分析数字化体层摄影术对胸部X线疑似肺部疾病病人的影像学检查的作用

目的评价数字化体层摄影术(DTS)对胸部X线摄影(CXR)疑似肺部疾病病人的影像学检查的作用。方法 CXR疑似肺部疾病经过DTS检查的病人有339例[男200例,平均(71.19±11.9)岁]。2名研究人员前瞻性分析DTS和CXR影像,并且记录他们的诊断意见:1或者2表示确定的或很可能为良性病变或假性病变,而不需要进一步检查;3表示不确定的;4或者5表示很可能或确定为肺部病变,需要进一步行CT检查。经CT(76例)、CXR(256例)定期复查的影像,或组织学检查(7例)为参考标准。结果 DTS明确了339例病人中256例(76%)CXR不能确定的病灶,而339例中83例(24%)进一步行CT检查。DTS的平均检查时间[(220±40)s]高于CXR的[(110±30)s](P<0.05),但是低于CT的[(600±150)s]。平均有效辐射剂量,CXR为0.06mSv(0.03～0.1mSv),DTS为0.17mSv(0.094～0.12mSv),CT为3mSv(2～4mSv)。结论相对于CXR而言,平均检查时间和有效辐射剂量略有增加的DTS避免了3/4的病人行CT检查。要点①DTS提高了CXR的诊断正确率。②DTS减少了肺部可疑病变对CT的需求。③DTS仅产生了大约2倍于CXR的辐射剂量。④DTS检查时间长于传统胸部X线的检查时间。     

数字合成体层成像和X线数字摄影在肺内结节探测中敏感度的比较

目的 比较数字合成体层成像(DTS)和普通X线数字摄影对肺内结节探测的敏感度,评价DTS检测肺内小结节的能力.方法 22名有肺内小结节的患者进行随访性CT检查,由2名放射医师共同对CT扫描图像进行阅读,来证实结节的存在并为其定位,作为结节存在的标准.另外为患者进行了后前位胸部X线数字摄影(PA)和DTS检查.再由另外3位胸部放射医师独立阅读DTS影像和PA影像,来确定CT所证实的结节在这两种影像上的显示情况.结节按以下标准进行分级:肯定可见,不确定,不可见.3个级别按直径大小分为以下三组:＜5,5～10,＞10mm.分析那些标记为肯定可见的结节的真阳性结果.结果 CT断层扫描共检出180个直径范围在3.5～19.5mm的结节,DTS和PA的敏感度分别是67％和23％(P＜0.0001).一致性检验表明,在所有三组不同大小的结节中,DTS和PA对肺内结节的检出率均有统计学差异,其中对小结节(直径＜5mm)的探测敏感度,两者分别达到49％和10％.结论 和PA相比,在各类大小不同的肺内小结节的探测中,DTS都显示出较大的敏感性.     

Role of chest radiography in predicting the extent of airway disease in patients with suspected pulmonary embolism

An independent evaluation of the chest radiographs and ventilation-perfusion (VP) scintigrams of 119 patients (121 studies) was performed to assess the ability of radiographic findings to indicate the extent of ventilation abnormalities in patients suspected of having pulmonary embolism (PE). VP scans were obtained with krypton-81m in 72 cases and with xenon-133 in 49. All scintigrams showing ventilation abnormalities in greater than 50% of the lung were considered indeterminate for PE, owing to an increased likelihood of false-negative interpretations, as reported in previous studies. Indeterminate VP studies were found in all 21 patients who had radiographic findings of widespread obstructive pulmonary disease (OPD), in 35% with radiographic findings of focal OPD (P less than .001), and in only 18% with no OPD seen radiographically (P less than .001). VP scintigraphy is likely to be indeterminate for PE when widespread OPD is seen by chest radiography and ventilation imaging may not be warranted in these patients.     

Impact of clinical data on chest radiography sensitivity in detecting pulmonary abnormalities in immunocompromised patients with suspected pneumonia

Purpose

Chest radiography (CXR) of immunocompromised patients has low sensitivity in the early evaluation of pulmonary abnormalities suspected to be infectious. The purpose of the study was to evaluate whether the knowledge of clinical data improves the diagnostic sensitivity of CXR in the particular setting of immunocompromised patients after hematopoietic stem cell transplantation (HSCT).

Materials and methods

Sixty-four CXRs of immunocompromised patients with clinically suspected pneumonia were retrospectively and independently evaluated by two radiologists to assess the presence of radiological signs of pneumonia, before (first reading) and after (second reading) the knowledge of clinical data. A chest computed tomography (CT) performed within 3 days was assumed as the standard of reference. For each reading, sensitivity of both radiologists was calculated.

Results

Readers showed a sensitivity of 39% and 58.5% for the first reading, and 43.9% and 41.5% for the second reading, respectively. For both readers, these values were not significantly different from those obtained at first reading (McNemar’s test, p>0.05). Interobserver agreement at second reading was fair (Cohen test, k=0.33).

Conclusions

The sensitivity of CXR is too low to consider it a stand-alone technique for the evaluation of immunocompromised patients after HSCT with suspected pneumonia, even if the radiologist knows detailed clinical data. For these patients, an early chest CT evaluation is therefore recommended.     

放射防护最优化对数字X射线摄影中受检者辐射剂量降低的价值

目的 通过评价辐射防护最优化前后患者剂量和废弃影像的差异,探讨在应用数字X射线摄影(DR)系统进行日常摄影中实施最优化的必要性.方法 200名近标准体格患者纳入研究,制定DR摄影防护最优化程序,100例执行最优化前方案摄影,100例执行最优化方案摄影.测量最优化前后患者剂量-面积乘积(DAP)和体表入射剂量(ESD).同时统计最优化前后各2个月内的废弃影像,并按废弃原因分类.比较最优化前后患者辐射剂量和影像废弃率的差异.结果 最优化后的ESD和DAP显著低于最优化前(z=9.31、16.22,P＜0.05),影像废弃率明显低于最优化前(x2=36.5,P＜0.05).结论 使用最优化程序的DR摄影可以有效降低患者辐射剂量并减小影像废弃率.     

Postoperative follow-up of olecranon fracture by digital tomosynthesis radiography

Digital tomosynthesis with flat-panel detector radiography is a novel application that allows easy, swift volume data acquisition of any anatomical site of interest with arbitrary patient posture. A single sweep of the X-ray tube provides multiple tomographic images of high resolution. We present the first patient with olecranon fracture who underwent internal fixation and 1-year postoperative follow-up with tomosynthesis. The minimal metallic artifact by this modality successfully provided detailed information regarding the healing process of the fracture.     

数字化体层融合在胸部检查中辐射剂量的研究

目的 通过评价数字化体层融合(DTS)在胸部检查中的辐射剂量,探讨DTS应用于胸部病变筛查的可行性.方法 采用自动曝光控制技术对Fluke肺-胸体模分别进行后前位、左侧位数字X线平片与DTS检查,应用RTI DoseGuard剂量面积乘积仪和RTI WinODS剂量软件检测并计算出胸部数字X线平片与DTS的剂量面积乘积与有效剂量.采用CareDose技术对Fluke肺-胸体模进行MSCT与低剂量MSCT扫描,得出剂量长度乘积,依据转换系数(k)将剂量长度乘积转化为有效剂量.4种检查方法分别进行5次成像,所得辐射剂量数据取均值,采用配对t检验比较DTS与数字X线平片、DTS与低剂量MSCT有效剂量的差异性.结果 胸部数字X线平片、DTS、低剂量MSCT与MSCT胸部扫描的有效剂量分别为0.13、0.11、1.13与6.38 mSv.胸部DTS的有效剂量基本与数字X线平片相当,差异无统计学意义(t =3.514,P＞0.01);为低剂量MSCT的1/10和MSCT的1/60,差异有统计学意义(t=178.769,P＜0.01).结论 与低剂量MSCT相比,DTS作为一种新的体层成像方法,应用于胸部病变筛查具有明显的低辐射剂量优势.     

A survey of digital chest radiography

The problems of chest radiography as they relate to digital systems are described, the current approaches to these problems are reviewed, and the utility of digital chest radiography is demonstrated.     

Comparison of chest radiography,chest digital tomosynthesis and low dose MDCT to detect small ground-glass opacity nodules: an anthropomorphic chest phantom study

Objectives

The purpose of this study was to evaluate the diagnostic performance of chest radiography (CXR), chest digital tomosynthesis (DT) and low dose multidetector computed tomography (LDCT) for the detection of small pulmonary ground-glass opacity (GGO) nodules, using an anthropomorphic chest phantom.

Methods

Artificial pulmonary nodules were placed in a phantom and a total of 40 samples of different nodule settings underwent CXR, DT and LDCT. The images were randomly read by three experienced chest radiologists. Free-response receiver-operating characteristics (FROC) were used.

Results

The figures of merit for the FROC curves averaged for the three observers were 0.41, 0.37 and 0.76 for CXR, DT and LDCT, respectively. FROC analyses revealed significantly better performance of LDCT over CXR or DT for the detection of GGO nodules (P?P?=?0.73).

Conclusion

The diagnostic performance of DT for the detection of pulmonary small GGO nodules was not significantly different from that of CXR, but LDCT performed significantly better than both CXR and DT. DT is not a suitable alternative to CT for small GGO nodule detection, and LDCT remains the method of choice for this purpose.

Key Points

? For GGO nodule detection, DT was not significantly different from CXR. ? DT is not a suitable alternative to CT for GGO nodule detection. ? LDCT is the method of choice for GGO nodule detection.     

Aortopulmonary window lesions: detection with chest radiography

A retrospective morphologic study of 80 cases was undertaken to determine factors affecting detectability of computed tomographically (CT) proved aortopulmonary (AP) window lesions on conventional posteroanterior (PA) and lateral chest radiographs. Criteria used for determining abnormality were: solitary lymph node enlargement over 1.5 cm or three or more 1-cm nodes and obvious large masses or vascular anomalies. CT scans and corresponding PA and lateral radiographs were analyzed for lesion detectability, size, and location. In 49% of cases there was no detectable lesion in the AP window on radiographs; a definite AP window lesion was seen in 41%, and 10% were equivocal. Major contributing factors to low detectability of AP window lesions on radiographs include size and, more important, location of the lesion. An additional 45 cases of CT-proved normal AP windows were retrospectively reviewed to determine the false-positive rate of PA and lateral radiographs in detection of AP window lesions: 43 (96%) were classified as negative, the remaining two (4%) as equivocal. Although the AP window is a small space, it is the site of many pathologic conditions; the study results indicate that CT may be an essential procedure for its evaluation.     

DR胸部X线摄影技术在临床的应用

目的评价直接数字X线摄影系统在胸部疾病诊断与筛查中的实用意义。方法自2005年9月以来,应用西门子FX直接数字X线摄影系统对我院门诊、急诊、住院患者及来院体检者进行了胸部检查。DR影像经激光打印机打印后,以数字化形式传入我院PACS供实时共享。DR影像显示病变的能力与常规X线平片进行了比较。结果自2005年9月应用西门子FX直接数字X线摄影系统以来,基本满足了我院门诊、急诊、住院患者胸部疾病诊断和来院体检者胸部疾病筛查的实际需要。与常规X线平片比较,DR影像能更清晰、准确地显示病灶。结论DR是诊断和筛查胸部疾病的重要影像技术,尤其与PACS联合应用是医院数字化管理的重要标志。     

Evaluation of usefulness of color digital summation radiography for solitary pulmonary nodules on chest radiographs

Purpose The aim of this study was to evaluate the usefulness of novel color digital summation radiography (CDSR) for detecting solitary pulmonary nodules on chest radiographs by observers with different levels of experience. Materials and methods A total of 30 healthy controls and 30 patients with newly detected solitary pulmonary nodules were evaluated. Six radiologists and five residents evaluated three image sets: set A, current and prior radiographs only; set B, set A with temporal subtraction images; and set C, set A with CDSR. The observers were asked to rate each image set using a continuous rating scale. In addition, the reading time required for each set was recorded. Results The radiologists showed no significant differences in the mean A_z value between set A, set B, and set C. However, the residents showed significant differences between set A and set B and between set A and set C. In addition, for set B and set C, the mean reading time per case of all readers was significantly shorter than that for set A. Conclusion The detection capability of observers with little experience is comparable to that of experienced observers when reading radiographs with temporal subtraction images or with CDSR. The usefulness of CDSR is comparable to that of temporal subtraction.     

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.     

胸部数字摄影参数的最优化探索

目的探索胸部X线数字化摄影优化条件。方法应用柯尼卡Regins350(直接数字转换器350型)CR、柯达DirectviewCR-900、柯达DirectviewDR5000;西门子-MultixX光机;胸部X线摄影质量控制体模;EBM-上海岱嘉公司PACS系统-医学图像诊断工作站软件:Unisight;Barco1K显示器,采用不同摄影条件对专用测试体模进行摄影,同时,还对12名正常成人志愿者进行胸部X线摄影试验,分别对所获60幅体模图像和人体胸部图像的质量进行分析。结果通过对采集的60幅体模图像的肺野、心脏后缘及膈下的3个点测试表明获得最佳空间分辨率的摄影参数,对于柯尼卡Regins350为10mAs、109kV和20mAs、99kV,柯达CR-900和柯达DR5000均为10mAs、109kV和20mAs、109kV。结论DR图像显示胸部结构的清晰度和信息量均明显优于CR图像,胸部数字化摄影的最优化摄影条件为90kV～110kV,10mAs～(20±5)mAs。     

Image processing in the digital tomosynthesis for pulmonary imaging

Digital tomosynthesis makes it possible to reconstruct multiple tomographs from digital data obtained during a single tomographic motion and permits digital processing, which adds a number of special advantages to the well-known advantages of conventional tomography. We performed digital tomosynthesis with a fluororadiographic TV unit with tomographic function which was capable of producing pulsed low-and high-energy X-rays alternately, and we studied digital image processing to improve the image clarity of the reconstructed tomographs. To identify the optimal parameters for processing image data by means of spatial frequency filtration we evaluated the spatial frequency distribution of image data in linear tomographs of the lung, and on the basis of the results of this study we developed several types of digital image processing to reduce tomographic blur and system noise, to improve visualisation of faint opacities, to reduce resistant tomographic blur as well as overall blur, and to generate low-noise bone images based on dual-energy subtraction tomosynthesis. Correspondence to: S. Sone     

Variable compensation technique for digital radiography of the chest

The authors describe a new technique, variable compensation (VC) radiography, for digital radiography of the chest. It permits retrospective adjustment of image display while maintaining improved mediastinal signal-to-noise ratio (S/N) from aggressive x-ray equalization. A fraction of a logarithmic image representing the profile of the beam intensity incident on the patient is subtracted from a logarithmic equalized image. VC images of a chest phantom were generated with various weightings of the beam-profile image. Edge artifacts were substantially reduced with a weighting of greater than 0.5 and eliminated with a weighting of 1.0. The S/N properties of VC images were measured with a series of plastic squares placed over various regions of the chest phantom. The S/N of the squares in the dense sub-diaphragm were improved twofold compared with the S/N on unequalized radiographs, whereas the S/N in the lung was reduced by 30%. Studies of a volunteer revealed the ability to render images with aggressive equalization (for improved mediastinal visualization) and images with the appearance of traditional chest radiographs.