Computation of realistic virtual phantom images for an objective lesion detectability assessment in digital mammography

Image quality assessment is required for an optimal use of mammographic units. On the one hand, there are objective image quality assessment methods based on the measurement of technical parameters such as modulation transfer function (MTF), noise power spectrum (NPS) or detection quantum efficiency (DQE) describing performances of digital detectors. These parameters are, however, without direct relationship with lesion detectability in clinical practice. On the other hand, there are image quality assessment methods involving time consuming procedures, but presenting a direct relationship with lesion detectability. This contribution describes an X-ray source/digital detector model leading to the simulation of virtual contrast-detail phantom (CDMAM) images. The virtual image computation method requires the acquisition of only few real images and allows for an objective image quality assessment presenting a direct relationship with lesion detectability. The transfer function of the proposed model takes as input physical parameters (MTF* and noise) measured under clinical conditions on mammographic units. As presented in this contribution, MTF* is a modified MTF taking into account the effects due to X-ray scatter in the breast and magnification. Results obtained with the structural similarity index prove that the simulated images are quite realistic in terms of contrast and noise. Tests using contrast detail curves highlight the fact that the simulated and real images lead to very similar data quality in terms of lesion detectability. Finally, various statistical tests show that quality factors computed for both the simulated images and the real images are very close for the two data sets.     

乳腺癌X线表现分析

目的分析乳腺癌典型及不典型X线征象,提高对乳腺癌不典型X线表现的认识。方法对61例经手术病理证实的乳腺癌资料进行回顾性分析。结果61例乳腺癌主要X线征象:肿块39例;微小钙化30例;不伴肿块及微小钙化的乳腺局部结构紊乱4例、星芒征3例、非对称性密度增高3例。结论肿块及微小钙化是乳腺癌最主要、最直接的X线征象,但部分乳腺癌X线上缺乏上述2种表现,单纯以结构紊乱、非对称性密度增高或星芒征为主要表现。提高对此类乳腺癌不典型X线表现的认识,有利于防止误、漏诊。     

CR系统与屏-片系统在小乳房钼靶摄影中的应用对比

目的比较CR系统与屏-片系统在小乳房钼靶摄影中的优缺点。方法使用意大利Giotto高频钼靶乳腺机、屏-片系统和日本FUJIFILMXG5000型CR系统对233例小乳房检查者进行钼靶摄影,并对两者的应用进行研究分析。结果使用CR系统产生的图像质量明显优于屏-片系统,重拍率显著下降,被检者接受的辐射大幅度减少。结论CR在小乳房钼靶摄影中优于传统的屏-片系统。     

Comparison of LCD and CRT displays based on efficacy for digital mammography

RATIONALE AND OBJECTIVES: To compare two display technologies, cathode ray tube (CRT) and liquid crystal display (LCD), in terms of diagnostic accuracy for several common clinical tasks in digital mammography. MATERIALS AND METHODS: Simulated masses and microcalcifications were inserted into normal digital mammograms to produce an image set of 400 images. Images were viewed on one CRT and one LCD medical-quality display device by five experienced breast-imaging radiologists who rated the images using a categorical rating paradigm. The observer data were analyzed to determine overall classification accuracy, overall lesion detection accuracy, and accuracy for four specific diagnostic tasks: detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses. RESULTS: Radiologists had similar overall classification accuracy (LCD: 0.83 +/- 0.01, CRT: 0.82 +/- 0.01) and lesion detection accuracy (LCD: 0.87 +/- 0.01, CRT: 0.85 +/- 0.01) on both displays. The difference in accuracy between LCD and CRT for the detection of benign masses, malignant masses, and microcalcifications, and discrimination of benign and malignant masses was -0.019 +/- 0.009, 0.020 +/- 0.008, 0.012 +/- 0.013, and 0.0094 +/- 0.011, respectively. Overall, the two displays did not exhibit any statistically significant difference (P > .05). CONCLUSION: This study explored the suitability of two different soft-copy displays for the viewing of mammographic images. It found that LCD and CRT displays offer similar clinical utility for mammographic tasks.     

Accuracy of assigned BI-RADS breast density category definitions

RATIONALE AND OBJECTIVES: Quantitative criteria for the Breast Imaging Reporting and Data System (BI-RADS) mammographic density categories have recently been defined as <25% dense for almost entirely fatty, 25%-50% dense for scattered fibroglandular densities, 51%-75% for heterogeneously dense, and >75% dense for the extremely dense category. The purpose of this study is to compare the range of percent mammographic densities with radiologist-assigned BI-RADS mammographic density categories and compare with the recently issued definitions. MATERIALS AND METHODS: In this study, 200 consecutive negative analog screening mammograms were assigned BI-RADS mammographic density categories independently by three radiologists blinded to the other readers' density assignment. Quantitative assessment of percent mammographic density was performed using previously validated software. RESULTS: All three readers agreed on BI-RADS mammographic density categories in 98 cases (49%), and two of three readers agreed in all 200 cases. Using two reader's consensus, median mammographic density (range) was 6.0% (0.5%-19.2%) for fatty, 14.8% (1.2%-52.7%) for scattered densities, 51.2% (15.9%-82.2%) for heterogeneously dense, and 78.4% (60.1%-87.9%) for extremely dense breasts. The percent mammographic density ranges for fatty and extremely dense breasts correlated well with BI-RADS definitions, whereas the ranges of densities in the scattered and heterogeneously dense categories were considerably broader. CONCLUSION: Fatty and extremely dense BI-RADS categories compare relatively well to defined criteria, and therefore may be helpful in breast cancer risk models. Scattered fibroglandular densities and heterogeneously dense categories have broad percent mammographic density ranges and may not function well in breast cancer risk models.     

乳腺癌钼靶X线表现与C-erbB-2癌基因相关性

目的:探讨乳腺癌钼靶X线表现与c-erbB-2癌基因表达之间的相关性。方法:将165例乳腺癌患者X线征象中钙化、边缘浸润、病变密度、是否同时合并乳腺囊性增生症与经免疫组织化学染色测定c-erbB-2基因的表达状态进行对照研究。结果:165例乳腺癌患者中,有钙化者84例,占50.91%;80例有边缘浸润,占48.40%;病变区表现为高密度87例,占52.73%;乳腺癌同时合并乳腺囊性增生症85例,占51.52%。95例c-erbB-2基因表达阳性,占57.58%。结论:乳腺癌钼靶X线征象在一定程度上反映了c-erbB-2表达状态,X线表现为钙化、边缘浸润、病变区为高密度及乳腺癌同时合并乳腺囊性增生症的乳腺癌患者c-erbB-2基因表达阳性可能性更高。     

乳腺错构瘤X线与病理分析

目的探讨乳腺错构瘤的X线表现与病理基础。方法收集经手术病理证实的乳腺错构瘤19例,分析其X线表现与病理学基础,全部病例均采用全数字化乳腺X线摄影。结果X线表现脂肪型5例,致密型4例,混合型10例。病理上本病均有完整的包膜,由数量不等、杂乱无章的乳腺导管、小叶和成熟的脂肪及纤维组织混杂组成。结论乳腺错构瘤的X线表现因其病灶内脂肪组织、腺体和纤维组织的比例不同而不同,混杂密度肿块为本病的特征性X线表现。     

青年性乳腺癌CR钼靶影像与病理对照研究

目的探讨钼靶CR摄影在青年性乳腺癌诊断中的价值。方法回顾性分析50例35岁以下经病理证实的青年乳腺癌的X线表现。结果浸润性小叶癌26例,浸润性导管癌24例。肿块影13例,单纯钙化7例,结构扭曲5例,片状阴影16例,片状阴影伴钙化4例,肿块伴钙化5例,晕环征6例。结论钼靶CR摄影仍然是青年性乳腺癌最佳和首选的检查方法。     

乳腺脂肪坏死的X线表现

目的探讨乳腺脂肪坏死影像学表现。方法9例病理证实的乳腺脂肪坏死病例,均有钼靶片,3例行CT检查,对其影像学表现进行回顾性分析。结果7例腺体外型表现为:随机分布纤维条索影和小结节样高密度影与脂肪密度影混杂存在;2例腺体内型表现为:规则和不规则肿物影。结论影像学检查较临床检查在鉴别脂肪坏死和乳腺癌方面更有价值。随机分布纤维条索影和小结节样高密度影与脂肪密度影混杂存在是乳腺脂肪坏死的典型表现。     

乳腺病变的数字化摄影与屏片摄影之比较研究

目的:比较数字化乳腺摄影与屏片乳腺摄影对于乳腺病变的显示效果,明确数字化乳腺摄影的临床应用价值.材料和方法:本研究包括60例本院乳腺手术患者,同时进行前瞻性的屏片和数字化乳腺摄影,根据BI-RADS描述、诊断影像,并与病理结果对照分析,比较两者对乳腺病变的诊断价值.结果:数字化和屏片乳腺摄影对于乳腺病变的大多数影像学表现,其显示效果差异无统计学意义.数字化乳腺摄影显示钙化灶的效果优于屏片乳腺摄影,且有明显的统计学意义.结论:数字化乳腺摄影已达到与屏片乳腺摄影相同的诊断效果,且数字化乳腺摄影显示钙化灶具有相当的优势.