The Evaluation Of The Destruction Of The Bony Structures Caused By Chronic Ottitis Media By Temporal Bone HRCT

Objective:By optimizing the proper reconstruction and the combination of reconstruction methods processed by using HRCT to detect the destruction of the malleus and incus caused by Chronic Ottitis Media(COM),and investigate the principle of the damage to acouesthesia.,when different parts of malleus and incus are destructed or different COMs occur.Materials and Methods:Scan sixty-three patients(sixty-six ears)of COM with HRCT.To observe the destruction of the malleus and incus with image of the original axial image,the multi—planar reconstruction(MPR)and the hybrid rendering,then Compared them with the Pathological specimens by Chi-square test;divided all patients into cholesteatoma group of thirty-nine cases(forty-one ears),granuloma group of twenty-two cases(twenty-three ears),and simple group of two cases(two ears).Then compared the acouesthesia of the three groups by rank sum test;Devide the patients into four groups according to the degree acouesthesia:mild group(20dB-55dB),moderate group(56dB—70dB),severe group(71dB-90dB),very severe group (＞91dB),Then compared the difference of the destruction and vanishing of the malleus and incus by Chi-square test;According to the different locations or the cholesteatoma divided the cases into attic group,mesotympanum group,then compared the rule of the destruction and vanishing of the the malleus and incus in the two groups.Results:the Axial image can't properly show the the destruction of the the malleus and incus(P=0.000＜0.001).The image of MPR and hybrid rendering of SSD and VE can show the destruction of the malleus and incus clearly and directly(P＞0.05);MPR combined with hybrid rendering can elevate the diagnostic ratio of the destruction of the the malleus and incus;Different damages to the malleus and incus caused different degrees of hearing loss(P=0.044＜0.005);And different typs of COM induced different degrees of hearing loss(P= 0.024＜0.005).Conclusion:MPR and Hybrid rendenng of SSD and VE can evaluate the destruction of the the malleus and incus.Different damages to the malleus and incus and different typs of COM induced different degrees of hearing loss;Different locations of the cholesteatoma cause different damages to the malleus and incus.Different types of COM result in different degree of hearing loss.Combination of MPR and hybrid rendering of SSD and VE can elevate the diagnostic ratio of the destruction and vanishing of the malleus and incus;Objective:To investigate the damage to the bony labyrinth,facial canal,tegmen tympani, tympanic sinus,sigmoid sinus in COM by using MPR and curved planar reconstruction (CPR);To investigate the hearing loss cused by the damage of the bony labyrinth;To evaluate the typ of the COM by the character of the damage.Materials and Methods:Scan sixty-three patients(sixty-six ears)of COM with HRCT,Use MPR or CPR image to observe the damage of bony labyrinth,facial canal, tegmen tympani,tympanic sinus and sigmoid sinus.Compared these image with the operation by rank sum test;Compared the character of the damage of the cholesteatoma COM with the granuloma COM by Fisher exact probability.Compared the acouesthesia of the patients with labyrinthine fistula or without labyrinthine fistula.Results:MPR and CPR can indicate the degree of damage to the bony labyrinth,facial canal,tegmen tympani,tympanic sinus,sigmoid sinus suitably(P＞0.05).There are different damage characters between cholesteatoma COM and the granuloma COM(P=0.042＜0.05),the former one is more serious than the latter one.The threshold of hearing of the patients with labyrinthine fistula is higher than that without labyrinthine fistula(Z=4.225,P=0.000＜0.001);HRCT can classified the typ of the COM exactly.Conclusion:MPR combined with CPR can display the damage to the bony labyrinth, facial canal,tegmen tympani,tympanic sinus,sigmoid sinus properly;The destruction of tympanica with the cholesteatoma COM is more severe than that with the granuloma COM.The threshold of hearing of the patients with labyrinthine fistula is higher than those without labyrinthine fistula.HRCT can classify the typ of the COM properly.