Findings of suspicious calcifications on contrast-enhanced mammography and their pathological correlation.

Purpose: This study aimed to determine the performance of contrast-enhanced mammography (CEM) in evaluating suspicious calcifications not associated with a mass.

Methods: Patients with suspicious calcifications detected on CEM performed at our center between February 2021 and December 2023 were included in the study. Retrospectively, the morphology, distribution, and longest axis length of the calcifications were assessed on low-energy images, whereas contrast enhancement intensity, pattern, longest axis length, and enhancement curves were analyzed on recombined images. The pathological diagnosis, grade, Ki-67 index, and (if available) the longest lesion length in the surgical specimen were recorded. Using pathology as the gold standard, various CEM parameters were evaluated for their performance in assessing this group of calcifications. Primary and secondary analyses were performed based on combined low or no enhancement and no enhancement alone, respectively.

Results: Our study includes 132 lesions in 114 patients,18 of whom had bilateral calcifications. Of the 132 lesions included in the study, 78 were benign, and 54 were malignant. Sensitivity, specificity, positive predictive value, and negative predictive value were determined as follows: 72.2%, 62.8%, 57.3%, and 76% in low-energy images; 79.6%, 80.8%, 74.1%, and 85.1% in the primary analysis of recombined images; and 98.2%, 47.4%, 56.4%, and 97.4% in the secondary analysis. Contrast enhancement intensity was identified as a significant parameter influencing malignancy risk. A strong statistical correlation was observed between lesion length measurements in both low-energy and recombined images compared with pathology (r = 0.733 and r = 0.879, P < 0.001 for both), with mean differences of -4.75 mm and +4.45 mm. No statistically significant relationship was found between contrast enhancement intensity and the distinction between invasive and in situ carcinoma (P = 0.698) or the differentiation of ductal carcinoma in situ grade (P = 0.336). A significant correlation was detected between pathology and dynamic contrast enhancement types adapted from magnetic resonance imaging (MRI) (P = 0.019). Although no statistically significant linear correlation was found between the Ki-67 index and contrast enhancement intensity, the P value was close to significance (P = 0.057).

Conclusion: CEM demonstrates strong performance in the assessment of suspicious calcifications by combining the morphological and distributional features of digital mammography with enhancement characteristics similar to MRI.

Clinical significance: The findings support that CEM exhibits effective performance in evaluating suspicious calcifications not associated with a mass and may have a potential role in routine clinical practice.