Groups Of Microcalcifications Research Articles

Deep learning performance for detection and classification of microcalcifications on mammography

BackgroundBreast cancer screening through mammography is crucial for early detection, yet the demand for mammography services surpasses the capacity of radiologists. Artificial intelligence (AI) can assist in evaluating microcalcifications on mammography. We developed and tested an AI model for localizing and characterizing microcalcifications.MethodsThree expert radiologists annotated a dataset of mammograms using histology-based ground truth. The dataset was partitioned for training, validation, and testing. Three neural networks (AlexNet, ResNet18, and ResNet34) were trained and evaluated using specific metrics including receiver operating characteristics area under the curve (AUC), sensitivity, and specificity. The reported metrics were computed on the test set (10% of the whole dataset).ResultsThe dataset included 1,000 patients aged 21–73 years and 1,986 mammograms (180 density A, 220 density B, 380 density C, and 220 density D), with 389 malignant and 611 benign groups of microcalcifications. AlexNet achieved the best performance with 0.98 sensitivity, 0.89 specificity of, and 0.98 AUC for microcalcifications detection and 0.85 sensitivity, 0.89 specificity, and 0.94 AUC of for microcalcifications classification. For microcalcifications detection, ResNet18 and ResNet34 achieved 0.96 and 0.97 sensitivity, 0.91 and 0.90 specificity and 0.98 and 0.98 AUC, retrospectively. For microcalcifications classification, ResNet18 and ResNet34 exhibited 0.75 and 0.84 sensitivity, 0.85 and 0.84 specificity, and 0.88 and 0.92 AUC, respectively.ConclusionsThe developed AI models accurately detect and characterize microcalcifications on mammography.Relevance statementAI-based systems have the potential to assist radiologists in interpreting microcalcifications on mammograms. The study highlights the importance of developing reliable deep learning models possibly applied to breast cancer screening.Key points• A novel AI tool was developed and tested to aid radiologists in the interpretation of mammography by accurately detecting and characterizing microcalcifications.• Three neural networks (AlexNet, ResNet18, and ResNet34) were trained, validated, and tested using an annotated dataset of 1,000 patients and 1,986 mammograms.• The AI tool demonstrated high accuracy in detecting/localizing and characterizing microcalcifications on mammography, highlighting the potential of AI-based systems to assist radiologists in the interpretation of mammograms.Graphical

Diagnostic performance of DCE-MRI, multiparametric MRI and multimodality imaging for discrimination of breast non-mass-like enhancement lesions.

The aim of this study was to investigate and compare the diagnostic performance of dynamic contrast-enhanced (DCE)-MRI, multiparametric MRI (mpMRI), and multimodality imaging (MMI) combining mpMRI and mammography (MG) for discriminating breast non-mass-like enhancement (NME) lesions. This retrospective study enrolled 193 patients with 199 lesions who underwent 3.0 T MRI and MG from January 2017 to December 2019. The features of DCE-MRI, turbo inversion recovery magnitude (TIRM), and diffusion-weighted imaging (DWI) were assessed by two breast radiologists. Then, all lesions were divided into microcalcification and non-microcalcification groups to assess the features of MG. Comparisons were performed between groups using univariate analyses. Then, multivariate analyses were performed to construct diagnostic models for distinguishing NME lesions. Diagnostic performance was evaluated by using the area under the curve (AUC) and the differences between AUCs were evaluated by using the DeLong test. Overall (n = 199), mpMRI outperformed DCE-MRI alone (AUCmpMRI = 0.924 vs. AUCDCE-MRI = 0.884; p = 0.007). Furthermore, MMI outperformed both mpMRI and MG (the microcalcification group [n = 140]: AUCMMI = 0.997 vs. AUCmpMRI = 0.978, p = 0.018 and AUCMMI = 0.997 vs. AUCMG = 0.912, p < 0.001; the non-microcalcification group [n = 59]: AUCMMI = 0.857 vs. AUCmpMRI = 0.768, p = 0.044 and AUCMMI = 0.857 vs. AUCMG = 0.759, p = 0.039). DCE-MRI combined with DWI and TIRM information could improve the diagnostic performance for discriminating NME lesions compared with DCE-MRI alone. Furthermore, MMI combining mpMRI and MG showed better discrimination than both mpMRI and MG.

Usefulness of the twinkling artifact on Doppler ultrasound for the detection of breast microcalcifications

ObjectiveTo determine whether the twinkling artifact on Doppler ultrasound imaging corresponds to microcalcifications previously seen on mammograms and to evaluate the usefulness of this finding in the ultrasound management of suspicious microcalcifications. Material and methodsWe used ultrasonography to prospectively examine 46 consecutive patients with groups of microcalcifications suspicious for malignancy identified at mammography, searching for the presence of the twinkling artifact to identify the microcalcifications. Once we identified the microcalcifications, we obtained core-needle biopsy specimens with 11G needles and then used X-rays to check the specimens for the presence of microcalcifications. We analyzed the percentage of detection and obtainment of microcalcifications by core-needle biopsy with this technique and the radiopathologic correlation. Microcalcifications that were not detected by ultrasound or discordant lesions were biopsied by stereotaxy at another center. We also used ultrasound guidance for preoperative marking with clips, usually orienting them radially. ResultsWe identified and biopsied 41 of the 46 lesions under ultrasound guidance, including 24 of 25 carcinomas (17 in situ). B-mode ultrasound was sufficient for biopsying the microcalcifications in 14 patients, although the presence of the twinkling artifact increased the number of microcalcifications detected and thus enabled more accurate preoperative marking. Thanks to the twinkling sign, we were able to identify 27 additional groups of microcalcifications (89% vs. 30%; p<0.05). All the surgical specimens had margins free of disease. ConclusionsThe twinkling artifact is useful for microcalcifications in ultrasound examinations, enabling a significant increase in the yield of ultrasound-guided biopsies and better preoperative marking of groups of microcalcifications.

Utilidad del artefacto Doppler de centelleo de color (twinkle) en la detección ecográfica de microcalcificaciones mamarias

ObjectiveTo determine whether the twinkling artifact on Doppler ultrasound imaging corresponds to microcalcifications previously seen on mammograms and to evaluate the usefulness of this finding in the ultrasound management of suspicious microcalcifications. Material and methodsWe used ultrasonography to prospectively examine 46 consecutive patients with groups of microcalcifications suspicious for malignancy identified at mammography, searching for the presence of the twinkling artifact to identify the microcalcifications. Once we identified the microcalcifications, we obtained core-needle biopsy specimens with 11G needles and then used X-rays to check the specimens for the presence of microcalcifications. We analyzed the percentage of detection and obtainment of microcalcifications by core-needle biopsy with this technique and the radiopathologic correlation. Microcalcifications that were not detected by ultrasound or discordant lesions were biopsied by stereotaxy at another center. We also used ultrasound guidance for preoperative marking with clips, usually orienting them radially. ResultsWe identified and biopsied 41 of the 46 lesions under ultrasound guidance, including 24 of 25 carcinomas (17 in situ). B-mode ultrasound was sufficient for biopsying the microcalcifications in 14 patients, although the presence of the twinkling artifact increased the number of microcalcifications detected and thus enabled more accurate preoperative marking. Thanks to the twinkling sign, we were able to identify 27 additional groups of microcalcifications (89% vs. 30%; p < 0.05). All the surgical specimens had margins free of disease. ConclusionsThe twinkling artifact is useful for microcalcifications in ultrasound examinations, enabling a significant increase in the yield of ultrasound-guided biopsies and better preoperative marking of groups of microcalcifications.

Evaluation of Suspicious Appearing Microcalcification Groups on Mammogram: Comparing BI-RADS 5th Edition Descriptors with the BI-RADS 4th Edition and Pathologic Association

Background: Groups of microcalcifications are the most frequent recognized features of ductal carcinoma on mammograms. However, heterogeneity (in size, morphology and density) and number of microcalcification groups as well as presence of accompanied soft-tissue density are not included in breast imaging reporting and data system (BI-RADS) descriptors. Objectives: The study purposes to determine the malignancy risk of microcalcification groups regarding these characteristics and also compare the 4th and 5th versions of BI-RADS. Patients and Methods: In a cross sectional study, 88 patients with microcalcification groups (age range, 26 - 80 years; mean, 53.4 years) who had undergone mammographically guided biopsy between March 2013 and March 2015 were evaluated. The overall number of microcalcification groups in each patient, number of deposits within each group, group location and heterogeneity in size, density and morphology were assessed and subsequently BI-RADS descriptors for 4th and 5th editions were recorded separately. Finally, correlation with histopathology was performed. Results: Overall, positive predictive value (PPV) of suspicious microcalcifications was 22.4%. PPVs of morphology descriptors were as follows: amorphous, 7.9%; coarse heterogeneous, 17.8%; fine pleomorphic, 63.2%; fine linear/fine linear branching, 100%; (P < 0.001). Heterogenicity in size existed in 81 cases (92%), in density in 69 cases (86.4%) and in morphology in 86 cases (97.7%). Additionally, microcalcification groups that were accompanied with soft-tissue density had a higher percentage of malignancy (67.5% vs. 54.5%) but with no significant difference (P = 0.2). According to BI-RADS 4th edition, the risk of malignancy was 49.1%, 66.7% and 88.1% in 4b, 4c and 5, respectively. These figures were 30%, 82.9%, and 100% for BI-RADS 5th version, respectively. The area under the receiver (AUC) of 4th and 5th versions of BI-RADS was 0.76 and 0.74 (both P values < 0.001, 95% confidence intervals = 0.66-0.87 and 0.63 - 0.85 respectively). P value for comparison was insignificant. Conclusion: The risk of malignancy increased with the heterogeneity of microcalcifications, especially in the groups with heterogeneity in density, however with no statistically significant difference. BI-RADS 5th edition could predict the likelihood of malignancy as well as 4th version.

Vacuum assisted breast biopsy (VAB) excision of subcentimeter microcalcifications as an alternative to open biopsy for atypical ductal hyperplasia.

Atypical ductal hyperplasia (ADH) is a proliferative lesion associated with a variable increased risk of breast malignancy, but the management of the patients is still not completely defined, with mandatory surgical excision in most cases. To report the results of the conservative management with mammographic checks of patients with ADH diagnosed by vacuum assisted breast biopsy (VAB), without residual calcifications. The authors accessed the institutional database of radiological, surgical and pathological anatomy. Inclusion criteria were: ADH diagnosed by VAB on a single group of microcalcifications, without residual post-procedure; follow-up at least of 12 months. Exclusion criteria were the presence of personal history of breast cancer or other high-risk lesions; association with other synchronous lesions, both more and less advanced proliferative lesions. The 65 included patients were all females, with age range of 40-79 years (mean 54 years). The maximum diameter range of the groups of microcalcifications was 4-11 mm (mean 6.2 mm), all classified as BI-RADS 4b (Breast Imaging Reporting and Data System 4b) and defined as fine pleomorphic in 29 cases (45%) or amorphous in 36 cases (55%). The range of follow-up length was 12-156 months (mean 67 months). Only one patients developed new microcalcifications, in the same breast, 48 months after and 15 mm from the first VAB, interpreted as low-grade ductal carcinoma in situ (DCIS) at surgical excision. These results could justify the conservative management, in a selected group of patients, being the malignancy rate lower than 2%, considered in the literature as the "probably benign" definition. Advances in knowledge: Increasing the length of follow-up of selected patients conservatively managed can improve the management of ADH cases.

99mTc sestamibi scintimammography. Screening mammographic non-palpable suspicious breast lesions: preliminary results.

Investigation of the diagnostic role of technetium-99m methoxyisobutylisonitrile ((99m)Tc sestamibi) scintimammography in non-palpable, suspicious breast lesions described as microcalcification, mass and increased density using mammography. 35 women with non-palpable breast lesions were enrolled in the study. Anterior, left and right lateral, ipsilateral posterior oblique images were obtained 15 min after the injection of 740 MBq of (99m)Tc sestamibi. All scintigraphic images were evaluated visually and focal increased (99m)Tc sestamibi uptake was accepted as malignant lesion. Breast lesions were classified as microcalcification (13 women), mammographic mass (16 women) and increased density (6 women). Excisional biopsy was performed in all of them irrespective of the scintigraphic results. The focally increased (99m)Tc sestamibi uptake was seen in 11 breast lesions with malignant lesions and in 4 breast lesions with benign lesions. The diffuse uptake of (99m)Tc sestamibi was seen in 18 breast lesions with benign lesions and 2 breast lesions with malignant lesions. There was no false positive result of (99m)Tc sestamibi in microcalcification group and there was no false negative result of the mammographic mass and increased density groups. Scintimammography might be a complementary method in decision making for the non-palpable, suspicious breast lesions that were evaluated as microcalcification, mass and increased density mammograpically.

Flat epithelial atypia: conservative management of patients without residual microcalcifications post-vacuum-assisted breast biopsy.

To determine the malignancy rate (defined in this study as stability or absence of malignancy developed on close imaging follow-up post-biopsy) of conservative management in patients with a vacuum-assisted breast biopsy (VAB) diagnosis of flat epithelial atypia (FEA), performed on single group of microcalcifications, completely removed during procedure. This is a retrospective, monocentric, observational study, approved by IRB. Inclusion criteria were: VAB performed on a single group of microcalcifications; the absence of residual calcifications post-VAB; diagnosis of isolated FEA as the most advanced proliferative lesion; radiological follow-up at least of 12 months. The personal history of breast cancer or other high-risk lesions was an exclusion criteria. The patients enrolled were conservatively managed, without surgical excision, through close follow-up: the first two mammographies performed with an interval of 6 months after biopsy, followed by annual mammographic and clinical checks. 48 consecutive patients were enrolled in the study, all females, with age range of 39-76 years (mean 53,3 years) and radiological follow-up range of 13-75 months (mean 41.5 months). All the lesions were classified as BI-RADS 4b. The diameter range of the group of calcifications was 3-10 mm (mean 5, 6 mm). In each patient, 7 to 15 samples (mean 11) were obtained. Among all the patients, there was only one case (2%) of new microcalcifications, developed in the same breast, 26 months after and 8 mm from the site of previous VAB, and interpreted as ADH at surgical excision. All the checks of the other patients were negative. Even with a limited follow-up, we found a malignancy rate lower than 2%, through a defined population. Further studies with bigger number of patients and extended follow-up are needed to reinforce this hypothesis. Advances in knowledge: Surgical excision may not be necessary in patients with VAB diagnosis of isolated FEA, without residual microcalcifications post-procedure and considered concordant with the mammographic presentation, considering the low rate of malignancy at subsequent follow-ups.

Glycogen-rich Clear Cell Carcinoma of Breast: A Case with an Unusual Macroscopic Presentation and A Good Clinical Outcome

Background: Glycogen-rich clear cell breast carcinoma is a rare histological subtype of breast carcinoma with intermediate-high grade histology, mostly detected as a breast lump with unfavourable prognosis and an aggressive clinical course. Herein is described a case detected on a screening program as two groups of microcalcifications within a non-palpable area of parenchymal distortion in the upper-outer quadrant of the right breast. Fine needle aspiration cytology confirmed malignancy. Distant metastases were ruled out. The patient underwent a quadrantectomy with sentinel lymph node biopsy followed by a modified radical mastectomy. She was alive and disease free four years after conventional chemotherapy. Materials and methods: Quadrantectomy and mastectomy specimens were processed for routine histology. Three sentinel lymph nodes were analysed in intraoperative consultation and completely submitted for histology. Immunohistochemistry and in situ hybridization were applied on representative samples of tumor. Results: Quadrantectomy showed multiple scattered foci of white tissue, ranging from <1 mm to 5 mm, in an adipose area of 36 mm in diameter. Both groups of microcalcifications were indistinct on gross examination. Microscopically multiple foci of invasive glycogen-rich clear cell carcinoma grade 2, Nottingham score 7, were observed. High grade intraductal clear cell carcinoma was also present. One sentinel lymph node showed micrometastases. Rare eosinophilic cells were a minor component identified in tumor as well as in micrometastases. Both cell types expressed the same tumor profile. Mastectomy contained residual high grade intraductal carcinoma without axillary metastases. Conclusions: The aim of this report is to illustrate a clinically silent tumor with an unusual multifocal invasive growth pattern not previously described in this tumor type, with lymph node micrometastases as an early event revealing an aggressive biology. In this case, early detection and treatment favored a good clinical outcome and provided an insight into the development of this histological subtype.

Design of a model observer to evaluate calcification detectability in breast tomosynthesis and application to smoothing prior optimization.

In this work, the authors design and validate a model observer that can detect groups of microcalcifications in a four-alternative forced choice experiment and use it to optimize a smoothing prior for detectability of microcalcifications. A channelized Hotelling observer (CHO) with eight Laguerre-Gauss channels was designed to detect groups of five microcalcifications in a background of acrylic spheres by adding the CHO log-likelihood ratios calculated at the expected locations of the five calcifications. This model observer is then applied to optimize the detectability of the microcalcifications as a function of the smoothing prior. The authors examine the quadratic and total variation (TV) priors, and a combination of both. A selection of these reconstructions was then evaluated by human observers to validate the correct working of the model observer. The authors found a clear maximum for the detectability of microcalcification when using the total variation prior with weight βTV = 35. Detectability only varied over a small range for the quadratic and combined quadratic-TV priors when weight βQ of the quadratic prior was changed by two orders of magnitude. Spearman correlation with human observers was good except for the highest value of β for the quadratic and TV priors. Excluding those, the authors found ρ = 0.93 when comparing detection fractions, and ρ = 0.86 for the fitted detection threshold diameter. The authors successfully designed a model observer that was able to predict human performance over a large range of settings of the smoothing prior, except for the highest values of β which were outside the useful range for good image quality. Since detectability only depends weakly on the strength of the combined prior, it is not possible to pick an optimal smoothness based only on this criterion. On the other hand, such choice can now be made based on other criteria without worrying about calcification detectability.

Comparison of two psychometric functions in analyzing 4-AFC detection results using a task-based structured phantom for digital mammography

Introduction Detectability of spiculated and non-spiculated mass models and microcalcifications, in a structured background phantom of acrylic spheres and water, was studied for digital mammography via the four-alternative forced-choice (4-AFC) paradigm. Purpose To compare the threshold diameters for mass and microcalcification detection using two types of psychometric curves applied on the contrast-detail data. Material and methods Ten images of the structured phantom were acquired on 23 digital mammography systems under automatic exposure control. The 4-AFC study was performed with in-house developed software and 5 medical physicists as observers. Percentage correctly detected lesions (PC) was obtained for each target type. Two psychometric curves (Weibull and Logistic functions) were applied to determine the threshold diameters and number of detected targets (at PC = 62.5%). Results Both fitting procedures were successfully applied on all systems. After averaging over 23 systems, the threshold diameters for spiculated and non-spiculated masses and microcalcifications, with the Weibull psychometric curves, were 4.0 ± 0.3 mm (R2 = 0.61 ± 0.08), 4.6 ± 0.7 mm (R2 = 0.51 ± 0.11), and 0.114 ± 0.003 mm (R2 = 0.91 ± 0.03) respectively, and the values of 4.0 ± 0.4 mm (R2 = 0.61 ± 0.08), 4.7 ± 0.6 mm (R2 = 0.50 ± 0.11), and 0.114 ± 0.003 mm (R2 = 0.91 ± 0.03) were obtained with the Logistic function. The numbers of detected targets assessed from the two functions were not different (3–4 spiculated masses, 1–2 non-spiculated masses, and 4 groups of microcalcifications). If the PC values were not completely covering the lower and upper than 62.5%, there will be possibility different results occurred from these two functions. Conclusion Weibull and Logistic curve fits gave similar and reproducible threshold diameters for the structured phantom.

Tomosynthesis-guided vacuum-assisted breast biopsy: A feasibility study.

Evaluation of feasibility and clinical performance of a tomosynthesis-guided vacuum-assisted breast biopsy (TVAB) system compared to Stereotaxy (SVAB). All biopsies were performed on consecutive patients: 148 TVAB biopsies and 86 biopsies on different patients using SVAB. Evaluation criteria for each biopsy were technical feasibility, histopathology, procedure time, and complications. All 148 TVAB biopsies were technically successful, and gained the targeted groups of microcalcifications (100%). In 1 of 86 SVAB procedures, it was not possible to gain the targeted microcalcifications (1%), in 3 of 86 the needle had to be adjusted (4%). All TVAB biopsies were performed without clinically relevant complications. Distortions were biopsied exclusively by TVAB, mean size 0.9cm, p < 0.0001. Of the 24 distortions, 13 were cancer, 11 Radial Scars/ CSL. The mean procedure time for TVAB was 15.4minutes (range 7-28min), for SVAB 23minutes (range 11-46min), p < 0.0001. TVAB is able to biopsy small architectural distortions with high accuracy. TVAB is easily feasible and appears to have the same degree of clinical performance for diagnosing microcalcifications. The increased number of biopsied distortions by TVAB is presumably due to increased use of tomosynthesis and its diagnostic potential. • TVAB is easily feasible. • TVAB is able to target architectural distortions with high accuracy. • TVAB diagnoses microcalcifications with the same clinical performance as SVAB.

An experimental phantom study on the effect of calcifications on ultrasound shear wave elastography.

In this study, we investigated the effects of single macrocalcifications and groups of microcalcifications on shear wave elastography. Supersonic shear imaging (SSI) and comb-push ultrasound shear elastography (CUSE) were performed on three sets of phantoms to investigate how calcifications of different sizes and distributions influence measured elasticity. Our results demonstrate that the presence of large isolated macrocalcifications and highly concentrated clusters of microcalcifications can introduce areas with apparent high elasticity when they are evaluated by shear wave elastography.

Photoacoustic imaging of breast microcalcifications: a preliminary study with 8-gauge core-biopsied breast specimens.

BackgroundWe presented the photoacoustic imaging (PAI) tool and to evaluate whether microcalcifications in breast tissue can be detected on photoacoustic (PA) images.MethodsWe collected 21 cores containing microcalcifications (n = 11, microcalcification group) and none (n = 10, control group) in stereotactic or ultrasound (US) guided 8-gauge vacuum-assisted biopsies. Photoacoustic (PA) images were acquired through ex vivo experiments by transmitting laser pulses with two different wavelengths (700 nm and 800 nm). The presence of microcalcifications in PA images were blindly assessed by two radiologists and compared with specimen mammography. A ratio of the signal amplitude occurring at 700 nm to that occurring at 800 nm was calculated for each PA focus and was called the PAI ratio.ResultsBased on the change of PA signal amplitude between 700 nm and 800 nm, 10 out of 11 specimens containing microcalcifications and 8 out of 10 specimens without calcifications were correctly identified on blind review; the sensitivity, specificity, accuracy, positive predictive and negative predictive values of our blind review were 90.91%, 80.0%, 85.71%, 83.33% and 88.89%. The PAI ratio in the microcalcification group was significantly higher than that in the control group (the median PAI ratio, 2.46 versus 1.11, respectively, P = .001). On subgroup analysis in the microcalcification group, neither malignant diagnosis nor the number or size of calcification-foci was proven to contribute to PAI ratios.ConclusionBreast microcalcifications generated distinguishable PA signals unlike breast tissue without calcifications. So, PAI, a non-ionizing and non-invasive hybrid imaging technique, can be an alternative in overcoming the limitations of conventional US imaging.

Cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS flat panel detector: visibility of simulated microcalcifications.

To measure and investigate the improvement of microcalcification (MC) visibility in cone beam breast CT with a high pitch (75 μm), thick (500 μm) scintillator CMOS/CsI flat panel detector (Dexela 2923, Perkin Elmer). Aluminum wires and calcium carbonate grains of various sizes were embedded in a paraffin cylinder to simulate imaging of calcifications in a breast. Phantoms were imaged with a benchtop experimental cone beam CT system at various exposure levels. In addition to the Dexela detector, a high pitch (50 μm), thin (150 μm) scintillator CMOS/CsI flat panel detector (C7921CA-09, Hamamatsu Corporation, Hamamatsu City, Japan) and a widely used low pitch (194 μm), thick (600 μm) scintillator aSi/CsI flat panel detector (PaxScan 4030CB, Varian Medical Systems) were also used in scanning for comparison. The images were independently reviewed by six readers (imaging physicists). The MC visibility was quantified as the fraction of visible MCs and measured as a function of the estimated mean glandular dose (MGD) level for various MC sizes and detectors. The modulation transfer functions (MTFs) and detective quantum efficiencies (DQEs) were also measured and compared for the three detectors used. The authors have demonstrated that the use of a high pitch (75 μm) CMOS detector coupled with a thick (500 μm) CsI scintillator helped make the smaller 150-160, 160-180, and 180-200 μm MC groups more visible at MGDs up to 10.8, 9, and 10.8 mGy, respectively. It also made the larger 200-212 and 212-224 μm MC groups more visible at MGDs up to 7.2 mGy. No performance improvement was observed for 224-250 μm or larger size groups. With the higher spatial resolution of the Dexela detector based system, the apparent dimensions and shapes of MCs were more accurately rendered. The results show that with the aforementioned detector, a 73% visibility could be achieved in imaging 160-180 μm MCs as compared to 28% visibility achieved by the low pitch (194 μm) aSi/CsI flat panel detector. The measurements confirm that the Hamamatsu detector has the highest MTF, followed by the Dexel detector, and then the Varian detector. However, the Dexela detector, with its thick (500 μm) CsI scintillator and low noise level, has the highest DQE at all frequencies, followed by the Varian detector, and then the Hamamatsu detector. The findings on the MC visibility correlated well with the differences in MTFs, noise power spectra, and DQEs measured for these three detectors. The authors have demonstrated that the use of the CMOS type Dexela detector with its high pitch (75 μm) and thick (500 μm) CsI scintillator could help improve the MC visibility. However, the improvement depended on the exposure level and the MC size. For imaging larger MCs or scanning at high exposure levels, there was little advantage in using the Dexela detector as compared to the aSi type Varian detector. These findings correlate well with the higher measured DQEs of the Dexela detector, especially at higher frequencies.

Mammographic findings in locally advanced breast carcinoma treated with neoadjuvant chemotherapy.

e12538 Background: Breast Cancer (BC) is a heterogeneous disease. Mammograpy images of BC has been associated with tumor features. We evaluated relationship between radiologic features of pre-neoadjuvant chemotherapy (NAC) lesions and clinico pathological tumor features. Methods: We evaluated mammography films and clinicopathological information of BC patient who received NAC followed by tumor resection at Instituto Nacional de Enfermedades Neoplásicas from 2000 to 2011. Results: 495 BC cases were selected. Most cases were staged in clinical Tumor size stage 4 (48.2%) and node stage 1 (58.7%); and had a GIII histological grade (51.2%). Breast density (BD) was classified as BIRADS grade 1 in 17%, grade 2 in 22%, grade 3 in 35% and grade 4 in 25.3%. High BD has been associated to younger age (p&lt;0.001) and obesity (p=0.012). An association between mammographic rounded shape and triple-negative (TN) phenotype was found (p=0.002). An association between the dusty microcalcification and HER2 group as well as between the casting and the TN BC group (p=0.001) is found. NAC included anthracyclines and taxanes in 422 (85.4%) cases. Four and 5 Miller Payne pathologic response (pR) in the primary lesion and absence of axilary lymph nodes involvement were found in14.8% of the whole population, and in 10.5% of luminal cases, 17.7% of HER2- enriched and 23% of TN BC. pCR was associated to patient age (p&lt;0.001), tumor grade (p&lt;0.001) and high breast density (p=0.001), as well as better DFS (p=0.05). Conclusions: Radiographic images are related to tumor features in pre-NAC BC cases. pCR is associated to high density breast as well as previously described clinicopathological features.

P5-08-01: Quantitative Analysis of Strain Ratio of Microcalcification Lesions with Surgical Specimen Mammography.

Abstract Measurement of the strain induced by compression can be useful in the diagnosis of breast tumors. Microcalcification (MC) detected by mammography could be the only symptom of early breast cancers. The purpose of this study was to develop a quantitative method for a differential diagnosis of MC lesions based on the strain ratio (SR) obtained by applying different breast compression pressure during mammography. Methods: This prospective study was conducted with institutional review board approval and the written informed consent was obtained. Twenty-five mastectomy specimens (24 for treatment of breast cancer and 1 from contralateral prophylactic mastectomy) with MCs were examined by digital mammography. There were 24 malignant MCs (mean size of 18.8 mm) detected in the 24 separate specimens, including 14 lesions of invasive carcinoma and 10 lesions of carcinoma in situ. Five benign MCs (mean size of 21.6 mm) were detected, including four lesions which coexisted with malignant MCs in the four separate specimens, and one was discovered in the prophylactic mastectomy specimen. Each specimen experienced four different magnitudes of compression force and the corresponding images were acquired for further analysis. Images in Digital Imaging and Communications in Medicine format (DICOM) were exported into custom software, written in Matlab, to contour the region of interest. Stress was defined as the force divided by the whole specimen area, and the square root of MC area was calculated to represent strain deformation. The SR was the slope of the best-fit line through the four points of each lesion. Histology of the MC was correlated with SR. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic performance of SR for discrimination between benign and malignant MC. Results: The SRs were higher in the malignant MC group (139.10 a.u.) than in the benign MC group (34.09 a.u.; p = 0.024). The SR between invasive carcinoma and carcinoma in situ showed no statistic significance (127.03 a.u. vs. 156.00 a.u.; p = 0.642). The area under the ROC curve for the diagnosis of benign and malignant MC was 0.825 (95% CI, 0.667 to 0.982). Conclusion: This study demonstrated that the SR detected by mammography showed potential for distinguishing benign from malignant MCs. Further in vivo investigations of larger cohorts are necessary to validate these results. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-08-01.

SU‐FF‐I‐01: Determination of Subjective Similarity for Pairs of Lesions On Mammograms: Comparison of Ranking Scores in 2AFC Versus Absolute Ratings for Masses and Microcalcifications

Purpose: We previously obtained the subjective similarity ratings for pairs of lesions on mammograms for quantitative evaluation of similar images. Our purpose in this study was to investigate whether the absolute similarity ratings can be determined reliably by comparison with ranking scores obtained in a 2‐alternative forced‐choice (2AFC) method. Method and Materials: We selected 8 pairs of masses and 8 pairs of clustered microcalcifications based on radiologists' average similarity ratings; similarity ratings for the two sets of 8 pairs were approximately evenly distributed. In the first study, each pair was compared one by one to all other 7 pairs in each group of masses and microcalcifications. In the second study, we combined four pairs of masses and four pairs of microcalcifications to compare the similarity of a pair of masses with that of microcalcifications. Seven radiologists and 3 senior residents were asked to choose one pair that was more similar than another pair with the 2AFC method. The cases were presented in randomized order. The number of times that a pair was selected as more similar was counted as the subjective ranking score. The average scores were compared with the average similarity ratings determined previously. Results: The average ranking scores from the first study were highly correlated (0.93 and 0.98 for masses and calcifications, respectively) with absolute similarity ratings. When mass pairs were compared with calcification pairs, the correlations between ranking scores and absolute ratings were also very high (0.92 and 0.96). In both studies, observers were very consistent in selecting more similar pairs. Conclusion: The result indicates that absolute similarity ratings determined previously are reliable and useful for selection of similar images. The concept of similarity is robust and meaningful even when mass pairs are compared with microcalcification pairs.

99mTc sestamibi scintimammography

Summary Aim: Investigation of the diagnostic role of technetium-99m methoxyisobutylisonitrile (99mTc sestamibi) scintimammography in non-palpable, suspicious breast lesions described as microcalcification, mass and increased density using mammography. Patients, method: 35 women with non-palpable breast lesions were enrolled in the study. Anterior, left and right lateral, ipsilateral posterior oblique images were obtained 15 min after the injection of 740 MBq of 99mTc sestamibi. All scintigraphic images were evaluated visually and focal increased 99mTc sestamibi uptake was accepted as malignant lesion. Breast lesions were classified as microcalcification (13 women), mammographic mass (16 women) and increased density (6 women). Excisional biopsy was performed in all of them irrespective of the scintigraphic results. Results: The focally increased 99mTc sestamibi uptake was seen in 11 breast lesions with malignant lesions and in 4 breast lesions with benign lesions. The diffuse uptake of 99mTc sestamibi was seen in 18 breast lesions with benign lesions and 2 breast lesions with malignant lesions. There was no false positive result of 99mTc sestamibi in microcalcification group and there was no false negative result of the mammographic mass and increased density groups. Conclusion: Scintimammography might be a complementary method in decision making for the non-palpable, suspicious breast lesions that were evaluated as microcalcification, mass and increased density mammograpically.

Effect on mammographic CR image quality of removing the anti-scatter grid

Purpose: To investigate the effect of removing the antiscatter grid on mammographic image quality using computed radiography (CR). To compare experimental results with those recently published in a similar study using a full-field digital mammography (FFDM) detector.Method: A mammographic test phantom was used to evaluate CR image quality both with and without the antiscatter grid in operation. The test images were examined on a Philips ‘Easy Vision RAD’ workstation and were evaluated by assigning visibility scores to the various test details using a standard protocol.Results: The study shows that the visualization of subtle, low-contrast details was compromized when the grid was removed. However, the visibility of groups of micro-calcifications was largely unaffected, even when the dose was reduced.Conclusions: The reduction in detail visibility was due mainly to the contrast loss and background non-uniformity caused by scattered radiation, although this was partially offset by lower levels of quantum noise. In general, the findings did not correlate with the previously published grid-free FFDM results.