CT中耳仿真内窥镜成像对中耳结构空间解剖关系的显示价值

背景：中耳结构复杂、细微，位置深而隐匿。CT仿真内窥镜成像可利用螺旋CT容积扫描数据重建出空腔器官内表面的立体图像，类似纤维内镜所见。 目的：验证64排螺旋CT中耳仿真内窥镜对中耳正常结构的显示能力以及在病变中耳中的临床应用价值。 设计、时间及地点：验证性对比观察，于2005-10/2006-03在中山大学附属第一医院放射科完成。 对象：选择33例(66耳)疑有中耳疾病行双耳螺旋CT检查患者，其中正常35耳；病变31耳包括慢性化脓性中耳炎24耳，慢性化脓性中耳炎乳突根治术后复发2耳、中耳癌2耳、外耳道异物肉芽肿1耳及颞骨骨折2耳。 方法：行颞骨64排螺旋CT容积扫描，软组织算法密集重建后，利用Navigator软件行中耳CT仿真内窥镜成像。所有CT仿真内窥镜成像均与常规二维CT图像及手术对照。 主要观察指标：观察的主要结构包括各听小骨及其间的关节、上中下鼓室、鼓窦及外耳道、鼓室各壁结构、面隐窝、鼓室天盖、锤骨前、上韧带、砧骨后韧带及后鼓室的结构。 结果：100%的CT仿真内窥镜图像可清晰显示正常中耳大部分听小骨及鼓室各壁结构，68.6%(24/35)及74.3%(26/35)的CT仿真内窥镜图像可分别清晰显示镫骨前、后脚，而且CT仿真内窥镜图像可清晰显示后鼓室重要解剖结构。慢性化脓性中耳炎病例中，CT仿真内窥镜显示锤骨柄、砧骨长脚骨质破坏与手术所见的符合率为91.7%(22/24)，锤骨头、砧骨短脚、镫骨脚骨质骨质破坏的符合率分别为95.8%(23/24)，100%(24/24)及87.5%(21/24)；1耳中耳癌中CT仿真内窥镜可清晰、立体显示鼓室盖、鼓岬及外半规管的骨质破坏；1耳颞骨骨折中CT仿真内窥镜可清晰显示锤砧关节脱位。中耳CT仿真内窥镜成像平均耗时约10 min。 结论：64排螺旋CT中耳CT仿真内窥镜可以清晰显示中耳的正常解剖细节，对病变中耳骨质破坏显示的符合率较高，且CT仿真内窥镜耗时不长，可以临床常规使用。

Computed tomography virtual endoscopy imaging for spacial anatomy of the middle ear

BACKGROUND: The middle ear is a little aerated cavity with a complex anatomy and a deep location. Computed tomagraphy virtual endoscopy (CTVE) can be used to reconstruct the stereoscopic images of internal surface of hollow organs using spiral CT volumetric data, providing findings similar to fiberendoscope. OBJECTIVE: To verify the ability to show the normal middle ear and the clinical application of virtual endoscopy based on 64-detector CT data. DESIGN, TIME AND SETTING: A confirmatory controlled observation was performed at Department of Radiology, First Affiliated Hospital of Sun Yat-sen University between October 2005 and March 2006. PARTICIPANTS: A total of 33 patients (66 ears) with suspected middle ear disease who underwent spiral CT examination were included in this study. Among included ears, 35 were normal, and 31 were impaired, including 24 ears presenting with chronic suppurative otitis media (10 simple otitis media, 5 granulomatous otitis media, and 9 middle ear cholesteatoma), 2 ears with post-operative recurred suppurative otitis media, 2 ears with carcinoma of middle ear, and 2 ears with temporal bone fracture, and 1ear with foreign body granuloma. METHODS: CT images of the temporal bone were obtained using 0.5 mm thick axis slices with a soft reconstruction kernel at 0.3 mm intervals. Virtual endoscopic images of middle ear on CT were generated from volumetric data using the Navigator software. CTVE images were observed from multiple directions using the Fly Through software, and compared with the axial and coronal images and surgery findings. MAIN OUTCOME MEASURES: The following structures were observed: auditory ossicle and joints, superior, middle, and inferior tympanum, sinus tympani, external acoustic meatus, tympanum, facial recess, tegmental wall, anterior and superior ligaments of malleus, posterior ligament of incus, and retrotympanum. RESULTS: A series of images were acquired as the virtual endoscope moved from the external auditory canal to the middle ear cavity. CTVE displayed the structures of normal middle ear with high details in 100%, except the anterior and posterior limbs of stapes in 68.6% (24/35) and 74.3 %( 26/35), respectively. In the ears with supperative otitis media, the destruction of bone of handle, head of malleus, long and short limbs of incus, and limbs of stapes was found on CTVE in 91.7%(22/24), 95.8%(23/24), 95.8%(23/24), 100%(24/24), and 87.5%(21/24), respectively. CTVE clearly showed the destruction of promontory, tegmental wall and facial nerve tube in one ear with carcinoma. CTVE showed the dislocation of incudomallear joint in one ear with temporal bone fracture. It took about 10-15 minutes to perform CTVE. CONCLUSION: CTVE can be used as a noninvasive and reliable method in displaying normal and pathologic middle ears. In cases of suspected bony destruction and confirmed trauma, it is helpful for diagnosis and surgical planning. CTVE of the middle ear can currently be considered as a complementary technique to conventional CT, and it is time-saving and reserves clinical generalization.