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Background: Recent evidence suggests that computer-aided detection (CAD) may have a negative impact on the interpretation of mammography-this necessitates timely evaluation of CAD in practice. We report a retrospective study of the incremental effect of CAD on the accuracy of full-field digital mammography (DM) as applied prospectively in breast assessment., Methods: Subjects were all consecutive women attending a self-referral breast centre in Florence between September 2005 and January 2007 (N = 3,425). DM was reported without, then with, CAD according to a standard protocol; all mammograms recalled on the basis of either the radiologist's reading alone, or the radiologist's reading after viewing CAD, were recalled to assessment., Results: Overall recall rate (RR) was 13.1% and 107 cancers were diagnosed (90 invasive cancers, 8 DCIS, 9 malignant on cytology). The use of CAD allowed the additional detection of 5 cancers (three invasive cancers, one DCIS, one malignant on cytology) and caused one additional benign surgical biopsy, with a relative RR of 4.9%, and an incremental RR of 1.17%. The cancer detection rate (CDR) of DM interpreted with the use of CAD was 3.12% and did not significantly differ from the CDR of 2.9% based on DM without CAD (chi(2) = 3.2, P = 0.07)., Conclusion: While the increase in CDR with the use of CAD only approached statistical significance, representing modest gains in absolute terms, the incremental number of cancers detected justifies the incremental recall and benign surgical biopsy attributable to CAD use. In our clinical setting, these data suggest more benefit than harm in using CAD with DM, and we will continue the use of CAD with ongoing monitoring of patient outcomes.

Surveillance of interval cancers (IC) lacks standardisation of review methodologies. We investigated the extent to which 'informed' or 'blinded' review may affect IC classification. This is a retrospective study of 100 validated screening mammograms (20 IC, 80 negative screens) independently reviewed by six radiologists. Three sequenced review methods with increasing information were used: (1) blinded (no IC information, case mix), (2) partially informed, and (3) fully informed. IC 'screening error' (SE) reports averaged 24% (10-40), 33% (20-55), and 42% (35-50) for phases 1, 2, and 3, while 'minimal signs' (MS) reports averaged 6% (5-15), 10% (10-20), and 20% (15-30), respectively. Negative mammograms classification was MS in 18% (7-39) or SE in 19% (11-29), respectively. MS or SE classification was more likely for method 2 (OR=1.78, p=0.033) and method 3 (OR=3.91, p=0.000) relative to method 1, but no reader effect was evident. Inter-observer agreement in classifying at method 1 was slight (k 0.20), lowest (k 0.06) for MS, and fair (k 0.25) for negative and SE categories. More 'informed' review is more likely to yield an IC classification as MS or SE. Due to expected variability, review methods need standardisation to improve screening quality. Our data support blinded review of IC in mammography screening.

Aim: To assess the role of breast ultrasonography as a complement to negative mammography in radiologically dense breasts., Material and Methods: Out of a total series of 49,044 consecutive mammograms reported as negative in asymptomatic women, 25,665 (52.3%) were coded as dense (BI-RADS D3-4) and ultrasonography was recommended. Due to organizational problems, ultrasonography was performed immediately or within 1 month only in 5,227 cases, representing the study series., Results: Two cancers were detected at immediate ultrasonography (0.03%). The cancer detection rate in women aged 40-49 and 50-69 years was 0.002% and 0.07%, respectively. The benign biopsy rate was 0.5% for core biopsies and 0.02% for surgical biopsies. The cost per ultrasonography-assessed woman was Euro 56.05, whereas the cost per additional mammographically occult but ultrasonography-detected cancer was Euro 146,496.53. The mammograms of the 2 cancer cases underwent blind review by an expert reader and were confirmed as negative., Discussion: Our findings show a low cancer detection rate, substantially lower compared to other clinical studies of ultrasonography in dense breasts, though in accordance with preliminary evidence from an Italian randomized clinical trial within a population-based screening program. The policy of adding ultrasonography to negative mammography in dense breasts seems to have very limited cost-effectiveness, and should not be adopted in routine practice before results of ongoing clinical trials are available.

We evaluated the role of computer-aided detection (CAD) in cancers undergoing double reading and detected by one reader only. A series of 33 cancers, originally missed by the first reader and detected by the second reader, and 75 negative controls were processed to assess CAD sensitivity, and was read by the six radiologists who originally missed the cancers with the help of CAD printouts. CAD case-based sensitivity, specificity and positive predictive value were 51.5%, 18.6% and 21.7%, respectively. Average sensitivity of all radiologists in all cancers in the series was 74.7%, being higher for CAD+ (86.2%) than for CAD- (62.5%) cancers (P<0.01). When reading cancer cases that they had originally missed, radiologists had a sensitivity of 75.8%, which was higher for CAD+ (100.0%) than for CAD- (58.3%) cancers. The average recall rate was 14.2%, the majority of recalls (45 out of 64) occurring for lesions marked by CAD. CAD may help in detecting at most half of cancers missed at a single reading but detected by a second reader.

The inter- and intraobserver agreement (K statistic) in reporting according to BI-RADS assessment categories was tested on 12 dedicated breast radiologists, with little prior working knowledge of BI-RADS, reading a set of 50 lesions (29 malignant, 21 benign). Intraobserver agreement (four categories: R2, R3, R4, R5) was fair (0.21-0.40), moderate (0.41-0.60), substantial (0.61-0.80) or almost perfect (>0.80) for one, two, five or four radiologists, or (six categories: R2, R3, R4a, R4b, R4c, R5) fair, moderate, substantial or almost perfect for three, three, three or three radiologists, respectively. Interobserver agreement (four categories) was fair, moderate or substantial for three, six, or three radiologists, or (six categories) slight, fair or moderate for one, six, or five radiologists. Major disagreement occurred for intermediate categories (R3=0.12, R4=0.25, R4a=0.08, R4b=0.07, R4c=0.10). We found insufficient intra- and interobserver consistency of breast radiologists in reporting BI-RADS assessment categories. Although training may improve these results, simpler alternative reporting methods (systems), focused on clinical decision-making, should be explored.

The inter- and intraobserver agreement (kappa-statistic) in reporting according to Breast Imaging Reporting and Data System (BI-RADS((R))) breast density categories was tested in 12 dedicated breast radiologists reading a digitized set of 100 two-view mammograms. Average intraobserver agreement was substantial (kappa=0.71, range 0.32-0.88) on a four-grade scale (D1/D2/D3/D4) and almost perfect (kappa=0.81, range 0.62-1.00) on a two-grade scale (D1-2/D3-4). Average interobserver agreement was moderate (kappa=0.54, range 0.02-0.77) on a four-grade scale and substantial (kappa=0.71, range 0.31-0.88) on a two-grade scale. Major disagreement was found for intermediate categories (D2=0.25, D3=0.28). Categorization of breast density according to BI-RADS is feasible and consistency is good within readers and reasonable between readers. Interobserver inconsistency does occur, and checking the adoption of proper criteria through a proficiency test and appropriate training might be useful. As inconsistency is probably due to erroneous perception of classification criteria, standard sets of reference images should be made available for training.

Objective: To assess double reading effectiveness in mammography screening., Design: Retrospective study of 177,631 consecutive mammograms double read during 1998-2003., Setting: The Florence screening programme, involving 11 trained radiologists. Abnormalities reported by at least one reader prompted assessment., Results: The referral rate was 2.89% for the first reader, 3.15% for the second reader, and 3.59% for either reader. Of 713 total cancers detected, 43 were suspected only by the second reader (6.4% relative, 0.024% increase in absolute detection rate) and had a lower stage compared to the first reader (pTis-pT1b = 65.7 versus 52.0%): 41 were reviewed and classified (error type) as "minimal sign" in six, and "screening error" in 35 cases, or as BI-RADS 3 in one, 4a in 20, 4b in 13, and 4c in three cases. The second reading cost was 2.70 per woman examined, or 11,168 per additional cancer detected (versus 11,585 at a single reading)., Discussion: Second reading is effective in detecting a limited number of additional cancer cases. Tumour stage (one-third over 1 cm in diameter) and review findings (high rate of "screening errors" and BI-RADS R4b-c categories) suggest that second reading detects small "difficult cases" as well as larger cancers missed due to fatigue or loss of attention. Second reading reduces screening specificity to a minor extent, and since cancer detection at second reading seems cost-effective the procedure is recommendable in routine practice.

Objective: To asses the effectiveness of arbitration of discordant double readings in mammography screening., Design: A retrospective study of 1217 consecutive arbitrations., Setting: A subset of discordant double readings from the Florence screening programme underwent arbitration by a third reader., Results: Positive arbitration of 1217 discordant double readings prompted assessment in 476 cases (39.2%), detecting 30 cancers (6.3%). Of 741 negative arbitrations (60.8%), 311 have been followed up thus far, and two cancers (0.64%) occurred in the site previously suspected at one of the two independent readings. Arbitration had a sensitivity of 86.3% and a negative predictive value of 99.3%. Arbitration reduced the overall referral rates from 3.82% to 2.59% (relative decrease 32.1%). Due to false-negative arbitration, cancers detected per 1000 women screened would decrease from 4.58 to 4.50 (relative decrease 1.7%). For every cancer missed due to false-negative arbitration, 151 unnecessary recalls and 21,248 euro would have been saved, whereas the saved cost per screened woman due to arbitration was 1.72 euro., Discussion: Arbitration of discordant double reading would substantially reduce referral rates with a limited reduction in cancer detection rate, and may be recommended as a routine procedure. Greater benefit from arbitration might be expected in the presence of high referral rates at independent double reading, a common scenario in a newly implemented service screening.

Purpose: To compare the diagnostic accuracy of two commercial CAD systems (CADx and R2) and their impact as an aid to conventional reading of screening mammograms., Materials and Methods: The image set considered consisted of 120 mammograms, 89 confirmed negative and 31 with subsequent interval cancers (11 classified as false negatives (FN), 20 as "minimal signs" (MS)). The set was digitised and processed with CAD, and printouts obtained of the mammograms with indications of the areas warranting review. Six expert radiologists read the mammograms three times, once using conventional reading and twice using CAD reading with CADx and R2, respectively. The two CAD systems were compared in terms of diagnostic accuracy of the marks and the impact of CAD reading compared to conventional reading and to the use of independent second reading simulated by combining pairs of single conventional readings., Results: R2 highlighted more calcifications (218 vs 132, +65%) and CADx highlighted more masses (208 vs 105, +98%). CADx and R2 marked 15 and 17 out of 31 cancers, respectively (sensitivity 48.3% vs 54.8%, chi squared=6.4, p=0.79), 10 and 6 out of 11 FN (90.9% vs 54.5%, chi squared=2.0, p=0.15), respectively, and 5 and 11 out of 20 MS (25.0% vs 55.0%, chi squared=2.6, p=0.10), respectively. As for specificity, the false positive markings for masses were on average (per case) 1.60 for CADx and 0.75 for R2, those for calcifications were 1.08 for CADx and 1.77 for R2 and the total false positive markings were 2.68 for CADx and 2.52 for R2. CADx and R2 marked 73 and 63 of 89 negative controls (specificity = 0.18 vs 0.29, chi squared=2.52, p=0.11), respectively. All the radiologists showed greater sensitivity with CAD reading compared to conventional reading. On average, sensitivity with conventional reading was 58.6% (109/186), as against 70.9% (132/186) for CADx or R2 (chi squared=5.71, p=0.016). Sensitivity for FN cases was 71.2% (47/66) with conventional reading, 84.8% (56/66) with CADx (chi squared=2.82, p=0.09) and 80.3% (53/66) for R2 (chi squared=1.03, p=0.30) (CADx vs R2, chi squared=0.21, p=0.64). Sensitivity for MS cases was 51.6% (62/120) for conventional reading, 63.3% (76/120) for CADx (chi squared=2.88, p=0.08) and 65.8% (79/120) for R2 (chi squared=4.40, p=0.03) (CADx vs R2, chi squared=0.07, p=0.78). The recall rates were 18.1% (97/534) for conventional reading, 29.7% (159/534) for CADx (chi squared=5.72, p=0.01) and 24.3% (130/534) for R2 (chi squared=10.11, p=10-5) (CADx vs R2, chi squared=3.71, p=0.05). Double reading was significantly more sensitive than conventional reading (chi squared=29.6, p=10-6), CADx (chi squared=5.33, p=0.02) and R2 (chi squared=5.33, p=0.02). The recall rate for double reading was significantly higher than for conventional reading (chi squared=21.5, p=10-6) whereas no significant difference was detected when compared to CADx (chi squared=0.16, p=0.68) or R2 (chi squared=3.4, p=0.06)., Conclusions: Despite using different algorithms, the two CAD systems exhibit comparable levels of diagnostic accuracy and a similar positive impact on sensitivity when used as an aid to conventional reading. Single reading with either CAD system is as specific but not as sensitive to double independent reading: its use as an alternative to double reading cannot be recommended and should be investigated further by means of controlled prospective studies.

Purpose: To evaluate the role of computer aided diagnosis (CAD) to improve screening mammograms interpretation., Materials and Methods: Six radiologists underwent a screening mammography proficiency test first by conventional, then by CAD assisted reading. Sensitivity and recall rate at conventional and CAD reading were compared. Independent conventional double reading was simulated (15 pair combinations) and compared to single CAD reading., Results: CAD marked 31 of 32 cancers (case-based sensitivity=96.8%). On a film and lesion basis, CAD identified 31 of 32 (96.8%) malignant calcifications and 29 of 42 (69.0%) malignant opacities, the only cancer not identified by CAD being depicted as an isolated opacity. CAD marked 348 areas (153 microcalcifications and 195 opacities) in 88 of 108 non cancer cases, with a case-based specificity of 18.5% (20/108). Considering all six readings, cancer was identified in 164 or 174 of 192 readings (85.4 vs 90.6%, c2 2.03, df=1, p=0.15) and recalls of non-cancer cases were 108 or 159 of 648 readings (16.6 vs 24.5%, c2 11.7, df=1, p<0.001) at conventional or CAD reading, respectively. CAD reading (average of 6 readings, 192 cancer, 648 non-cancer readings) was slightly, non significantly less sensitive (sensitivity 90.6 vs 92.9%, c2 0.73, df=1, p=0.39) and slightly, but not significantly more specific (recall rate 24.5 vs 26.1%, c2 0.56, df=1, p=0.45) as compared to simulated independent double reading (average of 15 combinations, 480 cancer, 1620 non-cancer readings)., Conclusion: CAD seems to allow for a limited absolute increase (+5.2%) in sensitivity and for a limited absolute increase (+7.9%) in recall rate, the latter difference only reaching statistical significance. CAD reading showed no significant difference in diagnostic accuracy as compared to conventional (simulated) double reading, although further studies are needed to confirm it as possible alternative to double reading in the current screening practice.

Objective: To evaluate the role of computer aided detection (CAD) in improving the interpretation of screening mammograms, Material and Methods: Ten radiologists underwent a proficiency test of screening mammography first by conventional reading and then with the help of CAD. Radiologists were blinded to test results for the whole study duration. Results of conventional and CAD reading were compared in terms of sensitivity and recall rate. Double reading was simulated combining conventional readings of four expert radiologists and compared with CAD reading., Results: Considering all ten readings, cancer was identified in 146 or 153 of 170 cases (85.8 vs. 90.0%; chi(2)=0.99, df=1, P=0.31) and recalls were 106 or 152 of 1330 cases (7.9 vs. 11.4%; chi(2)=8.69, df=1, P=0.003) at conventional or CAD reading, respectively. CAD reading was essentially the same (sensitivity 97.0 vs. 96.0%; chi(2)=7.1, df=1, P=0.93; recall rate 10.7 vs. 10.6%; chi(2)=1.5, df=1, P=0.96) as compared with simulated conventional double reading., Conclusion: CAD reading seems to improve the sensitivity of conventional reading while reducing specificity, both effects being of limited size. CAD reading had almost the same performance of simulated conventional double reading, suggesting a possible use of CAD which needs to be confirmed by further studies inclusive of cost-effective analysis.

Summary: The inter- and intraobserver agreement (K statistic) in reporting according to BI-RADS assessment categories was tested on 12 dedicated breast radiologists, with little prior working knowledge of BI-RADS, reading a set of 50 lesions (29 malignant, 21 benign). Intraobserver agreement (four categories: R2, R3, R4, R5) was fair (0.21–0.40), moderate (0.41–0.60), substantial (0.61–0.80) or almost perfect (>0.80) for one, two, five or four radiologists, or (six categories: R2, R3, R4a, R4b, R4c, R5) fair, moderate, substantial or almost perfect for three, three, three or three radiologists, respectively. Interobserver agreement (four categories) was fair, moderate or substantial for three, six, or three radiologists, or (six categories) slight, fair or moderate for one, six, or five radiologists. Major disagreement occurred for intermediate categories (R3=0.12, R4=0.25, R4a=0.08, R4b=0.07, R4c=0.10). We found insufficient intra- and interobserver consistency of breast radiologists in reporting BI-RADS assessment categories. Although training may improve these results, simpler alternative reporting methods (systems), focused on clinical decision-making, should be explored. [Copyright &y& Elsevier]