A. CT-like imaging for bone and calcification visualization.

 When breast contrast-enhanced MRI was ordered, the FRACTURE sequence was additionally performed on the contralateral side only for cases with abnormal calcifications detected on mammography. MRI examination was performed with 3.0-T MRI unit (Ingenia 3.0T CX, Philips), using a breast coil. The parameters of Fracture were set at TR shortest, TE in-phase 2.3 4.6 6.9 9.2 ms, field of view 320×320mm2, matrix 364×364, slice thickness 0.55 mm, Filp angle 20 deg. Scan time was 4min 53sec[5].

 We compared the visualization of calcifications on mammography, contrast-enhanced MRI, and FRACTURE to assess lesion imaging diagnosis. Additionally, we evaluated the detectability of calcifications and explored the clinical utility of visualizing calcifications on MRI. The findings are presented here.

B. Case Presentation

 We present cases focusing on calcifications detected on mammography, their visualization using the FRACTURE method in MRI, and findings from contrast-enhanced MRI. Some calcifications appear clearly on MRI, while others are less distinct. Particular attention should be given to the correlation between calcifications and contrast enhancement on MRI.

Fig 1: Mammography revealed coarse calcifications (thin arrows) and a cluster of amorphous calcifications (thick arrows). While the coarse calcifications were clearly visualized on MRI, the faint, indistinct calcifications were barely distinguishable from noise. No abnormal enhancement was observed on contrast-enhanced MRI (not shown). The detectability of calcifications depends on their characteristics, and faint, indistinct calcifications remain particularly difficult to visualize at present. Considering this, it is important to evaluate the significance of attempting to visualize calcifications using MRI.

Fig 2: Left breast cancer (DCIS) Mammography revealed regional amorphous calcifications, which were also detected on MRI (FRACTURE) in nearly the same area. Contrast-enhanced MRI demonstrated regional non-mass enhancement, extending beyond the area of calcifications. This case illustrates that even amorphous calcifications can sometimes be clearly visualized on MRI. However, it remains unclear whether malignancy makes calcifications more detectable on MRI or if other factors are involved. By recognizing that the area of enhancement extends significantly beyond the calcified region, MRI findings can aid in determining the appropriate surgical margins.

Fig 3: DCIS Mammography showed a cluster of fine pleomorphic to small round calcifications. FRACTURE imaging clearly visualized the corresponding calcifications, and contrast-enhanced MRI revealed a mass enhancement at the same location.

Fig 4: Mammography showed regional fine pleomomorphic to coarse calcifications. FRACTURE imaging also demonstrated calcification signals on MRI, but no abnormal enhancement was observed on contrast-enhanced MRI. The findings were considered consistent with benign, chronic calcifications, and the patient was followed up.

Fig 5: Invasive ductal carcinoma, Luminal A type Grouped fine pleomorphic to round calcifications were superimposed on an irregular mass. On MRI, the calcifications corresponded to the tumor area, and no additional tumor extension was observed.

Fig 6: DCIS with Paget’s disease of the nipple Mammography revealed regional fine pleomorphic calcifications, which were clearly visualized on MRI as well. A corresponding area of non-mass enhancement was also observed.

Fig 7: Mammography showed clustered small round calcifications, which were also detected using FRACTURE imaging. However, the area of contrast enhancement was completely different. This highlights the importance of precisely correlating MRI findings with the location of calcifications.

Fig 8: Invasive ductal carcinoma, Luminal A type Mammography revealed clustered small round calcifications, and ultrasound showed calcifications corresponding to the mass. MRI FRACTURE imaging also visualized clustered calcifications, with contrast enhancement confirming a corresponding mass. The findings suggest a localized breast cancer.

Fig 9: Mammography revealed unilateral regional amorphous calcifications. These calcifications were not clearly visualized on FRACTURE imaging, and no abnormal enhancement was observed on contrast-enhanced MRI. Since no enhancing lesion was present, the findings suggest a high likelihood of a benign condition. However, low-grade DCIS may not always be detected on contrast-enhanced MRI. With the accumulation of future cases, further evaluation is needed to determine the frequency of malignancy in calcifications that are not visualized on MRI.

Fig 10: Post-neoadjuvant chemotherapy for invasive ductal carcinoma Mammography showed residual calcifications, which were also visualized on FRACTURE imaging. Contrast-enhanced MRI revealed residual enhancing lesions extending beyond the calcified region. The role of calcification imaging in the context of neoadjuvant therapy should be further investigated.

C. Future Applications and Clinical Utility

 Visualization of calcifications with breast MRI enables pinpoint observation of calcified areas detected on mammography. This approach offers:- Improved assessment and management of calcified lesions detected during screening.- Enhanced preoperative evaluation of breast cancer, including qualitative and extent assessments of lesions.

 The visibility of calcifications on MRI varies depending on their characteristics, with faint and indistinct calcifications currently remaining undetectable. If further research clarifies the differences in malignancy, histological types, and invasiveness between calcifications that are visible and those that are not on MRI, its clinical utility will be further enhanced.