterior semicircular canals,hypoglossal canal and condylar canal et al.Because of deepen of its position,compactness of its structure and complexity of anatomy and adjacency,in recent years, it is highlights of researchs on neuroanatomy,surgery of skullbase,imaging diagnosis of head and neurosurgery.To the diagnosis of diseases in the region of jugular foramen,CT and MRI have become a very essential examinary methods,with gradually development of imaging equipments, allowed us to discuss more exactly in sectional and imaging anatomy of the region of jugular foramen.AIM:Based on thin-slice radioanatomic studies,to study CT and MRI imaging features of jugular foramen area, to provide imaging foundation for clinics more exactly and objectively.METHODS: Three skulls fixed by formalin and without lesion of skull-base were selected to make transverse and coronary serial sections respectively, slice thickness was 1mm without interlayer distances.Twenty healthy volunteers were selected to make MSCT plain scan,contrast enhancement scan and MR scan, sequences of scan include spin echo sequenceT1 weighted imaging(SE T1WI),fast spin echo T2 weighted imaging (FSE T2WI) and three-dimensional fast imaging employing steady state acquisition sequence(3D-Fiesta).In order to describe better, cross-section were selected four slices:channel of glosspharyngeum,channel of vagus,vestibule of jugular vein,external aperture of jugular foramen; coronal-section were selected three slices: glomus jugular slice,slice of nerve,slice of transition from sigmoid sinus to glomus jugulare.RESULTS: On cross-section, MSCT manifested forms of channel of glosspharyngeum and vagus clearly at internal opening of jugular foramen, MRI manifested respectively that glossopharyngeal nerve entered channel of glosspharyngeum,vagus and accessory nerve entered channel of vagus; MSCT plain scan displayed bony structures of jugular foramen at slice of vestibule of jugular vein, in which temporal and occipital process divided it into nerve parts and vascular parts, but soft tissues couldnot be distinguished, enhancement scan displayed location where inferior petrosal sinus flow into glomus jugulare, on upper slice of vestibule of jugular vein, through 3D-Fiesta sequences of MRI scan, 76.6% cases with directions of antero-posterior displayed inferior petrosal sinus,vagus nerve,compound bundle of accessory nerve and glomus jugulare gradually; at slice of external aperture of jugular foramen, CT could menifest forms of bony jugular foramen and hypoglossal canal, through 3D-Fiesta sequences MRI could menifest the internal carotid artery and internal jugular vein,besides, hypoglossal nerve could be menifest clesrly. On coronal-section MSCT plain scan manifested forms of bony glomus jugulare, enhancement scan and 3D-Fiesta sequences of MRI displayed about 93.3% inferior petrosal sinus flow into glomus jugulare, while transition from sigmoid sinus to internal jugular vein,there were 47 laterals which shapes of glomus jugulare were projection ( 78.3% ) and 13 laterals were flat(21.7%).CONCLUSION:There are a good corresponding relation of imaging features and cross-sectional anatomy between MSCT and MRI in jugular foramen area, through informations provided by both been supplementary mutual, structure of jugular foramen area can be manifested better.Objectives of this text: MSCT becomes the first selected method in bony structures of the region of jugular foramen,it can reduce pseudo-images of posterior cranial fossa,so manifest bony structures of the region of jugular foramen more effectly.In Enhanced scanning, MSCT can shorten scanning period,it can establish foundation for dynamic scanning of exact phase.To menifest structures of neural soft tissue in the region of jugular foramen,MRI is supperior than CT obviously.The manifested rate of the lower cranial nerves will be improved obviously by exact scanning flatness and proper checking sequence.Hence, to develop their complement in superiority of CT and MR imagines,imaging informations of this region will be enriched greatly,it has so important clinic meanings to manifest structures of skullbase and definite the ranges of lesion,that it can provide more objective imaging basis for skullbase surgery.