Congenital malformations of the inner ear and the vestibulocochlear nerve in children with sensorineural hearing loss: evaluation with CT and MRI

PURPOSE: The purpose of this work was to study the diagnostic value of CT and MRI in children with sensorineural hearing loss and to analyze anatomic abnormalities of the inner ear and the vestibulocochlear nerve in this patient group. METHOD: We evaluated 42 inner ears in 21 children with congenital deafness who had congenital inner ear malformations and who were candidates for cochlear implants. All patients were studied with high resolution MR and helical CT examinations. The MR study included a T2-weighted 3D fast SE sequence. We describe and tabulate the anatomic abnormalities. Special attention was given to abnormalities of the vestibulocochlear nerve. The field of view in the plane according to the length axis of the internal auditory canal (IAC) was 4 cm. Additional continuous parasagittal reformations perpendicular to the length axis of the IAC were studied with a field of view of 3 cm. RESULTS: CT and MRI allowed accurate identification of malformations of the inner ear in children with congenital deafness. We identified 99 malformations, with a majority of patients demonstrating multiple abnormalities. Common imaging findings were Mondini abnormality and Mondini variants (12/42) and fusion of the lateral or superior semicircular canal with the vestibule (12/42). MRI demonstrated in 9 of 21 patients a rudimentary or absent vestibulocochlear nerve in the auditory canal. CONCLUSION: CT and MRI are important modalities to analyze the inner ear in children who are candidates for cochlear implants. MRI with an extremely small field of view should be used to study possible abnormalities of the vestibulocochlear nerves. This may alter clinical care and allow cochlear implant placement in patients whose electrodiagnostic studies suggest that the implant should not be performed. The detailed analysis of abnormalities of the inner ear might establish prognostic factors.     

Review of congenital inner ear abnormalities on CT temporal bone

The aetiology of profound hearing loss in children is complex and multifactorial. Congenital inner ear abnormality is a major cause of hearing loss in children. CT temporal bone imaging is the modality of choice in the investigation of hearing loss. Recognising the congenital abnormalities of the inner ear guides the clinician's management of the condition. This pictorial essay illustrates the congenital abnormalities of the inner ear on high resolution CT temporal bone images and correlation with developmental arrest during embryology.     

MR内耳水成像在儿童人工耳蜗植入术前评估中的价值

目的：探讨MR内耳水成像在儿童人工耳蜗植入术前评估中的临床应用价值。方法使用Siemens Avanto 1．5 T磁共振扫描仪对24例听觉障碍拟行人工耳蜗植入术的患儿进行扫描,采集内耳所在区域内的水信号,并送后处理工作站进行图像后处理。最后分析其影像学表现及特征。结果24例患者中内耳形态正常18例,耳蜗发育畸形伴前庭导水管扩张1例,单纯前庭导水管扩张3例,半规管异常1例,Mondini畸形1例。结论 M R内耳水成像技术能清晰显示内耳膜迷路以及内听道精细解剖结构,对于内耳病变的诊断及人工耳蜗植入术的术前评估提供重要信息。     

Virtual endoscopy of the inner ear and the auditory canal

To assess the role of virtual endoscopy (VE) in the examination of intracisternal structures and of the inner ear, we studied the anatomy of the labyrinth and internal auditory canal using the original CT slices and VE on the unaffected side in three female and three male patients, age range 3–46 years, with contralateral retrocochlear hearing loss. We also examined seven patients with different pathological findings. VE was performed using an advanced postprocessing program with high- resolution 3D data sets of CT (1–1.5 mm thickness, pitch 1.25) and MRI-CISS-3D (constructive interference in steady state) images of the basal cisterns (1.5 T, slice thickness 0.7–1 mm). VE provides an endoscopic-like view from a given point within the basal cisterns of vessels and nerves (on MRI) or of the structures of the inner ear (on CT). The complex anatomy and pathological changes in the inner ear can be faithfully shown. The main advantage is not basic diagnostic information but demonstration of topographically complex situations, such as the canalicular system of the inner ear, for discussion, preoperative planning and teaching. Received: 12 July 1999 Accepted: 3 September 1999     

CT and MRI of the middle ear

Summary High-resolution computed tomography (HRCT) provides excellent contrast between osseous structures, air and soft tissue in conjunction with high spatial resolution. Therefore, thin-section HRCT with bone window setting is the method of choice for the examination of the middle ear structures. The indications are acute and chronic inflammatory changes, cholesteatoma and tumor, the “postoperative middle ear”, and malformations. In most cases, HRCT enables differentiation between inflammatory changes, cholesteatoma, and tumor. The excellent depiction of subtle osseous details enables the identification of erosions of the ossicles or of the bony walls of the mastoid cells, of osseous defects of the tegmen, of the bony labyrinth, and of the tympanic course of the facial canal. In addition, HRCT enables excellent depiction of reconstructions of the ossicles or prosthesis of the ossicles. Although HRCT is the first method of choice, magnetic resonance imaging (MRI) may provide additional information and lead to a more accurate diagnosis in some cases. This is explained by the excellent soft tissue contrast provided by MRI. In addition, MRI offers the possibility of using various pulse sequences and the administration of IV contrast material. Therefore, MRI may allow the differentiation between inflammatory changes, cholesteatoma, and tumor in those cases in which accurate diagnosis cannot be made by HRCT. The differentiation between a meningocele or meningoencephalocele and other entities such as tumors or cholesteatoma can be established by MRI. Furthermore, MRI can accurately depict cases of labyrinthitis or of neuritis of the facial nerve or of intracranial disease caused by middle ear processes, while this is not always possible by HRCT. In summary, HRCT of the middle ear is the method of choice, but MRI may provide supplementary information in those cases in which accurate diagnosis cannot be established by HRCT.      

直肠癌MRI术前评估价值与术后病理对比研究

目的 探讨MRI对直肠癌术前评估的价值。方法 选取84例行外科手术治疗的直肠癌患者的MRI、病理、临床资料。用卡方检验评价MRI对诊断肿瘤T分期、N分期、环周切缘（CRM）受累情况、壁外血管浸润的准确性,用配对t检验评估MRI分析病灶与齿状线位置关系的准确性。结果 MRI可较准确地评估对诊断肿瘤T分期、N分期、环周切缘受累情况、壁外血管浸润状态（P<0.01）,可大致评估低位直肠癌病灶距齿状线距离（P> 0.05）。结论 MRI可较准确地评估对诊断肿瘤T分期、N分期、环周切缘受累情况、壁外血管浸润状态。受测量习惯、测量误差、肠管走行等因素的影响,MRI可大致评估病灶距齿状线距离,且测量误差在外科可接受范围内。MRI为临床手术选择及术前评估提供了有价值的影像学依据。     

Role and effectiveness of cardiovascular magnetic resonance in the diagnosis, preoperative evaluation and follow-up of patients with congenital heart diseases

The substantial advances in the medical and surgical treatment of congenital heart diseases have dramatically improved patients' life expectancy, as well as increased the number of those needing lifelong monitoring to identify complications and residual defects. Magnetic resonance imaging (MRI) is an ideal imaging modality for the follow-up of these young patients owing to its noninvasiveness, high reproducibility and morphological and functional accuracy. This paper describes the most appropriate MRI techniques and sequences for the study of cardiovascular heart diseases on the basis of an analysis of MRI studies carried out between January 2003 and June 2006 on 274 patients affected by all of the main congenital cardiovascular malformations, as well as a review of the literature. The advantages of MRI with respect to other imaging techniques, the problems encountered and the main clinical applications and indications of MRI, with special reference to the most common disease entities, are then discussed to define the role, the utility and the future perspectives of this imaging technique in the study of congenital heart diseases.     

High-resolution multidetector CT in the preoperative evaluation of patients with renal cell carcinoma

OBJECTIVE: The purpose of our study was to evaluate the accuracy of multidetector CT (MDCT) using a high-resolution protocol in the preoperative assessment of patients with renal cell carcinoma who are possible candidates for nephron-sparing surgery. MATERIALS AND METHODS: Forty patients with suspected renal cell carcinoma underwent MDCT. Contrast-enhanced acquisitions were obtained during arterial, nephrographic, and urographic phases using a thin-slice protocol. One-millimeter-thick source images were evaluated by two observers on a dedicated workstation for the identification and characterization of the tumor, presence of a pseudocapsule or invasion of perirenal fat, involvement of adrenal glands or surrounding tissues, presence of satellite lesions within Gerota's fascia, infiltration of renal vein and inferior vena cava, involvement of lymph nodes, and presence of distant metastases. Imaging findings were compared with surgical specimens using criteria from the Robson and TNM classification systems. RESULTS: The presence and size of all lesions were correctly shown in all patients. In evaluating Robson stage I of renal cell carcinoma, we were able to diagnose fat infiltration on 1-mm scans with 96% sensitivity, 93% specificity, and 95% accuracy; the positive and negative predictive values were, respectively, 100% and 93%. One hundred percent accuracy was achieved in staging high-grade lesions. CONCLUSION: High-resolution MDCT is accurate in the preoperative evaluation of patients with renal cell carcinoma.     

Imaging of congenital anomalies and acquired lesions of the inner ear

Imaging of the temporal bone is under continous developement. In the recent decades the technical advances of magnetic resonance imaging and computed tomography have contributed to improved imaging quality in assessment of the temporal bone. Dedicated imaging protocols have been developed and are routinely employed in most institutions. However, imaging interpretation remains challenging, since the temporal bone is an anatomically highly complex region and most diseases of the inner ear occur with low incidence, so that even radiologists experienced in the field may be confronted with such entities for the first time. The current review gives an overview about symptoms and imaging appearance of malformations and acquired lesion of the inner ear.     

Role of us in the preoperative evaluation of patients with anterior shoulder instability

PURPOSE: To assess the value of ultrasonography (US) in the preoperative evaluation of patients with anterior shoulder instability. MATERIALS AND METHODS: Twenty-two patients with one-sided anterior shoulder instability were examined with US by using three dynamic scanning approaches: two frontal and one axillary. The anterior labrum, the anterior ligamental-capsular complex, and the presence of humeral head and glenoid rim fractures were evaluated. Arthroscopy or arthrotomy was subsequently performed in all patients and was considered the standard. RESULTS: US correctly depicted the presence (n = 20) or absence (n = 1) of humeral head fractures and the presence (n = 10) or absence (n = 9) of glenoid rim fractures. All 22 patients had anterior labral tears; 21 tears were correctly depicted with US. The labral tear was seen as a hypoechoic zone larger than 2 mm (n = 15), labral movement (n = 10), a degenerated labrum (n = 6), or a vacuum phenomenon (n = 3). The anterior ligamental-capsular complex was correctly evaluated in 14 patients. The use of multiple approaches helped to prevent misinterpretation, but there were no substantial differences among the approaches in the depiction of the anterior shoulder structures. CONCLUSION: The high accuracy in the depiction of labral tears and associated fractures indicates that US can provide useful preoperative information in patients with anterior shoulder instability.     

Role of SPECT/CT in the preoperative assessment of hyperparathyroid patients

PURPOSE: Our purpose was to assess the clinical value and additional benefit of fusion single-photon computed tomography (SPECT) and computed tomography (CT) images in locating the parathyroids in a selected group of patients affected by primary (PHP) and secondary hyperparathyroidism (SHP). MATERIALS AND METHODS: Sixteen patients (11 women and five men; age range 35-80 years) with severe hyperparathyroidism (HP) (ten PHP, six SHP) were studied by ultrasound (US), and, after i.v. injection of 370 MBq of 99mTc-sestamibi, by planar parathyroid scintigraphy, SPECT and SPECT/CT using a dual-detector scintillation camera GE Infinia Hawkeye. All patients underwent parathyroidectomy. RESULTS: US findings were inconclusive in 12/16 patients affected by multinodular goitre, and two probable eutopic parathyroid glands were identified. "Double phase" parathyroid scintigraphy identified 14 probable parathyroid glands, SPECT 23 (14 ectopic and nine eutopic) and SPECT/CT confirmed all 23 probable parathyroid lesions, offering more precise localisation and an evident improvement in diagnostic accuracy. Sixteen of these foci of increased uptake were hyperplastic parathyroid glands, six were adenomas, one was a parathyroid carcinoma and one was a thyroid follicular carcinoma. Surgical detection of the 23 sestamibi-positive lesions was correctly matched with 100% of SPECT/CT images and 61% of SPECT data alone. Hybrid imaging thus provided additional data in 39% of lesions, and in three patients with retrotracheal glands, it modified the surgical approach. CONCLUSIONS: We believe 99mTc-sestamibi SPECT/CT to be a more reliable presurgical method to study a patient subgroup affected by PHP or SHP in whom conventional US and other scintigraphic methods have failed for intrinsic reasons due to the concomitant presence of multinodular goitre or ectopic parathyroid gland. The additional practical benefit derived from this methodology was evident. In fact, anatomical information provided by CT enables precise localisation of the functional abnormalities highlighted by SPECT, and both are essential to a correct surgical approach.     

3D-FIESTA序列在内耳及内听道MRI中的应用探讨

目的:探讨3D-FIESTA序列内耳及内听道成像技术及其临床应用价值.方法:用GE signa 3.0T超导型磁共振对25例共50耳应用3D-FIESTA序列做颞骨三维容积扫描,采用多平面重组(MPR)、最大强度投影(MIP)及仿真内窥镜(VE)行后处理,观察3D-FIESTA序列对内耳及内听道内各解剖结构的显示.结果:3D-FIESTA序列扫描结合MPR、MIP和VE重组对内耳迷路及内听道内神经及血管显示清晰,能够清晰显示两者之间的关系,MPR和VE重组对神经的显示优于MIP重组,MIP对半规管显示与双斜面MPR并无明显差别,VE和斜矢状面对于内听道内各神经孔的位置关系具有重要意义.结论:3D-FIESTA序列对内耳及内听道的结构显示清晰,具有较高的临床应用价值.     

内耳膜迷路MR成像技术的初步应用

目的 探讨磁共振内耳膜迷路成像的技术及临床价值。方法利用西门子公司1．0T MAGNETOM IMPACT超导型MR扫描机(软件版本VB33D),采用梯度回波序列中的三维镜像稳态快速成像序列(3D-PSIF),对1例疑有内耳疾病患者和20例健康志愿者作MR内耳膜迷路成像,所有患者均先行常规MR扫描,并行最大信号强度投影(MIP)及多平面重建(MPR)后处理。结果10例先天性感音性耳聋患者中,包括功能性(毛细胞)及器质性(耳硬化)等畸形;20例健康志愿者中,17例均能满意显示双侧内耳膜迷路及内听道的精细解剖结构,2例显示不佳,1例无法显示。结论内耳膜迷路MR成像为一种有效且无创的影像检查方法,它不仅可以显示内耳膜迷路、内听道的立体解剖结构,而且能够清晰显示其通畅程度,这样就可以帮助临床耳科医生分析病情,同时为内耳外科手术,尤其是电子耳蜗植入等手术提供重要信息,并在一定程度上可排除一些绝对或相对禁忌症,大大提高手术的准确性。     

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.     

MR of the inner ear in patients with Cogan syndrome.

PURPOSETo determine whether the bony and soft-tissue obliterations of the intralabyrinthine fluid spaces reported in pathologic studies of patients with Cogan syndrome can be detected with MR or CT.METHODSThe inner ears of six patients with Cogan syndrome were studied. High-resolution CT was performed in five patients; all six patients were studied with MR, including T1-weighted spin-echo images with and without gadolinium administration, T2-weighted spin-echo images, and three-dimensional Fourier transform constructive interference in steady state images.RESULTSIn two patients, small calcified obliterations were detected on CT but the three-dimensional Fourier transform constructive interference in steady state images revealed more extensive soft-tissue obliteration in five of the six patients. High signal inside the membranous labyrinth on precontrast T1-weighted images and contrast enhancement inside the membranous labyrinth on the postcontrast T1-weighted images were seen in one patient.CONCLUSIONSThe study showed that calcific obliteration and soft-tissue obliteration of the intralabyrinthine fluid spaces in patients with Cogan syndrome can be demonstrated radiologically and that soft-tissue obliteration is more frequent than calcified obliteration. MR detected the intralabyrinthine disease far more frequently than did CT. The three-dimensional Fourier transform constructive interference in steady state sequence proved to be the most sensitive MR sequence. Hyperintensity inside the membranous labyrinth on the precontrast T1-weighted images and enhancement on the contrast-enhanced T1 images were less frequent and probably represent leakage through the abnormal labyrinthine membrane from active disease.     

Complicated cholesteatomas: CT findings in inner ear complications of middle ear cholesteatomas

Patients with facial palsy and middle ear disease, which may be chronic but clinically occult, may have a cholesteatoma with extension medially along the facial canal. In two patients, axial computed tomographic (CT) scans demonstrated involvement of the medial petrous bone. Patients with vertigo and chronic middle ear disease may have a cholesteatoma with a "fistula" between the middle and inner ears. Although the fistula usually involves the lateral semicircular canal, the cholesteatoma may pass through the oval window. In two patients, coronal CT scans showed extension to the oval window in one and through it in the other.     

Usefulness of CT colonography in the preoperative evaluation of patients with distal occlusive colorectal carcinoma

PURPOSE: To evaluate the role of preoperative virtual colonoscopy to study the proximal colon in patients with distal occlusive carcinomas, diagnosed by conventional colonoscopy. MATERIAL AND METHODS: We examined 19 patients aged 46 to 83 years (13 men and 6 women) with distal occlusive colorectal carcinomas diagnosed by conventional colonoscopy, who were preoperatively studied with virtual colonoscopy. Patients with acute bowel obstruction were excluded. Results were compared with the findings of preoperative conventional colonoscopy and barium enema examination, intraoperative colon palpation, histopathologic outcome, postoperative conventional colonoscopy and barium enema examination. RESULTS: Virtual colonoscopy identified all 19 distal occlusive colon carcinomas and 22 synchronous lesions, 2 cancers (prevalence 10,6%) and 20 polyps (prevalence 68,4%). Both synchronous cancers were confirmed intraoperatively by direct palpation. Postoperative conventional colonoscopy, which was performed in 18 patients, confirmed the presence of 15 polyps in 12 patients. Three subcentimeter polyps were removed during conventional colonoscopy and were missed at virtual colonoscopy. Two polyps shown by virtual colonoscopy were not found at conventional colonoscopy. Postoperative barium enema was performed in three patients and confirmed three polyps identified at virtual colonoscopy. Preoperative barium enema was performed in five patients and failed to adequately demonstrate the proximal colon. Virtual colonoscopy showed a sensitivity of 87% and a specificity of 75%. CONCLUSIONS: Virtual CT colonoscopy can be considered an important diagnostic technique to evaluate preoperatively the proximal colon in patients with distal occlusive carcinomas,as it gives better results than barium enema or conventional colonoscopy, as well as being well tolerated and less invasive.     

MRI and CT of adenomatous tumours of the middle ear

We report three adenomatous middle-ear tumours, an adenoma, an adenocarcinoma and a semimalignant adenomatous tumour, with special attention to CT and MRI findings. In all cases we found small intratympanic masses in which the ossicles were embedded. All showed contrast enhancement and similar signal intensity as brain tissue on T1- and T2-weighted images. The biological nature of the tumours was not reflected by the imaging or operative findings. Received: 10 March 2000/Accepted: 17 May 2000     

Intracranial aspergillosis involving the internal auditory canal and inner ear in an immunocompetent patient

We report the MR imaging findings in a case of intracranial aspergillosis involving the internal auditory canal (IAC) and inner ear in an immunocompetent patient. The presence of rim enhancement of the vestibulocochlear nerve, abnormal signal intensity involving the labyrinth, and adjacent meningeal enhancement might help clinicians to make a correct diagnosis in patients with a mass in the IAC and previous history of ear surgery.