Observer variability in screen-film mammography versus full-field digital mammography with soft-copy reading

Full-field digital mammography (FFDM) with soft-copy reading is more complex than screen-film mammography (SFM) with hard-copy reading. The aim of this study was to compare inter- and intraobserver variability in SFM versus FFDM of paired mammograms from a breast cancer screening program. Six radiologists interpreted mammograms of 232 cases obtained with both techniques, including 46 cancers, 88 benign lesions, and 98 normals. Image interpretation included BI-RADS categories. A case consisted of standard two-view mammograms of one breast. Images were scored in two sessions separated by 5 weeks. Observer variability was substantial for SFM as well as for FFDM, but overall there was no significant difference between the observer variability at SFM and FFDM. Mean kappa values were lower, indicating less agreement, for microcalcifications compared with masses. The lower observer agreement for microcalcifications, and especially the low intraobserver concordance between the two imaging techniques for three readers, was noticeable. The level of observer agreement might be an indicator of radiologist performance and could confound studies designed to separate diagnostic differences between the two imaging techniques. The results of our study confirm the need for proper training for radiologists starting FFDM with soft-copy reading in breast cancer screening. Presented at ECR, Wien 2006.     

Randomized trial of screen-film versus full-field digital mammography with soft-copy reading in population-based screening program: follow-up and final results of Oslo II study

PURPOSE: To prospectively compare performance indicators at screen-film mammography (SFM) and full-field digital mammography (FFDM) in a population-based screening program. MATERIALS AND METHODS: The regional ethics committee approved the study; informed consent was obtained from patients. Women aged 45-69 years were assigned to undergo SFM (n=16 985) or FFDM (n=6944). Two-view mammograms were interpreted by using independent double reading and a five-point rating scale for probability of cancer. Positive scores were discussed at consensus meetings before decision for recall. The group was followed up for 1.5 years (women aged 45-49 years) and 2.0 years (women aged 50-69 years) to include subsequent cancers with positive scores at baseline interpretation and to estimate interval cancer rate. Recall rates, cancer detection, positive predictive values (PPVs), sensitivity, specificity, tumor characteristics, and discordant interpretations of cancers were compared. RESULTS: Recall rate was 4.2% at FFDM and 2.5% at SFM (P<.001). Cancer detection rate was 0.59% at FFDM and 0.38% at SFM (P=.02). There was no significant difference in PPVs. Median size of screening-detected invasive cancers was 14 mm at FFDM and 13 mm at SFM. Including cancers dismissed at consensus meetings, overall true-positive rate at baseline reading was 0.63% at FFDM and 0.43% at SFM (P=.04). Sensitivity was 77.4% at FFDM and 61.5% at SFM (P=.07); specificity was 96.5% and 97.9%, respectively (P<.005). Interval cancer rate was 17.4 at FFDM and 23.6 at SFM. The proportion of cancers with discordant double readings was comparable at FFDM and SFM. CONCLUSION: FFDM resulted in a significantly higher cancer detection rate than did SFM. The PPVs were comparable for the two imaging modalities.     

全数字化乳腺X线摄影对乳腺炎性疾病的诊断价值

目的:分析乳腺炎性疾病的全数字化乳腺X线摄影(FFDM)表现,提高该病与乳腺癌的鉴别诊断水平。方法:回顾性分析39例经穿刺或手术病理证实的乳腺炎性疾病的FFDM表现。结果:39例患者中,26例为慢性乳腺炎,5例为浆细胞性乳腺炎,8例为肉芽肿性乳腺炎。X线表现为肿块影17例,局部腺体非对称性致密影20例,结构扭曲2例。伴同侧腋下淋巴结致密影7例,局部或乳晕区皮肤增厚12例,乳头凹陷7例。结论:结合临床资料并细致分析乳腺炎性疾病的FFDM表现,有助于提高该病诊断与鉴别诊断水平。     

Comparison of full-field digital mammography to screen-film mammography with respect to diagnostic accuracy of lesion characterization in breast tissue biopsy specimens

RATIONALE AND OBJECTIVES: This study was performed to investigate whether full-field digital mammography (FFDM) is at least as accurate as screen-film mammography with respect to breast lesion characterization. MATERIALS AND METHODS: Seventy-nine breast surgical specimens were obtained by means of preoperative needle localization with surgical excision from 79 patients. The specimens were imaged with both screen-film mammography and FFDM. Six radiologists specialized in breast imaging analyzed both sets of images and characterized the visualized lesions on a five-point scale: 1, definitely not malignant; 2, probably not malignant; 3, possibly malignant; 4, probably malignant; and 5, definitely malignant. Receiver operating characteristic curve analysis of the data was then performed to assess for differences between modalities in the radiologists' ability to predict breast malignancy. RESULTS: The areas under the receiver operating characteristic curves for the prediction of breast malignancy in surgical biopsy specimens were not statistically significantly different for FFDM and screen-film mammography. CONCLUSION: The results demonstrate that with breast surgical specimens, FFDM is similar in diagnostic accuracy to screen-film mammography.     

Population-based mammography screening: comparison of screen-film and full-field digital mammography with soft-copy reading--Oslo I study

PURPOSE: To compare screen-film and full-field digital mammography with soft-copy reading in a population-based screening program. MATERIALS AND METHODS: Full-field digital and screen-film mammography were performed in 3,683 women aged 50-69 years. Two standard views of each breast were acquired with each modality. Images underwent independent double reading with use of a five-point rating scale for probability of cancer. Recall rates and positive predictive values were calculated. Cancer detection rates determined with both modalities were compared by using the McNemar test for paired proportions. Retrospective side-by-side analysis for conspicuity of cancers was performed by an external independent radiologist group with experience in both modalities. RESULTS: In 3,683 cases, 31 cancers were detected. Screen-film mammography depicted 28 (0.76%) malignancies, and full-field digital mammography depicted 23 (0.62%) malignancies. The difference between cancer detection rates was not significant (P =.23). The recall rate for full-field digital mammography (4.6%; 168 of 3,683 cases) was slightly higher than that for screen-film mammography (3.5%; 128 of 3,683 cases). The positive predictive value based on needle biopsy results was 46% for screen-film mammography and 39% for full-field digital mammography. Side-by-side image comparison for cancer conspicuity led to classification of 19 cancers as equal for probability of malignancy, six cancers as slightly better demonstrated at screen-film mammography, and six cancers as slightly better demonstrated at full-field digital mammography. CONCLUSION: There was no statistically significant difference in cancer detection rate between screen-film and full-field digital mammography. Cancer conspicuity was equal with both modalities. Full-field digital mammography with soft-copy reading is comparable to screen-film mammography in population-based screening.     

Screen film vs full-field digital mammography: image quality,detectability and characterization of lesions

The objective of this study was to compare screen-film mammography (SFM) to full-field digital mammography (FFDM) regarding image quality as well as detectability and characterization of lesions using equivalent images of the same patient acquired with both systems. Two mammography units were used, one with a screen-film system (Senographe DMR) and the other with a digital detector (Senographe 2000D, both GEMS). Screen-film and digital mammograms were performed on 55 patients with cytologically or histologically proven tumors on the same day. Together with these, 75 digital mammograms of patients without tumor and the corresponding previous screen-film mammograms not older than 1.5 years were reviewed by three observers in a random order. Contrast, exposure, and the presence of artifacts were evaluated. Different details, such as the skin, the retromamillary region, and the parenchymal structures, were judged according to a three-point ranking scale. Finally, the detectability of microcalcifications and lesions were compared and correlated to histology. Image contrast was judged to be good in 76%, satisfactory in 20%, and unsatisfactory in 4% of screen-film mammograms. Digital mammograms were judged to be good in 99% and unsatisfactory in 1% of cases. Improper exposure of screen-film system occurred in 18% (10% overexposed and 8% underexposed). Digital mammograms were improperly exposed in 4% of all cases but were of acceptable quality after post-processing. Artifacts, most of them of no significance, were found in 78% of screen-film and in none of the digital mammograms. Different anatomical regions, such as the skin, the retromamillary region, and dense parenchymal areas, were better visualized in digital than in screen-film mammography. All malignant tumors were seen by the three radiologists; however, digital mammograms allowed a better characterization of these lesions to the Breast Imaging Reporting and Data System (BI-RADS;) [corrected] categories (FFDM better than SFM in 23 of 165 vs 9 of 165 judged cases in SFM). In conclusion, digital mammography offers a consistent, high image quality in combination with a better contrast and without artifacts. Lesion detection in digital images was equal to that in screen-film images; however, categorization of the lesions to the BI-RADS classification was slightly better.     

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。     

Comparison of 5-megapixel cathode ray tube monitors and 5-megapixel liquid crystal monitors for soft-copy reading in full-field digital mammography

Purpose

To retrospectively compare the image quality, lesion detection, and the diagnostic efficacy of 5-megapixel (MP) cathode ray tube monitors (CRTs) and 5-MP liquid crystal display monitors (LCDs) for soft-copy reading in full-field digital mammography (FFDM).

Materials and methods

Informed consent was waived by the Institutional Review Board for the data analysis. A total of 220 cases were compared with two 5-MP (2048 × 2560 pixels) CRTs and two 5-MP (2048 × 2560 pixels) LCDs. Nine aspects of image quality (brightness, contrast, sharpness, noise, skin, fat, retromamillary space, glandular tissue, and detection of calcifications) were evaluated. In addition, the detection of breast lesions (mass, calcifications) and diagnostic efficacy, based on the BI-RADS classification, were correlated with histologic results (n = 70) and follow-up (n = 150).

Results

Each aspect of the image quality was rated significantly better for 5-MP LCDs (p < 0.05) compared to the 5-MP CRTs. With 5-MP CRTs, 31 masses and 119 calcifications were detected, compared to 30 and 121 with 5-MP LCDs. The differences in diagnostic efficacy between 5-MP CRTs and 5-MP LCDs were not significant (p = 0.157) although 5-MP CRTs yielded two false-negative results. Both lesions were rated BI-RADS 3 with 5-MP CRTs. Both were invasive carcinomas at histology. The sensitivity, specificity, positive and negative predictive values, and accuracy were 0.966, 0.975, 0.933, 0.988, and 0.973 for 5-MP CRTs, compared to 1.0, 0.963, 0.903, 1.0, 0.973 for 5-MP LCDs.

Conclusion

The image quality of 5-MP LCDs is significantly better than that of 5-MP CRTs for soft-copy reading in FFDM, based on histologic and follow-up correlation. However, lesion detection and diagnostic efficacy are comparable to 5-MP CRTs. The interpretation of the false-negative results suggests that the characterization of breast lesions with FFDM is not defined solely by the monitors, but is strongly influenced by the radiologist.     

全数字化乳腺摄影对乳腺疾病的诊断价值

目的 评价全数字化乳腺摄影在临床中对乳腺疾病的诊断价值.方法 回顾215例经手术或活检的术前全数字化乳腺摄影资料,对比影像诊断与最终病理诊断异同.分析不同疾病的误诊原因,初步分析及探讨全数字化乳腺摄影对乳腺疾病的诊断价值.结果 215例经手术或活检的病例中,132例被病理确诊为乳腺癌,83例被诊断为良性病变.在被病理证实为乳腺癌的132例乳腺癌病例中,14例被全数字化乳腺摄影诊断漏诊或误诊.而同时被影像诊断为恶性病变可能的130例(BI-RADS大于4级)的病例中,12例最终病理诊断确定为良性病变.结论 全数字化乳腺摄影是乳腺疾病的重要检查手段,尤其对发现及筛查乳腺癌具有重要价值,但对某些乳腺良性病变,其诊断准确率较低,需要结合其他临床诊断方式.     

全数字化乳腺摄影与MRI对乳腺恶性病变诊断的对比分析

目的 探讨乳腺癌全数字化乳腺摄影(full-field digital mammography,FFDM)与乳腺MRI的影像学表现,评价其对乳腺癌的诊断价值.方法 收集68例经穿刺或手术病理证实的乳腺癌病例,对比分析其X线摄影及MRI表现.全数字化乳腺摄影采用常规方法摄片,MRI采用自旋回波T1WI,T2WI序列及动态增强扫描等.结果 68例乳腺恶性肿瘤中,浸润性导管癌57例,浸润性小叶癌3例,叶状囊肉瘤1例,血管肉瘤1例,导管内癌2例,炎性乳癌2例,印戒细胞癌1例,Paget's病1例.乳腺X线摄影诊断正确61例,诊断准确率89.7％.MRI诊断正确66例,诊断准确率97.1％.结论 乳腺X线摄影是乳腺恶性病变的首选检查方法,MRI能更多的显示乳腺病灶的内部特征,二者联合应用对乳腺癌的临床诊断具有重要意义.     

Detection of masses and calcifications by soft-copy reading: comparison of two postprocessing algorithms for full-field digital mammography

Purpose  The purpose of this study was to determine the effects of a commercially available postprocessing algorithm on the detection of masses and microcalcifications of breast cancer by soft-copy reading. Materials and methods  The study included 64 digital mammograms with 16 histologically proven abnormal findings (eight masses and eight microcalcifications) and 48 normal breasts. Two image-processing algorithms were applied to the digital images, which were acquired using General Electric units. The commercially available advanced and standard postprocessed digital mammograms were evaluated in a localization receiver operating characteristic (ROC) curve experiment involving seven mammography radiographers. Results  The mean area under the ROC curve was 0.921 ± 0.022 for the commercially available advanced postprocessed digital mammograms session and 0.904 ± 0.026 for the standard postprocessed digital mammograms session (P = 0.1953). Observer agreement among the readers was better for the advanced postprocessed digital mammograms than for the standard postprocessed digital mammograms. Conclusion  During soft-copy reading, the interpretation accuracy might be influenced by the postprocessing algorithm.     

Computer-aided diagnosis of masses with full-field digital mammography

RATIONALE AND OBJECTIVES: The authors developed and evaluated a method of computer-aided diagnosis (CAD) for mass detection with full-field digital mammography (FFDM). MATERIALS AND METHODS: The new CAD method for FFDM employs adaptive, nonlinear multiscale processing and hybrid classification methods. The major strategies are (a) to "standardize" the mammographic image before it is input to the analysis modules, (b) to adapt the segmentation of suspicious regions adapt to accommodate different characteristics of masses and mammograms, and (c) to use combined "hard" and "soft" decision making in discriminating between mass and normal tissue regions. Two data sets of diagnostic FFDM mammograms were used. The training data set includes 36 normal and 24 abnormal mammograms (34 masses), and the testing data set includes 24 normal and 10 abnormal mammograms (10 masses). The tumors in this diagnostic database were more subtle and difficult to detect than those in screening databases the authors have used before. RESULTS: With the limited database and a partial optimization, a sensitivity of 91% was obtained in training, with a false-positive rate of 3.21 per image. At this trained operating point of the CAD system, six of 10 subtle masses were detected in testing. CONCLUSION: The CAD algorithms developed in screen-film mammography can be modified for FFDM. More data analysis and system optimization and evaluation will be needed before CAD can be integrated efficiently into the performance of FFDM.     

数字乳腺断层摄影及其合成二维影像技术在乳腺癌筛查中的研究进展

目前乳腺X线检查仍是乳腺癌早期诊断的有效检查方法之一,主要包括全视野数字化乳腺摄影（FFDM）、数字乳腺断层摄影（DBT）、合成乳腺X线摄影（SM）以及3种技术的联合应用（FFDM联合DBT、SM联合DBT）。对DBT、SM和SM联合DBT在乳腺筛查中诊断效能、影像质量及辐射剂量等进行比较。SM联合DBT可有效平衡辐射剂量和诊断效能,但仍然在判读时间、信息的存储与传输和检查成本方面存在局限性。就以上3种检查技术在乳腺癌筛查中的研究进展予以综述。     

Independent evaluation of computer classification of malignant and benign calcifications in full-field digital mammograms

RATIONALE AND OBJECTIVES: To evaluate whether a computer-aided diagnosis (CADx) technique can accurately classify breast calcifications in full-field digital mammograms (FFDMs) as malignant or benign. The computer technique was developed previously on screen-film mammograms (SFMs) in which individual calcifications were identified manually. The present study evaluated the computer technique independently on a new database of FFDM images with automatic detection of the individual calcifications. MATERIALS AND METHODS: We analyzed 49 consecutive FFDM cases (19 cancers) that showed suspicious calcifications. Four mammography radiologists read soft-copy mammograms retrospectively and electronically indicated the region of calcifications in each image. The computer then automatically detected the individual calcifications within the indicated region and analyzed eight features of calcification morphology and distribution to arrive at an estimated likelihood of malignancy. The radiologists entered Breast Imaging Report and Data System assessments before and after seeing the computer results. Performance was analyzed using receiver operating characteristic analysis. RESULTS: Despite variability in radiologist-indicated regions of calcifications, the computer achieved consistently high performance taking input from the four radiologists (receiver operating characteristic curve area, A(z): 0.80, 0.80, 0.78, and 0.77; differences not statistically significant). Previous results showed that the computer technique achieved an A(z) value of 0.80 on SFMs, which improved radiologists' performance significantly. CONCLUSIONS: The computer technique appears to maintain consistently high performance in classifying calcifications in FFDMs as malignant or benign without requiring substantial modification from its initial development on SFMs. The computer performance appears to be robust with respect to variations in radiologists' input.     

The positive predictive value for diagnosis of breast cancer full-field digital mammography versus film-screen mammography in the diagnostic mammographic population

RATIONALE AND OBJECTIVES: Diagnostic mammography is performed on women with clinical symptoms that suggest breast cancer or women for whom further mammographic evaluation has been requested because of an abnormal screening mammography. We assessed whether the use of full-field digital mammography would improve the positive predictive value (PPV) for the diagnosis of breast cancer in a diagnostic population compared with film-screen mammography. MATERIALS AND METHODS: From January 2002 to December 2003, 11,621 patients underwent diagnostic mammography at the University of North Carolina Hospital, Chapel Hill. Among these 11,621 patients, 1400 lesions in 1121 patients underwent biopsy. We included the biopsy-performed lesions, so PPV3 was used for comparison of PPVs between film-screen mammography and full-field digital mammography. Six breast radiologists interpreted the images using the Breast Imaging Reporting and Data System of the American College of Radiology. PPV3s were compared between film-screen and full-field digital mammography in the entire study cohort and in specified subgroups according to different radiologists, breast density, and lesion type on mammography. The chi(2) and Fisher's exact tests were used for comparison of PPV3s between two modalities of mammography with the Bonferroni procedure for subgroup analysis. RESULTS: In the entire study cohort, PPV3s of full-field digital mammography and film-screen mammography were similar (difference in PPV3,-0.007; 95% confidence interval, -0.081 to 0.068; P = .8602). In predefined subgroups, there was no difference in PPV3 by the radiologist, breast density, or lesion type between two modalities of mammography (P > .005). CONCLUSION: There is no improvement in PPV for the diagnosis of breast cancer with full-field digital mammography compared with film-screen mammography in a large diagnostic population.     

Effect on sensitivity and specificity of mammography screening with or without comparison of old mammograms

Purpose:
To evaluate the effect of old mammograms on the specificity and sensitivity of radiologists in mammography screening.
Material and Methods:
One hundred and fifty sets of screening mammograms were examined by 3 experienced screeners twice: once without and once in comparison with older mammograms. The films came from a population-based screening done during the first half of 1994 and comprised all 35 cancers detected during screening in 1994, 12/24 interval cancers, 14/34 cancers detected in the following screening and 89 normal mammograms.
Results:
Without old mammograms, the screeners detected an average of 40.3 cancers (range 37-42), with a specificity of 87% (85-88%). With old mammograms, the screeners detected 37.7 cancers (range 34-42) with a specificity of 96% (94-99%). The change in detection rate was not significant. However, the increase in specificity was significant for each screener (p=0.0002-0.03).
Conclusion:
Mammography screening with old mammograms available for comparison decreased the false-positive recall rate. The effect on sensitivity, however, was unclear.     

Evaluation of linear and nonlinear tomosynthetic reconstruction methods in digital mammography

RATIONALE AND OBJECTIVES: The purpose of this study was to comparatively evaluate digital planar mammography and both linear and nonlinear tomosynthetic reconstruction methods. MATERIALS AND METHODS: A "disk" (ie, target) identification study was conducted to compare planar and reconstruction methods. Projective data using a composite phantom with circular disks were acquired in both planar and tomographic modes by using a full-field, digital mammographic system. Two-dimensional projections were reconstructed with both linear (ie, backprojection) and nonlinear (ie, maximization and minimization) tuned-aperture computed tomographic (TACT) methods to produce three-dimensional data sets. Four board-certified radiologists and one 4th-year radiology resident participated as observers. All images were compared by these observers in terms of the number of disks identified. RESULTS: Significant differences (P < .05, Bonferroni adjusted) were observed between all reconstruction and planar methods. No significant difference, however, was observed between the planar methods, and only a marginally significant difference (P < .054, Bonferroni adjusted) was observed between TACT-backprojection and TACT-minimization. CONCLUSION: A combination of linear and nonlinear reconstruction schemes may have potential implications in terms of enhancing image visualization to provide radiologists with valuable diagnostic information.     

Digital Breast Tomosynthesis: A Decade of Practice in Review

Digital breast tomosynthesis (DBT), introduced in 2011, was thought to be a further evolution of full-field digital mammography (DM). Assessing DBT presents unique challenges. The widely variable settings in which DBT has been applied affect outcomes. In initial studies comparing DM-DBT with DM, outcomes for cancer detection rates (CDRs) and recall rates have been mixed. CDR improves most in biennial screening settings, with little or no improvement in annual screening. Recall rates improve most where rates are highest; no improvement is seen in European prospective trials. Adoption of synthesized mammography (SM), derived from the tomosynthesis acquisition and intended to avoid the DM exposure, has been slow because of inferior image quality. Despite this, SM-DBT has shown equivalent outcomes measures to DM-DBT. An important exception is the To-Be randomized controlled trial, which showed that SM-DBT was equivalent to DM in CDR, not better. To date, interval cancer rate, a surrogate for mortality reduction, has not been shown to be improved by DBT. We may have reached the limit of morphological assessment in x-ray technique. Its use may evolve with advancements in technology as use of contrast agents expands, algorithms for SM progress, and tomosynthesis-guided biopsy proliferates. Our expectations of the contributions of DBT will evolve as well.     

Breast cancer detection: Comparison of digital mammography and digital breast tomosynthesis across non-dense and dense breasts

IntroductionBreast density is associated with an increase in breast cancer risk and limits early detection of the disease. This study assesses the diagnostic performance of mammogram readers in digital mammography (DM) and digital breast tomosynthesis (DBT).MethodsEleven breast readers with 1–39 years of experience reading mammograms and 0–4 years of experience reading DBT participated in the study. All readers independently interpreted 60 DM cases (40 normal/20 abnormal) and 35 DBT cases (20 normal/15 abnormal). Sensitivity, specificity, ROC AUC, and diagnostic confidence were calculated and compared between DM and DBT.ResultsDBT significantly improved diagnostic confidence in both dense breasts (p = 0.03) and non-dense breasts (p = 0.003) but not in other diagnostic performance metrics. Specificity was higher in DM for readers with >7 years' experience (p = 0.03) in reading mammography, non-radiologists (p = 0.04), readers who had completed a 3–6 months training fellowship in breast imaging (p = 0.04), and those with ≤2 years’ experience in reading DBT (p = 0.02), particularly in non-dense breasts.ConclusionDiagnostic confidence was higher in DBT when compared to DM. In contrast, other performance metrics appeared to be similar or better with DM and may be influenced by the lack of experience of the reader cohort in reading DBT.Implications for practiceThe benefits of DBT may not be entirely accrued until radiologists attain expertise in DBT interpretation. Specificity of DBT varied according to reader characteristics, and these characteristics may be useful for optimising pairing strategies in independent double reading of DBT as practiced in Australia to reduce false positive diagnostic errors.