Spiral CT Three-dimensional Reconstruction Observations And Clinical Significance Of The Main Structures In Temporal Bone

Background The malformation of middle ear,inner ear and facial nerve canal in the temporal bone were the main causes of sensorineural deafness and facial paralysis in the clinical aspect,which greatly impacted the patient’s life quality.Spiral CT could do the three-dimensional reconstruction,includes multiplanar reconstruction(MPR).It showed well the structure of bone.The main structure inside or outside of the temporal bone could be fully displayed on the CT image.Its microstructure also could be more clearly displayed.But few data mainly concerning MPR reconstruction of temporal bone.Objective By using spiral CT image post-processing technology such as multiplanar reconstruction(MPR),observed the location,shape,size,angle,etc.of the tympanic cavity,mastoid antrum,malleus,incus,stapes,cochlea,vestibule,semicircular canal,round window,vestibular window of the middle ear and inner ear,labyrinthine segment,anterior knee,tympanic segment,posterior knee and vertical segment of the facial nerve canal.The purpose was to provide morphological basis for the structure lesions of temporal bone in clinical diagnosis.Methods 300 cases(150 male and 150 female,Age from 8 months and 61 years old)were collected from January 2013 to December 2015 in the department of Imaging,Xinyang First people’s hospital.Divided into 2 age groups,(1)≤6 years old group(8 months to 6 years old),100 cases(200 ears,50 males,50 females),mean age(4.2±0.3)years;(2)> 6 years old group,200 cases of(400 ears,100 males and 100 female),mean age of(38.5±3.8)years.Inputed the image date to CT reconstruction workstation.Used ADW 4.2 reconstruction software multiplanar reconstruction(MPR)technology to anlysis the structure of the temporal bone.The image post-processing showed its whole or maximum journey.The main structure size in temporal bone was measured.Statistical anlysis was done by SPSS 17.0.All measurement data were showed by using mean±standard((?)±s)deviation.Results 1.The multiplanar reconstruction(MPR)images of the middle ear clearly displayed the main anatomical structure of malleus,incus,hammer anvil joint,stapes,anvil stirrup joints,vestibular window and etc.There were no significant difference between left and right side or male and female(P > 0.05).There were significant difference in the superioinferior diameter of superior tympanic cavity,transerver diameter and anterioposterior diameter of mastoid antrum between under 6 years and over 6 years old(P < 0.05),Other structures such as otosteon,etc.No significant difference existed between different age groups(P > 0.05).The superioinferior diameter of superior tympanic cavity,transerver diameter and anterioposterior diameter of mastoid antrum under 6 years old were(6.41±1.07)mm,(8.06±1.71)mm,(10.81±1.20)mm respectively.Over 6 years old group were(9.08±0.63)mm,(6.70±0.66)mm,(8.36±0.72)mm respectively.2.The multiplanar reconstruction(MPR)images of the inner ear could clearly display the main anatomical structures of the anterior bony semicircular canal,posterior bony semicircular canal,horizontal bony semicircular canal,vestibular,cochlear,etc.There were no significant difference in the inner ear structure between the left and right,male and female,over 6 years and under 6 years old(P > 0.05).The perimeter of the anterior,posterior,horizontal bony semicircular canal and the diameter of the round window,vestibular window were(13.02±1.68)mm,(13.59±1.60)mm,(13.05 ±1.23),(2.08±2.08)mm and(2.70±0.49)mm respectively.The height,length of the cochlea,the length and wide diameter of the vestibular were(3.50±0.52)mm,(6.21±1.04)mm and(5.75±0.50)mm,(2.90±0.67)mm respectively.3.The multiplanar reconstruction(MPR)oblique transerve images of Facial nerve canal could clearly show the labyrinthine segment,anterior knee,tympanic segment.The oblique sagittal images could clearly show the tympanic segment,posterior knee,vertical segment.There was no significant difference in Facial nerve canal between the left and right,male and female(P > 0.05).There were significant difference(P < 0.05)in the length of labyrinthine segment,tympanic segment,vertical segment and the angle of posterior knee between over 6 years and under 6 years old group.The other structures such as the angle of anterior knee,there were no significant difference(P > 0.05).The length of labyrinthine segment,tympanic segment,vertical segment and the angle of posterior knee of under 6 years old group were(3.31±0.73)mm,(10.64±0.77)mm,(12.09±1.1)mm,(115.62±6.44)° respectively.Over 6 years old group were(3.66±0.39)mm,(11.50±1.06)mm,(13.68±1.05)mm,(10.10±6.13)° respectively.Conclusion 1.There was difference between age groups in superioinferior diameter of superior tympanic cavity and length of the facial nerve canal.The age factor should be considered carefully in the clinical diagnosis and surgery.2.No difference was found between age groups in ear ossicles,bony semicircular canals,cochlea,width of canales facialis.These structures were up to the level of the adult at the date of birth.This result provided the anatomical basis for cochlear implants,etc.