Potential contribution of computer-aided detection to the sensitivity of screening mammography

PURPOSE: To determine the false-negative rate in screening mammography, the capability of computer-aided detection (CAD) to identify these missed lesions, and whether or not CAD increases the radiologists' recall rate. MATERIALS AND METHODS: All available screening mammograms that led to the detection of biopsy-proved cancer (n = 1,083) and the most recent corresponding prior mammograms (n = 427) were collected from 13 facilities. Panels of radiologists evaluated the retrospectively visible prior mammograms by means of blinded review. All mammograms were analyzed by a CAD system that marks features associated with cancer. The recall rates of 14 radiologists were prospectively measured before and after installation of the CAD system. RESULTS: At retrospective review, 67% (286 of 427) of screening mammography-detected breast cancers were visible on the prior mammograms. At independent, blinded review by panels of radiologists, 27% (115 of 427) were interpreted as warranting recall on the basis of a statistical evaluation index; and the CAD system correctly marked 77% (89 of 115) of these cases. The original attending radiologists' sensitivity was 79% (427 of [427 + 115]). There was no statistically significant increase in the radiologists' recall rate when comparing the values before (8.3%) with those after (7.6%) installation of the CAD system. CONCLUSION: The original attending radiologists had a false-negative rate of 21% (115 of [427 + 115]). CAD prompting could have potentially helped reduce this false-negative rate by 77% (89 of 115) without an increase in the recall rate.     

Computer-aided detection versus independent double reading of masses on mammograms

PURPOSE: To evaluate the use of a computer-aided detection (CAD) system (designed for mammographic mass detection) to help improve mass interpretation and to compare CAD results with independent double-reading results. MATERIALS AND METHODS: Screening mammograms from 500 cases were collected; 125 of these cases were screening-detected cancers, and 125 were interval cancers. Previously obtained screening mammograms (ie, prior mammograms) were available in all cases. All mammograms were analyzed by a CAD system, which detected mass regions and assigned a level of (cancer) suspicion to each mass. Ten experienced screening radiologists read the prior mammograms. For independent interpretation with CAD, the suspicion rating assigned to each finding by the radiologist was weighted with the CAD output at the area of the finding. CAD markers on areas that were not reported by the radiologist were not used. Independent double reading was implemented by using a rule to combine the levels of suspicion assigned to findings by two radiologists. Results were evaluated by using localized-response receiver operating characteristic analysis. RESULTS: In a total of 141 cases, there was a visible abnormality at the location of the cancer on the prior mammogram, and 115 of these were classified as mass cases. For prior mammograms that depicted masses, the mean sensitivity of the radiologists, as averaged among the false-positive rates lower than 10%, was 39.4%; this increased by 7.0% with CAD and by 10.5% with double reading. Differences among single, double, and CAD readings were statistically significant (P <.001). CONCLUSION: Although independent double reading yields the best detection performance, the presence and probability of CAD mass markers can improve mammogram interpretation.     

Assessment of diagnostic accuracy of mammography carried out for secondary prevention. Results of a test with a sample caseload conducted by 75 Italian radiologists

PURPOSE: To report the results of a test performed by 75 volunteer radiologists involved in screening program in Italy. MATERIAL AND METHODS: The test includes 12 screening detected cancers and 6 cancers (4 screening detected and 2 interval lesions) with minimal signs at review of a previous negative mammogram. Data on previous experience in mammography (years of activity, years of screening activity, total number of mammograms read and number of mammograms read per year) were also collected. RESULTS: Standards for passing the test were at least 83.3% for sensitivity for screening detected cancers and at most 30% for recall rate among negative cases. Mean sensitivity was 83.9% (median 83.3%, range 50-100%) and mean recall rate was 16.3 (median 14.4%, range 3.8-42.4%). In all, 44 radiologists (58.7%) passed the test. On average 1.4 of 6 cancers with minimal signs were correctly identified. According to readers' experience (at least 5 years in mammographic activity, at least 3 years in screening mammography, at least 10,000 total mammograms read, at least 5,000 per year) radiologists were classified as expert (13) or not (62): no difference in test performance was observed between the two groups. The only significant association occurred for years of mammographic activity and sensitivity. DISCUSSION AND CONCLUSIONS: Test results suggest the need for proper training of radiologists prior to involvement in a screening program. Seeding proficiency tests with cancers with minimal signs was of no benefit as far as evaluation is concerned.     

Computer-aided detection of amorphous calcifications

OBJECTIVE: Computer-aided detection (CAD) systems have been used successfully to detect malignant calcifications on mammography, with sensitivities ranging from 86% to 99%. Amorphous calcifications are a subset of small indistinct calcifications of intermediate concern that have a 20% likelihood of being malignant and that are frequently overlooked on mammography. The purpose of our study was to determine the sensitivity of one commercially available CAD system for detecting amorphous calcifications. MATERIALS AND METHODS: A commercially available CAD system evaluated mammograms of 82 patients with 85 mammographically detected and histologically sampled groups of amorphous calcifications (21 malignant, 14 high risk, and 50 benign). The sensitivity of the system for detecting the calcifications on at least one image of the two-view mammographic examination (case sensitivity) and on each individual mammographic image (image sensitivity) was determined. Findings were correlated with results from large core needle biopsy or surgical excision in each case. RESULTS: The CAD system detected amorphous calcifications in 43 of 85 cases (case sensitivity, 51%) and in 59 of 146 mammographic images (image sensitivity, 40%). The case sensitivities by histologic outcome were 57% for malignant calcifications, 29% for high-risk calcifications, and 54% for benign calcifications. An average of 2.0 false-positive marks were displayed per case. CONCLUSION: The CAD sensitivity for malignant amorphous calcifications is markedly lower than previously reported for all malignant calcifications. Breast imaging radiologists who use CAD systems should continue to search diligently for these difficult-to-detect lesions.     

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.     

Radiologists' detection of mammographic abnormalities with and without a computer-aided detection system

The aim of this study was to to evaluate the role of a computer-aided program (CAD) in assisting detection of mammographic lesions by radiologists not specifically trained in mammography and its potential utility in breast screening. Mammograms were evaluated by radiologists not specifically trained in mammography first without, and then with, the CAD. Finally, the mammograms were evaluated by experienced mammographers who formed the reference standard. Two hundred and ninety four breasts were studied. In 257 breasts (87.4%), the CAD system did not help with the detection of abnormalities. It assisted radiologists in detecting abnormalities in 21 breasts (7.1%) with potential for detecting abnormalities in a further 13 breasts (4.4%). Only in three cases (1%) did it cause confusion in interpretation. There is overall increased sensitivity in detecting mammographic abnormalities with the aid of the CAD system from 74.4 to 87.2%, which is statistically significant. However, it failed to detect suspicious abnormalities in 71 breasts (24.1%). The CAD system improved detection of suspicious mammographic abnormalities by radiologists who are not specifically trained in mammography. However, there is also a substantial failure to detect suspicious mammographic features that cautions against over-reliance on the system, emphasizing its role as a second reader at best.     

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.     

Mammographic features predicting an extensive intraductal component in early-stage infiltrating ductal carcinoma.

Several studies have shown that the presence of an extensive intraductal component in patients with infiltrating ductal carcinoma is a major factor for predicting local recurrence after breast-conserving surgery and radiotherapy. A prospective study of 101 consecutive mammograms in patients with stage I or II infiltrating ductal carcinoma was performed to determine the predictive values of mammographic features in determining the presence or absence of an extensive intraductal component. Thirty-five (35%) of the lesions contained a pathologically verified extensive intraductal component. Sixty-five percent (22/34) of lesions showing mammographic evidence of calcifications with or without a mass were associated with an extensive intraductal component (p less than .001). Lesions with calcifications greater than 3 cm in extent were significantly (p less than .05) more likely to have an extensive intraductal component (9/10; 90%) than those with calcifications less than 3 cm in extent (13/24; 54%). Only 17% (8/46) of patients in whom mammograms showed only a mass or architectural distortion and 24% (5/21) of patients who had a mass palpable clinically or who had normal findings on mammograms had lesions with an extensive intraductal component. We conclude that infiltrating ductal carcinomas associated with calcifications on mammography, especially if the calcifications are extensive, are likely to be associated with an extensive intraductal component. Carcinomas without calcifications that show masses or architectural distortion on mammography, or carcinomas with palpable masses and normal findings on mammography, are unlikely to have an extensive intraductal component.     

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.     

Does computer-aided detection assist in the early detection of breast cancer?

PURPOSE: To evaluate whether breast cancers detected at screening are visible in previous mammograms, and to assess the performance of a computer-aided detection (CAD) system in detecting lesions in preoperative and previous mammograms. MATERIAL AND METHODS: Initial screening detected 67 women with 69 surgically verified breast cancers (Group A). An experienced screening radiologist retrospectively analyzed previous mammograms for visible lesions (Group B), noting in particular their size and morphology. Preoperative and previous mammograms were analyzed with CAD; a relatively inexperienced resident also analyzed previous mammograms. The performances of CAD and resident were then compared. RESULTS: Of the 69 lesions identified, 36 were visible in previous mammograms. Of these 36 "missed" lesions, 14 were under 10 mm in diameter and 29 were mass lesions. The sensitivity of CAD was 81% in Group A and 64% in Group B. Small mass lesions were harder for CAD to detect. The specificity of CAD was 3% in Group A and 9% in Group B. Together, CAD and the resident found more "missed" lesions than separately. CONCLUSION: Of the 69 breast cancers, 36 were visible in previous mammograms. CAD's sensitivity in detecting cancer lesions ranged from 64% to 81%, while specificity ranged from 9% to as low as 3%. CAD may be helpful if the radiologist is less subspecialized in mammography.     

Reproducibility of prompts in computer-aided detection (CAD) of breast cancer

AIM: We evaluated the reproducibility of prompts using the R2 ImageChecker M2000 computer-aided detection (CAD) system. MATERIALS AND METHODS: Forty selected two-view mammograms of women with breast cancer were digitized and analysed using the ImageChecker on 10 separate occasions. The mammograms were chosen to provide both straightforward and subtle signs of malignancy. Data analysed included mammographic abnormality, pathology, and whether the cancer was prompted or given an emphasized prompt. RESULTS: Correct prompts were generated in 86 out of 100 occasions for screen-detected cancers. Reproducibility was less in the other categories of more subtle cancers: 21% for cancers previously missed by CAD, a group that contained more grade 1 and small (<10 mm) tumours. Prompts for calcifications were more reproducible than those for masses (76% versus 53%) and these cancers were more likely to have an emphasized prompt. CONCLUSIONS: Probably the most important cause of variability of prompts is shifts in film position between sequential digitizations. Consequently subtle lesions that are only just above the threshold for display may not be prompted on repeat scanning. However, users of CAD should be aware that even emphasized prompts are not consistently reproducible.     

Can computer-aided detection with double reading of screening mammograms help decrease the false-negative rate? Initial experience

PURPOSE: To retrospectively evaluate the role of computer-aided detection (CAD) in reducing the rate of false-negative (FN) findings on screening mammograms considered normal at initial double reading. MATERIALS AND METHODS: At the authors' institution, independent prospective double readings in which the second reader is not blinded to results of the first reading are performed routinely for all mammograms. When cancer is diagnosed, prior mammograms also are reviewed with double reading to determine cancer visibility. Findings are categorized as (a) no evidence of cancer on any prior screening mammogram and patient presents more than 1 year after prior screening, (b) no evidence of cancer on any prior screening mammogram and patient presents with symptoms within 1 year after prior screening (year-interval occult false-negative), or (c) cancer visible. The clinical director separately evaluates each case in the same way. In 2000, 519 histologically proved breast cancers were diagnosed, including 132 for which patients sought a second opinion and FN findings were not tracked. Prior screening mammograms were available in 318 of the other 387 cases. Five radiologists in two reading sessions independently reviewed current and prior mammograms to categorize visible cancers as either threshold or actionable FN findings. Visible cancers deemed actionable by at least three of five readers were analyzed with a commercially available CAD system. FN rates were calculated prior to and after CAD analysis. RESULTS: Twenty-seven occult and 71 visible cancers were found (total FN findings, 98). Three of five readers considered 52 (73%) of 71 visible cancers actionable. The CAD system correctly marked 37 (71%) of these 52 on prior screening mammograms (19 [65%] of 29 masses, seven [88%] of eight microcalcifications, seven [78%] of nine architectural distortions, and four [67%] of six masses with microcalcifications). The FN rate was 98 (31%) of 318 before CAD and 61 (19%) of 318 after CAD. CONCLUSION: In this retrospective review of this small subset of cancers, it appears that CAD has the potential to decrease the FN rate at double reading by more than one-third (from 31% to 19%). The CAD system correctly marked 37 (71%) of 52 actionable findings read as negative in previous screening years.     

Sensitivity of noncommercial computer-aided detection system for mammographic breast cancer detection: pilot clinical trial

PURPOSE: To evaluate a noncommercial computer-aided detection (CAD) program for breast cancer detection with screening mammography. MATERIALS AND METHODS: A CAD program was developed for mammographic breast cancer detection. The program was applied to 2,389 patients' screening mammograms at two geographically remote academic institutions (institutions A and B). Thirteen radiologists who specialized in breast imaging participated in this pilot study. For each case, the individual radiologist performed a prospective Breast Imaging Reporting and Data System (BI-RADS) assessment after viewing of the screening mammogram. Subsequently, the radiologist was shown CAD results and rendered a second BI-RADS assessment by using knowledge of both mammographic appearance and CAD results. Outcome analysis of results of examination in patients recalled for a repeat examination, of biopsy, and of 1-year follow-up examination was recorded. Correct detection with CAD included a computer-generated mark indicating a possible malignancy on craniocaudal or mediolateral oblique views or both. RESULTS: Eleven (0.46%) of 2,389 patients had mammographically detected nonpalpable breast cancers. Ten (91%) of 11 (95% CI: 74%, 100%) cancers were correctly identified with CAD. Radiologist sensitivity without CAD was 91% (10 of 11; 95% CI: 74%, 100%). In 1,077 patients, follow-up findings were documented at 1 year. Five (0.46%) patients developed cancers, which were found on subsequent screening mammograms. The area where the cancers developed in two (40%) of these five patients was marked (true-positive finding) by the computer in the preceding year. Because of CAD results, a 9.7% increase in recall rate from 14.4% (344 of 2,389) to 15.8% (378 of 2,389) occurred. Radiologists' recall rate of study patients prior to use of CAD was 31% higher than the average rate for nonstudy cases (10.3%) during the same time period at institution A. CONCLUSION: Performance of the CAD program had a very high sensitivity of 91% (95% CI: 74%, 100%).     

Performance parameters for screening and diagnostic mammography: specialist and general radiologists

PURPOSE: To evaluate performance parameters for radiologists in a practice of breast imaging specialists and general diagnostic radiologists who interpret a large series of consecutive screening and diagnostic mammographic studies. MATERIALS AND METHODS: Data (ie, patient age; family history of breast cancer; availability of previous mammograms for comparison; and abnormal interpretation, cancer detection, and stage 0-I cancer detection rates) were derived from review of mammographic studies obtained from January 1997 through August 2001. The breast imaging specialists have substantially more initial training in mammography and at least six times more continuing education in mammography, and they interpret 10 times more mammographic studies per year than the general radiologists. Differences between specialist and general radiologist performances at both screening and diagnostic examinations were assessed for significance by using Student t and chi(2) tests. RESULTS: The study involved 47,798 screening and 13,286 diagnostic mammographic examinations. Abnormal interpretation rates for screening mammography (ie, recall rate) were 4.9% for specialists and 7.1% for generalists (P <.001); and for diagnostic mammography (ie, recommended biopsy rate), 15.8% and 9.9%, respectively (P <.001). Cancer detection rates at screening mammography were 6.0 cancer cases per 1,000 examinations for specialists and 3.4 per 1,000 for generalists (P =.007); and at diagnostic mammography, 59.0 per 1,000 and 36.6 per 1,000, respectively (P <.001). Stage 0-I cancer detection rates at screening mammography were 5.3 cancer cases per 1,000 examinations for specialists and 3.0 per 1,000 for generalists (P =.012); and at diagnostic mammography, 43.9 per 1,000 and 27.0 per 1,000, respectively (P <.001). CONCLUSION: Specialist radiologists detect more cancers and more early-stage cancers, recommend more biopsies, and have lower recall rates than general radiologists.     

Breast cancer: importance of spiculation in computer-aided detection

PURPOSE: To determine the prevalence of spiculation in a large series of screening-detected breast cancers appearing as masses on mammograms and to assess the sensitivity of a computer-aided detection (CAD) algorithm that uses spiculation measures in the detection of such lesions. MATERIALS AND METHODS: Six hundred seventy-seven consecutive cases of breast cancers detected as masses on mammograms were independently reviewed by three radiologists who determined if the lesions were spiculated. All cancers were then analyzed by the CAD system. RESULTS: All three radiologists interpreted 375 (55%) of the 677 masses as being spiculated on at least one view. The CAD algorithm correctly marked 322 (86%) of the 375 clearly spiculated masses, with a mean of 0.24 additional mass mark per image. With a looser definition of spiculation, 585 (86%) of the 677 masses were called spiculated by at least one radiologist on one view. The algorithm correctly marked 464 (79%) of the 585 lesions that were spiculated or possibly spiculated. CONCLUSION: Spiculation was clearly present in a majority (55%) of consecutive screening-detected breast cancer masses found on mammograms in a large clinical trial. Incorporation of spiculation measures is, therefore, an important strategy in the detection of breast cancer with CAD. A present-generation CAD algorithm correctly identified a large proportion (86%) of spiculated breast cancers.     

Screening mammography-detected cancers: sensitivity of a computer-aided detection system applied to full-field digital mammograms

PURPOSE: To retrospectively evaluate the sensitivity of the performance of a computer-aided detection (CAD) system applied to full-field digital mammograms for detection of breast cancers in a screening group, with histologic findings as the reference standard. MATERIALS AND METHODS: This study had institutional review board approval, and patient informed consent was waived. A commercially available CAD system was applied to the digital mammograms of 103 women (mean age, 51 years; range, 35-69 years) with 103 breast cancers detected with screening. Sensitivity values of the CAD system according to mammographic appearance, breast composition, and histologic findings were analyzed. Normal mammograms from 100 women (mean age, 54 years; age range, 35-75 years) with no mammographic and clinical abnormality during 2-year follow-up were used to determine false-positive CAD system marks. Differences between the cancer detection rates in fatty and dense breasts for the CAD system were compared by using the chi(2) test. RESULTS: The CAD system correctly marked 99 (96.1%) of 103 breast cancers. The CAD system marked all 44 breast cancers that manifested as microcalcifications only, all 23 breast cancers that manifested as a mass with microcalcifications, and 32 (89%) of 36 lesions that appeared as a mass only. The sensitivity of the CAD system in the fatty breast group was 95% (59 of 62) and in the dense breast group was 98% (40 of 41) (P = .537). The CAD system correctly marked all 31 lesions of ductal carcinoma in situ (DCIS), all 22 lesions of invasive ductal carcinoma with DCIS, the single invasive lobular carcinoma lesion, and 45 (92%) of 49 lesions of invasive ductal carcinoma. On normal mammograms, the mean number of false-positive marks per patient was 1.80 (range, 0-10 marks; median, 1 mark). CONCLUSION: The CAD system can correctly mark most (96.1%) asymptomatic breast cancers detected with digital mammographic screening, with acceptable false-positive marks (1.80 per patient).     

Breast carcinoma diagnosed in mammographic screening incidentally. Research on the radiologic signs in prior mammograms

PURPOSE: To determine how many cancers screen-detected at subsequent rounds were already visible on previous screening mammograms, and to study their radiological features. MATERIALS AND METHODS: The previous screening mammograms of 100 women who had cancers screen-detected at subsequent rounds (group A), and the negative screening mammograms of 200 women (group B) who had a further negative screening test two years later, were mixed for a new reading. The two groups were similar for age and year of examination. These films were blindly reviewed by 5 radiologists. Then, mammograms were reviewed retrospectively, with knowledge of subsequent diagnostic results. Finally the A group findings were classified as: 1) true negative: no radiological signs; 2) minimal sign: a nonspecific abnormality is retrospectively visible at the site of subsequent cancer; 3) false negative: "she should have been recalled"; 4) misdiagnosis at assessment: the woman had been recalled, but the cancer was missed after the assessment procedures. RESULTS: 60% of cases were true negatives, 29% were minimal signs, 9% were false negative and 2% were misdiagnosed at assessment. The most common radiological sign found among false negative cases was an architectural distortion: opacities and calcifications were more frequent among minimal signs. Only 10 of 40 cancers retrospectively visible on previous mammograms had reached stage II at diagnosis. At blinded review, the radiologists found false abnormalities in a considerable number of healthy women (average: 29%). DISCUSSION AND CONCLUSIONS: Our study shows that mammography sensitivity can be improved. Cancer radiological signs may go undetected due to difficult interpretation (opacities, calcifications) or perception (architectural distortions). The use of a low threshold of suspicion (as in a reading test) in real screening might permit to detect more cancers (most of them, however, would not reach advanced stages at subsequent rounds), but might also lead to many unnecessary assessments and, probably, to some benign biopsies in healthy women. In conclusion, an attempt at improving mammography sensitivity by lowering the threshold of suspicion can not be directly recommended due to the considerable negative effects related to a loss in specificity. A reading test similar to the one presented in our study would be a useful training procedure for radiologists who are involved in a screening program.     

Breast cancers in women 35 years of age and younger: mammographic findings

During an 8-year period, 74 breast cancers were diagnosed in 66 patients 35 years of age and younger who underwent preoperative mammography. Mammograms and clinical data in these women were reviewed retrospectively to evaluate the mammographic findings and the efficacy of mammography. In 58 cases the cancer was detected by means of both clinical examination and mammography; in eight cases, mammography alone enabled readers to find the lesion; in seven cases, the lesion was found by means of clinical examination, but mammograms were negative; and in one case a cancer was found by means of incidental biopsy of the contralateral breast. Although 34 patients (52%) had dense breasts, mammography demonstrated the lesion in 66 cases (89%); the most common mammographic finding was microcalcifications, with or without associated masses (n = 28 [38%]). The authors do not suggest that screening of women younger than 35 years be performed routinely, but they believe that mammography can be valuable in screening young women at high risk for breast cancer or in confirming and suggesting prompt biopsy of a suspicious lesion.