数字化X线摄影曝光条件对影像质量的影响

目的 研究数字X线摄影曝光条件对影像质量的影响.方法 确认数字X线摄影处于良好状态,用CDRAD2.0体模,测试kV、mAs、过滤等曝光条件对影像质量及剂量学参数的影响.结果 影像质量存在随管电压的增加而降低的趋势,在70 kV和90 kV时影像质量最好,IQFinv分别为6.27和6.10,而在110 kV时影像质量最差,IQFinv为4.27.从60～80 kV,图像的像素值下降13%;而80～130 kV,图像的像素值在很小范围内波动,变化率仅在2%左右.随着kV数的增加,图像噪声呈逐渐增高趋势,与60 kV时相比,90 kV、120 kV时的噪声值分别上升了9.6%和16.9%.在70 kV、90 kV和110 kV条件下,分别在32 mAs、6.4 mAs 和3.2 mAs时影像质量最佳.图像的像素值随mAs增加而升高,而图像的噪声总体上随mAs的增加而降低.IQFinv与剂量与面积之积之间呈明显正相关(P<0.05),与kV呈负相关,而与mAs呈正相关,但这种相关性统计学意义不显著(P>0.05).结论 对于数字化X线摄影,合适的管电压和mAs为曝光参数可以获得较好图像质量,并有效控制受检者辐射剂量.     

数字乳腺X线摄影技术的研究进展

随着数字化乳腺X线检查技术的发展,屏/片系统乳腺X线摄影(SFM)技术已逐步被取代,一些技术改进的优势已在致密型乳腺的女性中得到证实。比较数字乳腺体层摄影(DBT)技术、对比增强双能数字乳腺X线摄影(CEDM)技术及常规数字乳腺X线摄影(DM)技术,并综述数字乳腺摄影技术发展中一些新技术的特点,分析其优势、局限性及对病人的潜在影响等,从而预测它们的发展前景。     

乳腺密度评估:使用全自动软件一对一比较数字乳腺X线摄影和数字乳腺体层摄影

正摘要目的使用全自动化软件比较数字乳腺X线摄影和数字乳腺体层摄影(DBT)的乳腺密度。方法该研究获得机构批准并得到全部参与者的知情同意,每位参与者均进行DBT和全视野乳腺X线摄影(FFDM)。通过软件计算两种检查的乳腺密度百分比。结果50例连续病人(平均51岁,35~83岁)接     

屏胶乳腺X线摄影和数字化乳腺X线摄影的对比研究

数字乳腺X线摄影（DM）较屏胶乳腺X线摄影（SFM）具有更多的优势,其对于图像的获取、储存和显示都是相互分离的,每个系统都能优化产生最佳效果,而且数字图像能够由计算机处理并显示为多种形式。因此,DM系统正逐渐替代SFM系统并成为筛查及诊断乳腺癌的常规手段。就DM和SFM的成像原理、图像质量、图像处理以及临床应用进行比较。     

不同曝光模式对数字乳腺X线摄影影像质量和辐射剂量的影响

目的探讨数字乳腺X线摄影中不同曝光模式对影像质量及辐射剂量的影响,便于实际工作中在保证影像质量的前提下,通过对曝光模式及曝光条件选择有效降低病人的辐射损伤。方法先采用自动曝光模式(28kV、60mAs)对乳腺模体进行曝光,然后采用相同的压迫厚度和压力,根据自动曝光模式的摄影条件,在手动曝光模式下,分别固定管电压和管电流量,依次改变相应的管电流量及管电压对模体进行曝光,记录各曝光条件下入射剂量(ESD)、平均腺体剂量(AGD)和美国放射学会(ACR)标准的影像评分值。采用SPSS17.0软件中KruskalWallis检验对自动和手动曝光模式产生的各值进行统计学处理。结果手动曝光模式下,当管电压固定为28kV,管电流量由60mAs升至70mAs时,ESD和AGD分别增加了15.4%;当管电流量降至45mAs时,ESD和AGD分别降低了26.1%。当管电流量固定为60mAs,管电压由28kV升至32kV时,ESD和AGD分别增加了47.0%和62.7%;当管电压降至26kV时,ESD和AGD分别降低了22.6%和28.2%。不同曝光模式下影像的整体质量均无明显差别(P>0.05)。结论自动曝光模式下所得到的ESD与AGD均不是最低剂量。以自动曝光模式为基础,分别固定管电压或管电流量,在一定范围内分别手动降低管电流量或管电压值,在不影响影像质量的前提下,可降低辐射剂量。同时,影像质量达到一定水平后,不再随摄影条件增加而提高。     

屏胶乳腺X线摄影和数字化乳腺X线摄影的对比研究

数字乳腺X线摄影(DM)较屏胶乳腺X线摄影(SFM)具有更多的优势,其对于图像的获取、储存和显示都是相互分离的,每个系统都能优化产生最佳效果,而且数字图像能够由计算机处理并显示为多种形式。因此,DM系统正逐渐替代SFM系统并成为筛查及诊断乳腺癌的常规手段。就DM和SFM的成像原理、图像质量、图像处理以及临床应用进行比较。     

对比增强乳腺X线摄影技术曝光时间与乳腺良恶性病变关系的Logistic回归分析

目的 应用Logistic回归模型探讨对比增强乳腺X线摄影(CESM)技术曝光时间对鉴别乳腺良恶性病变的价值,建立最优拍摄方案。方法 回顾性分析术前行CESM检查且临床资料完整的病例73例(其中良性27例,恶性46例),以曝光时间不同随机分成4组,以病理结果为因变量,乳腺肿块的影像及临床特征为自变量,建立Logistic回归模型,应用绘制受试者工作特征曲线评价各组回归模型的诊断效能。结果 Logistic逐步回归分析显示,年龄变量均能进入组1、组3、组4回归模型(P<0.05),病灶面积变量仅能进入组1回归模型(P<0.05)。无独立变量进入组2回归模型(P>0.05)。组3回归模型的诊断效能及敏感度最高(准确率=0.809,敏感度=0.778,P<0.05),组1的特异度最高(特异度=0.722,P<0.05)。结论 进行CESM检查时,采取组1和组3联合拍摄的方案对鉴别乳腺良恶性病变最有诊断价值。     

全野数字乳腺X线摄影降低辐射剂量的初步研究

＿目的：探讨全野数字乳腺X线摄影的曝光条件,找出影响图像质量和平均腺体剂量（AGD）的因素,为乳腺摄影提供参考。方法：采用GE全野数字乳腺X线机对fluke NA 18-220乳腺模体进行摄影,首先采用AOP 模式下的标准模式曝光,压力设定为12daN,厚度为42 mm,结果形成28 kV,45 mAs,Mo／Rh 曝光条件,以此为参照基准,设定两组实验：以管电流为单变量,设值为8～90 mAs（间隔为机器旋钮可调节的数值）;以管电压为单变量,设值为22～36 kV（间隔为1）,曝光并记录AGD值。上述过程重复3次取平均值。2位影像学医师和1位技师分别独立进行软阅读,参照美国放射学会评分标准,对模体中钙化点、尼龙纤维、肿块灶的显示进行评分。结果：与自动曝光模式相比,手动曝光模式管电压下降3 kV,管电流下降20 mAs,影像质量符合诊断标准,辐射剂量有效下降。管电压的变化对 AGD 的影响比管电流要大。结论：以自动条件作为参照标准,在保障图像诊断质量前提下,管电压和管电流可分别有效降低,以减少辐射。     

Tomosynthesis and contrast-enhanced digital mammography: recent advances in digital mammography

Digital mammography is more and more replacing conventional mammography. Initial concerns about an inferior image quality of digital mammography have been largely overcome and recent studies even show digital mammography to be superior in women with dense breasts, while at the same time reducing radiation exposure. Nevertheless, an important limitation of digital mammography remains: namely, the fact that summation may obscure lesions in dense breast tissue. However, digital mammography offers the option of so-called advanced applications, and two of these, contrast-enhanced mammography and tomosynthesis, are promising candidates for improving the detection of breast lesions otherwise obscured by the summation of dense tissue. Two techniques of contrast-enhanced mammography are available: temporal subtraction of images acquired before and after contrast administration and the so-called dual-energy technique, which means that pairs of low/high-energy images acquired after contrast administration are subtracted. Tomosynthesis on the other hand provides three-dimensional information on the breast. The images are acquired with different angulations of the X-ray tube while the object or detector is static. Various reconstruction algorithms can then be applied to the set of typically nine to 28 source images to reconstruct 1-mm slices with a reduced risk of obscuring pathology. Combinations of both advanced applications have only been investigated in individual experimental studies; more advanced software algorithms and CAD systems are still in their infancy and have only undergone preliminary clinical evaluation.     

Image quality, lesion detection, and diagnostic efficacy in digital mammography: full-field digital mammography versus computed radiography-based mammography using digital storage phosphor plates

OBJECTIVE: To compare image quality, the lesion detection, and the diagnostic efficacy of full-field digital mammography (FFDM) and computed radiography-based mammography using digital storage phosphor plates (DSPM) in the evaluation of breast lesions. MATERIALS AND METHODS: In this prospective study, 150 patients with suspicious breast lesions underwent FFDM and DSPM. Nine aspects of image quality (brightness, contrast, sharpness, noise, artifacts, and the detection of anatomic structures, i.e., skin, retromamillary space, glandular tissue, and calcifications) were evaluated by five radiologists. In addition, the detection of breast lesions and the diagnostic efficacy, based on the BI-RADS classification, were evaluated with histologic and follow-up correlation. RESULTS: For contrast, sharpness, and the detection of all anatomic structures, FFDM was rated significantly better (p<0.05). Mass lesions were equally detected, whereas FFDM detected more lesions consisting of calcifications (85 versus 75). DSPM yielded two false-negative results. Both lesions were rated BI-RADS 4 with FFDM, but BI-RADS 2 with DSPM. Both were invasive carcinoma at histology. The sensitivity, specificity, PPV, NPV, and accuracy of FFDM were 1.0, 0.397, 0.636, 1.0, and 0.707, compared to 0.974, 0.397, 0.630, 0.935, and 0.693 of DSPM. CONCLUSION: Based on image quality parameters, FFDM is, in part, significantly better than DSPM. Furthermore, the detection of breast lesions with calcifications is favorable with FFDM. However, the diagnostic efficacy of FFDM and DSPM was equal. The interpretation of the false-negative results suggests that the perception and characterization of breast lesions is not defined solely by the digital mammography system but is strongly influenced by the radiologist, who is one of the determinants in the interpretation of breast imaging.     

全数字乳腺X线3种摄影模式的影像质量和辐射剂量比较

目的 探讨全数字乳腺X线摄影(FFDM)不同摄影模式影像质量与辐射剂量的比较研究.方法 用全数字乳腺X线摄影的对比度优先模式(CNT)、标准模式(STD)及辐射剂量优先模式(DOSE)对FLUKE NA 18-220乳腺模体进行摄影,摄影采用自动曝光模式(AEC),记录摄影条件和辐射剂量.由4位影像学医师在相同条件下进行软阅读,并按照美国放射学会(ACR)的评分标准对模体中的钙化点、尼龙纤维、肿块灶进行评分.结果 标准模式、辐射剂量优先模式及对比度优先模式的模体影像评分值分别是11.5、11.0和14.5,标准模式及辐射剂量优先模式与对比度优先模式的影像质量差异有统计学意义(F=41.321,P＜0.05).标准模式与辐射剂量优先模式之间影像质量差异无统计学意义,但两种模式的辐射剂量却不相同,其表面入射剂量分别是4.5和3.15 mGy,腺体平均剂量(AGD)分别是1.18和0.78 mGy.结论 全数字乳腺摄影的辐射剂量优先模式和标准模式适合大多数被检者,特别是辐射剂量优先模式.对比度优先模式应严格控制使用.

Abstract：

Objective To study the difference of image quality and radiation dose between different exposure modes with full-field digital mammography (FFDM).Methods The Fluke18-220mammographic phantom was exposed by FFDM system with different exposure modes at automatic exposure control ( AEC ) ,including contrast mode,standard mode and dose mode,and the exposure factors and radiation dose were recorded.The images on monitor with the best window width and window level were read by four independent radiologists.The images of specks groups,nylon fibers and masses was assessed by the four experienced readers at the criterion of American College of Radiology.Results The detection of specks groups,nylon fibers and masses were statistically different at the contrast mode and standard mode (F =41.321,P ＜ 0.05),further at the contrast mode and dose mode.The detection of specks groups、nylon fibers and masses were not statistically different( P ＞ 0.05 ) at standard mode and dose mode,but the radiation doses were different.The ESD at standard mode and dose mode was 4.5 and 3.15 mGy,respectively.The AGD of standard mode and dose mode was 1.18 mGy and 0.78 mGy,respectively.Conclusions The standard mode and dose mode of FFDM might be fit for most patients,especially at the dose mode.Contrast mode of FFDM should be strictly controled in use.     

Two-modality mammography may confer an advantage over either full-field digital mammography or screen-film mammography

RATIONALE AND OBJECTIVES: We sought to compare the cancer detection rate and receiver operating characteristic (ROC) area under the curve of full-field digital mammography, screen-film mammography, and a combined technique that allowed diagnosis if a finding was suspicious on film mammography, on digital mammography, or both. MATERIALS AND METHODS: We used the data originally analyzed by Lewin and associates in 2002. In that trial, 6,736 paired full-field and digital mammograms were performed in 4,489 women. We used parametric and nonparametric tests to compare the area under the curve for ROC scores of film-screen only, digital mammography only, and the combined test. We used McNemar's test for paired proportions to compare the cancer detection rates. RESULTS: With the parametric test, neither the difference in the area under the curve between the film and combined nor the difference between the digital and combined ROC curves was significant at the Bonferroni-corrected 0.025 alpha level (film versus combined difference = 0.0563, P = .0712; digital versus combined difference = 0.0894, P = .0455). The nonparametric test showed that there was a significant difference between both film and combined (difference = 0.073, P = .008) and digital versus combined ROC curves (difference = 0.1164, P = .0008). The continuity-corrected McNemar's test showed a significant increase in the proportion of cancers detected by the combined modality over film (chi(2) = 7.111, df = 1, P = .0077), and over digital (chi(2) = 12.071, df = 1, P = .0005). CONCLUSION: Using two mammograms, one film and one digital, significantly increases the detection of breast cancer.     

数字乳腺X射线摄影中管电流量优化的实验研究

目的:探讨数字乳腺X射线摄影中不同靶/滤过组合时降低管电流量(mAs)对图像质量与辐射剂量的影响。方法:不同靶/滤过组合时,以自动曝光模式(AEC)的mAs为基础,分别降低10%、20%、30%、40%、50%时对厚度为4.4 cm的模体进行曝光,测量所得图像的对比噪声比(CNR)、信噪比(SNR)、品质因子(FOM)...     

The effect of different exposure parameters on radiation dose in digital mammography and digital breast tomosynthesis: A phantom study

IntroductionThere are concerns regarding the increase in radiation dose among women undergoing both digital mammography (DM) and digital breast tomosynthesis (DBT). The aim of this study was to evaluate the effect of different exposure parameters on entrance skin dose (ESD) and average glandular dose (AGD) for DM and DBT using a phantom.MethodsThe ESD and AGD of 30 DM and DBT (cranio-caudal projection) examinations using a tissue equivalent phantom where acquired using a GE Senographe Essential DM unit. Commercial phantoms were used to simulate three different breast thicknesses and compositions. Tube potential, tube load, and target/filter combinations were also varied with ESD and AGD recorded directly from the DM unit. Comparisons were made using the non-parametric Kruskal Wallis, Mann–Whitney, and Wilcoxon signed rank tests.ResultsThe individual ESD values for 4 cm, 5 cm, and 6 cm thick phantoms for DM and DBT at Rh/Rh target/filter combination and 30–32 kV/56 mAs levels were 5.06 and 4.18 mGy; 5.82 and 5.08 mGy; and 7.26 and 11.4 mGy, respectively; while AGDs were 1.57 and 1.30 mGy, 1.33 and 1.39 mGy; and 1.29 and 3.60 mGy, respectively. The Kruskal–Wallis test showed a statistically significant difference in AGD for DM (P = .029) but not for DBT (P = 0.368). The Mann–Whitney and Wilcoxon signed rank tests showed no statistically significant difference for ESD or AGD between both DM and DBT techniques (P = .827 and .513). The percentage differences in ESD for phantom thicknesses of 4 cm, 5 cm, and 6 cm between DBT and DM ranged between −21% and 36%; while for AGD between −21% and 64.2%.ConclusionsThe ESD and AGD for single view projection in DM and DBT showed differences at 4 and 6 cm breast thicknesses and compositions but not at 5 cm thickness with 30–32 kV and a Rh/Rh target/filter combination.Implications for practiceA fibro-fatty breast results in less radiation dose variations in terms of ESD and AGD between DM and DBT techniques.     

数字化乳腺摄影与普通钼靶摄影在小乳癌诊断中的对比分析

目的：探讨数字化乳腺摄影在小乳癌诊断中的优越性。方法：经手术病理证实的小乳癌57例，采用数字化乳腺摄影及普通钼靶摄影方法。结果：数字化乳腺摄影诊断51例，其敏感性、特异性、准确性分别为89．4％、95．O％、90.9％；普通钼靶摄影术前诊断46例，其敏感性、特异性、准确性分别为80．7％、85．O％、81．8％。结论：在小乳癌诊断中。数字化乳腺摄影在敏感性、特异性、准确性方面均优于普通钼靶摄影。