成人中耳、内耳解剖结构螺旋CT三维重建技术

目的：探讨成人中耳，内耳解剖结构CT三维重建技术，方法：采用螺旋CT薄层扫描（层厚1mm或2mm)，小视野（FOV=5cm)，密集重建技术（间隔0.2mm或0.5mm），对75例成人中耳，内耳进行三维成像，包括多平面重组（MPR），最大密度投影（MaxIP)，表面成像（SSD）和仿真内镜成像（CTVE）。结果：中耳鼓室，听骨链，内耳及内耳道均获得满意三维图像。结论：螺旋CT三维重建技术的应用能够真实准确观察成人中耳，内耳立体结构。     

Evaluation of the middle and inner ear structures: comparison of hybrid rendering, virtual endoscopy and axial 2D source images

Recent developments in 3D reconstructions can enhance the quality and diagnostic value of axial 2D image data sets with direct benefits for clinical practice. To show the possible advantages of a hybrid rendering method [color-coded 3D shaded-surface display (SSD)- and volume rendering method] with the possibility of virtual endoscopy we have specifically highlighted the use in relation to the middle and inner ear structures. We examined 12 patients with both normal findings and postoperative changes, using image data sets from high-resolution spiral computed tomography (HRSCT). The middle and inner ear was segmented using an interactive threshold interval density volume-growing method and visualized with a color-coded SSD rendering method. The temporal bone was visualized using a transparent volume rendering method. The 3D- and virtual reconstructions were compared with the axial 2D source images. The evaluated middle and inner ear structures could be seen in their complete form and correct topographical relationship, and the 3D- and virtual reconstructions indicated an improved representation and spatial orientation of these structures. A hybrid and virtual endoscopic method could add information and improve the value of imaging in the diagnosis and management of patients with middle or inner ear diseases making the understanding and interpretation of axial 2D CT image data sets easier. The introduction of an improved rendering algorithm aids radiological diagnostics, medical education, surgical planning, surgical training, and postoperative assessment. Received: 22 July 1998; Revised: 15 April 1999; Accepted: 19 April 1999     

Virtual endoscopy of the middle ear

Virtual endoscopy is a computer-generated simulation of fiberoptic endoscopy, and its application to the study of the middle ear has been recently proposed. The need to represent the middle ear anatomy by means of virtual endoscopy arose from the increased interest of otolarygologists in transtympanic endoscopy. In fact, this imaging method allows the visualization of middle ear anatomy with high detail, but it is evasive and is essentially used for surgical guidance. Virtual endoscopy provides similar perspectives of the tympanic cavity but does not require the tympanic perforation. In the study of the middle ear, specific attention is given to the retroperitoneum. This region contains elevations of the medial wall (pyramidal eminence and ridge, styloid eminence and ridge, subiculum, ponticulus) and depressions (sinus tympani, posterior sinus tympani, facial sinus, fossula of Grivot, oval window fossula), which can be effectively displayed by virtual endoscopy. Virtual endoscopy is foreseen as a useful tool in preoperative management of patients who are candidates for middle ear surgery, since it can predict with high detail the patient's specific anatomy by imaging perspectives familiar to otosurgeons. Received: 3 May 2000 Accepted: 8 June 2000     

CT仿真内窥镜的初步临床应用

目的：探讨ＣＴ新技术仿真内窥镜的临床应用价值。方法：对４０例患者及正常人（鼻部１７例、喉７例、气管支气管５例、胃４例、结肠７例）行螺旋ＣＴ扫描后经软件处理进行仿真内窥镜成像,并与纤维内窥镜、手术所见对照研究。结果：ＣＴ仿真内窥镜显示正常解剖结构、病变位置,范围与纤维内窥镜所见类似,并可进入纤维内窥镜无法到达的腔道,如副鼻窦内、狭窄的管腔内以及梗阻病变的远端。结论：ＣＴ仿真内窥镜提供了一种无创性的诊断方法,可作为纤维内窥镜的补充手段,具有一定的应用潜力,值得临床上进一步推广应用。     

CTVE对胆脂瘤型中耳炎听骨链病变的诊断价值

目的：探讨螺旋CT仿真内镜（CTVE）对胆脂瘤型中耳炎听骨链病变的诊断价值。方法：比较28耳胆脂瘤型慢性中耳炎听骨链的CTVE表现与临床手术所见。结果：CTVE显示的胆脂瘤型中耳炎听骨链破坏与手术所见基本相符，但对听骨链的细微病变价值有限，结论：CTVE是一种全新的多角度立体地观察听骨链结构的非侵入性影像手段。     

双层螺旋CT仿真内镜成像在结肠肿瘤术前评价中的价值

目的:探讨双层螺旋CT仿真内镜成像在结肠肿瘤性疾病的术前评价中的价值。方法:30例高度怀疑结肠肿瘤性疾病的患者行双层螺旋CT扫描后,采用仿真内镜软件生成结肠仿真内镜图像,同时结合MPR、SSD、MIP和透明技术,观察结肠肿瘤的形态、位置、对肠管浸润的范围及长度、肠管周围及远处脏器的情况,并与电子结肠镜及手术病理结果对比。结果:30例中仿真结肠镜对肿块型结肠肿瘤的判断较电子结肠镜准确,两种方法的分型符合率分别为100%、89.4%;电子结肠镜对浸润型及溃疡型结肠肿瘤的判断较仿真结肠镜准确,其分型符合率分别为83.4%、100%;仿真结肠镜对病变肠管浸润的范围及长度的判定均高于电子结肠镜。结论:双层螺旋CT仿真内镜成像在结肠肿瘤术前诊断中有较大的价值,是电子结肠镜的重要补充检查技术。     

CT仿真内窥镜技术诊断脑血管病变的临床价值

目的探讨CT仿真内窥镜技术诊断脑血管病变的临床价值.材料和方法选择经DSA证实的6例颅内动脉瘤,2例脑血管狭窄性病变,颈内动脉夹层和AVM各1例,行螺旋CT血管造影检查,应用Navigator软件三维重建血管图像模拟内窥镜观察血管腔内结构.结果CT仿真内窥镜能精确显示动脉瘤颈部的解剖关系,帮助了解狭窄处血管的内壁情况和病变程度.结论CT仿真内窥镜是一种无创的血管内腔检查技术,可直观地显示脑血管病变的内腔形态及其三维解剖关系,是DSA和其它三维CT重建方法的重要信息补充.     

Virtual endoscopy of the nose and paranasal sinuses

The purpose of this study was to evaluate the applicability of virtual endoscopy (VE) in the region of the nose and paranasal sinuses on the basis of volume-rendered spiral CT data. Forty-five patients underwent a low-dose spiral CT of the sinuses. The data were transferred to a workstation running software for volume rendering (EasyVision, Philips Medical Systems, Eindhoven, The Netherlands). Six orthogonal views of the maxillary sinuses and the nasopharynx and a fly-through movie of the nose were calculated. Two radiologists evaluated the coronal reconstructions and virtual endoscopy with respect to detectability of pathology using a checklist comprising 10 points. In 30 patients who underwent subsequent endoscopic surgery, surgeons were asked to rank the degree of assistance of the preoperative virtual endoscopy. In general, virtual endoscopy was possible in all 45 patients. The mean time required for path definition and movie calculation for virtual endoscopy were 8 ( ± 2) min and 3 ( ± 1) min, respectively. Overall, more anatomical details were depicted on coronal reconstructions; however, a high degree of similarity between virtual endoscopy and the intraoperative impression was reported by the surgeons. We conclude that virtual endoscopy of the nose and paranasal sinuses may develop into a standard means to guide surgeons during endoscopic interventions. Received 17 September 1997; Revision received 23 December 1997; Accepted 29 December 1997     

CT仿真内镜对中耳解剖结构的观察

目的　评价螺旋CT仿真内镜 (CTVE)对中耳解剖结构的显示能力。方法　对 10 0例健康志愿者两侧中耳进行了CTVE成像 ,观察中耳腔的解剖结构。结果　CTVE从不同角度、多方位立体地显示了中耳腔的解剖结构 ,但对表浅和细微结构显示欠佳。结论　CTVE是一种崭新的多角度立体地观察中耳腔解剖结构的非侵入性影像手段     

Virtual endoscopy of the middle ear: experimental and clinical results of a standardised approach using multi-slice helical computed tomography

Virtual endoscopy (VE) enables non-invasive 3D endoluminal imaging of the middle ear by post-processing of CT data. To optimise the clinical application a standardised approach was evaluated in normal and pathologic cases. Data acquisition was performed using multi-slice helical CT in 20 normal patients and 15 patients with malformation or trauma. Virtual endoscopy of the tympanic cavity and 3D images of the ossicles were generated using surface and volume rendering. Qualitative assessment of the representation of anatomical structures was performed in normal patients. In 15 pathological cases the diagnostic benefit was evaluated by comparing the 3D images to the 2D images and intra-operative findings. In all 35 cases 3D imaging was possible using the standardised approach. The ossicular chain as well as the bony and soft tissue structures of the tympanic cavity were visualised in 20 normal patients. In 7 of 8 patients with malformation and 1 of 7 patients with trauma the original diagnosis was changed by 3D imaging. Standardisation and evaluation of the method in normal patients is essential as it enhances the diagnostic reliability. Virtual endoscopy facilitates understanding of the complex anatomy of the middle ear. In cases of suspected malformation and confirmed trauma it is helpful for diagnosis and surgical planning.     

中耳疾病的CT诊断及与传统X线的比较

目的 探讨ＣＴ在中耳疾病诊断中的应用及其价值。材料与方法 搜集本院经手术病理证实的中耳疾病４３例４６耳;慢性化脓性中耳炎３６耳,其中单纯型５耳,骨疡型（肉芽肿型）１０耳,胆脂瘤型２１耳（其中１耳为乳突根治术后复发）,中耳癌４例,中耳先天畸形６耳。所有病例术前均行双侧乳突Ｍａｙｅｒ’ｓ位和Ｓｃｈｕｌｌｅｒ’ｓ位摄片及螺旋ＣＴ轴位、冠状靶放大扫描。ＣＴ、平片所见与手术、病理对照。结果 ３６耳慢性化脓性     

CT仿真内镜临床应用的评价

目的 初步评价ＣＴ仿真内镜（ＣＴＶＥ）临床应用的价值。材料与方法 应用ＧＥ公司ＨｉｓｐｅｅｄＣＴ１螺旋ＣＴ扫描机及ＣＴＶＥ软件Ｎａｖｉｇａｔｏｒ对１１３例（８６例患者,２７例正常人）进行临床应用,其中气道３９例,消化道３３例,喉１３例,心血管１２例,耳部６例,胆道４例,膀胱、输尿管３例,副鼻窦３例。７２例患者经病理证实。结果 ＣＴＶＥ所见正常解剖及病纤维内镜所见类似。ＣＴＶＥ可清楚显示管腔狭窄与闭     

Diagnostic potential of virtual bronchoscopy: advantages in comparison with axial CT slices, MPR and mIP?

The aim of this study was to evaluate the diagnostic potential of virtual endoscopy (VE) and to compare it with axial CT slices, multiplanar reconstructions (MPR), minimal intensity projections (mIP), and bronchoscopy in patients diagnosed with bronchogenic carcinoma. Thirty patients underwent a spiral CT. Axial CT images were transferred to an Onyx workstation (Silicon Graphics, Sun Microsystems, Mountain View, Calif.) for performing virtual endoscopy. Accuracy for this procedure was tested by three radiologists on a monitor in comparison with axial CT slices, MPR, mIP, and bronchoscopy concerning the localization and degree of stenoses. Endoluminal tumors were identified by virtual bronchoscopy with no statistically significant difference of localization or grading of stenosis in comparison with bronchoscopy, axial CT slices, MPR and mIP. Axial CT slices, MPR, and mIP showed poorer results with over- or underestimation of stenoses compared with VE and bronchoscopy. Passing of stenoses was only possible with VE in 5 patients. Virtual endoscopy is a non-invasive method for identification of endoluminal tumors and is comparable to real bronchoscopy. Received: 18 March 1999; Revised: 21 May 1999; Accepted: 22 July 1999     

Virtual CT endoscopy in determining safe surgical entrance points for paranasal mucoceles

The goal of this work was to evaluate virtual CT endoscopy for determining safe surgical entrance points for paranasal mucoceles. Twelve mucoceles in 11 cases were scanned with helical CT, and multiplanar reconstruction (MPR) and virtual endoscopic images were obtained. After a safe surgical entrance point was determined by MPR images, the entrance point was specified on the virtual endoscopic images. The combination of virtual endoscopic images and MPR images is a suitable method for determining a safe surgical entrance point for simple mucoceles.     

CT evaluation of gastric lesions with three-dimensional display and interactive virtual endoscopy: comparison with conventional barium study and endoscopy

OBJECTIVE: This study was undertaken to assess the feasibility of three-dimensional (3D) CT rendering using shaded-surface display (SSD) and ray sum display and virtual endoscopic images of the stomach for simultaneous evaluation of intraluminal and extraluminal abnormalities compared with conventional upper gastrointestinal barium studies and endoscopy. SUBJECTS AND METHODS: Our prospective study consisted of 39 patients with gastric lesions (17 gastric carcinomas, nine gastric polyps, five gastric varices, five gastric submucosal tumors, one lymphoma, one case of Menetrier's disease, and one gastric erosion) detected by endoscopy and barium study. All 3D CT images were reconstructed using SSD, ray sum display, and virtual endoscopic techniques. Three-dimensional images were evaluated for ability to reveal the range and morphologic features of the gastric lesions. RESULTS: All SSD, ray sum display, and virtual endoscopic images successfully revealed five of the eight early-stage gastric carcinomas and all nine advanced-stage gastric carcinomas. Submucosal tumors were revealed on 3D CT approximately as well as on conventional endoscopy. Interactive evaluation of virtual endoscopic images and multiplanar reconstructions provided useful information regarding intraluminal and submucosal gastric involvement by gastric varices, submucosal tumor, advanced gastric carcinomas, and lymphoma. This kind of information could not be obtained by conventional endoscopy or double-contrast study. CONCLUSION: Three-dimensional CT used in conjunction with virtual CT endoscopy proved helpful in identifying gastric lesions. Also, virtual CT endoscopic images with the interactive display of multiplanar reconstructions proved useful in identifying both intraluminal and submucosal components.     

多层面螺旋CT仿真内窥镜在大肠肿瘤的临床应用

目的　探讨多层面螺旋CT仿真内窥镜（multi-slice helical CT virtual endoscopy,     

多层螺旋CT血管仿真内窥镜在主--髂动脉病变中的应用

目的　探讨多层螺旋CT(MSCT)血管仿真内窥镜在主 -髂动脉病变中的临床应用价值。方法　对 3 6例临床疑诊主 -髂动脉疾病及 40例腹部检查患者行MSCT血管造影检查 ,之后在图像后处理工作站对可疑血管病变部位行CTVE并观察所获图像质量与扫描技术参数之间的关系。结果　 10例夹层动脉瘤均见撕裂内膜及双腔征 ,16例动脉瘤样病变见瘤腔扩大 ,48例见内膜钙化斑 ,血管内支架及血管置换术后各 1例可见支架形状及换血管部位狭窄 ,血管闭塞 1例见闭塞管腔。结论　CTVE图像质量的好坏与增强技术、扫描参数、运动伪影相关。CTVE是MIP、MPR及SSD的重要补充 ,在血管性疾病的诊断、治疗及疗效观察中有极高的参考价值。     

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     

Virtual endoscopy of the nasopharynx in the evaluation of its normal anatomy and alterations due to lymphoid hyperplasia: preliminary report

The purpose of this study was to evaluate the diagnostic usefulness of virtual endoscopy in establishing the anatomic appearance of nasopharynx, both normal and affected by lymphoid hyperplasia. Thirty-seven patients affected by chronic rhinosinusal and otomastoid pathology, all studied by rhinoscopy, were examined with multislice computed tomography (CT) and virtual endoscopy of the nasopharynx. Rhinoscopy showed a completely normal nasopharynx in 15 cases and a variable grade of lymphoid hypertrophy in 22 patients. A general agreement was observed between traditional and virtual endoscopy findings in both subgroups. The tasca of Luschka was detected in 13/15 of normal subjects and only in 3/22 patients. The Rosenmuller fossae appeared deeper in normal subjects and their symmetry could be considered an important criterion of normality. In all cases, a good evaluation of the tubaric ostium was obtained. Differentiation between hyperplasic lymphoid tissue and neoplasms is possible only in lymphoid hyperplasia characterized by median crest-like swelling with a narrow base. In most cases, differential diagnosis cannot be based only on morphological criteria of virtual endoscopy, but it should be evaluated considering the overall CT findings and clinical presentation.     

Virtual bronchoscopy versus thin section computed tomography in evaluation of moderate and low grade stenoses: receiver operating characteristic curve analysis

Purpose: To evaluate the impact of virtual bronchoscopy, under proper threshold settings, on observer level of confidence in the assessment of bronchial abnormalities producing stenoses ≤75% compared to interpretation of thin section computed tomography (CT) images.

Material and Methods: Sixty-five patients with fiberoptic bronchoscopy positive for tracheobronchial abnormalities were evaluated in a blinded observer study using a commercially available virtual endoscopy software package. The findings of virtual endoscopy were compared with those of fiberoptic bronchoscopy using receiver operating characteristic curves (ROCs) and other statistical tools.

Results: A total of 102 lesions were identified by fiberoptic bronchoscopy, with 44 of these producing bronchial stenoses ≤75%. Concerning the latter lesions, for virtual bronchoscopy the areas under the ROCs were 0.93 and 0.96 for the two observers, respectively, while for thin section CT the corresponding values were 0.86 and 0.88; the differences observed were statistically significant. Contrary to thin section CT, virtual bronchoscopy did not show statistically significant differences from fiberoptic bronchoscopy regarding estimation of degree of stenosis.

Conclusion: Virtual bronchoscopy under proper threshold settings has a statistically significant impact on observer performance where moderate and low-grade bronchial stenoses are concerned and gives an estimate of the degree of stenosis more precisely than thin section CT.