两种数字化X射线摄影技术影像质量与成像剂量的比较

目的对比研究非晶硒平板探测器直接数字化X射线摄影(DR)及计算机x射线摄影(CR)两种数字化X射线摄影技术影像质量与吸收剂量的关系。方法应用DR和CR系统分别对对比度．细节体模(CDRAD2．0)进行不同吸收剂量的曝光成像。记录每次曝光的体模表面吸收剂量，并将所获取的影像在图像诊断工作站显示器上由4位观片者进行观察，计算影像质量表征因子(IQF)。应用ANOVA检验法统计、比较两种数字化摄影技术的图像质量与吸收剂量的差别。结果与CR相比，DR具有更低的IQF值，对人体组织对比度和结构细节有更好的信息检出特性。两种成像技术产生相同IQF值时，DR系统在体模表面产生的表面剂量比CR系统降低了77％。结论DR技术对于低对比度组织细节的检测好于CR技术。在获得相同影像信息的前提下，与CR相比应用DR大大降低了被检者吸收剂量。     

数字血管减影中kVp及mAs选择对患者剂量及低对比度血管检出能力的影响

目的分析数字血管减影中kVp及mAs设置对患者皮肤剂量、有效剂量及低对比度血管检出能力的影响。方法以不同浓度碘造影剂自制低对比度血管减影体模，保持影像增强器输入端X射线比释动能为1．1μGy／帧，改变不同kVp设置，测量体模表面X射线入射剂量ESD，观察影像，确定可检测的最低碘造影剂浓度。管电压保持70kV，改变mAs设置，测量影像增强器输入端每帧影像所需X射线空气比释动能、体模ESD剂量及可检测的最低碘造影及浓度。以Monte Carlo模拟程序PCXMCV1．5模拟计算有效剂量。结果体模ESD及患者有效剂量随mAs呈线性变化。保持影像增强器输入端空气比释动能1．1μGy／帧，kVp由50变化到100，体模DSA影像可分辨的最低碘造影剂浓度线性增大；保持管电压70kV，mAs由6．4变化到64，体模DSA影像可分辨的最低碘造影剂浓度按指数规律减小。当曝光量（mAs）超过40后，其对低对比度血管检出的影响不明显。结论对DSA系统而言，降低X射线机管电压要比增大X射线机输出强度更能有效改善其低对比度血管的检测能力。     

阅片室内环境照度对影像识读的影响

目的 探讨阅片室环境照度（ＩＲＲ）对影像识读的影响。方法 采用观测者操作特性（ＲＯＣ）曲线主观评价和观察测试卡分辨率２种实验方案：（１）将６种带有低对比度微小信号的Ｘ线胶片置于观片灯上;设置阅片室内环境照度分别为８０ｌｘ和５００ｌｘ,请３位放射诊断医师进行影像识读,绘制ＲＯＣ曲线并计算检出的最大信息量Ｉｍａｘ。（２）将０．６～１０ＬＰ／ｍｍ的矩形波测试卡紧贴于暗盒上,摄胸部正侧位片共１０张,使测试     

影像检查对乳腺癌诊断价值的探讨

目的探讨多种影像检查手段在乳腺癌诊断中的价值。材料与方法回顾性研究１３４例手术治疗乳腺癌病人,比较超声影像、钼靶摄片及物理查体同病理检查结果的符合率。结果超声影像和钼靶摄片对乳腺癌诊断的敏感性分别为７０％（９８／１３４）和７３．１（３２／４６）,超声影像对腋窝淋巴结转移评价的符合率为５６％（４７／８４）,物理查体的符合率为３３．３％（２／８４）。结论超声影像和钼靶摄片对乳腺癌诊断的敏感性高于物理查体。超声影像和钼靶摄片均可用于乳腺癌普查和术前评价,超声影像对乳腺癌术前腋窝淋巴结检查具有较高价值。     

外伤性胸骨骨折15例诊治体会

胸外伤中胸骨骨折很少见。１９８６～１９９８年,我们共收治各类胸外伤６１８例,其中胸骨骨折１５例。１临床资料１．１一般情况本组男１３例,女２例;年龄１７～７２岁,平均４７．５岁。车祸伤１０例,压伤４例,钝器撞击伤１例;单纯胸骨骨折６例,合并肋骨骨折９例,连枷胸４例;合并血胸１１例,血气胸２例,肺挫伤７例,心包积血５例,心包裂伤３例,心肌裂伤１例,支气管破裂１例;合并脑外伤５例,四肢伤６例,腹腔脏器伤１例。骨折部位：胸骨体上端１０例,胸骨柄２例,胸骨体下１／３处３例;骨折有移位８例,无移位７例。胸部…     

思密达治疗婴幼儿腹泻86例临床实验

目的 评价思密达治疗婴幼儿腹泻的疗效。方法 思密达口服治疗婴幼儿腹泻。病例为儿科门诊病人,年龄２－６０个月,疗程在３天内,症状为排稀水样便。就诊前未服用过本组实验组物的腹泻病人１７３人,随机分二组,分别给予服思密达或黄连素片。结果 治疗组平均疗程２．９３天,对照组４．４７天,ｘ＾２＝４．３９,ｐ〈０．０５。思密达总有效率９４．１％,对照组７９．３％,ｘ＾２＝１３．８,ｐ〈０．０１。两组结果比较,差     

螺旋CT扫描成像质量分析

目的：通过对螺旋与常规ＣＴ扫描的比较，图像的分析和讨论，以期为临床诊断提供有用的依据。材料和方法：螺旋及常规ＣＴ扫描采用Ｓｏｍａｔｏｍ Ｐｌｕｓ全身ＣＴ扫描机。扫描体模：（１）玻璃球，直径１．５ｃｍ，误差〈１０μｍ；（２）有机圆柱体，直径３．０ｃｍ，误差〈８μｍ；（３）水模，直径２５ｃｍ。扫描条件相同情况下，在下述方面进行比较：（１）不同物体螺旋ＣＴ扫描图像还原性的影响；（２）不同螺距扫描与图像分     

螺旋CT双期增强扫描诊断胰岛素瘤(附13例报告)

目的 研究螺旋ＣＴ胰腺双期薄层增强扫描对胰岛素瘤的诊断价值。方法 １３例胰岛素瘤行螺旋ＣＴ胰腺双期薄层增强扫描,１００ｍｌ对比剂,３ｍｌ／ｓ单相注射,延迟２５秒行动脉期扫描,延迟６５秒行门脉期扫描。结果 检出１３例中的１０例（７７％）,检出的１０例在动脉期均表现为高密度,门脉期４例为等密度,５例为略高密度,１例为高密度。３例假阴性中２例在两个时相均表现为等密度,１例在两个时相均表现为高密度,因与脾     

结,直肠癌术后孤立性肺转移

目的：探讨结、直肠癌术后肺孤立性转移瘤的影像表现，与原发肺癌的鉴别。材料与方法：３１年间１３例结、直肠癌术后肺孤立肿物，均经手术切除及病理证实。转移性腺癌１１例１３次，原发肺癌２例。结、直肠癌切除与肺转移瘤切除间隔时间为３￣９６个月，中位３３个月。均有正侧位胸片，病灶体层和ＣＴ各６例。结果：肿物直肠１．５￣８．５ｃｍ（中位３．４ｃｍ），类圆形３例，椭圆形８例１０个，浅分叶１０例；边缘光整８例１０个     

食管支架治疗食管良恶性狭窄：附23例分析

作者总结了采用２７根镍钛合金Ｕｌｔｒａｆｌｅｘ食管支架置入术治疗各种良恶性食管狭窄２３例。其中食管化学烧伤后狭窄１例，食管－胃吻合口狭窄６例，食管和／或贲门癌１６例。将吞咽困难分为０￣３级。２３例中，３级１２例，２级１１例。经治疗后，０级１３例（５６．５２％），１级６级（２６．０８％），２级３例（１３．０４％），３级１例（４．３５％）。其中，２级中的３例治疗前为３级，因此，总有效率为９５．６６％。     

医学图像融合的临床应用与新进展

医学图像融合是医学图像后处理的研究热点,它充分利用多模态图像,获得互补信息,使临床的诊断和治疗更加准确完善。本文综述了近年来医学图像融合研究的临床应用与最新进展,认为多模态医学图像融合是一个发展趋势,在临床疾病的早期诊断、治疗定位中将发挥重要的作用。     

Registered image subtraction for CT-, MR- and coronary angiography

Conventional post-processing of digital subtraction angiography (DSA) by 3D spiral CT, 3D MRI and 2D DSA is often hampered by extended artefacts due to patient movements during examination. In this paper an image registration procedure prior to the digital subtraction is introduced allowing an enhanced visualization of the contrast agent. The object displacement is detected by analysis of image deformations in small local regions. The motion pattern is used to compute a new synthetic mask of maximum congruence with the contrast medium image. This new mask image is then used in the subsequent subtraction. The algorithm works fully automatically and does not need any interactive placement of landmarks. Results obtained from subtraction of uncorrected and corrected sequences were compared with each other. The registration procedure provided good results in the suppression of subtraction artefacts and in the enhancement of vascular structures. Results are presented from subtraction of 2D and 3D data from CTA, MR mammography and coronary angiography. Received 10 August 1995; Revision received 18 March 1996; Accepted 12 April 1996     

Image quality in conventional lumbar spine radiography: evaluation using the post-processing tool Diamond View

Conventional radiography contributes for the majority of examinations in radiology departments. Based on the European Commission Quality Criteria we evaluated the effects on image quality when applying the new post-processing tool Diamond View (Siemens AG Medical Solutions, Germany) to conventional lumbar spine radiographs. 100 digital image pairs in two directions in two planes of lumbar spine radiographs were prospectively evaluated by two radiologists. Statistical analysis was performed with a p-value<.05 considered as significant. Images were evaluated on basis of the modified imaging Quality Criteria by the Commission of the European Communities, rated on a five-point scale. Statistical analysis showed an overall tendency for improved image quality of Diamond View (DV) for all criteria. Significant differences could be found in most of the criteria. Additional phantom analyses supported the advantage of DV. In conclusion DV improves image quality in conventional lumbar spine radiographs.     

WINDOWS环境下DICOM医学图像显示方法的初步研究

目的：探讨WINDOWS环境下显示DICOM格式图像的方法.方法：通过自编程序读出DICOM图像的相关数据,实现DICOM格式图像在WINDOWS下的显示.结果：选取MR、CT、DR等不同模态的DICOM图像进行实验,均可正确显示.结论：针对DICOM图像文件存储的格式编制的程序,实现了DICOM图像文件的读取显示.本程序运行于WINDOWS环境,不依赖于具体的DICOM工作站,便于科研教学使用.     

Computer-aided evaluation of anatomical accuracy of image fusion between X-ray CT and SPECT

Hybrid scanners, which enable the performance of single photon emission computed tomography (SPECT) and X-ray computed tomography (CT) in one imaging session, have considerable diagnostic potential. However, evaluating the anatomical accuracy of image fusion inherent to these systems remains a challenge. This paper proposes a method for evaluating this variable with minimum user interaction. It focuses on measuring the distance between the centers of gravity of the SPECT hot spot and its counterpart in the CT image. A localized maximally stable extremal regions method is proposed to automatically segment SPECT hot spots, while the corresponding CT structures are segmented by the semi-automatic random walk method, based on a fast multigrid solver. Accuracy and reproducibility of the validation method have been preliminary confirmed by the test with 21 clinical data-sets.     

Phase-constrained data extrapolation method for reduction of truncation artifacts

The authors present an improvement to a sigma-filter extrapolation method for the reconstruction of magnetic resonance (MR) images from symmetric discrete Fourier data. By making use of the phase information in the image data, the proposed method can overcome the data inconsistency problem of the original method for handling MR image data with large phase variations, such as those obtained in gradient-echo pulse sequences. Reconstruction results show that its performance is comparable with that of the modified complex sigma-filter method proposed previously to handle the inconsistency problem. However, the new approach has the advantage of reducing computation time by a factor of two with use of a sigma filter applied to real instead of complex images. It is expected that this method will be more practical for use in clinical MR imaging systems.     

Application of newly developed Fluoro-QC software for image quality evaluation in cardiac X-ray systems

IntroductionA quality assurance (QA) program is a valuable tool for the continuous production of optimal quality images. The aim of this paper is to assess a newly developed automatic computer software for image quality (IR) evaluation in fluoroscopy X-ray systems.MethodsTest object images were acquired using one fluoroscopy system, Siemens Axiom Artis model (Siemens AG, Medical Solutions Erlangen, Germany). The software was developed as an ImageJ plugin. Two image quality parameters were assessed: high-contrast spatial resolution (HCSR) and signal-to-noise ratio (SNR). The time between manual and automatic image quality assessment procedures were compared. The paired t-test was used to assess the data. p Values of less than 0.05 were considered significant.ResultsThe Fluoro-QC software generated faster IQ evaluation results (mean = 0.31 ± 0.08 min) than manual procedure (mean = 4.68 ± 0.09 min). The mean difference between techniques was 4.36 min. Discrepancies were identified in the region of interest (ROI) areas drawn manually with evidence of user dependence. The new software presented the results of two tests (HCSR = 3.06, SNR = 5.17) and also collected information from the DICOM header. Significant differences were not identified between manual and automatic measures of SNR (p value = 0.22) and HCRS (p value = 0.46).ConclusionThe Fluoro-QC software is a feasible, fast and free to use method for evaluating imaging quality parameters on fluoroscopy systems.     

Multimodality Image Fusion and Planning and Dose Delivery for Radiation Therapy

Image-guided radiation therapy (IGRT) relies on the quality of fused images to yield accurate and reproducible patient setup prior to dose delivery. The registration of 2 image datasets can be characterized as hardware-based or software-based image fusion. Hardware-based image fusion is performed by hybrid scanners that combine 2 distinct medical imaging modalities such as positron emission tomography (PET) and computed tomography (CT) into a single device. In hybrid scanners, the patient maintains the same position during both studies making the fusion of image data sets simple. However, it cannot perform temporal image registration where image datasets are acquired at different times. On the other hand, software-based image fusion technique can merge image datasets taken at different times or with different medical imaging modalities. Software-based image fusion can be performed either manually, using landmarks, or automatically. In the automatic image fusion method, the best fit is evaluated using mutual information coefficient. Manual image fusion is typically performed at dose planning and for patient setup prior to dose delivery for IGRT. The fusion of orthogonal live radiographic images taken prior to dose delivery to digitally reconstructed radiographs will be presented. Although manual image fusion has been routinely used, the use of fiducial markers has shortened the fusion time. Automated image fusion should be possible for IGRT because the image datasets are derived basically from the same imaging modality, resulting in further shortening the fusion time. The advantages and limitations of both hardware-based and software-based image fusion methodologies are discussed.     

Vessel enhancement filtering in three-dimensional MR angiography

For a variety of reasons, small vessels have low signal intensity in magnetic resonance angiography. When the vessel signal Intensity is lower than the signal intensity of background tissues, these vessels tend not to be visible on maximum-intensity-projection images. The authors developed a nonlinear second-difference spatial filtering technique that enhances the details of small vessels while suppressing both noise and uniform background tissue. Two similar nonlinear second-difference filters are presented and compared with the linear Laplacian second-difference filter. To evaluate the performance of these filters, they were applied to intracranial three-dimensional time-of-night MR angiographic data and the results compared with the vessel enhancement obtained with a simple second-difference Laplacian filter and with magnetization transfer contrast (MTC) techniques. The comparisons demonstrated that nonlinear filtering and MTC techniques result in similar improvement in small-vessel visibility and apparent continuity. A quantitative comparison demonstrated that the improvement in the contrast-to-noise ratio is much greater with the nonlinear filters than the Laplacian filter.     

Toward comparability of coronary magnetic resonance angiography: proposal for a standardized quantitative assessment

A method is proposed for the quantitative assessment of coronary magnetic resonance angiography (MRA) acquisitions. The method is based on four parameters: signal-to-noise ratio (SNR); contrast-to-noise ratio (CNR); vessel length; and vessel-edge definition. A pig model (n=7) was used to illustrate the proposed quantitative analysis method. Three-dimensional gradient-echo coronary MRA was performed with and without exogenous contrast enhancement using a gadolinium-based blood-pool contrast agent (Vistarem, Guerbet, Aulnay-Sous-Bois, France). The acquired images could be well differentiated based on the four parameters. The SNR was calculated as 9.0±1.4 vs 10.4±2.1, the CNR as 6.2±0.8 vs 8.2±0.9, the vessel length as 48.2±11.6 vs 86.5±13.8 mm, and the vessel-edge definition as 4.9±1.5 vs 7.7±3.4. Different coronary MRA techniques can be evaluated objectively with the combined use of SNR, CNR, vessel length, and vessel-edge parameters.