Computer-aided detection in screening mammography: variability in cues

PURPOSE: To evaluate the variability of true-positive and false-positive cues by using a commercially available computer-aided detection (CAD) system for analysis of 50 malignancies in a screening population. MATERIALS AND METHODS: Fifty breast cancers detected at screening were analyzed by using a commercially available CAD system. Mean patient age was 62.2 years. Each set of mammograms (craniocaudal and mediolateral oblique views) was digitized and analyzed by the CAD system 10 times. One radiologist compared CAD output with the location of the malignancy at mammography and determined whether each lesion was marked accurately in one mammographic view, both views, or neither. Sensitivity and reproducibility of the CAD system were determined for both case- and image-based analysis. RESULTS: Overall sensitivity of the CAD system when at least one of the two mammographic views was marked correctly (case-base sensitivity) was 82.4%. Sensitivity when each mammographic view was considered separately (image-based sensitivity) was 61.1%. For case-based analysis, variability in true-positive CAD cues was demonstrated for 14 of 50 (28%) cases. For image-based analysis, inconsistency in CAD output was observed in 33 of 100 (33%) mammographic views that contained malignancies detected at screening. However, the CAD system consistently detected 40-43 of the 50 breast cancers in each of the 10 CAD runs. Variability for false-positive marks was significantly greater than that for true-positive marks. CONCLUSION: Inconsistency was demonstrated for CAD analysis of breast cancers detected at screening. However, the CAD system was reasonably consistent in the overall number of cancers identified from run to run. Greater variability of the CAD system was also demonstrated for false-positive marks, as compared with true-positive marks.     

Influence of breast lesion size and histologic findings on tumor detection rate of a computer-aided detection system

PURPOSE: To evaluate associations between histopathologic findings, tumor size, and detection rate of malignant mammographic findings by using a computer-aided detection (CAD) system. MATERIALS AND METHODS: The study included 208 mammographically detected histologically proven malignant breast lesions in 208 women. Findings were 150 masses and 114 microcalcifications; 56 lesions showed both findings; 94 lesions, mass only; and 58 lesions, microcalcification only. CAD was used to evaluate mammograms in two views retrospectively. Also, corresponding histopathologic findings and lesion size were evaluated. CAD marks were considered positive if, on at least one view, they correctly identified the corresponding mammographic lesion location. RESULTS: Ninety percent (135 of 150) of masses and 93.0% (106 of 114) of microcalcifications were marked correctly by the CAD system. Overall tumor detection rate was 93.8% (195 of 208). Size-related detection rate for masses was 83.3% (25 of 30) for lesions up to 10 mm, 100% (45 of 45) for lesions 11-20 mm, 100% (46 of 46) for lesions 21-30 mm, 83.3% (10 of 12) for lesions 31-40 mm, and 52.9% (nine of 17) for lesions larger than 40 mm. Size-related tumor detection rate for microcalcifications was 92.5% (37 of 40) for microcalcifications up to 10 mm, 93.1% (27 of 29) for lesions 11-20 mm, 100% (20 of 20) for lesions 21-30 mm, 87.5% (seven of eight) for lesions 31-40 mm, and 88.2% (15 of 17) for larger microcalcifications. Detection rates for mammographically visible masses (invasive ductal carcinoma, invasive lobular carcinoma, invasive tubular carcinoma, noninvasive cancers, mucinoid cancers, and others) were 92.3% (84 of 91), 89.3% (25 of 28), 75.0% (six of eight), 100% (15 of 15), 33.3% (one of three), and 80.0% (four of five), respectively. Detectability rates for mammographically visible areas suspicious for microcalcifications (invasive ductal carcinoma, invasive lobular carcinoma, invasive tubular carcinoma, and noninvasive cancers) were 92.3% (60 of 65), 100% (eight of eight), 100% (five of five), and 91.9% (31 of 34), respectively. Highest overall detection rates were observed for invasive ductal carcinomas (96.6% [112 of 116]) and noninvasive cancers (92.9% [39 of 42]). CONCLUSION: Highest detection rates were observed for 10-30-mm tumor masses and for invasive ductal carcinomas and noninvasive cancers.     

Ductal carcinoma in situ: computer-aided detection in screening mammography

PURPOSE: To retrospectively evaluate the sensitivity of computer-aided detection (CAD) in depicting ductal carcinoma in situ (DCIS) on screening mammograms by using biopsy proved lesion location as the reference standard. MATERIALS AND METHODS: Institutional review board approval was obtained, with a waiver of patient informed consent for this HIPAA-compliant study. Findings of all image-guided biopsies with a pathologic diagnosis of DCIS during a 1-year period were reviewed. Fifty-eight lesions in 55 women (average age, 61.41 years +/- 12.89 [standard deviation]) were available for review. The screening mammogram of the affected breast and, if available, the prior screening mammogram were digitized by the CAD system. An assessment was then made as to whether the CAD system marked the area of DCIS on the current and prior mammograms. Patient age, location and mammographic size of the lesion, type of lesion, and breast density were recorded and were analyzed by using chi2, Fisher exact, or Cochran-Mantel-Haenzel tests, where applicable. RESULTS: CAD identified DCIS in 53 (91%) of 58 lesions on craniocaudal (CC) and mediolateral oblique (MLO) views of screening mammograms obtained in the year of the diagnosis. On screening mammograms obtained prior to the year of the diagnosis (34 patients), no radiologically or CAD-detected lesion was present on 11 (32%) of 34 mammograms. CAD identified DCIS in 16 (70%) of 23 lesions on one of the two views. Seven (30%) of 23 lesions had mammographic findings at retrospective review that were not identified with CAD. CONCLUSION: CAD had a high sensitivity in the depiction of DCIS.     

早期乳腺癌的CR表现及病理基础

目的评价早期乳腺癌的CR表现及其病理基础。方法回顾性分析经病理证实的43例早期乳腺癌的CR片,包括导管原位癌及导管原位癌伴微浸润30例、浸润性导管癌12例和浸润性小叶癌1例,观察早期乳腺癌的CR表现,并与病理对照。结果(1)43例早期乳腺癌中,CR表现钙化21例(49%),结节15例(35%),非对称性局限性密度增高影伴结构紊乱7例(16%)。(2)乳腺数字化图像可以显示早期乳腺癌病变的细微结构。结论乳腺CR成像对早期乳腺癌的诊断具有重要意义。     

Aspects in mammographic screening. Detection,prediction, recurrence and prognosis

Screening mammograms comprising of 32 first round, 10 interval and 32 second round detected cancers and 46 normal were examined by an expert screener, a screening radiologist, a clinical radiologist and a computer-assisted diagnosis (CAD) system. The expert screener, screening radiologist, clinical radiologist and the CAD detected 44, 41, 34 and 37 cancers, respectively, while their respective specificities were 80%, 83%, 100% and 22%. Later, with CAD prompting, the screening and the clinical radiologist detected 1 and 3 additional cancers each with unchanged specificities. Screening mammograms comprising 35 first round, 12 interval and 14 second round detected cancers and 89 normal findings were examined without and with previous mammograms by experienced screeners. Without previous mammograms, the screeners detected 40.3 cancers with a specificity of 87%. With previous mammograms, 37.7 cancers were detected with a 96% specificity. The decrease in sensitivity was not significant but the screeners showed significant increase in specificity. Local recurrences in 303 nonpalpable breast cancers with preoperative localizations and breast conservation therapy were evaluated for needle-caused implant metastasis. A total of 214 percutaneous biopsies were performed. There were 33 local recurrences. Needle-caused seeding or implantation as based on the location of the recurrence in comparison to the needle path in the mammograms was suspected in 3/44 (7%) invasive cancers without radiotherapy. The mammographic characteristics of 317 nonpalpable breast cancers were categorized. Logistic regression showed that the risk ratios for a spiculated mass without calcifications and calcifications alone were 12 and 19 for invasive cancer and ductal cancer in situ (DCIS), respectively. Invasive ductal grade 1, ductal grade 2, lobular and ductal grade 3, had a risk ratio (RR) of 28, 17, 11 and 4.6, respectively, for a spiculated mass without calcifications. DCIS nuclear grade 3 and invasive ductal grade 3 had an RR of 17 and 9.7, respectively, for sole casting calcifications. The eight-year survival of 96 1-9-mm invasive breast cancers were investigated in relation to their mammographic appearance, node status and histologic grade. After a median follow-up of 7 years, 6/96 died from breast cancer: 3/14 had calcifications alone, 2/56 had spiculated masses, 1/12 had rounded mass, 5/78 were node-negative and 1/4 was node-positive. The survival rate was 93%: 77% for the calcifications alone, 95% for spiculated masses, 91% for rounded masses, 92% for node-negative and 75% for node-positive. Calcifications alone and node positivity, each, carried a significantly higher risk of death.     

Nonpalpable breast cancer: mammographic appearance as predictor of histologic type.

PURPOSE: To investigate the association between mammographic appearance and histologic diagnosis of nonpalpable breast cancers. MATERIALS AND METHODS: Mammographic characteristics of 317 consecutive clinically nonpalpable breast cancers in patients treated with breast-conserving surgery were reviewed. Malignant lesions were categorized as spiculated masses, other lesions, calcifications, and combined findings. Calcifications were characterized as amorphous, pleomorphic, or fine linear and branching. Logistic regression was used for the evaluation. Odds ratios (ORs) represent the magnitude of the association between a histologic diagnosis and a mammographic finding. RESULTS: Spiculated mass without calcifications (n = 150) and calcifications alone (n = 79) accounted for three of four cancers. A spiculated mass without calcifications was strongly associated with invasive cancers (OR = 12). Calcifications alone were strongly associated with ductal carcinoma in situ (DCIS) (OR = 19). In a decreasing order, the following invasive cancers were each associated with spiculated lesions without calcifications: ductal carcinoma grade 1 (OR = 28), ductal carcinoma grade 2 (OR = 17), lobular carcinoma (OR = 11), and ductal carcinoma grade 3 (OR = 4.6). Fine linear and branching calcifications alone were associated with not only DCIS nuclear grades 3 (OR = 17) and 2 (OR = 9.7) but also with invasive ductal carcinoma grade 3 (OR = 13). CONCLUSION: Mammographic appearance can be a predictor of histologic diagnosis in three of four nonpalpable breast cancers.     

Light scan evaluation of nonpalpable breast lesions

Transillumination light scanning of the breast was performed immediately before needle localization of 112 nonpalpable mammographic abnormalities detected in 103 patients. Twenty-four cancers were diagnosed in 23 patients. The positive predictive value for mammography was 21%. Ten (42%) of these nonpalpable cancers were not visible on transillumination light scanning. Eleven of 16 invasive ductal cancers and three of seven intraductal cancers were evident on transillumination light scans, but a single case of lobular carcinoma in situ was not evident. There were 12 false-positive light scan examinations. Transillumination light scanning had a 58% sensitivity, an 86% specificity, a 54% positive predictive value, and an 88% negative predictive value for small breast lesions. Therefore, the authors are unable to recommend delaying biopsy in patients with mammographic abnormalities on the basis of a negative light scan study.     

Breast imaging findings in women with BRCA1- and BRCA2-associated breast carcinoma

AIM: To document the breast imaging findings of women with BRCA1 and BRCA2-associated breast carcinoma. MATERIALS AND METHODS: Family history clinic records identified 18 BRCA1 and 10 BRCA2 cases who collectively were diagnosed with 27 invasive breast carcinomas and four ductal carcinoma in situ (DCIS) lesions. All underwent pre-operative imaging (29 mammogram and 22 ultrasound examinations). All invasive BRCA-associated breast carcinoma cases were compared with age-matched cases of sporadic breast carcinoma. RESULTS: Within the BRCA cases the age range was 26-62 years, mean 36 years. Two mammograms were normal and 27 (93%) abnormal. The most common mammographic features were defined mass (63%) and microcalcifications (37%). Thirty-four percent of women had a dense mammographic pattern, 59% mixed and 7% fatty. Ultrasound was performed in 22 patients and in 21 (95%) indicated a mass. This was classified as benign in 24%, indeterminate in 29% and malignant in 48%. Mammograms of BRCA1-associated carcinomas more frequently showed a defined mass compared with BRCA2-associated carcinomas, 72 versus 36% (73% control group) whilst mammograms of BRCA2-associated carcinomas more frequently showed microcalcification, 73 versus 12% (8% control group; p < 0.001). Thirty-six percent of the BRCA2-associated carcinomas were pure DCIS while none of the BRCA1 associated carcinomas were pure DCIS (p = 0.004). Of those patients undergoing regular mammographic screening, 100% of BRCA2-associated carcinomas were detected compared with 75% of BRCA1-associated carcinomas. CONCLUSION: These data suggest that the imaging findings of BRCA1 and BRCA2-associated carcinomas differ from each other and from age-matched cases of sporadic breast carcinoma.     

Invasive lobular carcinoma of the breast: mammographic characteristics and computer-aided detection

PURPOSE: To characterize the mammographic appearance of invasive lobular carcinoma in a large series of screening-detected consecutive breast cancers and to evaluate the ability of a computer-aided detection system to mark these carcinomas. MATERIALS AND METHODS: Investigators used the Breast Imaging Reporting and Data System lexicon to characterize lesions as part of a retrospective review of 90 screening mammographic examinations that led to biopsy-proved diagnosis of 94 invasive lobular carcinoma lesions. The 40 available prior mammographic examinations (obtained 9-24 months earlier) were also reviewed to characterize any visible findings. The results of a computer-aided detection analysis were compared with the images, and the sensitivity of the algorithm was calculated for correct detection of the lesions. RESULTS: Fifty-six (60%) of 94 lesions manifested as masses, of which 40 (71%) were described as irregular and spiculated; 20 (21%) of 94, as architectural distortions; and the remainder, 18 (20%), as either asymmetric densities or calcifications. On the screening mammograms showing biopsy-proved cancers, the sensitivity of the computer-aided detection system was 86 (91%) of 94 lesions. Thirty-one of the 40 prior mammograms showed retrospectively visible findings, and 24 (77%) of 31 were marked by the computer-aided detection system. CONCLUSION: Spiculated masses and architectural distortions are the predominant appearances of invasive lobular carcinoma, and a computer-aided detection system correctly marked a high percentage of invasive lobular carcinoma lesions.     

Computer-aided detection output on 172 subtle findings on normal mammograms previously obtained in women with breast cancer detected at follow-up screening mammography

PURPOSE: To evaluate, by using a computer-aided detection (CAD) program, the nonspecific findings on normal screening mammograms obtained in women in whom breast cancer was later detected at follow-up screening mammography. MATERIALS AND METHODS: Four hundred ninety-three mammogram pairs-an initial negative screening mammogram and a subsequently obtained screening mammogram showing cancer-were collected. The mean interval between examinations was 14.6 months. In 169 cases, in which 172 cancers were later depicted, findings on the initial mammogram were subtle enough that either none or only one or two of five blinded radiologists recommended screening recall. On the initial negative mammograms, of the 172 areas where cancer later developed, 137 (80%) had subtle nonspecific findings and were retrospectively judged as having a benign or normal appearance. The mammograms with these subtle findings were evaluated with a commercially available CAD program, and the numbers of CAD marks on these nonspecific findings were analyzed. RESULTS: Of the 172 cancers, 129 (75%) were invasive and 43 (25%) were ductal carcinoma in situ. The CAD program marked 72 (42%) of the 172 findings that subsequently developed into cancer: 24 (29%) of 82 findings recalled by none, 25 (49%) of 51 findings recalled by one, and 23 (59%) of 39 findings recalled by two of the five radiologists. Among the 137 areas with nonspecific normal or benign findings, 41 (30%) areas where cancer subsequently developed were marked by the CAD program. CONCLUSION: A subset of cancers have perceptible but nonspecific mammographic findings that may be marked by a CAD program, even when the findings do not warrant recall as judged at blinded and unblinded radiologist review. The authors believe failure to act on such nonspecific but CAD-marked findings prospectively does not constitute interpretation below a reasonable standard of care.     

Radial sclerosing lesions of the breast: mammographic and pathologic correlation.

OBJECTIVE: The purpose of this study was to define the mammographic appearance of 96 pathologically proven radial sclerosing lesions (RSLs) and to determine the frequency of association with malignancy in and around the lesions. METHODS: Ninety-three patients with 96 RSLs were identified from the pathology files of the BC Cancer Agency, and the reasons for biopsy were obtained. All preoperative mammograms were reviewed, and the RSLs were categorized as classic (typical), non-classic (atypical), or incidental. The histopathologic results were retrospectively examined for atypia, ductal carcinoma in situ (DCIS) and invasive carcinoma. RESULTS: In 67 of the 96 biopsies, the RSL was the primary mammographic abnormality that led to biopsy. In this group, 17 cases (25.4%) contained atypia, 17 (25.4%) DCIS, and 4 (6%) invasive carcinoma. Nineteen of these RSLs presented as mass-like opacities that mimicked carcinoma. No single mammographic feature consistently predicted premalignant or malignant lesions. In the remaining 29 patients, biopsy was carried out because of pleomorphic calcifications or masses, and RSLs were found incidentally in specimens. These specimens included 4 cases (13.8%) of atypia, and 1 case (3.4%) of DCIS. CONCLUSION: Of the 67 mammographically detected RSLs, only 48 (71.6%) had a typical mammographic appearance. We found a significant amount of atypia (25.4%) and malignancy (25.4% DCIS and 6% invasive carcinoma) in mammographically detected RSLs. Because of the lack of predictable radiological features, adequate open surgical biopsy is recommended for all focal abnormalities in which a RSL is a possible diagnosis.     

Mammographic characteristics of 115 missed cancers later detected with screening mammography and the potential utility of computer-aided detection

PURPOSE: To retrospectively determine the mammographic characteristics of cancers missed at screening mammography and assess the ability of computer-aided detection (CAD) to mark the missed cancers. MATERIALS AND METHODS: A multicenter retrospective study accrued 1,083 consecutive cases of breast cancer detected at screening mammography. Prior mammograms were available in 427 cases. Of these, 286 had lesions visible in retrospect. The 286 cases underwent blinded review by panels of radiologists; a majority recommended recall for 112 cases. Two experienced radiologists compared prior mammograms in 110 of these cases with the subsequent screening mammograms (when cancer was detected), noting mammographic characteristics of breast density, lesion type, size, morphology, and subjective reasons for possible miss. The prior mammograms were then analyzed with a CAD program. RESULTS: There were 110 patients with 115 cancers. On the prior mammograms with missed cancers, 35 (30%) of the 115 lesions were calcifications, with 17 of 35 (49%) clustered or pleomorphic. Eighty of the 115 (70%) were mass lesions, with 32 of 80 (40%) spiculated or irregular. For calcifications and masses, the most frequently suggested reasons for possible miss were dense breasts (12 of 35; 34%) and distracting lesions (35 of 80; 44%), respectively. CAD marked 30 (86%) of 35 missed calcifications and 58 (73%) of 80 missed masses. CONCLUSION: Detection errors affected cases with calcifications and masses. CAD marked most (77%; 88 of 115) cancers missed at screening mammography that radiologists retrospectively judged to merit recall.     

Evaluation of breast amorphous calcifications by a computer-aided detection system in full-field digital mammography

Objectives

The purpose of this study was to evaluate the performance of a direct computer-aided detection (d-CAD) system integrated with full-field digital mammography (FFDM) in assessment of amorphous calcifications.

Methods

From 1438 consecutive stereotactic-guided biopsies, FFDM images with amorphous calcifications were selected for retrospective evaluation by d-CAD in 122 females (mean age, 56 years; range, 35–84 years). The sensitivity, specificity, accuracy and false-positive rate of the d-CAD system were calculated in the total group of 124 lesions and in the subgroups based on breast density, mammographic lesion distribution and extension. Logistic regression analysis was used to stratify the risk of malignancy by patient risk factors and age.

Results

The d-CAD marked all (36/36) breast cancers, 85% (11/13) of the high-risk lesions and 80% (60/75) of benign amorphous calcifications (p<0.01) correctly. The sensitivity, specificity and diagnostic accuracy for the combined malignant and “high-risk” lesions was 96, 80 and 86%, respectively. The likelihood of malignancy was 29%. There was no significant difference between the marking of fatty or dense breasts (p>0.05); however, d-CAD marks showed differences for small (<7 mm) lesions (p=0.02) and clustered calcifications (p=0.03). The false-positive rate of d-CAD was 1.76 marks per full examination.

Conclusion

The d-CAD system correctly marked all biopsy-proven breast cancers and a large number of biopsy-proven high-risk lesions that presented as amorphous calcifications. Given our 29% likelihood of malignancy, imaging-guided biopsy appears to be a reasonable recommendation in cases of amorphous calcifications marked by d-CAD.Many cancers that cannot be detected with mammography are in dense tissue, and digital mammography is more accurate in females with radiographically dense breasts [1]. In order for a radiologist to diagnose a breast cancer, this cancer must first be detected and second be correctly interpreted. Computer-aided detection (CAD) systems help radiologists with the perception of the cancer, marking regions of interest on the screen. The use of CAD software primarily in full-field digital mammography (FFDM), also known as direct CAD (d-CAD), does not require digitisation of the films and by definition, once an image is acquired, the CAD detection result will be reproducible when the same d-CAD scheme is applied repeatedly to such an image [2].Breast microcalcifications are detected by high-quality mammography [3-8]. Amorphous calcifications are frequently difficult to identify on routine mammograms, with 78% seen retrospectively but not prospectively by Berg et al [9] in their series using screen-film mammograms. The purpose of CAD systems in breast imaging is to help the radiologist by marking suspicious regions that were initially missed; however, the radiologist has to decide whether true areas of concern are present in the highlighted locations and thus retains the ability to make the final decision about whether biopsy is deemed necessary.Because amorphous calcifications without associated findings can be easily overlooked on routine screening mammograms, the use of d-CAD systems to aid in detection could be beneficial to the radiologist. Therefore, the purpose of our study was to determine the performance of one commercially available d-CAD system in marking non-palpable amorphous calcifications not associated with other mammographic findings and comparing this with the histopathology results.     

Impact of breast density on computer-aided detection for breast cancer

OBJECTIVE: Our aim was to determine whether breast density affects the performance of a computer-aided detection (CAD) system for the detection of breast cancer. MATERIALS AND METHODS: Nine hundred six sequential mammographically detected breast cancers and 147 normal screening mammograms from 18 facilities were classified by mammographic density. BI-RADS 1 and 2 density cases were classified as nondense breasts; BI-RADS 3 and 4 density cases were classified as dense breasts. Cancers were classified as either masses or microcalcifications. All mammograms from the cancer and normal cases were evaluated by the CAD system. The sensitivity and false-positive rates from CAD in dense and nondense breasts were evaluated and compared. RESULTS: Overall, 809 (89%) of 906 cancer cases were detected by CAD; 455/505 (90%) cancers in nondense breasts and 354/401 (88%) cancers in dense breasts were detected. CAD sensitivity was not affected by breast density (p=0.38). Across both breast density categories, 280/296 (95%) microcalcification cases and 529/610 (87%) mass cases were detected. One hundred fourteen (93%) of the 122 microcalcifications in nondense breasts and 166 (95%) of 174 microcalcifications in dense breasts were detected, showing that CAD sensitivity to microcalcifications is not dependent on breast density (p=0.46). Three hundred forty-one (89%) of 383 masses in nondense breasts, and 188 (83%) of 227 masses in dense breasts were detected-that is, CAD sensitivity to masses is affected by breast density (p=0.03). There were more false-positive marks on dense versus nondense mammograms (p=0.04). CONCLUSION: Breast density does not impact overall CAD detection of breast cancer. There is no statistically significant difference in breast cancer detection in dense and nondense breasts. However, the detection of breast cancer manifesting as masses is impacted by breast density. The false-positive rate is lower in nondense versus dense breasts. CAD may be particularly advantageous in patients with dense breasts, in which mammography is most challenging.     

Modern concepts of ductal carcinoma in situ (DCIS) and its diagnosis through percutaneous biopsy

The incidence of ductal breast carcinoma in situ (DCIS) is increasing and currently lies at about 15% of all breast cancers. Detection of DCIS reduces the subsequent incidence of invasive ductal carcinoma. Patients with Breast Imaging Reporting and Data System (BI-RADS) category 4 lesions are best served by minimally invasive biopsies to improve the precision of diagnosing DCIS lesions. Vacuum-assisted biopsies have the greatest sensitivity and specificity of the biopsy techniques and reduce tumor upgrading of DCIS lesions at operation by at least half compared with core-needle biopsy. Moreover, vacuum-assisted biopsies have proved to be safe and reduce health care costs. Since they provide a maximum of preoperative information, vacuum-assisted biopsies could improve outcomes in patients with DCIS.     

Computer-aided detection (CAD) in screening mammography: sensitivity of commercial CAD systems for detecting architectural distortion

OBJECTIVE: Computer-aided detection (CAD) algorithms have successfully revealed breast masses and microcalcifications on screening mammography. The purpose of our study was to evaluate the sensitivity of commercially available CAD systems for revealing architectural distortion, the third most common appearance of breast cancer. MATERIALS AND METHODS: Two commercially available CAD systems were used to evaluate screening mammograms obtained in 43 patients with 45 mammographically detected regions of architectural distortion. For each CAD system, we determined the sensitivity for revealing architectural distortion on at least one image of the two-view mammographic examination (case sensitivity) and for each individual mammogram (image sensitivity). Surgical biopsy results were available for each case of architectural distortion. RESULTS: Architectural distortion was deemed present and actionable by a panel of expert breast imagers in 80 views of the 45 cases. One CAD system detected distortion in 22 of 45 cases of distortion (case sensitivity, 49%) and in 30 of 80 mammograms (image sensitivity, 38%); it displayed 0.7 false-positive marks per image. Another CAD system identified distortion in 15 of 45 cases (case sensitivity, 33%) and 17 of 80 mammograms (image sensitivity, 21%); it displayed 1.27 false-positive marks per image. Sensitivity for malignancy-caused distortion was similar to or lower than sensitivity for all causes of distortion. CONCLUSION: Fewer than one half of the cases of architectural distortion were detected by the two most widely available CAD systems used for interpretations of screening mammograms. Considerable improvement in the sensitivity of CAD systems is needed for detecting this type of lesion. Practicing breast imagers who use CAD systems should remain vigilant for architectural distortion.     

Mammographic predictors of the presence and size of invasive carcinomas associated with malignant microcalcification lesions without a mass

OBJECTIVE: Our objective was to determine the degree with which mammographic features predict the presence and size of invasive carcinomas associated with malignant mammographic microcalcification lesions without a mass. MATERIALS AND METHODS: Mammographic features were correlated with pathologic features in 304 consecutive breast carcinomas manifested by mammographic calcifications only in a prospective evaluation. RESULTS: Mammographic calcifications associated with breast carcinoma had the final pathologic diagnoses of pure ductal carcinoma in situ (DCIS) in 65% of patients, DCIS with a focus of invasion in 32%, and invasive carcinoma only in 4%. Invasive foci were more likely associated with mammographic calcification size of 11 mm and greater (40%, 77/194) compared with 1-10 mm (26%, 29/110; p = 0.019). Invasive foci were also more likely associated with linear calcifications (44%, 55/126) compared with granular calcifications (29%, 51/178; p = 0.007). The frequency of invasion did not increase with calcification extents greater than 10 mm. The frequency of invasion ranged from 22% for less than or equal to 5-mm granular calcifications to 45% for linear calcifications of 11 mm and greater. Only 11% of cancers characterized by fine granular calcifications were associated with invasion as compared with 32% of those with coarse and mixed granular calcifications (p = 0.002). CONCLUSION: Mammographic calcification features of malignant lesions cannot predict the absence of invasion with greater than 90% predictive value or predict the presence of invasion with greater than 45% predictive value. Increased extent of calcifications greater than 10 mm was not associated with greater likelihood of invasion.     

Computer-aided detection in direct digital full-field mammography: initial results

For the first time, full-field digital mammography (FFDM) allows computer-aided detection (CAD) analysis of directly acquired digital image data. The purpose of this study was to evaluate a CAD system in patients with histologically correlated breast cancer depicted with FFDM. Sixty-three cases of histologically proven breast cancer detected with FFDM (Senographe 2000D, GE Medical Systems, Buc, France) were analyzed using a CAD system (Image Checker V2.3, R2 Technology, Los Altos, Calif.). Fourteen of these malignancies were characterized as microcalcifications, 37 as masses, and 12 as both. The mammographic findings were categorized as BI-RADS 3 (n=5), BI-RADS 4 (n=17) and BI-RADS 5 (n=40). The sensitivity for malignant lesions and the rate of false-positive marks per image were calculated. The sensitivity and its 95% confidence interval (CI) were estimated. The sensitivity of the CAD R2 system in breast cancer seen on FFDM was 89% for microcalcifications [CI_95%=(70%; 98%)] and 81% for masses [CI_95%=(67%; 91%)]. As expected, the detection rate was higher in lesions categorized as BI-RADS 5 (37 of 40) compared with lesions categorized as BI-RADS 4 (11 of 17). In the group categorized as BI-RADS 3 the detection rate was 4 of 5 lesions; however, this group was very small. The rate of false-positive marks was 0.35 microcalcification marks/image and 0.26 mass marks/image. The overall rate of false-positive marks was 0.61 per image. CAD based on FFDM provides an optimized work flow. Results are equivalent to the results reported for CAD analysis of secondarily digitized image data. Sensitivity for microcalcifications is acceptable and for masses is low. The number of false-positive marks per image should be reduced. Electronic Publication     

Tumour detection rate of a new commercially available computer-aided detection system

The aim of this study was to determine the tumour detection rate and false positive rate of a new mammographic computer-aided detection system (CAD) in order to assess its clinical usefulness. The craniocaudal and oblique images of 150 suspicious mammograms from 150 patients that were histologically proven to be malignant were analysed using the Second Look CAD (CADx Medical Systems, Quebec, Canada). Cases were selected randomly using the clinic's internal tumour case sampler. Correct marking of the malignant lesion in at least one view was scored as a true positive. Marks not at the location of the malignant lesion were scored as false positives. In addition, mammograms with histologically proven benign masses ( n=50) and microcalcifications ( n=50), as well as 100 non-suspicious mammograms, were scanned in order to determine the value of false-positive marks per image. The 150 mammograms included 94 lesions that were suspicious due to masses, 26 due to microcalcifications and 30 showed both signs of malignancy. The overall sensitivity was 90.0% (135 of 150). Sensitivity on subsets of the data was 88.7% (110 of 124) for suspicious masses (MA) and 98.2% (55 of 56) for microcalcifications. Eight of 14 false-negative cases were large lesions. The overall false-positive rate was observed as 0.28 and 0.97 marks per image of microcalcifications and masses, respectively. The lowest false-positive rates for microcalcifications and MA were observed in the cancer subgroup, whereas the highest false-positive rates were scored in the benign but mammographically suspicious subgroups, respectively. The new CAD system shows a high tumour detection rate, with approximately 1.3 false positive marks per image. These results suggest that this system might be clinically useful as a second reader of mammograms. The system performance was particularly useful for detecting microcalcifications.     

Multifocal,multicentric, and contralateral breast cancers: bilateral whole-breast US in the preoperative evaluation of patients

PURPOSE: To evaluate the efficacy of preoperative bilateral whole-breast ultrasonography (US) in the detection of additional multifocal, multicentric, and contralateral cancers and the effect of US information on therapeutic decisions. MATERIALS AND METHODS: Two hundred one patients who had newly diagnosed breast cancer or who were suspected of having breast cancer underwent US examination of the ipsilateral and contralateral breasts with a 10-, 12-, or 13-MHz transducer. All solid lesions found at US alone were classified according to level of suspicion and were selected for biopsy. The US results were compared with mammographic findings. Sensitivity, specificity, and positive and negative predictive values were calculated. RESULTS: In ipsilateral breasts, US depicted 194 (97%) of 201 foci of invasive cancer and 52 (75%) of 69 foci of ductal carcinoma in situ (DCIS), whereas mammography and physical examination depicted 173 (86%) foci of invasive cancer and 56 (81%) foci of DCIS. In the contralateral breast, US depicted 11 (92%) of 12 foci of invasive cancer and four (57%) of seven foci of DCIS, whereas mammography and physical examination depicted six (50%) foci of invasive cancer and five (71%) foci of DCIS. Overall, US depicted mammographically and clinically unsuspected multifocal or multicentric cancers in 28 patients (14%) and contralateral cancer in eight patients (4%). On the basis of these US findings, therapy was correctly changed in 32 patients (16%). The sensitivity, specificity, and positive and negative predictive values of prospective classification of 77 solid lesions detected at US alone were 100% (36 of 36), 51% (21 of 41), 64% (36 of 56), and 100% (21 of 21), respectively. CONCLUSION: Bilateral whole-breast US complements mammography in the preoperative evaluation of patients with breast cancer.