计算机辅助检测肺结节在数字化X线胸片肺癌筛查中的应用价值

目的 评价计算机辅助检测(CAD)肺结节系统在数字化X线胸片上肺癌筛查中的应用价值.方法 由1名放射科医师和CAD肺结节检测系统独立阅读100例连续的数字摄影(DR)X线胸片,CAD系统可以检出最长直径在5～15 mm的肺结节.由2名放射科专家(有15年胸部影像诊断经验)进行回顾性阅读,参照相应的CT图像,两人意见达成一致后标记真结节的个数和位置并保存标记结果,将标记结果作为金标准来比较放射科医师和CAD系统的肺结节检测敏感性和假阳性率.结果 放射科医师共检测到95个结节,CAD系统共检测到304个结节.在回顾性检查中2名放射科专家共标记134个真结节,其中放射科医师检测到82个(61.2%),CAD检测到105个(78.4%),CAD系统检测到而被放射科医师漏诊的结节35个,放射科医师检测到而CAD系统漏诊的结节10个.放射科医师应用CAD系统后检测到112个真结节,检测率提高到83.6%.放射科专家意见一致后认为CAD系统检出199个假阳性结节,平均每张胸片约2.0个.结论 在肺癌筛查中放射科医师和CAD系统必须联合应用才可以识别X线胸片中所有的结节.     

早期肺癌的筛查方法的研究

介绍了胸片、低剂量螺旋CT及痰液分析等筛查方法(主要是影像学方法)在肺癌筛查中的不同价值及目前的研究现状。     

胸部计算机放射摄影术与传统胸片在肺癌诊断中的对比研究

目的　研究胸部计算机放射摄影 (CR)术在肺癌诊断中的价值。方法　经手术病理证实的肺癌 5 6例 ,其中中央型肺癌3 4例 ,周围型肺癌 2 2例。 4种胸部CR图像 :平片CR( plainCR)、宽幅高频响应CR(wideCR )、高频响应CR(HE -CR )、低频响应CR (LE -CR) ;2种胸部CR体层摄影 :平片CR体层摄影 (plainCR -TOMO)、高频CR体层摄影 (HE -CR -TOMO) ;分别与传统胸片及传统体层摄影在正常结构及异常阴影的显示进行对比。结果　①正常结构的观测 :除wideCR、HE -CR对右下肺动脉的显示不如常规X线 (CXR)外 ,其余项目的各种CR图像均不同程度地优于CXR。体层摄影 :所有观测项目 ,CR体层摄影均优于CXR体层摄影。②异常阴影的观测 :中央型肺癌 ,PlainCR与LE -CR对所有观测项目的显示均优于CXR ;wideCR对受累支气管的显示优于CXR ,而对肿块内部密度分布及周围血管影的显示与CXR相同 ,对肺门肿块边缘的显示不如CXR。HE -CR所有观测项目均不如CXR。周围型肺癌 ,plainCR、LE -CR对肿块边缘特征及空洞的显示优于CXR ,而对密度分布的显示与CXR相同 ;wideCR对肿块边缘特征的显示不如CXR ;HE -CR对所有观测项目的显示均不如CXR。体层摄影 :PlainCR -TOMO及HE-CR -TOMO均优于CXR体层摄影。结论　通过对胸部正常结构及异常阴影的CR与C     

X线胸片与CT诊断1cm左右周围型小肺癌

目的：探讨Ｘ线胸片与ＣＴ对１ｃｍ左右周围型小肺癌的诊断价值。资料与方法：回顾性分析经病理证实的１７例直径在１ｃｍ左右的周围型小肺癌的Ｘ线胸片资料与其中１１例ＣＴ资料。结果：胸片上分叶征２例，胸膜凹陷征１例。有系列Ｘ线胸片者见病变逐渐增大或从无到有。ＣＴ片病灶显示边缘清楚较整齐者７例，毛刺征３例，分叶征７例，血管集束征９例，空泡征或支气管充气征４例，胸膜凹陷征３例，空洞２例。结论：Ｘ线胸片是检出１ｃｍ左右周围型小肺癌的主要方法，但不能定性；ＣＴ是诊断１ｃｍ左右小肺癌的较好方法，但也有一定限度；二者结合可提高诊断准确率。     

周围型小肺癌影像学误诊原因分析

本文搜集1990年以来经手术，活检等病理证实而影像学误诊的周围型小肺癌48例，究其误诊原因回顾分析如下。     

低剂量MSCT与DR诊断周围型肺癌的对比分析

目的 :探讨低剂量MSCT与DR胸片在诊断周围型肺癌中的应用价值,并比较两者检查效果,为肺部病变特别是周围型肺癌等检查手段的选择提供重要依据。方法:选择我院经低剂量MSCT及DR胸片检查的40例周围型肺癌患者,对其CT及胸部DR检查结果进行对照分析。结果:CT检查所示肿瘤分叶征、毛刺征、胸膜凹陷征、空泡征及血管集束征的显示率明显高于胸部DR检查(均P0.05)。结论:DR胸片是一种常用的胸部X线检查手段,但受分辨力及组织密度等因素的影响,易漏诊、误诊,检查阳性率低于低剂量MSCT。低剂量MSCT辐射剂量远低于常规CT检查,且检查结果能满足诊断要求,易被临床接受,因此低剂量MSCT在周围型肺癌的检查中具有更高的应用价值。     

周围型小肺癌动态X线表现分析(附20例报告)

目的:探讨周围型小肺癌早期X线表现及动态变化特点。方法:对胸部X线诊断为周围型小肺癌的20例系列胸片作了回顾性复习。19例小肺癌经病理证实,1例具有典型的临床影像学表现。将本组病例按检出前和检出时病灶形态、大小、密度和边缘进行了对比。结果:从回顾性阅片小肺癌初次显现至病灶检出相距时间为8~48 个月,平均21.6个月。倍增时间为30~300 d,平均为133 d。初次显现病变的X线表现有3 种形态:微结节聚集状、灶状浸润、不规则结节状。所有这些病灶至检出时均长成为平均直径(20.7±9.1) mm的结节。结论:认识小肺癌早期的X线表现,进一步行CT扫描将有助于小肺癌的检出。     

数字摄影曝光参数的探讨

目的：通过数字摄影曝光参数的合理选择与正确运用，以求达到改善Ｘ线图像质量，提高诊断率的目的。材料与方法：运用图像质量测试板模体实验，结合ＰｏｌｙｓｔａｒＸ线透视系统中１１项曝光参数选择项目，逐一地进行调整试验，对曝光参数修改前后各抽５０份照片进行对照分析，确立最佳曝光参数。结果：经对曝光参数修改前后各５０份照片分析比较，最佳照片率由８％提高到５６％，稍差者由４％降到２％。结论：数字摄影曝光参数的合理选择与应用，是提高照片质量的一项重要技术内容。与普通Ｘ线摄影曝光参数的选择相比，数字摄影曝光参数选择中有四大特点：（１）曝光条件宽容度大；（２）减低投照辐射量；（３）广范围的放射感应性；（４）原始局部放大可提高影像分辨率。     

螺旋CT气管重建技术评价肺癌与气管支气管的关系

目的探讨螺旋CT气管重建技术在评价肺癌与气管支气管的关系中的价值。方法对34例拟手术的病例和5例已手术的病例进行CT扫描,在工作站上进行重建处理,重建方法包括MPR,SSD及VR,分别分析轴位图像和重建图像并进行对比。结果在显示狭窄部位方面,重建图像优于轴位图像,可纠正轴位图像错误3例。在显示肿瘤与支气管的空间关系方面,重建图像可以非常清楚显示,而轴位图像没有一例可以提供这方面的信息。在显示狭窄程度方面,轴位图像判断的敏感性、特异性分别为67．4％,75．3％;重建图像判断的敏感性、特异性分别为86．2％,83．2％。在显示支气管侵犯范围方面,轴位图像判断的敏感性、特异性分别为72．4％,66．5％;重建图像判断的敏感性、特异性为89．3％,90．4％。结论螺旋CT气管重建技术对判断肺癌与气管支气管的关系很有帮助。     

低剂量多层螺旋CT薄层扫描筛查肺癌的可行性分析

目的　分析低剂量多层螺旋CT(MSCT)全肺薄层扫描筛查早期肺癌的可行性,以提高其实际应用价值。方法　选择肺癌高危人群(≥50岁,吸烟总量≥20年包)387例行胸片及低剂量MSCT全肺薄层( 2. 5 ~3. 75mm)扫描检查,分析胸片和低剂量MSCT检出中央型和周围型肺癌的敏感性与特异性,分析低剂量MSCT扫描参数、权重CT剂量指数(CTDIW )和剂量长度乘积(DLP),评价该扫描技术的可靠性与安全性。结果　胸片检出周围型肺癌2例,中央型肺癌1例,敏感性分别为33. 3%、20. 0%,特异性分别为99. 2%、99. 2%。低剂量MSCT检出周围型肺癌5例,中央型肺癌4例,敏感性为83. 3% 、80. 0% ,特异性为94. 2%、96. 9%,CTDIW 和DLP分别为1. 63mGy和47. 1mGy·cm,约为常规剂量的6%和7%。结论　低剂量MSCT全肺薄层扫描是一种敏感、安全、可行的筛查早期(特别是早期中央型)肺癌的方法,能取代胸片筛查早期肺癌。     

低剂量螺旋CT筛选检查早期肺癌的初步研究

目的 评价低剂量螺旋CT筛选检查（简称筛检）对肺癌高危险人群早期肺癌的检出率。方法 对无症状300例体检者胸片及CT进行前瞻性研究，纳入标准为年龄45岁以上，吸烟10年包（10年以上，每日1包）以上，或既往有慢性阻塞性肺疾病病史，以前无癌症史，身体状况适合手术治疗者，低剂量CT扫描采用Philip SR 7000及GE LightSpeed Plus多层面CT扫描机。图像由2位放射医师在工作站显示器上以电影显示方式观察，存储至影像存储与传输系统（PACS）。结果 低剂量CT共检出56例（19％）非钙化结节（其中恶性4例），胸片检出9例（3％）（其中恶性3例），均为1期病变。低剂量CT检出叶支气管或段支气管病变9例（3％），其中早期中央型肺癌例（1％），胸片均未检出，胸片、CT对肺癌筛检的敏感度分别为43％、100％，特异度分别为89％、80％。结论 初步筛检结果表明低剂量螺旋CT明显提高了对肺内非钙化小结节及支气管细微病变的检出，可检出早期肺癌。     

Characteristics of missed lung cancer on chest radiographs: a French experience

The purpose of this study was to report 30 cases of missed lung cancers and describe characteristics of each case. Reasons for misdiagnosis were analyzed from the report. Each radiograph was subsequently reviewed by a panel of two experts who quantified several parameters regarding image analysis and film quality. Lesions were not described in 67 % of the cases and were misinterpreted as benign processes in 33 % of cases. Comparison to previous chest radiographs and clinical information were seldom available on the report. Size of the lesions varied between 1 and 7 cm, location was primarily apical and paramediastinal, normal anatomy was highly or moderately complex in 87 %, and distracting lesions were present in 63 % of the cases. Image quality was considered perfect in 3 cases only. Among all the factors responsible for missed lung cancer, certain factors can be improved as film quality, comparison with previous radiographs, and better awareness of clinical information. Received: 13 March 2000 Revised: 30 June 2000 Accepted: 3 July 2000     

Multiple brain abscesses presented with monoparesis in a patient with lung abscess mimicking lung cancer

Multiple brain abscesses associated with the lung mass require differential diagnosis from cancerous diseases. Here, we report a rare case of multiple brain abscesses originating from a lung abscess. A 65-year-old man presented with a 2-day history of motor weakness during antibiotic treatment for pneumonia. Brain magnetic resonance imaging (MRI) revealed multiple enhanced lesions of various sizes in the whole brain. Diffusion-weighted MRI showed high signal intensity in several lesions, and magnetic resonance (MR) spectroscopy showed reduced N-acetyl-aspartate (NAA) and high lactate-lipid complex levels. Positron emission tomography/computed tomography revealed a hypermetabolic mass-like lesion (size: 5 × 3 cm) in the right lower lobe. The patient was diagnosed with organizing pneumonia by bronchoscopy and was successfully treated with empirical antibiotics for multiple brain abscesses and lung abscesses. If new neurological deficits occur during the treatment of inflammatory diseases such as pneumonia, the possibility of brain abscesses and cancerous conditions should be considered. Appropriate diagnosis and antibiotic treatment should be performed to ensure favorable outcomes.     

数字X线摄影平板探测器斜射效应的研究

目的 探讨DR平板探测器在倾斜X线管摄影时,斜射效应与X线管倾斜角度的关系.方法 使用Kodak DR3000系统,X线管分别倾斜0°、10°、20°、30°、40°对R-1型矩形波测试卡进行摄影,计算X线管不同倾斜角度的预采样调制传递函数(MTF).采用配对资料的Wilcoxon符号秩和检验(倾斜角0°作为控制组)比较不同X线管倾斜角度的MTF系数值.结果 X线管倾斜角度越大,预采样MTF曲线的位置越低,X线管倾斜40°时的MTF曲线明显居于最低位置.斜射效应对低频的组织结构影响小,对中、高频的组织结构影响大.与0°的结果比较,倾斜角10°的MTF参数差异无统计学意义(Z=-1.893,P=0.058),倾斜角20°、30°、40°时的MTF参数差异均有统计学意义(Z值分别为-2.547、-2.666、-2.666,P值均＜0.05).结论 对于DR平板探测器,X线管倾斜角度越大,斜射效应越严重,X线管倾斜角度不宜超过10°.     

Quantitative assessment of the influence of anatomic noise on the detection of subtle lung nodule in digital chest radiography using fractal-feature distance

Purpose

To confirm whether or not the influence of anatomic noise on the detection of nodules in digital chest radiography can be evaluated by the fractal-feature distance.

Materials and methods

We used the square images with and without a simulated nodule which were generated in our previous observer performance study; the simulated nodule was located on the upper margin of a rib, the inside of a rib, the lower margin of a rib, or the central region between two adjoining ribs. For the square chest images, fractal analysis was conducted using the virtual volume method. The fractal-feature distances between the considered and the reference images were calculated using the pseudo-fractal dimension and complexity, and the square images without the simulated nodule were employed as the reference images. We compared the fractal-feature distances with the observer's confidence level regarding the presence of a nodule in plain chest radiograph.

Results

For all square chest images, the relationships between the length of the square boxes and the mean of the virtual volumes were linear on a log–log scale. For all types of the simulated nodules, the fractal-feature distance was the highest for the simulated nodules located on the central region between two adjoining ribs and was the lowest for those located in the inside of a rib. The fractal-feature distance showed a linear relation to an observer's confidence level.

Conclusion

The fractal-feature distance would be useful for evaluating the influence of anatomic noise on the detection of nodules in digital chest radiography.     

Clinical evaluation of a new digital chest imaging system

A digital chest imaging system based on a selenium detector has been installed in a large teaching hospital. Up to 1 May 1994, 7000 patients have been studied by this new technique. Hard copies are printed on a laser imager. Image quality of the digital system was analysed by day-to-day comparison with a conventional chest system. In a pilot study of 40 patients conventional and digital images were compared by analysing six different anatomical regions. Two readers judged the image quality of the digital system to be better than that of a conventional chest system, all regions being better visualised on the digital images (P <0.01). Acceptance of the digital chest system by radiographers, radiologists and other medical specialists is good. More than half of the normal patient load is routinely dealth with using the new system. Retakes were hardly necessary. Post-processing is possible, but was seldom used. These preliminary overall results of a digital chest imaging system based on a selenium detector in routine clinical practice are promising and further phantom studies and clinical studies using receiver operating characteristic (ROC) analysis are currently being performed. Correspondence to: J. P. M. van Heesewijk     

Lung cancer screening-don’t forget the chest radiograph

Lung cancer is a major health burden and early detection only bears the possibility of curative treatment. Screening with computed tomography (CT) recently demonstrated a mortality reduction in selected patients and has been incorporated in clinical guidelines. Problems of screening with CT are the excessive number of false positive findings, costs, radiation burden and from a global point of view shortage of CT capacity. In contrast, chest radiography could be an ideal screening tool in the early detection of lung cancer. It is widely available, easy to perform, cheap, the radiation burden is negligible and there is only a low rate of false positive findings. Large randomized controlled trials could not show a mortality reduction, but different large population-based cohort studies have shown a lung cancer mortality reduction. It has been argued that community-based cohort studies are more closely reflecting the “real world” of everyday medicine. Radiologists should be aware of the found mortality reduction and realize that early detection of lung cancer is possible when reading their daily chest radiographs. Offering a chest radiograph in selected scenarios for the early detection of lung cancer is therefore still justified.     

SARS的胸部X线表现特征

目的 探讨严重急性呼吸综合征(SARS)，又称急性传染性非典型肺炎的胸部S线表现特征。方法 52例SARS患者，每隔l～3d摄胸部正侧位片，而且在7次以上；回顾性分析经临床、流行病学、放射学、实验室检查确诊的52例SARS患者的胸部X线表现。结果SARS患者的胸部X线表现为：3l例见两肺大片状、小片状密度增高阴影；18例见l侧肺叶或肺段有片状影；l例表现为肺段内结节影；2例见两肺纹理增粗，呈网格状及不规则线状影；16例见磨玻璃样影。动态观察并综合分析SARS的X线表现，可有如下特征：三片一间(病人出现大片状、小片状、斑片状阴影，有些病人出现间质性改变)；三多一个不相符(病灶在两肺中下野多；磨玻璃样影多；游走性多，即上下游走或左右游走；症状与X征象不相符；一快一慢(胸部X线表现病灶变化快，最终吸收慢)。结论SARS的胸部X线表现如单独和单次静态观察似乎无明显特征改变；但是，进行动态观察并综合分析胸部X线征象及变化，还是有其一定特征性。     

不典型外围型肺癌的CT误诊分析

目的 :探讨不典型外围型肺癌的CT诊断。方法 :对 7例不典型外围型肺癌进行回顾性分析 ,全部患者均摄有胸部正侧位片 ,并行常规CT平扫及强化扫描 ,病变区行 3.0mm薄扫 ,并对前后CT片进行比较。结果 :7例病变中 ,位于左肺上叶 2例 ,下叶 1例 ,右肺下叶 3例 ,中叶 1例。术后病理为中分化腺癌 4例 ,鳞状细胞癌 2例 ,细支气管肺泡癌 1例。结论 :X线胸片、CT平扫及强化扫描对不典型外围型肺癌较难作出正确诊断。缺乏影像特征性病变的患者应短期治疗后复查 ,重点观察病变有无变化。病变无好转者应及早行肺穿刺细胞学检查或手术治疗