"Category 4A" microcalcifications: how should this subcategory be applied to microcalcifications seen on mammography?

Utility of Second-look Ultrasonography in Distinguishing BI-RADS 4 Calcifications Detected on Mammography: An observational study

This study aimed to assess the utility of second-look ultrasonography (US) in differentiating breast imaging reporting and data system (BI-RADS) 4 calcifications initially detected on mammography (MG). BI-RADS 4 calcifications have a wide range of positive predictive values. We hypothesized that second-look US would help distinguish BI-RADS 4 calcifications without clinical manifestations and other abnormalities on MG. This study included 1622 pure BI-RADS 4 calcifications in 1510 women (112 patients with bilateral calcifications). The cases were randomly divided into training (85%) and testing (15%) datasets. Two nomograms were developed to differentiate BI-RADS 4 calcifications in the training dataset: the MG-US nomogram, based on multifactorial logistic regression and incorporated clinical information, MG, and second-look US characteristics, and the MG nomogram, based on clinical information and mammographic characteristics. Calibration of the MG-US nomogram was performed using calibration curves. The discriminative ability and clinical utility of both nomograms were compared using the area under the receiver operating characteristic curve (AUC) and the decision analysis curve (DCA) in the test dataset. The clinical information and imaging characteristics were comparable between the training and test datasets. The bias-corrected calibration curves of the MG-US nomogram closely approximate the ideal line for both datasets. In the test dataset, the MG-US nomogram exhibited a higher AUC than the MG nomogram (0.899 vs 0.852, P = .01). DCA demonstrated the superiority of the MG-US nomogram over the MG nomogram. Second-look US features, including ultrasonic calcifications, lesions, and moderate or marked color flow, were valuable for distinguishing BI-RADS 4 calcifications without clinical manifestations and other abnormalities on MG.

Assessment of malignant risk stratification for microcalcifications interpreted as “amorphous” morphology on mammography: A study based on the 5th edition of breast Imaging Reporting and Data System

PURPOSE

To investigate the malignant risk stratification of microcalcifications interpreted as amorphous morphology on mammography according to the coexistence of punctate microcalcifications based on the 5th edition of the Breast Imaging Reporting and Data System.

METHOD

Between March 2013 and September 2020, 367 microcalcifications interpreted as amorphous morphology on mammography with surgical biopsies were included. The amorphous microcalcifications were classified into a predominantly punctate group (A, <50% of amorphous), a predominantly amorphous group (B, >50% of amorphous), and an only amorphous group (C, 100% of amorphous). The distribution was classified into diffuse, regional, grouped, and linear/segmental. The reference standard was the pathology. The positive predictive values (PPV) were calculated and compared using the Chi-square's test or Fisher's exact test and Kruskal-Wallis test.

RESULTS

The overall PPV of microcalcifications interpreted as having an amorphous morphology was 5.2%. The PPV across groups significantly increased in proportion to the amorphous morphology, with 1.0% in group A, 5.6% in group B, and 23.3% in group C (p <.001). Furthermore, the PPV between group A and groups B plus C (10.1%) and groups A plus B (2.8%) and group C were significantly different (p <.001). The PPV of distribution was 0% for diffuse, 4.9% for regional, 5.0% for grouped, and 11.1% for linear/segmental distributions, without statistical significance.

CONCLUSIONS

Pure amorphous microcalcifications are suitable for category 4B. However, when they coexist with punctate morphology, the malignant risk decreases suitable for category 4A or lower. When amorphous microcalcifications coexist with a predominantly punctate morphology, follow-up should be considered.

Amorphous breast calcifications: is BI-RADS 4a appropriate?

Objective

To evaluate the positive predictive value (PPV) of amorphous calcifications and to analyze the imaging variables that could alter the risk of malignancy associated with this finding.

Materials and Methods

This was a retrospective study of 138 stereotactically guided percutaneous vacuum-assisted biopsies of amorphous calcifications, performed between January 2012 and December 2017. All of the patients included were referred for radiological follow-up for a minimum of one year (if the histopathology showed a benign lesion) or for surgical treatment (if the histopathology showed malignancy or a lesion of uncertain malignant potential).

Results

We found that the PPV of amorphous calcifications was 9.42%. However, most of the malignant amorphous calcifications were in cases of invasive carcinoma or high-grade ductal carcinoma in situ, indicating clinically relevant disease. The relative risk of malignancy associated with amorphous calcifications was 6.15 times higher in patients with a family or personal history of breast or ovarian cancer. Neither being postmenopausal nor having dense breasts was found to be predictive of malignancy in patients with amorphous calcifications.

Conclusion

Amorphous calcifications in the breast had a PPV for malignancy of 9.42%, indicating the possibility of placing the finding in subcategory 4a, which requires histopathological analysis. Our finding that the risk of malignancy associated with this subtype of calcifications is up to 6.15 times higher in patients with a family or personal history of breast cancer warrants greater concern regarding the clinical, radiologic, and histopathologic correlations after biopsy.

Comprehensive quantitative malignant risk prediction of pure grouped amorphous calcifications: clinico-mammographic nomogram

BACKGROUND

Pure grouped amorphous calcifications are classified as Breast Imaging Reporting and Data System (BI-RADS) category 4B suspicious calcifications and recommended for biopsy. However, the biopsies often reveal benign findings, especially in screening mammograms (92.4-97.2%).

METHODS

Mammograms of 699 pure grouped amorphous calcifications with final pathological results were analyzed in this retrospective study. The maximum span (MS) of the group of calcifications and the MS of the parallel/vertical direction of the mammary duct (MPS/MVS) were measured, and the MPS to MVS ratio was calculated. Based on the MS and ratio, 2 prediction nomograms with other clinic-mammographic features were developed. The discrimination performance of the models was assessed and compared by the area under the receiver operating characteristic curve (AUC). Scatterplots were created to determine the cutoff values with fewer misdiagnoses of malignant calcifications and fewer false positives.

RESULTS

Ultimately, 2 prediction models were successfully developed based on the 4 risk factors of age, purpose of the mammogram, whether multiple or single calcifications, and the MS [odds ratio (OR) =1.06, P=0.02]/ratio (OR =6.05, P<0.001). Both models had good discrimination. The ratio model performed better than the MS model in the training cohort (AUC of 0.875 and 0.834, respectively, P=0.003) and validation cohort (AUC 0.908 and 0.867, respectively, P=0.047). For the group with probably benign calcifications (as detected by the ratio nomogram), the malignancy rates were 2.7% [95% confidence interval (CI): 1.00% to 6.53%] and 1.19% (95% CI: 0.06% to 7.37%) in the training and validation cohorts, respectively, and 44.12% and 47.70% of benign biopsies were detected in the training and validation cohorts, respectively.

CONCLUSIONS

The clinico-mammographic quantitative malignancy risk prediction nomogram showed favorable discrimination and calibration performance. The ratio model showed better diagnostic efficiency than the MS model, and identified >40% of benign biopsies.

Malignancy Risk Stratification Prediction of Amorphous Calcifications Based on Clinical and Mammographic Features

Purpose

To explore the potential factors influencing the malignancy risk of amorphous calcifications and establish a predictive nomogram for malignancy risk stratification.

Patients and Methods

Consecutive mammograms from January 2013 to December 2018 were retrospectively reviewed. Traditional clinical features were recorded, and mammographic features were estimated according to the 5th BI-RADS. Included calcifications were randomly divided into the training and validation cohorts. A nomogram was developed to graphically predict the risk of malignancy (risk) based on stepwise multivariate logistic regression analysis. The discrimination and calibration performance of the model were assessed in both the training and validation cohorts.

Results

Finally, 1018 amorphous calcifications with final pathological results in 907 women were identified with a malignancy rate of 28.4% (95% CI: 25.7%, 31.3%). The malignancy rates of subgroups divided by the distribution of calcifications, quantity of calcifications, age, menopausal status and family history of cancer were significantly different. There were 712 cases and 306 cases in the training and validation cohorts. The prediction nomogram was finally developed based on four risk factors, including age and distribution, maximum diameter and quantity of calcifications. The AUC of the nomogram was 0.799 (95% CI: 0.761, 0.836) in the training cohort and 0.795 (95% CI: 0.738, 0.852) in the validation cohort.

Conclusion

On mammography, the distribution, maximum diameter and quantity of calcifications are independent predictors of malignant amorphous calcifications and can be easily obtained in the clinic. The nomogram developed in this study for individualized malignancy risk stratification of amorphous calcifications shows good discrimination performance.

Scoring System to Stratify Malignancy Risks for Mammographic Microcalcifications Based on Breast Imaging Reporting and Data System 5th Edition Descriptors

Objective

To develop a scoring system stratifying the malignancy risk of mammographic microcalcifications using the 5th edition of the Breast Imaging Reporting and Data System (BI-RADS).

Materials and Methods

One hundred ninety-four lesions with microcalcifications for which surgical excision was performed were independently reviewed by two radiologists according to the 5th edition of BI-RADS. Each category's positive predictive value (PPV) was calculated and a scoring system was developed using multivariate logistic regression. The scores for benign and malignant lesions or BI-RADS categories were compared using an independent t test or by ANOVA. The area under the receiver operating characteristic curve (AUROC) was assessed to determine the discriminatory ability of the scoring system. Our scoring system was validated using an external dataset.

Results

After excision, 69 lesions were malignant (36%). The PPV of BI-RADS descriptors and categories for calcification showed significant differences. Using the developed scoring system, mean scores for benign and malignant lesions or BI-RADS categories were significantly different (p < 0.001). The AUROC of our scoring system was 0.874 (95% confidence interval, 0.840–0.909) and the PPV of each BI-RADS category determined by the scoring system was as follows: category 3 (0%), 4A (6.8%), 4B (19.0%), 4C (68.2%), and 5 (100%). The validation set showed an AUROC of 0.905 and PPVs of 0%, 8.3%, 11.9%, 68.3%, and 94.7% for categories 3, 4A, 4B, 4C, and 5, respectively.

Conclusion

A scoring system based on BI-RADS morphology and distribution descriptors could be used to stratify the malignancy risk of mammographic microcalcifications.