探讨MR内耳水成像技术的应用

目的回顾性分析35例怀疑内耳病变患者的内耳MRI水成像特点,探讨磁共振内耳水成像技术的临床应用价值。方法利用西门子公司1.5T超导型扫描机,采用三维快速自旋回波序列(3D-TSE),对35例疑有内耳疾病患者作内耳水成像检查,所有患者均先行常规MR扫描,并行最大信号强度投影MIP及MPR后处理。结果均能满意显示两侧内耳的解剖结构:前庭、耳蜗、半规管、内听道。结论内耳水成像是一种有效且无创的显示双侧内耳膜迷路及内听道精细解剖结构的检查方法,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。     

3T MRI在内耳诊断中的应用

目的:探讨3T磁共振内耳水成像在内耳病变中的应用价值。方法:分析35例3TMRI内耳水成像影像资料。使用快速三维梯度回波序列(3D-FIESTA),采集内耳所在区域内水信号,送图像工作站进行图像三维重建。结果:3D-FIESTA能满意显示内听道及内耳膜迷路的精细解剖结构,最大强度投影(MIP)重建可获得内耳膜迷路立体图像,多平面容积重建技术(MPVR)能三维立体观察膜迷路结构的解剖关系。结论:MR膜迷路成像可为内耳结构提供可靠的影像学解剖依据,具有一定的临床应用价值。     

内听道及内耳结构的正常MRI表现

目的:探讨正常内听道及内耳解剖结构的正常MRI表现.材料和方法:选择40例(80耳)无耳部病变患者,使用GE 1.5T超导型MR成像仪,头部环形线圈或颞下颌线圈FSE序列薄层扫描,用最大强度投影术(MIP)对兴趣区进行多轴位重建,多视角多平面旋转观察内听道及内耳膜迷路结构.结果:全部病例均能满意显示两侧内听道及内耳膜迷路结构,半规管、椭圆囊、球囊、耳蜗管及内听道呈高信号,面听神经呈低信号,半规管直径约1.17～1.40mm,耳蜗高度4.7～4.8mm,蜗底直径7.00～7.5mm,内听道宽度5.5mm左右,面神经、前庭上神经、耳蜗神经、前庭下神经截面直径约0.61～1.1mm.结论:MR水成像技术能立体直观的显示内听道及内耳膜迷路的细微结构,是一个值得重视的成像方法.     

螺旋CT三维透明重建对内耳解剖结构的观察

目的　评价螺旋三维RaySum重建技术对内耳解剖结构的显示能力。资料与方法　对 2 0位健康志愿者两侧内耳进行三维RaySum重建 ,沿X轴从 0°开始自前向后每 30°旋转 1次 ,再沿Y轴从 0°开始自上而下每 30°旋转1次 ,观察内耳骨迷路和内听道的解剖结构。结果　内耳三维RaySum重建清楚地显示了椭圆囊、球囊、膜半规管和蜗管等内耳膜迷路的解剖结构。该方法从前向后和从上向下各 12个位置的内耳膜迷路各结构的解剖清晰可见。结论　内耳三维RaySum重建成像能立体而直观地显示内耳膜迷路的解剖结构。     

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.     

MR三维稳态进动快速成像序列在内耳扫描中的初步应用研究

目的探讨三维稳态进动快速成像（3D—FIESTA）列在内耳及内听道扫描中的技术及临床应用。资料与方法使用GE Signa HD MR1．5T超导磁共振仪，3D-FIESTA序列，对43名健康志愿者及1例单侧先天性耳聋者行内耳扫描，并行最大强度投影（MIP）、多平面重组（MPR）及表面容积重组（VR）后处理。结果44例共88个部位均能良好地显示内耳及内听道的形态结构。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。     

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。     

3D-FIESTA序列在内耳及内听道磁共振检查上的应用

目的:探讨3I-FIESTA序列高分辨率影像在内听道成像技术上的应用.方法:对86例共172只内耳应用3D-FIESTA序列做颞骨的三维容积扫描,采用最大强度投影(MIP)进行后处理,观察由3D-FIESTA序列获得的高分辨率影像对内耳及内听道解剖结构及病变的显示.结果:3D-FIESTA序列扫描及MIP重建对内耳耳蜗、迷路及内听道内神经及血管显示清晰,能够清晰显示病变与周围结构的关系.结论:3D-FIESTA序列可以提供非常好的分辨率,对内耳及内听道充满水的结构及病变显示清晰,在内耳、内耳道和桥脑小脑角区具有较高的临床应用价值.     

脑池段面、前庭蜗神经及其病变的磁共振成像研究

目的:通过探讨3D-CISS磁共振成像序列对脑池段面、前庭蜗神经及内耳结构显示的价值,为临床耳科病例选择最优检查方式.方法:对48位正常体检者和8位伴有面神经或前庭蜗神经异常的病人行3D-CISS MR成像,在MPR、MIP图像上最大程度地显示面、前庭蜗神经及内耳膜迷路.结果:48位正常体检者的脑池段面神经、前庭蜗神经及其分支、内耳膜迷路显示率均为100%;8例面神经或前庭蜗神经异常患者均有明显异常MRI表现:其中1例显示双侧听神经瘤,1例显示右侧桥小脑角区胆脂瘤包绕面听神经,1例为右侧脑池内蛛网膜囊肿压迫前庭蜗神经,1例为面、前庭蜗神经及相邻血管粘连,1例获得性感音神经性聋患者显示蜗神经萎缩变细,3例显示动脉血管压迫面听神经.结论:3D-CISS能够清晰显示面神经、耳蜗前庭神经及内耳膜迷路的精细结构,对于内耳异常的发现具有重要价值.     

3D-CISS序列与3D-TSE序列对Ⅶ～Ⅸ对颅神经成像质量的比较

目的:通过3D-CISS序列与3D-TSE序列对Ⅶ~Ⅸ对颅神经成像质量的比较,确定3D-CISS序列对脑脊液包绕的Ⅶ~Ⅸ对颅神经和淋巴液充盈的内耳迷路成像显示的优势。方法:应用3D-CISS序列与3D-TSE序列分别对第Ⅶ~Ⅸ对颅神经及内耳迷路进行MR成像,在MPR图像及MIP重建图像上最大程度的显示颅神经及内耳迷路,并对两种序列的成像质量进行统计比较。结果:面神经的脑池段、内听道近段及远段、前庭蜗神经的脑池段及内听道近段、耳蜗、前庭及半规管在两个序列中全部以100%的几率显示;蜗神经、前庭上神经、前庭下神经及舌咽神经在3D-CISS序列、3D-TSE序列的显示几率依次分别为:100%、81.2%;100%、51.4%;100%、42.0%;100%、57.1%;面神经、前庭蜗神经的内听道段、内耳迷路、舌咽神经的3D-CISS序列成像质量明显优于3D-TSE序列成像;面神经、前庭蜗神经的脑池段3D-CISS序列成像质量略优于3D-TSE序列。结论:对于被脑脊液包绕的颅神经和淋巴液充盈的内耳迷路的成像,3D-CISS序列是最佳的选择。     

内耳系统磁共振三维成像及仿真内镜研究

目的 探讨磁共振仿真内镜(MRVE)显示内耳系统的可行性及其正常解剖学表现。资料与方法 对53例健康受试者106只内耳行3D FASE重T2WI横断面成像扫描。原始图像传至在网工作站进行图像后处理。在工作站行透视容积再现(PVR)成像，利用仿真内镜(VE)对内耳进行腔内结构观察。结果 MRVE可详细、明确显示内耳腔内的解剖结构，而且检查过程可以制成录像反复、多方位观察，是一种方便、易行、灵活的无创性检查手段。结论 MRVE可用于内耳膜迷路的腔内结构研究，为MRI发现内耳疾病打下了坚实的基础。     

Temporal bone region: high-resolution MR imaging using surface coils

Specially designed surface coils for the region of the temporal bone enable high-resolution magnetic resonance (MR) imaging of the structures of the inner ear. Eight healthy volunteers and 21 patients (six with cholesteatomas, five with acoustic neuromas, five with glomus tumors, and five with mastoiditis) were examined using a 0.5-T MR imager. The demarcation of tumor extent with MR imaging was better than with computed tomography because of improved soft-tissue contrast and because the surrounding bony tissue did not generate any signal. High-resolution MR imaging is particularly useful for small acoustic neuromas because of its higher specificity compared with gas cisternography.     

Fast spin-echo high-resolution MR imaging of the inner ear.

Advances in MR imaging continue to improve our ability to evaluate temporal bone anatomy and disease. CT remains the procedure of choice for fine-detail imaging of bone structures such as ossicular anatomy, but it is not the ideal imaging technique for soft-tissue structures (e.g., the membranous labyrinth and neural structures). Conventional spin-echo MR techniques used to image these structures cannot yield excellent contrast and spatial resolution in clinically acceptable time frames. Conventional spin-echo T1-weighted images lack tissue contrast between fluid (e.g., CSF, endolymph, perilymph), neural tissue, otic capsule septa, and surrounding temporal bone. Conventional T2-weighted imaging of the inner ear is needed to reveal the natural contrast between fluid, neural structures, and bone; unfortunately, the use of conventional T2-weighted images is limited by time constraints when large-matrix, thin-section techniques with more than one excitation are used. Fast spin-echo imaging is a recently developed technique that can provide T2-weighted, thin-section (2-mm) high-resolution images with excellent contrast in a fraction of the time needed for conventional spin-echo techniques. This speed advantage allows us to obtain high-resolution images in clinically acceptable time frames. Images produced by this technique are a useful addition, in conjunction with routine T1- and T2-weighted spin-echo images, in the diagnosis of disorders of the inner ear.     

内耳结构及病变的MRI技术应用研究

目的：探讨内耳膜迷路、面神经及位听神经的MRI技术方法及其临床应用价值。方法：对35例可疑内耳病变的急者采用平衡式三维梯度回波(B—TFE)尽三维快速自旋回波T2W序列(T2／3D／TSE)、轴位及斜失状位扫描，最大信号强度投影(MIP)、多平面投影(MPR)法图像重建。结果：所有内耳膜迷路、面神经及位听神经结构均得到了良好显示。其中26例正常，9例异常。结论：MRIB—TFE和T2／3D／TSE扫描序列及MIP、MPR重建技术，可很好地显示内耳结构及其微小病变，对内耳病变的诊断具有较高的临床应用价值。     

低场磁共振CISS序列内耳水成像相关参数的控制

目的:探讨低场磁共振CISS序列内耳水成像相关参数的选择,以提高其临床应用水平。方法:对10例正常成人的10对内耳分别使用常规CISS序列、参数调整后的CISS序列进行配对扫描,之后对图片质量进行评分形成配对数据资料。结果:参数调整后的CISS序列的内耳水成像图像质量明显优于常规CISS序列。结论:在低场磁共振上对CISS序列相关参数的选择优化后,能明显提高内耳水成像图像质量,从而提高其临床应用水平,适合基层医院使用。     

MR elastography of breast cancer: preliminary results

OBJECTIVE: Motivated by the long-recognized value of palpation in detecting breast cancer, we tested the feasibility of a technique for quantitatively evaluating the mechanical properties of breast tissues on the basis of direct MR imaging visualization of acoustic waves. SUBJECTS AND METHODS: The prototypic elasticity imaging technique consists of a device for generating acoustic shear waves in tissue, an MR imaging-based method for imaging the propagation of these waves, and an algorithm for processing the wave images to generate quantitative images depicting tissue stiffness. After tests with tissue-simulating phantom materials and breast cancer specimens, we used the prototypic breast MR elastography technique to image six healthy women and six patients with known breast cancer. RESULTS: Acoustic shear waves were clearly visualized in phantoms, breast cancer specimens, healthy volunteers, and patients with breast cancer. The elastograms of the tumor specimens showed focal areas of high shear stiffness. MR elastograms of healthy volunteers revealed moderately heterogeneous mechanical properties, with the shear stiffness of fibroglandular tissue measuring slightly higher than that of adipose tissue. The elastograms of patients with breast cancer showed focal areas of high shear stiffness corresponding to the locations of the known tumors. The mean shear stiffness of breast carcinoma was 418% higher than the mean value of surrounding breast tissues. CONCLUSION: The results confirm the hypothesis that the prototypic breast MR elastographic technique can quantitatively depict the elastic properties of breast tissues in vivo and reveal high shear elasticity in known breast tumors. Further research is needed to evaluate the potential applications of MR elastography, such as detecting breast carcinoma and characterizing suspicious breast lesions.     

Visualization of inner ear dysplasias in patients with sensorineural hearing loss : High-resolution MR imaging and volume-rendered reconstructions

Purpose: We evaluated a data acquisition and post-processing protocol for inner ear (IE) assessment by MR imaging in patients, suffering from various labyrinth malformations.Material and Methods: MR IE studies of 158 consecutive patients (316 IEs) suffering from sensorineural hearing loss without evidence of an acoustic neurinoma were reviewed for pathologies of the IE and internal acoustic meatus. High-resolution MR data of all abnormal IE studies (n=45) were post-processed to previously standardized 3D volume rendered (VR) reconstructions.Results: In 9 patients (5.7%) the following IE dysplasias were detected: malformation of the cochlea (6 IEs), vestibulum (4 IEs), semicircular canals (12 IEs) and vestibular aqueduct/endolymphatic sac (10 IEs). One patient showed evidence of an aplasia of the vestibulocochlear nerve. In 4 patients multiple IE dysplasias were encountered. Comprehensive 3D visualization of all labyrinthine dysplasias was achieved by the use of two VR reconstructions. The overall time for bilateral IE assessment amounted to 30-35 min.Conclusion: The imaging protocol allows for rapid and comprehensive visualization of various IE dysplasias, based on a limited number of VR reconstructions.     

Detection of acoustic schwannoma: use of constructive interference in the steady state three-dimensional MR.

PURPOSETo compare constructive interference in the steady state (CISS) three-dimensional Fourier transform (3DFT) MR imaging with contrast-enhanced T1-weighted spin-echo MR imaging for accuracy in detecting acoustic schwannoma.METHODSOne hundred twenty-five consecutive patients with possible acoustic schwannoma were examined. The accuracy of CISS-3DFT MR imaging in detecting abnormalities of the cerebellopontine angle, the internal auditory canal, and the inner ear was compared with T1-weighted contrast-enhanced spin-echo MR imaging by independent assessment of both image sets by two observers.RESULTSThe postcontrast T1-weighted MR images revealed 18 cases of unilateral disease of the cerebellopontine angle and/or the internal auditory canal and no case of an abnormal bilateral cerebellopontine angle and/or internal auditory canal. Twelve cases were pathologically proved acoustic schwannomas. One meningioma of the cerebellopontine angle and one metastatic ependymoma to the cerebellopontine angle and the internal auditory canal was encountered. The four remaining cases had a provisional diagnosis of acoustic schwannoma and were scheduled for follow-up imaging and clinical review. Analysis of whether contrast material would have been administered to the appropriate patients (ie, those with disease of the cerebellopontine angle and/or internal auditory canal) according to CISS MR imaging findings revealed a sensitivity of 100% and a specificity of 98% for observer 1 and a sensitivity of 94% and a specificity of 94% for observer 2.CONCLUSIONCISS-3DFT MR imaging, in this patient population, provided high sensitivity and specificity in detecting lesions of the cerebellopontine angle and internal auditory canal; however, further experience is required before a definitive statement regarding the suitability of this technique as a screening procedure can be made. When contrast material cannot be administered, CISS MR imaging may be considered an adequate examination for the evaluation of possible acoustic schwannoma.