256层螺旋CT轴位与冠状位重建对窦口-鼻道复合体正常解剖及变异的对比观察

目的：探讨多层螺旋CT（MSCT）轴位和冠状位重建对窦口-鼻道复合体（OMC）区域的正常解剖结构和变异显示能力及差异。方法：利用32例健康体检者和23例因非鼻及副鼻窦疾病而行头颈部CT扫描者,常规扫描后进行轴位和冠状位标准重建,分别对比观察OMC区域的正常解剖结构和变异及显示能力。结果：轴位和冠状位重建图像对双侧额窦开口、中鼻甲和中鼻道的显示能力无明显差异。但轴位图像在显示筛漏斗、前中组筛窦、上颌窦开口及钩突等的显示能力明显较冠状位差。结论：对OMC区域的正常结构和变异的显示冠状位明显优于轴位,冠状位重建可以代替冠状位扫描,以消除冠状位扫描给患者带来的不便。     

多层螺旋CT诊断颅底骨折的应用价值

目的 :探讨高分辨力多层螺旋CT扫描对颅底骨折诊断价值。方法 :对 48例患者行常规轴位CT扫描与高分辨力薄层轴位扫描及直接冠状位扫描 ,比较常规轴位CT扫描与高分辨力薄层轴位扫描图像对骨折的显示率 ,同时又对薄层扫描MPR冠状位重建图像与直接冠状位扫描图像对骨折的显示进行比较。结果 :前组二者有明显差异 (P <0 0 0 1 ) ,后组图像骨折显示率无明显差异。结论 :多层螺旋高分辨力薄层CT扫描对提高颅底骨折诊断率有明显价值 ,并可替代直接冠状位CT扫描成像     

眼眶副鼻窦区多层螺旋CT扫描冠状面重建与直接冠状面扫描图像的对比研究

目的分析眼眶、副鼻窦多层螺旋CT扫描MPR冠状面重建与直接冠状面扫描图像,探讨冠状面重建能否代替直接冠状面扫描。方法使用GE lightspeed p lus 4层面螺旋CT扫描仪对116例眼眶、副鼻窦病变患者进行扫描,在横断面图像基础上进行MPR重建。由资深专家对重建冠状面图像与直接冠状面扫描图像进行评价和对比分析。结果116例中,62例同时行MPR重建对眼眶、副鼻窦解剖结构及病变的显示与直接冠状面扫描图像相似,图像质量均为Ⅰ级。54例不能进行直接冠状面扫描者,冠状面重建多数也能达到诊断效果(Ⅰ级32例,Ⅱ级3例)。结论多层螺旋CT扫描对眼眶、副鼻窦的MPR冠状面重建图像能够代替直接冠状面扫描。     

16层螺旋CT鼻窦区冠状位重组图像与扫描图像的对比研究

目的对比分析16层螺旋CT不同扫描方法以及不同重建算法对鼻窦区解剖结构的显示。方法将56例鼻窦扫描患者分为正常组（34例）与炎症组（22例）。每组患者根据扫描方法不同分为轴位扫描冠状位重组组和直接冠状位扫描组,均用软组织算法重建。选取其中正常组18例、炎症组16例同时行高分辨率算法重建。评价不同扫描方法、不同重建算法时的图像质量。结果两组中冠状位重组图像与直接冠状位扫描图像的图像质量差异均无统计学意义。正常组中,高分辨率重建算法的图像质量均高于软组织重建算法,差异有统计学意义;炎症组中,高分辨率重建算法与软组织重建算法的图像质量的差异无统计学意义。结论利用16层螺旋CT轴位扫描图像并进行冠状位重组,所得信息明显优于只对患者进行一次冠状位扫描,且高分辨算法对正常组细小结构的显示优于软组织算法。     

螺旋CT多平面重建技术的临床应用

目的　探讨螺旋CT多平面重建图像临床应用价值。方法　对250例不同感兴趣区及不同病种的患者用1～5mm层厚,1～3mm重建间隔进行螺旋CT扫描和多平面重建。结果　所有病例MPR图像均能多方位地显示病变及其毗邻关系,绝大部分病例能帮助更好地确定病变部位、范围。结论　尽管轴位CT在显示正常和病变解剖方面有明显优势,但通过扫描数据重组的冠状位、矢状位、斜位、曲面MPR图像有助于对复杂病例的全面理解,它是对轴位CT的良好补充。     

西门子16层螺旋CT双向调节MPR技术在听小骨中的应用

随行螺旋CT扫描技术的进展，西门子16层螺旋CT扫描层厚最低可达0．75cm，重建层厚最低可达0．6cm，在此基础上进行的多平面重组（MPR）其图像质量可与直接扫描图像相媲美。常规轴位、冠状位、矢状位层面均不能显示听小骨全程，难以评价听小骨的发育、受侵及受损等情况。作者利用MPR技术，在西门子16层螺旋CT机上重组出了各听小骨最佳显示层面，探讨各种类型听小骨发育和疾病的CT特征。     

多层螺旋CT在腰椎病变中扫描方法的探讨

目的:探讨多层螺旋CT(MSCT)的螺旋扫描及轴层扫描方法在腰椎病变中的应用。方法:对126例临床上有腰腿痛症状的患者行腰椎螺旋CT扫描,其中28例加做轴层扫描,然后对螺旋扫描的数据进行后处理,将重组图像与轴层扫描的图像进行比较,分析图像的质量。结果:MSCT扫描后重组的横轴面图像与直接轴层扫描的图像相比无明显差别,完全符合诊断质量,提供的信息更丰富。结论:利用MSCT的螺旋扫描方法及重组技术,不仅能对椎间盘病变进行诊断,还能发现常规轴层扫描所遗漏的疾病,显著提高腰椎病变的检出率,使患者更容易固定,扫描架亦毋需倾斜,不受腰椎间隙角度的限制。     

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。     

MSCT三维重组在非标准体位CT扫描患者颅脑手术定位中的价值

目的 探讨多排螺旋CT图像三维重组技术在非标准体位头颅CT扫描患者颅脑手术定位中的价值.方法 实验组选择40例头颅扫描体位不标准但需要行颅脑手术的患者,对头颅CT扫描数据按OM基线及其垂直线行轴位及冠状位重组,根据所得重组图像定位并制定手术方案;对照组选择40例按标准体位头颅扫描、需要行颅脑手术的患者,根据OM基线手术定位;对两组患者手术定位准确率进行统计学分析.结果 实验组40例患者均行轴位及冠状位标准重组,39例通过后处理图像定位并顺利手术,1例患者未及手术死亡.其中手术医师认为定位非常准确36例,比较准确3例;对照组38例顺利完成手术,手术医师认为定位非常准确35例,比较准确3例.实验组手术定位准确率(92.3％)同标准体位扫描的对照组的手术定位准确率(92.1％)无显著统计学差异(P=0.97 ＞0.05).结论 多排螺旋CT图像三维重组技术对非标准体位头颅CT扫描患者颅脑手术定位有确实的帮助.     

多层螺旋CT在肋骨骨折中的应用

目的 :探讨多层螺旋CT扫描检查对肋骨骨折的诊断价值。方法 :65例肋骨骨折患者行X线及多层螺旋CT扫描检查 ,观察和分析骨折的位置、数量及周边的其他病变。结果 :65例中 ,CT检查共发现肋骨骨折 12 1处 ,肋软骨骨折 5处。冠状位及矢状位重组图像清晰地显示出骨折线的数目及断端移位情况。结合 4D重组图像 ,肋骨骨折线的显示更直观、明了。X线检查共发现肋骨骨折 117处 ,肋软骨骨折 0处。结论 :多层螺旋CT轴位图像、MPR及 4D重组图像的联合应用 ,对判断肋骨骨折有很高的诊断价值 ,优于常规X线检查。     

Comparison between coronal reformatted images and direct coronal CT images of the swine lung specimen: assessment of image quality with 64-detector row CT

The aims of this study were to compare the image quality of coronal multiplanar reconstruction (MPR) images from axial spiral images with that of direct coronal spiral and sequential images, and to estimate and analyse the effect of an incremental change on the image quality using 64-detector row CT. 12 swine lungs were used. Five kinds of images from each lung specimen were obtained using 64-detector row CT. All images were analysed by categories and grades, and the direct coronal sequential images were used as the reference standard for the image quality. Statistical analysis was performed for the following categories: (i) inter-observer reliability, (ii) interaction between the observers and images, (iii) image analysis, (iv) anatomical structural analysis of each observer, (v) stair-step artefact and (vi) background noise. The overall image quality and the image quality of all anatomical structures of coronal MPR images with 0.67 mm slice increments were inferior to the image quality of the other images; this difference was statistically significant (p<0.05). Stair-step artefact was detected on coronal MPR images, and was more prominent on coronal MPR images with 0.67 mm slice increments than on coronal MPR images with 0.34 mm slice increments. The most severe background noise was detected on the direct coronal sequential images, but there was no significant difference between the direct coronal sequential images and the direct coronal spiral images. Background noise was least prominent on coronal MPR images with 0.67 mm slice increments. The increment process is important for improving the image quality of MPR images even when using 64-detector row CT. Coronal MPR images with 0.34 mm slice increments using 64-detector row CT showed a similar image quality to that obtained from the direct coronal images, and can be used instead. This means that the coronal MPR images obtained with 64-detector row CT could be as useful for evaluating the lung parenchyma as the axial high-resolution CT images.     

Petrosal bone: coronal reconstructions from axial spiral CT data obtained with 0.5-mm collimation can replace direct coronal sequential CT scans.

PURPOSE: To investigate whether coronal multiplanar reconstruction (MPR) images of the petrosal bone from axial spiral computed tomographic (CT) data obtained with 0.5-mm collimation can replace direct coronal sequential CT scans obtained with 0.5- or 1.0-mm collimation. MATERIALS AND METHODS: The differences in diagnostic quality between thin-section coronal sequential CT scans of 24 petrosal bones in 12 patients and matched MPR images were assessed by five observers. The matched MPR images were calculated with both trilinear and tricubic interpolation. Image resolution was determined by measuring the three-dimensional point spread function. RESULTS: All observers preferred tricubically interpolated MPR images over trilinearly interpolated images. Subjective differences in image quality between direct coronal scans and matched tricubically interpolated MPR images were small. Only the direct coronal scans with the highest image quality (0.5-mm collimation, 465 mAs) were judged to be slightly better than the matched MPR images. With regard to direct coronal scans obtained at 245 mAs and/or 1.0-mm collimation, either there was no preference or the MPR images were preferred. CONCLUSION: Coronal MPR images from axial spiral CT obtained with 0.5-mm collimation can replace direct coronal sequential CT scans.     

Radiation dose to the lens of eye and thyroid gland in paranasal sinus multislice CT

CT has become an established examination in the evaluation of the paranasal sinuses. Until recently this was achieved by the direct coronal technique on conventional and single slice helical scanners. With the advent of multislice technology, thin slice axial CT with excellent coronal and sagittal reconstructions is now the norm. We describe a study designed to evaluate the radiation dose to the lens of the eye and thyroid gland in the axial and coronal planes on a Siemens Volume Zoom quad slice scanner at 140 kV and effective mAs of 100 using 1 mm collimation. Thermoluminescent dosimeters were placed on the eyelid and thyroid gland of 29 patients scanned axially in the supine position and a further 28 patients scanned coronally in the prone position with gantry tilt. The results show mean doses of 35.1 mGy (lens) and 2.9 mGy (thyroid gland) in the coronal plane compared with 24.5 mGy (lens) and 1.4 mGy (thyroid gland) in the axial plane. Results obtained from a head phantom and from using the ImPACT CT dose calculator were comparable. The kV and mAs were then reduced to 120 and 40, respectively, and the axial study repeated using the head phantom and predicted doses using the ImPACT CT dose calculator. The low dose scanning technique revealed a lens dose of 9.2 mGy and thyroid dose of 0.4 mGy. The eye dose on a multislice scanner is still substantially less than the threshold dose of 0.5-2 Gy for detectable lens opacities. These results indicate that, in addition to the established perceived advantages of multislice axial sinus CT, i.e. patient comfort, no artefact from dental amalgam and reproducible true coronal images, should be included a decreased radiation dose to both the eye lens and thyroid gland compared with direct coronal scanning.     

Optimization of techniques in screening CT of the sinuses

The number of screening examinations of the sinuses performed with CT has markedly increased owing to the widespread and increasing use of endoscopic sinonasal surgery. We reviewed scans from 500 patients who had screening CT examinations of the sinuses for preendoscopic evaluation of inflammatory sinonasal disease to better define an optimal imaging protocol. Three aspects of direct coronal imaging of the paranasal sinuses were investigated: (1) preparation of the patient prior to the examination; (2) technical factors of the CT study, including positioning of the patient, optimal coronal angle, slice thickness, and CT exposure factors; and (3) data display. Our experience indicates that pretreatment of the patient with maximal medical therapy enables the best preendoscopic definition of anatomy, disease pattern, and nonreversible disease component for the treating surgeon. CT technical factors are optimized with scanning in the prone position with thin (3-mm) sections obtained through the anterior paranasal sinuses. This allows optimal visualization of the ostiomeatal unit. The remaining posterior portions of the sinuses are adequately imaged with thicker slices (5 mm). The coronal scan angle used is less critical. Exposure factors (mAs) can be reduced dramatically without image compromise. Data display is optimized when the bone algorithm is used to acquire the data and with image display at intermediate window center and width level. Use of the techniques outlined in this article results in a cost-effective yet diagnostic scan of the sinuses with decreased radiation exposure to the patient.     

头颈部肿瘤多层螺旋CT冠状面多平面重建与常规扫描图像的对比研究

目的 分析头颈部肿瘤多层螺旋CT冠状面多平面重建(MPR)与常规扫描图像，探讨冠状面MPR能否替代常规冠状面扫描。方法 使用GE Lightspeed Ultra 8层螺旋CT扫描仪对90例头颈部肿瘤患者进行扫描，在横断面基础上行MPR。由3位资深放射科医生对冠状面MPR像与常规扫描图像进行对比分析。结果 90例冠状面MPR像对正常鼻咽、鼻腔、鼻窦、上颈部等部位软组织的显示与常规扫描冠状面像相似，图像质量好，均为1级。59例(65．6％)冠状面MPR像对骨质的显示优于常规扫描像，68例(75．6％)对颅底孔道的显示优于常规扫描像。增强CT扫描中，51例明显肿瘤病灶，46例(90．2％)对肿瘤的显示优于常规扫描冠状面像。结论 多层螺旋CT扫描MPR图像除对口腔、口咽的显示欠佳外，均近似或优于常规冠状面扫描像，多层螺旋CT扫描的冠状面MPR可以替代常规扫描。     

脑脊液鼻漏的X线诊断（附10例报告）

本文通过对10例脑脊液鼻漏分析，提示脑脊液鼻漏X线平片检查能见到漏侧之邻近鼻窦密度增高及骨折线，CT薄层扫描多能显示脑脊液鼻漏骨质缺损的部位及大小，以及颅内积气等，并提出筛窦，蝶窦应作冠状面CT薄层扫描，额窦作横断面CT薄层扫描为佳。     

Identification of the anterior ethmoid arteries on thin-section axial images and coronal reformatted orbit images by means of multidetector row CT

AIM: The aim of this study was to identify anterior ethmoid arteries on thin-section axial images and coronal reformatted images of the orbits using multidetector row computed tomography (CT). MATERIALS AND METHODS: One hundred and thirty-two patients underwent paranasal CT using a 16-row detector CT (n=59) or a 6-row detector CT machine (n=73) at 1 or 1.25 mm section width, respectively. Coronal images were reformatted at section widths of 3 and 1 mm. The anterior ethmoid arteries were identified for each patient. Differences were assessed using the chi-square test. RESULTS: All CT images were of approximately average diagnostic quality. Anterior ethmoid arteries were identified in 97.5 and 96.6% at section thicknesses of 1 and 1.25 mm on the axial images, respectively. There was no statistically significant difference in the detection rate (p=0.89). On the coronal images, anterior ethmoid arteries were presented tangentially in 75.4 and 90.2% at section widths of 3 and 1 mm, respectively. The visibility of the anterior ethmoid arteries was rated significantly better on coronal images at a section width of 1 mm than on those at section widths of 3 mm (p<0.001). CONCLUSION: Thin-section axial images and coronal reformatted images using multi-detector row CT mostly depict anterior ethmoid arteries, and are useful to identify anterior ethmoid arteries for preoperative evaluation of paranasal sinuses.     

多層螺旋CT在鼻竇及其相關結構檢查中的應用

目的:利用多層螺旋CT各向同性掃描進行多平面重組(multiplanar reformation,MPR)后處理,顯示鼻竇及其相關結構,探討多層螺旋CT檢查鼻竇及其相關結構的優勢。方法:搜集觀察對象55例(男32例,女23例),年齡9~75歲,利用多層螺旋CT各向同性掃描對副鼻竇進行檢查,然后對所得圖像進行多平面重組(multiplanar reformation,MPR)后處理,重組出標準層面及重點結構的最佳顯示平面,并對某些結構的常規顯示斷面和標準化斷面顯示結果進行統計學分析。結果:①標準橫斷面、冠狀面、矢狀面能清晰顯示各竇腔氣化類型以及左右結構的對稱情況等。②一些特殊結構如鉤突、額竇引流通道、鼻淚管以及蝶篩竇壁與視神經管、頸內動脈的關系需要在斜平面觀察。結論:①一次掃描后,可進行任意平面后處理。減少輻射,避免擺位困難。②多層螺旋CT各向同性一次掃描結合多平面重組(MPR)后處理能夠很好地顯示鼻竇及其相關結構。