急腹症螺旋CT扫描技术

急腹症为临床常见病，实验室检查、常规X线以及超声诊断均有一定的局限性，螺旋CT拥有先进的动态对比和高分辨率的容积扫描，能提供快速准确的诊断。根据各类急腹症的特殊性，在对比剂的应用、注射速度、扫描时相、准直、螺距、重建间隔等技术参数方面进行了探讨，并评价其应用价值。     

低剂量螺旋CT扫描技术

降低受检者CT检查辐射剂量一直是业内关心的热点问题。本文从CT辐射剂量的表达方法,图像质量评价指标,影响辐射剂量的因素以及低剂量扫描方案的合理应用等方面,介绍了低剂量螺旋CT扫描技术的研究进展。     

中耳术后的临床CT分析

目的 探讨中耳术后CT检查的价值和手术效果.资料与方法 中耳术后21耳进行了CT检查,将其手术类型、临床听力和CT表现进行比较分析.结果 术后患者主观听力与术前相似者7耳,其中1耳为单纯病灶清除,1耳为人工金属镫骨脱出于外耳道,1耳为同种异体听骨链重建,乳突根治术后听骨链消失和部分听小骨残留各2耳.术后听力明显提高9耳,其中同种异体听骨链重建5耳,自体听骨链重建4耳.术后听力提高后又突然下降3耳,其中1耳为重建听小骨与鼓膜分开,1耳为重建听小骨与卵圆窗分开,1耳为锤镫关节脱位,再次手术后听力均明显提高.2耳因胆脂瘤术后面瘫,CT示面神经管鼓室段缺损,再次手术后面瘫症状逐渐消失,但听力与术前相似.结论 术后CT检查可明确中耳手术效果,听骨链重建手术有助于提高听力.     

低剂量螺旋CT扫描技术的临床应用

低剂量螺旋CT扫描技术,即能保证图像质量,又能降低患者在接受检查时的辐射水平。适当降低螺旋CT扫描剂量,特别是在成人胸部、鼻窦及儿童颅脑中的应用很有价值,值得推广。本文对低剂量螺旋CT扫描技术在临床的应用现状及进展加以综述。     

听骨链和迷路螺旋CT三维重建技术初步临床应用报告

目的探讨听骨链和迷路螺旋ＣＴ三维重建技术的临床应用和局限性。方法采用薄层螺旋扫描（层厚１．０ｍｍ）、小视野（ＦＯＶ＝５ｃｍ）、密集重建（间隔０．１ｍｍ）技术，对１４例正常和１５例中耳病变患者行听骨链和迷路三维重建成像，包括多平面重组（ＭＰＲ）、最小密度或最大密度投影（ＭｉｎＩＰ或ＭａｘＩＰ）和表面成像（ＳＳＤ）。结果１４例正常患者中对其中１３例听骨链及８例迷路进行三维重建，听骨链重建显示锤骨柄和砧骨长突平行共同指向蜗岬，砧镫关节呈“Ｌ”形影，迷路三维重建显示耳蜗和三个半规管。１３例中耳炎患者中９例胆脂瘤形成，显示听骨链不同程度的破坏，２例先天中耳畸形显示听骨链发育异常。结论螺旋ＣＴ三维重建技术有利于中耳畸形和其他耳部病变的诊断，但尚存在重建时间长、损失部分信息等缺点，有待进一步改善。     

螺旋CT双期增强扫描对胰腺癌的诊断价值探讨

目的：探讨螺旋CT双期增强扫描在胰腺癌诊断中的价值。方法：对50例胰腺癌患者行螺旋CT双期增强扫描，比较平扫及增强情况并对图像进行分析研究。结果：50例肿瘤位于胰头部34例，胰体部11例，胰尾部5例。平扫肿瘤呈等密度或略低密度。增强后呈相对低密度。结论：螺旋CT双期增强扫描是诊断胰腺癌的理想检查手段，对判断肿瘤侵犯血管程度和能否手术切除的敏感性具有重要诊断价值。     

听骨链及迷路的螺旋CT三维成像技术及其临床应用

本文介绍了听骨链及迷路的螺旋CT三维成像技术,对该技术在听骨链及迷路病变的术前诊断及术后随访的应用进展进行了详细阐述,分析了普通二维CT和三维CT间的互补性.     

颞骨平行枕眶线多层螺旋CT扫描法及其价值

目的:探讨以平行枕眶线扫描图像为基础的常规轴位和冠状位MPR图像是否能够取代直接轴位和冠状位图像。方法:三位医师分别观察50例颞骨CT扫描图像,分析直接常规轴位(25例)、冠状位(25例)CT扫描图像和其相应的常规轴位、冠状位MPR图像显示颞骨结构的差异。结果:所有观察者均认为直接常规轴位、冠状位CT扫描图像略优于相应的轴位、冠状位MPR图像。直接轴位、冠状位CT扫描图像和相应的轴位、冠状位MPR图像的质量差异较小。结论:以平行枕眶线扫描图像为基础的常规轴位和冠状位MPR图像可取代直接轴位和冠状位扫描图像。     

鼻窦低剂量螺旋CT扫描的可行性探讨

目的:探讨鼻窦低剂量CT扫描的可行性,评估其影像效果。方法:对40例受检者在行鼻窦常规剂量(200mA)CT扫描后,再行低剂量(30mA)CT扫描;由2名医师盲法评价图像,按正常图像、图像有少许伪影、图像有严重伪影的等级对每一幅图像进行质量评判,并进行统计学处理。结果:98%以上鼻窦低剂量CT图像可以满足诊断需要,与常规剂量CT图像相比无显著性差异(P>0.05)。结论:鼻窦低剂量CT扫描是切实可行的,正确应用可以有效地保护病人和保证图像质量。     

螺旋CT多期扫描技术对胰腺癌的诊断价值

目的：探讨螺旋CT多期扫描对胰腺癌的诊断价值。方法：搜集行SCT动脉期、胰腺期、肝脏期三期扫描的胰腺肿块75例，均经手术病理证实，其中胰腺癌53例，局限性胰腺炎22例，比较肿瘤与炎症在SCT增强扫描各期中的表现。结果：本组胰腺癌53例，其中胰头癌33例，胰颈癌4例、胰体癌14例，胰尾癌2例。局限性胰腺炎22例，头、颈、体、尾分别为17例、2例、2例、1例。增强扫描，动脉期胰腺癌低密度43例，等密度10例，胰腺炎低密度2例，等密度20例；胰腺期胰腺癌低密度51例，等密度2例，胰腺炎低密度1例，等密度21例；肝脏期胰腺癌低密度42例，等密度11例；胰腺炎22例均为等密度。结论：胰腺螺旋CT动脉期、胰腺期、肝脏期三期增强扫描在胰腺癌诊断中具有非常重要的临床价值。     

CT of the normal suspensory ligaments of the ossicles in the middle ear.

PURPOSETo establish the range of normal variation in the CT appearance of the middle ear ligaments and the stapedius tendon as an aid in detecting abnormal changes in these structures.METHODSCT scans of the temporal bone in 75 normal middle ears, obtained with 1-mm-thick sections, were reviewed by two observers, who rated the visibility of the structures of interest on a scale of 1 to 5.RESULTSThe anterior, superior, and lateral malleal ligaments and the medial and lateral parts of the posterior incudal ligament were seen in 68%, 46%, 95%, 26%, and 34% of the ears, respectively. The stapedius tendon was seen in 27% of the cases. When visible, the ligaments were judged to be complete in 90% to 100% of the ears and the stapedius tendon was complete in 65% of cases. Their width varied considerably. Interobserver variability was high for most observations.CONCLUSIONCT scans are more likely to show the malleal than the incudal ligaments. Although the interobserver agreement was statistically significant for most study parameters, the percentage of agreement above that expected by chance was low. When seen, the ligaments usually appeared complete. Understanding the normal range of appearance may help identify abnormalities of the ligaments and tendons of the middle ear.     

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.      

Heterotopic brain in the middle ear: CT findings

A soft tissue mass was found by CT in the mesotympanum of the left middle ear of a 4-year-old boy. This lesion was without radiologic or surgical evidence of associated bony defect or communication with the intracranial cavity. Pathological examination revealed heterotopic brain tissue. Although heterotopic brain tissue in the middle ear is rare, it should be considered in the differential diagnosis of soft tissue middle ear masses.     

Virtual CT endoscopy of ossicles in the middle ear.

The purpose of this study is to evaluate how virtual computed tomography (CT) endoscopy may help in assessing ossicles in the middle ear. Our series consisted of 96 ears of 68 consecutive patients with conducting hearing loss. All examinations were performed with a high-resolution spiral CT using axial and direct coronal planes of the temporal bone. Perspective virtual endoscopy was processed using the virtual endoscopic software. Superstructure of the stapes was difficult to evaluate on the virtual endoscopy; however, virtual endoscopy of the middle ear provides further information on the pathological conditions including congenital anomaly, posttraumatic, and inflammatory processes.     

Three-dimensional CT of the middle ear and adjacent structures

Summary Three-dimensional (3D) computed tomography of the middle ear and adjacent structures has been carried out in two cadaveric heads from axial and coronal high-resolution images. The structures shown on the images of the walls of the tympanic cavity are illustrated. The usefulness and limitations of the technique, in this region, are discussed: use of grey level volumes at the surface of the slices and the inclusion of structural landmarks is emphasized. The 3D representations show the anatomical spacial relationships of the small structures in and around the middle ear to advantage. The information may be of use in surgical orientation.     

先天性耳畸形和正常颞骨的螺旋CT三维成像分析

目的：探讨螺旋CT扫描及三维重建成像技术在先天性耳畸形和正常颞骨的临床应用，方法：采用螺旋高分辨CT扫描技术，对16例先天性，中耳畸形及40例正常耳行多平面重建，曲面重建和三维表面成像，结果：16侧患耳畸形为：外耳道骨性闭锁，鼓室狭小，听小骨发育不育，面神经管异常等。小视野密集重建清晰显示了细微结构，多平面重建提供多位信息，三维表面成像立体直观地显示形态结构，结论：螺旋高分辨CT及三维重建成像技术有利于外，中、内耳正常结构的显示和先天畸形的诊断，三维重建成像技术能提供更多的诊断信息，建议临床选择应用。     

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.     

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     

Ultrashort echo time imaging of normal middle ear ossicles: a feasibility study

Objective

The aim of this study was to assess the feasibility of ultrashort echo time (UTE) imaging in the visualization of middle ear ossicles in normal subjects.

Methods

12 young adult volunteers (males/females = 6/6, age 25–44 years, mean 30.3 years) with normal hearing levels underwent MRI studies using a 3.0 T clinical unit with an eight-channel SENSE head coil. For each subject, the whole head was imaged using a three-dimensional dual-echo UTE imaging sequence with radial trajectory and the following parameters: field of view, 240 × 240 × 240 mm; matrix, 320 × 320; flip angle, 7°; repetition time/echo time (TE)1/TE2, 8.0 ms/0.14 ms/1.8 ms; acquisition voxel size, 0.75 × 0.75 × 0.75 mm; number of signals averaged, 1; imaging time, 27 min 20 s. Subsequently, subtraction images were obtained by subtracting long TE (1.8 ms) images from short TE (0.14 ms) images. By using these three images, the visibility of the bilateral middle ear ossicles was evaluated. Moreover, as a reference for the UTE findings, CT images of the temporal bone were obtained in one volunteer.

Results

In all subjects, the middle ear ossicles were clearly visualized as a high signal intensity spot surrounded by a signal void of air on short TE images bilaterally, while they were not visible in long TE images in any of the subjects. The subtraction images provided better contrast of the ossicles.

Conclusion

We demonstrated the feasibility of UTE imaging of the middle ear ossicle in normal subjects.     

螺旋CT在胆脂瘤型中耳炎中的应用

胆脂瘤型中耳炎并非真是平时所说的,而是位于中耳、乳突腔内的囊实性结构.胆脂瘤形成的确切机制尚不清楚.胆脂瘤引起骨质破坏的原因,目前认为一是胆脂瘤生长的压力引起周围骨质吸收,另一个因素是胆脂瘤基层的上皮及其下的肉芽内有胶原酶,这种胶原酶和其它蛋白分解酶有分解骨质内的胶原纤维致腐蚀骨质的作用[1].