CT densitometry of the cochlear capsule in otosclerosis

Cochlear otosclerosis can be recognized in most cases by high-definition axial and coronal CT images. However, routine technique does not allow a quantitative measurement of the changes. Reported here is a study of cochlear CT densitometry. The densitometric profile of the cochlear capsule was obtained in 10 ears with normal hearing and 50 ears in 27 patients with known clinical otosclerosis and progressive mixed-type hearing loss. Patients with hearing loss had decreased absorption of as much as 60% in comparison to the normal range. In 42 ears with abnormal densitometric profiles, the changes were visibly apparent on the CT images, whereas in eight others, the densitometric profile alone demonstrated decreased absorption.     

CT of cochlear otosclerosis (otospongiosis)

High-resolution CT is the method of choice in determining the extent of demineralization in otospongiosis. By comparing the maximum and minimum densities, this examination has become of clinical importance in the diagnostic approach to otosclerosis and in the follow-up of fluorine therapy.     

Use of CT in stapedial otosclerosis

Otosclerosis (otospongiosis) is a primary focal disease of the labyrinthine capsule. The stapes footplate is fixed when the spongiotic focus expands and invades the oval window. Persons with stapedial otosclerosis experience a progressive conductive hearing loss. In many cases, cochlear degeneration is observed, in which a mixed hearing loss occurs. Using computed tomography (CT), we studied the ears of 45 selected patients with conductive or mixed hearing loss. CT proved valuable in determining otosclerotic changes of the oval window and otic capsule. Spongiotic changes of the otic capsule are better appreciated by CT than complex motion tomography. The usefulness of CT in diagnosing other causes of conductive or mixed hearing loss is also described.     

MRI of cochlear otosclerosis

Cochlear otosclerosis is an uncommon cause of mixed and sensorineural hearing loss. This has a characteristic appearance on CT, producing a distinctive pericochlear hypodense double ring. However, its appearance on MRI is not as readily appreciated, producing a ring of intermediate signal in the pericochlear and perilabyrinthine regions on T(1) weighted images, demonstrating mild to moderate enhancement after gadolinium administration. Increased signal on T(2) weighted images may also be seen. Recognition of these MRI features is important as MRI may be the first modality of investigation, especially when patients present with symptoms indicative of sensorineural hearing loss. We review four patients who presented with sensoineural hearing loss, and who were imaged with MRI as the first line of investigation.     

Computerized tomography in cochlear otosclerosis

After a review on osseous labyrinthine modifications in cochlear otosclerosis, the authors report their experience, based on four patients, in CT evaluation of the disease. CT high resolution programs detect demineralization centres, which are distinctive of cochlear otosclerosis, at an early stage. CT must be considered a more informative investigation than multidirectional tomography.     

耳硬化症的高分辨率CT表现

目的 探讨耳硬化症的HRCT表现特征.方法 回顾性分析34例61耳临床诊断明确的耳硬化症的HRCT表现.结果 55耳HRCT表现耳囊骨密度减低区,6耳HRCT未发现异常.HRCT表现异常的55耳中,6耳仅表现为前庭窗前方耳囊低密度区,6耳表现为前庭窗前方耳囊低密度区、镫骨底板增厚及耳蜗周围低密度区,11耳表现为前庭窗前方耳囊低密度区、前庭窗后方低密度区及镫骨底板增厚,20耳表现为前庭窗前方耳囊低密度区和镫骨底板增厚,10耳表现为前庭窗前方耳囊低密度区及耳蜗周围耳囊低密度影,2耳仪表现为耳蜗周围耳囊低密度区.结论 HRCT可显示耳囊骨质及镫骨底板异常,有助于进一步证实耳硬化症诊断.     

耳硬化症的高分辨率CT表现

目的 探讨耳硬化症的HRCT表现特征.方法 回顾性分析34例61耳临床诊断明确的耳硬化症的HRCT表现.结果 55耳HRCT表现耳囊骨密度减低区,6耳HRCT未发现异常.HRCT表现异常的55耳中,6耳仅表现为前庭窗前方耳囊低密度区,6耳表现为前庭窗前方耳囊低密度区、镫骨底板增厚及耳蜗周围低密度区,11耳表现为前庭窗前方耳囊低密度区、前庭窗后方低密度区及镫骨底板增厚,20耳表现为前庭窗前方耳囊低密度区和镫骨底板增厚,10耳表现为前庭窗前方耳囊低密度区及耳蜗周围耳囊低密度影,2耳仪表现为耳蜗周围耳囊低密度区.结论 HRCT可显示耳囊骨质及镫骨底板异常,有助于进一步证实耳硬化症诊断.     

耳硬化症的高分辨率CT表现

目的 探讨耳硬化症的HRCT表现特征.方法 回顾性分析34例61耳临床诊断明确的耳硬化症的HRCT表现.结果 55耳HRCT表现耳囊骨密度减低区,6耳HRCT未发现异常.HRCT表现异常的55耳中,6耳仅表现为前庭窗前方耳囊低密度区,6耳表现为前庭窗前方耳囊低密度区、镫骨底板增厚及耳蜗周围低密度区,11耳表现为前庭窗前方耳囊低密度区、前庭窗后方低密度区及镫骨底板增厚,20耳表现为前庭窗前方耳囊低密度区和镫骨底板增厚,10耳表现为前庭窗前方耳囊低密度区及耳蜗周围耳囊低密度影,2耳仪表现为耳蜗周围耳囊低密度区.结论 HRCT可显示耳囊骨质及镫骨底板异常,有助于进一步证实耳硬化症诊断.     

Use of CT in evaluation of postcystectomy patients

Twenty-one patients with prior cystectomy for transitional cell carcinoma of the bladder were evaluated by computed tomography. In eight patients who developed local pelvic recurrence, CT diagnosis was correct in seven. CT also detected distant metastasis in five patients and local pelvic abscesses in two additional patients. Our data show CT to be a more sensitive means than conventional radiologic methods including gray scale sonography in the detection of local recurrence and postoperative complications. Examples of normal postcystectomy changes in the pelvis as well as recurrent disease and surgical complications are illustrated. The pitfalls and the proper role of CT in these patients are also discussed.     

Use of CT in the evaluation of primary cardiac tumors

Two cases of primary cardiac sarcomas diagnosed with CT are presented. CT demonstrated the origin, extent, and potential pathology of the tumors. In both cases CT provided more specific information for diagnosis and treatment planning than the 2D echocardiography. The advantages of CT in the detection of cardiac tumors as well as its potential advantages over 2D echocardiography are also discussed.     

Role of high resolution CT and radiography in postoperative evaluation of cochlear implantation

Objective

To assess the role of HRCT and Radiography in postoperative evaluation of cochlear implants.

Patients and methods

Radiography; including Stenver’s and modified Chause III positions, as well as HRCT were carried out in 12 patients with cochlear implants. HRCT images were obtained utilizing 0.625 mm slice thickness followed by reconstruction using 0.3-mm reconstruction increment and high-resolution algorithm.

Results

On HRCT, complete insertion of electrode array was noted in one patient, incomplete insertion in two and partial insertion in nine patients. The position of the electrode array as compared to CT and radiography revealed agreement in 11 patients; and disagreement in one. The radiologic position of the electrode array was compared to intra-operative electrophysiological testing and surgical data. In three patients, there was agreement. In one patient, contacts 11 and 12 were nonfunctioning with good impedance and were extra-cochlear. One patient had nonfunctioning contact 12 with high impedance and absent stapedial reflex and was extra-cochlear. In one patient, contacts 11 and 12 showed high impedance and were extracochlear. In nine patients, intra-operative electrophysiological testings were satisfactory with three having high impedance of last contact. Facial twitches were encountered in two patients.

Conclusion

Technological advances will expand the applications of HRCT in cochlear implant recipients.     

CT扫描在人工耳蜗植入中的价值

人工耳蜗植入是先天性内耳畸形引起极重度和全耳聋患者目前实现听力语言康复的唯一有效的治疗方法[1]。内耳畸形有其特殊的形态学表现,可被影像学方法所诊断,而高分辨率CT因其可以显示精细的骨结构而成为颞骨检查的首选方法[2]。1材料与方法回顾性分析我院于2001年5月~2005年12月内耳畸形患者39例,男17例,女22例,年龄1.5~20岁,平均年龄12·3岁。全部病例均采用澳大利亚Neuclear型不同型号的人工耳蜗。采用Simens Plus 4螺旋CT对所有病例均作横断面高分辨率扫描。患者仰卧位,收拢下颌,扫描基线与听上眶线平行,扫描范围包括整个乳突部位。…     

影像学评估在耳蜗植入术中的价值

目的：评价影像学检查在耳蜗植入术中的价值。方法：37例感音性神经性聋患者术前常规行颞骨HRCT及MRI检查，术后行改良斯氏位X线拍片，其中5例术后行CT复查。结果：CT显示2例Mondini畸形（4耳），2例前庭导水管扩张（4耳），1例迷路骨化（1耳），1例内听道狭窄（2耳）。MRI显示Mondini畸形3例（6耳），前庭导水管扩张2例（4耳），1例并内淋巴囊扩张（2耳），2例迷路纤维化（2耳）。术后改良斯氏位X线拍片显示植入电极形态、位置良好。CT显示1例电极滑脱。结论：CT及MRI对耳蜗植入术术前评估具有重要价值，改良斯氏位X线拍片结合CT对术后评估更有意义。     

Cochlear otosclerosis (otospongiosis): CT analysis with audiometric correlation

Ninety patients who had suspected or confirmed fenestral or cochlear otosclerosis underwent CT examination. Foci of demineralization in the otic capsule were discovered in 20 ears (12 patients). Audiometric studies of the 12 patients revealed sensorineural hearing loss (SNHL) with distinct correlation of CT findings with progressivity and with involvement of the frequency level subtended by the specific area of the cochlea involved. Foci of abnormal increased density, presumably representing the healed phase of this disorder, were found less frequently than expected. There was a predilection for the basilar turn. All patients had static SNHL in the higher frequencies. The healed phase of this disorder is probably not consistently diagnosable with CT.     

Fenestration surgery for otosclerosis: CT findings of an old surgical procedure

Numerous attempts to deal surgically with otosclerosis were made before the current method of stapedectomy with stapes prosthesis was established. We report a case with unique CT findings of a patient who underwent fenestration surgery for otosclerosis in the early 1940s. Recognition of this old surgical procedure on the imaging scans may avoid misdiagnosis of labyrinthine fistulae or middle and inner ear malformations.     

蜗神经孔发育不良的CT表现

目的探讨蜗神经孔发育不良的多层螺旋CT表现。方法观察了50例100耳无中内耳疾患的正常人及9例10耳蜗神经孔发育不良患者蜗神经孔的CT特征，并在轴面图像上测量了蜗神经孔的横径值。结果正常组50例100耳均见筛孔区基底部骨性裂隙显示，蜗神经孔横径测量值为（2．32±0．25）mm。异常组9例10耳均表现为蜗神经孔狭窄，8耳筛孔区基底部骨性裂隙未显示；2耳筛孔区基底部骨性裂隙存在。合并内听道狭窄4例，前庭与水平半规管异常1例。异常组蜗神经孔经线测量结果：蜗神经孔横径最大1．5mm，最小0．9mm。结论蜗神经孔发育不良的典型CT表现为蜗神经孔狭窄，筛孔区基底部骨性裂隙消失。蜗神经孔发育不良可能是耳蜗发育不良的一种亚型。