Telereporting in Breast Imaging Involving More Than 1 Country Requires Careful Consideration.

PURPOSE: To examine the effect that a test set from 1 region of the world has on the performance of expert breast radiologists from that region and from a distant region. METHODS: Forty-seven Australian and 15 Singaporean breast radiologists interpreted the same test set (ie, 60 mammograms of Australian women consisting of 40 typical and 20 atypical cases) in their respective locations. The radiologists assigned each case a confidence score of 1 to 5, where 1 was typical, 2 was benign, and 3 to 5 indicated identifiable cancer. Localization-response operating characteristic area under the curve (AUC), receiver operating characteristic AUC, location sensitivity, case sensitivity, and specificity were calculated for each radiologist and compared between Australian and Singaporean readers using nonparametric 2-tailed Mann-Whitney U tests. RESULTS: Australian readers performed better than did their Singaporean counterparts with respect to localization-response operating characteristic AUC (.738 vs .642, P = .0395) and location sensitivity (.775 vs .660, P = .0185). DISCUSSION: Technological advancement has made possible telereporting, in which radiologists report on mammograms originating from other countries. However, those readers' levels of performance might be affected by interpreting images from populations that are different from those with which they are familiar. CONCLUSION: Radiologist performance differed between the groups when localization of lesions was taken into account. This difference might be because of the Australians' reading mammograms from populations with which they were familiar, in contrast to the Singaporeans.

Mammographic detection of breast cancer in a non-screening country.

OBJECTIVE:: To compare the diagnostic accuracy between radiologists' from a country with and without breast cancer screening. METHODS:: All participating radiologists gave informed consent. A test-set involving 60 mammographic cases (20 cancer and 40 non-cancer) were read by 11 radiologists from a non-screening (NS) country during a workshop in July 2016. 52 radiologists from a screening country read the same test-set at the Royal Australian and New Zealand College of Radiologists' meetings in July 2015. The screening radiologists were classified into two groups: those with less than or equal to 5 years of experience; those with more than 5 years of experience, and each group was compared to the group of NS radiologists. A Kruskal-Wallis test followed by post-hoc multiple comparisons test were used to compare measures of diagnostic accuracy among the reader groups. RESULTS:: The diagnostic accuracy of the NS radiologists was significantly lower in terms of sensitivity [mean = 54.0; 95% confidence interval (CI) (40.0-67.0)], location sensitivity [mean = 26.0; 95% CI (16.0-37.0)], receive roperating characteristic area under curve [mean = 73.0; 95% CI (66.5-81.0)] and Jackknifefree-response receiver operating characteristics figure-of-merit [mean = 45.0; 95% CI (40.0-50.0)] when compared with the less and more experienced screening radiologists, whilst no difference in specificity [mean = 75.0; 95% CI (70.0- 81.0)] was found. No significant differences in all measured diagnostic accuracy were found between the two groups of screening radiologists. CONCLUSION:: The mammographic performance of a group of radiologists from a country without screening program was suboptimal compared with radiologists from Australia. ADVANCES IN KNOWLEDGE:: Identifying mammographic performance in developing countries is required to optimize breast cancer diagnosis.

Mammographic density and cancer detection: does digital imaging challenge our current understanding?

RATIONALE AND OBJECTIVES: To investigate the impact of breast density on the performance of radiologists when mammograms are digitally acquired and displayed. MATERIALS AND METHODS: A total of 150 craniocaudal digital mammograms including 75 cases with cancer were examined by 14 radiologists divided into two groups: those who read more (six) and less (eight) than 2000 mammograms per year. Cases were classified as low or high mammographic density. For both types of cases, detection of cancers within and outside the dense fibroglandular tissue was investigated. The performance of radiologist was measured using jack-knife free-response receiver operating characteristic (JAFROC) figure of merit (FOM). RESULTS: Radiologists with over 2000 annual reads had significantly higher JAFROC FOM (P = .03) for high (0.76) mammographic density compared to low (0.70) mammographic density cases. When lesions overlaid the fibroglandular tissue, cases with high mammographic density compared to low mammographic density displayed increased location sensitivity for all radiologists (P = .03) and for those radiologists reading more than 2000 mammograms annually (P = .04), whereas JAFROC FOMs increased for all radiologists (P = .05). No significant changes were observed when the lesion was outside the fibroglandular region. CONCLUSIONS: Increased mammographic density improves the performance of experienced radiologists when using digital mammograms. This finding, which does not align with those previously reported for film screen systems, may be because of windowing/leveling opportunities available with digital images.

How mammographic breast density affects radiologists' visual search patterns.

RATIONALE AND OBJECTIVES: To determine the impact of mammographic breast density on the visual search process of radiologists when reading digital mammograms. MATERIALS AND METHODS: Institutional review board approval was obtained. A set of 149 craniocaudal digital mammograms were read by seven radiologists, and observer search patterns were recorded. Total time examining each case, time to first hit the lesion, dwell time, and number of hits per area were calculated. The nonparametric Mann-Whitney U test was used for statistical evaluation. RESULTS: In both low- and high-mammographic density cases, significant increases were observed in the time to first hit lesions when they were located outside, compared to overlying fibroglandular dense tissue (P = .001). Significantly longer dwell time (P = .003) and greater number of fixations (P = .0003) were observed when the lesions were situated within--rather than outside--the dense fibroglandular tissue. CONCLUSIONS: Increased mammographic breast density changes radiologists' visual search patterns. Dense areas of the parenchyma attracted greater visual attention in both high- and low-mammographic density cases, resulting in faster detection of lesions overlying the fibroglandular dense tissue, along with longer dwell times and greater number of fixations, as compared to lesions located outside the dense fibroglandular regions.

Markers of good performance in mammography depend on number of annual readings.

PURPOSE: To explore relationships between reader performance and reader characteristics in mammography for specific radiologist groupings on the basis of annual number of readings. MATERIALS AND METHODS: The institutional review board approved the study and waived the need for patient consent to use all images. Readers gave informed consent. One hundred sixteen radiologists independently reviewed 60 mammographic cases: 20 cases with cancer and 40 cases with normal findings. Readers located any visualized cancer, and levels of confidence were scored from 1 to 5. A jackknifing free response operating characteristic (JAFROC) method was used, and figures of merit along with sensitivity and specificity were correlated with reader characteristics by using Spearman techniques and standard multiple regressions. RESULTS: Reader performance was positively correlated with number of years since qualification as a radiologist (P ≤ .01), number of years reading mammograms (P ≤ .03), and number of readings per year (P ≤ .0001). The number of years since qualification as a radiologist (P ≤ .004) and number of years of reading mammograms (P ≤ .002) were negatively related to JAFROC values for radiologists with annual volumes of less than 1000 mammographic readings. For individuals with more than 5000 mammographic readings per year, JAFROC values were positively related to the number of years that the reader was qualified as a radiologist (P ≤ .01), number of years of reading mammograms (P ≤ .002), and number of hours per week of reading mammograms (P ≤ .003). Number of mammographic readings per year was positively related with JAFROC scores for readers with an annual volume between 1000 and 5000 readings (P ≤ .03). Differences in JAFROC scores appear to be more related to specificity than location sensitivity, with the former demonstrating significant relationships with four of the five characteristics analyzed, whereas no relationships were shown for the latter. CONCLUSION: Radiologists' determinants of performance are associated with annual reading volumes. Ability to recognize normal images is a discriminating factor in individuals with a high volume of mammographic readings.

Quantitative measures confirm the inverse relationship between lesion spiculation and detection of breast masses.

OBJECTIVE: To identify specific mammographic appearances that reduce the mammographic detection of breast cancer. MATERIALS AND METHODS: This study received institutional board review approval and all readers gave informed consent. A set of 60 mammograms each consisting of craniocaudal and mediolateral oblique projections were presented to 129 mammogram Breastscreen readers. The images consisted of 20 positive cases with single and multicentric masses in 16 and 4 cases, respectively (resulting in a total of 24 cancers), and readers were asked to identify and locate the lesions. Each lesion was then ranked according to a detectability rating (ie, the number of observers who correctly located the lesion divided by the total number of observers), and this was correlated with breast density, lesion size, and various descriptors of lesion shape and texture. RESULTS: Negative and positive correlations between lesion detection and density (r = -0.64, P = .007) and size (r = 0.65, P = .005), respectively, were demonstrated. In terms of lesion size and shape, there were significant correlations between the probability of detection and area (r = 0.43, P = .04), perimeter (r = 0.66, P = .0004), lesion elongation (r = 0.49, P = .02), and lesion nonspiculation (r = 0.78, P < .0001). CONCLUSIONS: The results of this study have identified specific lesion characteristics associated with shape that may contribute to reduced cancer detection. Mammographic sensitivity may be adversely affected without appropriate attention to spiculation.

Malignancy detection in digital mammograms: important reader characteristics and required case numbers.

RATIONALE AND OBJECTIVES: To determine the relationship between heightened levels of reader performance and reader practice in terms of number of cases read and previous experience. MATERIALS AND METHODS: A test set of mammograms was developed comprising 50 cases. These cases consisted of 15 abnormals (biopsy proven) and 35 normals (confirmed at subsequent rescreen). Sixty-nine breast image readers reviewed these cases independently and their performance was measured by recording their individual receiver operating characteristic score (area under the curve), sensitivity, and specificity. These measures of performance were then compared to a range of factors relating to the reader such as years of certification and reporting, number of cases read per year, previous experiences, and satisfaction levels. Correlation analyses using Spearman methods were performed along with the Mann-Whitney test to detect differences in performance between specific reader groups. RESULTS: Improved reader performance was found for years certified (P = .004), years of experience (P = .0001), and hours reading per week (P = .003) shown by positive statistical significant relationships with Az values (area under receiver operating characteristic curve). Statistical comparisons of Az values scored for individuals who read varying number of cases per year showed that those individuals whose annual mammographic case load was 5000 or more (P = .03) or between 2000 and 4999 (P = .05), had statistically significantly higher scores than those who read less than 1000 cases per year. CONCLUSION: The results of this study have shown variations in reader performance relating to parameters of reader practice and experience. Levels of variance are shown and potential acceptance levels for diagnostic efficacy are proposed which may inform policy makers, judicial systems and public debate.