The Measurement of the Facial Nerve Canal in Curved Planar Reformation by Multislice Spiral CT / 实用放射学杂志

ABSTRACT

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.