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Objective To take the imaging anatomy and measurement of facial nerve canal for cochlear implantation patients,and to provide the reference for how to avoid the injury of facial nerve in the opreration.Methods 35 patients which would be given to cochlear implantation were taken 128 thin-slice CT scan preoperative,then using multi planar reformation (MPR) and curved planar reformation (CPR) techniques,the three-dimensional reconstruction were carried out,and referring the facial nerve anatomy of posterior tympanic facial recess approachartificial cochlear implantation,the relationship between the vertical segnent of facial nerve canal and facial recess,tympanic cavity structure was key displayed.The facial nerve canal sections in temporal bone were measured,and compared with measurement results of 35 cases of cochlear implant patients.Results 35 patients underwent 128-slice CT scan three-dimensional reconstruction of MPR and CPR techniques,the facial nerve segment was clearly displayed,and its vertical section of the posterior wall of the external auditory canal,facial recess distance was (3.31 + 0.88)mm,(1.89 + 0.29) mm,respectively,and the vertical segment of the facial nerve canal wall,the facial recess distance of intraoperative measurement was (3.22 + 0.69) mm,(1.85 + 0.26) mm,respectively,and there were.no significant difference between the the both results(all P ＞ 0.05).35 patients had no case of face paralysis.Conclusion 128-slice spiral CT thin scan combined with MPR and CPR techniques can understand the facial nerve canal and surrounding anatomical landmarks of the fine relationship,measurable facial nerve canal length,and provide basis for how to avoid facial nerve injury in the cochlear implant,temporal bone,and the other side of the skull base surgery.
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The vast majority of traumatic cranial nerve injuries are associated with compression of fragment fracture, and microsurgery outside the epidural can be used for most of the cases. Therefore, early and accurate diagnosis of cranial nerve injury is especially important. As the cranial nerves go out of the cranial cavity through the holes and cracks of the skull base, and there are a number of special structures through which cranial nerve goes into the human skull, and they include the optic canal, superior orbital fissure, facial nerve canal, jugular foramen and so on. Most traumatic cranial nerve injuries are associated with these structures; however, the common imaging examination is very difficult for these structures due to their deep location. To further study the imaging diagnosis of cranial nerve injury associated with traumatic brain injury, this paper reviews the radiological technology for examination of the special positions in the skull.
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Objective To observe and measure the anatomical structure of approach of vertical facial nerve canal and put forward the normal measurement range and the location relationship among the vertical segment of facial nerve canal, the posterior wall of external acoustic meatus and the rear edge of external ear,and discuss the relationship and clinical significance between the mastoid gasification and the vertical segment of facial nerve canal. Methods 1. Evaluate the accuracy of CT image of related structure, using spiral CT in scanning four skull specimens, get the horizontal distances of the vertical segment of facial nerve canal to the posterior wall of external acoustic meatus and the rear edge of external in the axial position, and get the sagittal diameter of mastoid (the horizontal distance from the lowest point of external auditory inferior canal to the rear edge of mastoid) and the height (the vertical distance between the lowest points of the external auditory canal wall to the mastoid tip) in the sagittal position. And then saw the skull specimens to measure the distance in the same lay with CT image, and discuss the statistics difference of the distance between the values of CT imaging measurements and the dry entities cranial measurements on hand. 2. Study on people: 118 patients (236 sides) with non-ear disorders were randomly selected, among which there were 63 females (126 sides) and 55 males (110 sides). They were subjected to maxillofacial CT scan in the same layer that used above, and the horizontal distances of the facial nerve canal to the posterior wall of external acoustic meatus and the rear edge of external ear were measured. In addition, half of the product of diameter and height of the mastoid was defined as mastoid area, which was used to define the extension of mastoid gasification. Then related analysis and regression analysis were done between the vertical segment of facial nerve canal and the posterior wall of external acoustic meatus, as well as the rear edge of external ear. Results 1.Part of the experiment: There was no significantly different on the indicator values between CT image the entity measurements among the four skull specimens (P>0.05). 2. Study on people: There was no significantly different between left side and right side(P>0.05), but significantly different between genders(P<0.05). Between mastoid area and the distance from the vertical segment of facial nerve canal to the posterior wall of external acoustic meatus there is inverse correlation, and the relevance has the remarkable significance. However, there was no correlation between mastoid area and the vertical segment of facial nerve canal to the rear edge of external ear. Conclusion There was some relationship between the location of the vertical segment of facial nerve canal and external acoustic meatus. Anatomic position of vertical facial nerve cancal and the posterior wall of external acoustic meatus can be showed clearly. CT and in combination with primitive axial images may provide reliable evidence for the diagnosis facial nerve dieases and the choice of ear surgery route.
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Objective To study the facial nerve canal (FNC) abnormalities of the congenital external auditory canal (EAC) atresia by MSCT curved planar reformation (CPR).Methods 15 cases(17 ears) of congenital EAC atresia were scanned by MSCT. Post-processing images were completed by Philips Mx8000 workstation.Results In 17 ears, there were 2 ears with stenosis of EAC, 2 ears with membranous atresia of EAC and 13 ears with bony atresia of EAC.There were 1 ear with congenital cholesteatoma, 3 ears with malformation of tympanum, 7 ears with malformation of the ossicular chain and 1ear with malformation of inner ear. In 17 ears with abnormalities of FNC, included 11 ears with the shortness of FNC general length, 5 ears with the anomalous course of FNC, 9 ears with the displacement of FNC, 1 ear with the narrowing of FNC and 1 ear with the branch of FNC.Conclusion MSCT CPR of FNC, combined with HRCT axial scan, can clearly show the FNC abnormalities of the congenital EAC atresia and provide valuable information for surgery.
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Objective To observe and measure the facial nerve canal(FNC) in curved planar reformation by multislice spiral CT.Methods High resolution computed tomography (HRCT)of temporal bone was performed in 40 cases (80 ears) by multislice spiral CT. Curved planar reformation of FNC was performed separately in axial, coronal and sagittal plane of multiplanar reconstruction. The morphology and measurement of FNC were studied.Results The mean length of FNC was (29.73?1.07)mm. The mean length of the labyrinthine, tympanic and mastoid segment was (5.6?0.74)mm, (10.66?0.79)mm and (13.47?1.01)mm respectively. The mean diameter of the l-abyrinthine, geniculate fossa, tympanic and mastoid segment was (0.76?0.16)mm, (2.37?0.63)mm, (1.03?0.16)mm and (1.57?0.31)mm respectively. The mean angle of first and second genu was 67.04??9.41? and 114.25??8.44? respectively. The distance between the tympanic segment and ampulla of the lateral semicircular canal was (0.57?0.19)mm. The distance between the tympanic segment and arch of the lateral semicircular canal was (1.59?0.61)mm. The mean angle between the tympanic segment of the facial nerve canal and the lateral semicircular canal was 10.63??3.60?. The tympanic course of the facial nerve canal formed an angle of 34.65??5.39? with the sagittal plane. Dehiscences was found in 89% FNC, 73.7% of them only located in the tympanic portion and 26.3% both in the mastoid and tympanic portions. Conclusion Curved planar reformation of FNC by multislice spiral CT is the good method to study the anatomy of FNC,and in combination with HRCT axial scan and multiplanar reconstrution can obtain more valuable information.
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Objective To evaluate the diagnostic value of oblique axial multiplanar reformation(MPR)imaging in detecting the fracture of geniculate fossa of facial nerve canal and its nearby.Methods 33 cases of facial nerve canal or nearby fracture confirmed by surgery were collected.CT findings(including conventional axial,coronal and oblique axial MPR images)were retrospectively analysed in comparison with that of operation.The diagnostic corresponding rate of two diagnostic modes(the combination of routine axial and coronal imagings,the combination of routine axial,coronal and oblique axial imagings)were compared.Results The fractures of geniculate fossa or the proximate of tympanic segment were seen in 22 cases on pre-operation CT images,including 8 cases on routine axial images,6 cases on routine coronal images and 20 cases on oblique axial MPR images.Local enlargement of geniculate fossa or the proximate of tympanic segment were seen in 26 cases on oblique axial MPR images.There were significant differences between these two diagnostic modes.Conclusion Oblique axial MPR images in combined with routine axial and coronal images can improve the diagnostic corresponding rate of the fracture of geniculate fossa and its nearby.