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双源CT诊断肺动脉吊带畸形一例

迭代重建技术降低踝关节内固定金属伪影的价值

目的 探讨迭代重建（iterative reconstruction，IR）技术在踝关节金属内固定术后数字化断层融合（digital radiographic tomosynthesis，DTS）检查中的临床应用价值。 方法 2014 年 10 月—2015 年 6 月采用 DTS 技术检查踝关节金属内固定术后复查患者 30 例，每例患者的原始数据分别采用 IR 算法和滤波反投影（filter back projection，FBP）算法进行重建。重建后图像根据图像噪声、内固定金属周围骨质清晰度和失真度，以 3 分法对图像质量进行主观评价，数值越高图像越清晰；测量螺钉伪影长度、螺钉与骨质结合程度作为客观数据评价，数据值越小图像质量越好。 结果 图像噪声、内固定周围骨质清晰度和失真度的主观评分：采用 IR 算法重建的图像中，优片 26 例（86.7%），良片 4 例（13.0%）；采用 FBP 算法重建的图像中，优片 3 例（10.0%），良片 27 例（90.0%）；两种算法重建图像优质率差异有统计学意义（χ2=21.043，P<0.001）。两种算法重建图像均无螺钉伪影。IR 算法重建图像螺钉与骨质结合紧密，间隙度为 0 mm；FBP 算法重建图像螺钉与骨质结合间隙度为 0.2～0.3 mm，系金属硬化束伪影。 结论 DTS 扫描 IR 技术能有效降低踝关节内固定金属伪影，图像质量明显优于 FBP 重建图像，踝关节金属内固定 DTS 检查 IR 技术有较高的临床应用价值。

Value of Multi-slice CT in Assessing the Features of Carotid Artery Plaques

目的　探讨多层螺旋CT在评价颈动脉斑块特征中的价值。 方法　回顾性分析2011年7月－10月132例行CT颈部血管造影患者的影像资料。对颈动脉斑块特征进行评价，重建方法包括多层面重建、容积再现技术、最大密度投影及曲面重建。 结果　132例患者中，80例检出颈动脉斑块，最常出现钙化斑块的部位为海绵窦段和床突上段，右侧海绵窦段52例（65.0%）、左侧海绵窦段49例（61.3%），右床突上段37例（46.3%）、左侧床突上段30例（37.5%）。最常出现软斑块的部位为双侧颈总动脉，均为12例（15.0%）。最常出现混合斑块的部位为颈总动脉，右侧颈总动脉9例（11.3%）、左侧颈总动脉12例（15.0%）。颈动脉最容易轻度狭窄294处（294/1 440，20.4%），中、重度狭窄少见，分别为8处（8/1 440，0.5%）和6处（6/1 440，0.4%）。颈部动脉血管斑块最易出现钙化，总计249处（249/1 440，17.3%），其次是软斑块和混合斑块，均为39处（39/1 440，2.7%）。 结论　多层螺旋CT可准确评价颈动脉斑块特征。

多层螺旋CT辐射剂量控制与监督的临床意义

【摘要】 多层螺旋CT检查已经成为临床诊断疾病的重要检查手段，然而CT检查产生的辐射剂量也越来越得到研究人员的关注。通过对MSCT辐射剂量的影响因素，降低MSCT辐射剂量的方法，合理选用CT检查，规范化设置CT检查方案，普及辐射防护知识，形成有效管理监督机制的论述、分析，探讨MSCT辐射剂量控制与监督的临床价值。

Advances in clinical application of stereoelectroencephalography-based electrical stimulation in the evaluation of refractory epilepsy

For refractory epilepsy requiring surgical treatment in clinic, precise preoperative positioning of the epileptogenic zone is the key to improving the success rate of clinical surgical treatment. Although the use of electrical stimulation to locate epileptogenic zone has been widely carried out in many medical centers, the preoperative implantation evaluation of stereoelectroencephalography (SEEG) and the interpretation of electrical stimulation induced EEG activity are still not perfect and rigorous. Especially, there are still technological limitations and unknown areas regarding electrode implantation mode, stimulation parameters design, and surgical prognosis correlation. In this paper, the clinical background, application status, technical progress and development trend of SEEG-based stereo-electric stimulation-induced cerebral electrical activity in the evaluation of refractory epilepsy are reviewed, and applications of this technology in clinical epileptogenic zone localization and cerebral cortical function evaluation are emphatically discussed. Additionally, the safety during both of high-frequency and low-frequency electrical stimulations which are commonly used in clinical evaluation of refractory epilepsy are also discussed.

The progress in imaging evaluation of liver iron concentration

ObjectiveTo summarize the methods and research progress of imaging evaluation of liver iron concentration.MethodsThe current status and progress of different imaging techniques in liver iron overload research were reviewed by studying the relevant literatures at home and abroad. The methods for determining liver iron concentration and their advantages and disadvantages were summarized.ResultsThe imaging methods for determining liver iron concentration mainly included traditional non-enhanced CT and dual energy CT examination, magnetic resonance signal intensity ratio, relative signal intensity index, T2 and R2 values, magnetic resonance spectroscopy, T2* and R2* values, susceptibility weighted imaging, and quantitative susceptibility mapping.ConclusionLiver iron quantification imaging method, including dual-energy CT and magnetic resonance imaging could non-invasively and accurately assess the liver iron overload.

MRI常规扫描及弥散加权成像在宫颈癌评价中的价值

MRI常规扫描凭借着较高的软组织分辨率对宫颈癌肿块在宫颈内部的生长情况、肿块对宫体的侵犯程度以及对宫旁癌周的侵犯、宫旁闭孔区淋巴结转移的评价方面具有较高准确性和特异性。MRI常规扫描可提高宫颈癌的定位、定性、分期的准确性，有助于临床国际妇产科联盟（FIGO）分期。MRI弥散加权成像，作为功能磁共振的一种，是唯一一种可以评价活体组织内水分子弥散状况的扫描方法，利用弥散加权成像获得表观弥散系数值可以对宫颈癌病灶组织病理学类型及分化程度、宫旁侵犯、淋巴结转移进行定量定性分析。将弥散加权成像与常规扫描结合起来在诊断宫颈癌、协助临床FIGO分期、制订优化个体化治疗方案及预后预测上有较大临床应用价值。

Study on the Feasibility of Brain CT Perfusion with 70 kV Tube Voltage

ObjectiveTo investigate the influence of 70 kV low-dose CT perfusion technique on brain CT perfusion parameter maps and image quality. MethodsRetrospective analysis of all patients who underwent CT perfusion of brain between October 2013 and February 2014 was carried out. The patients were randomly divided into two groups according to diTherent CT examination dose: group A (80 kV, 200 mAs) and group B (70 kV, 200 mAs). All patients were scanned on a dual-source-CT (Siemens Definition Flash). Fifteen normal subjects without brain diseases in each group were selected to be studied. Region of interest (ROI) with an area of 80 mm2 was placed in the nucleus, putamen, thalamus, periventricular white matter of the frontal lobe and temporo-occipital area, and the parameters in the ROI including cerebral blood flow, cerebral blood volume, mean transit time and time to peak were detected. The carrierto-noise ratio and signal-to-noise ratio of thalamus and periventricular white matter of the frontal lobe were contrasted. The image quality of perfusion was assessed by two senior radiologists using 5 point system for blind assessment (5=best, 1=worst). The measurement of radiation dose was studied through effective dose, volume CT dose index (CTDIVOL) and dose length product (DLP). Statistical analysis was performed by independent sample t test. ResultsThere was no significant difference between group A and group B in brain CT perfusion parameters (P>0.05). There was no significant diTherence in image quality between the two groups in the objective and subjective assessment (P>0.05). In comparison with group A, the measured effective dose, CTDIVOL and DLP for group B decreased by 35%. ConclusionThere was no significant influence on the brain CT perfusion parameters and image quality using 70 kV tube voltage, and radiation dose is decreased obviously.

Influence of the abduction angle of the double upper limbs on liver non-enhanced CT image quality in patients with vehicle accident

ObjectivesTo investigate the influence of the abduction angle of the upper extremities on the image quality of non-enhanced CT scan and clinical value of the patients who cannot lift with double upper limbs by vehicle accident.Methods60 patients with double upper limbs that could not lift by vehicle accidents were required to receive liver non-enhanced CT scan, the patients were divided into 3 groups according to the abduction angle (group A, B, C), 20 cases in each group, another 20 cases with standard pose as the control group (group D). The CT value and standard deviation of the liver region of interest, the erector and the background air were measured, and the contrast to noise ratio of liver images, image noise value were calculated, together with the assessment of image quality and statistic analysis.ResultsThe liver non-enhanced CT scan were completed successfully. The image quality of group D was significantly better than A, B, C (Z=–10.753, P<0.05;Z=–11.645, P<0.05;Z=–12.281, P<0.05), respectively. Group C was better than A and B (Z=–8.502, P<0.05;Z=–4.068, P<0.05), respectively. Group B was better than A (Z=–5.885, P<0.05). The CNR of the four groups of images increased gradually, group A (0.09±0.77), group B (1.56±0.83), group C (2.51±0.87), group D (2.59±0.97), respectively. There were significant differences between four groups (F=36.323, P<0.05). The image noise decreased systematically, group A (14.84±2.94), group B (13.04±1.59), group C (11.60±1.72), group D (10.44±1.13), respectively. There were significant differences between four groups (H=426.755, P<0.05).ConclusionOn the premise of safety inspection, with the enlargement of angle of the upper limbs of patients who cannot lift with double upper limbs by vehicle accidents, the image noise decreased and image quality is improved with the increase of signal noise ratio.

The Application of 70 kV and Sonogram-affirmed Iterative Reconstruction Technique in CT Examination for Children with Congenital Heart Disease

ObjectiveTo evaluate the value of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease. MethodsThirty children with congenital heart disease who underwent CT scan between January and September 2014 were included in this study. According to the different tube voltage, they were randomly divided into group A (80 kV) and group B (70 kV), with fifteen in each. All the children were scanned on a dual-source-CT (Siemens Definition Flash). Group A used filtered back projection reconstruction. Group B used sonogram-affirmed iterative reconstruction. We measured and calculated the pulmonary artery signal-to-noise ratio at the level of main pulmonary artery window, the signal-to-noise ratio of the ascending aorta, noise ratio contrast between the pulmonary artery and erector spinae and between the ascending aorta and erector spinae. The image quality for congenital heart disease was assessed by two senior radiologists. The measurement of radiation dose included effective dose (ED), volume CT dose index (CTDIvol) and dose length product (DLP). ResultsThere were no significant differences between group A and B in terms of pulmonary artery signal-to-noise ratio (14.54±3.77, 11.23±2.52), the signal-to-noise ratio of the ascending aorta (14.76±3.41, 12.31±3.47), the noise ratio contrast between pulmonary artery and erector spinae (12.04±3.96, 9.18±3.76) and between the ascending aorta and erector spinae (12.47±4.59, 9.77±4.41) (P > 0.05). There was significant difference between group A and group B in CTDIvol[(0.53±0.09), (0.38±0.03) mGy], DLP[(12.93±1.79), (6.67±0.72) mGy·cm], and ED[(0.34±0.05), (0.17±0.02) mSv] (P < 0.05). ConclusionThe application of 70 kV and sonogram-affirmed iterative reconstruction technique in CT examination for children with congenital heart disease can significantly reduce the radiation dose without any influence on image quality.