Background parenchymal enhancement in breast MRI before and after neoadjuvant chemotherapy: correlation with tumour response.

OBJECTIVES: To correlate the decrease in background parenchymal enhancement (BPE) and tumour response measured with MRI in breast cancer patients treated with neoadjuvant chemotherapy (NAC). METHODS: One hundred and forty-six MRI examinations of 73 patients with 80 biopsy-proven breast cancers who underwent breast MRI before and after NAC were retrospectively analysed. All images were reviewed by two blinded readers, who classified BPE into categories (BEC; 1 = minimal, 2 = mild, 3 = moderate, 4 = marked) before and after NAC. Histopathological and morphological tumour responses were analysed and compared. RESULTS: The distribution of BEC 1/2/3/4 was 25/46/18/11 % before and 78/20/2/0 % after NAC. On average, BPE decreased by 0.87 BEC. Cohen's kappa showed substantial agreement (k = 0.73-0.77) before and moderate agreement (k = 0.43-0.60) after NAC and moderate agreement (k = 0.62-0.60) concerning the change in BEC. Correlating the change in BPE with tumour response, the average decrease in BEC was 1.3 in cases of complete remission, 0.83 in cases with partial response, 0.85 in cases with stable disease and 0.40 in cases with progressive disease. Correlation analysis showed a significant correlation between the decrease in BEC and tumour response (r = -0.24, p = 0.03). CONCLUSIONS: BPE decreased by, on average, 0.87 BEC following NAC for breast cancer. The degree of BPE reduction seemed to correlate with tumour response. KEY POINTS: • BPE decreases by an average of 0.87 categories under neoadjuvant chemotherapy. • The reduction of BPE following neoadjuvant chemotherapy correlates with the tumour response. • The classification of the BPE shows good agreement among trained readers.

MR imaging-guided vacuum-assisted breast biopsy: reduction of false-negative biopsies by short-term control MRI 24-48 h after biopsy.

AIM: To evaluate whether another contrast-enhanced (CE) magnetic resonance imaging (MRI) examination 24-48 h after MRI-guided vacuum-assisted breast biopsy (MRI-VAB) can reduce the rate of false-negative cases. MATERIALS AND METHODS: The study included 252 patients who underwent MRI-VAB for the clarification of 299 lesions. The success of MRI-VAB was assessed at interventional MRI and another CE MRI 24-48 h after the intervention. In cases of successful MRI-VAB (complete or partial lesion removal) and benign histological results, follow-up breast MRI was performed. In cases of unsuccessful biopsy (unchanged lesion), tissue sampling was repeated. False-negative cases were calculated to assess the diagnostic value of MRI follow-up within 2 days after intervention. RESULTS: Ninety-eight malignant (32.8%) and 201 (67.2%) benign lesions were diagnosed using MRI-VAB. At immediate unenhanced control MRI, all lesions were assessed as successfully biopsied. In 18 benign cases (6%), CE MRI after 24-48 h showed an unsuccessful intervention. Further tissue sampling revealed another 13 cancers in these patients. This results in a false-negative rate of 11.7%. Follow-up MRI of the benign lesions presented no further malignancy. CONCLUSIONS: MRI-VAB with immediate unenhanced control offers a success rate of 94%. The rate of false-negative biopsies (11.7%) could be reduced to zero by using short-term follow-up MRI. Therefore, a further CE breast MRI 24-48 h after benign MRI-VAB to eliminate missed cancers is recommended.

Repeated surgeries in invasive lobular breast cancer with preoperative MRI: Role of additional carcinoma in situ and background parenchymal enhancement.

OBJECTIVES: Analysing the influence of additional carcinoma in situ (CIS) and background parenchymal enhancement (BPE) in preoperative MRI on repeated surgeries in patients with invasive lobular carcinoma (ILC) of the breast. METHODS: Retrospective analysis of 106 patients (mean age 58.6±9.9years) with 108 ILC. Preoperative tumour size as assessed by MRI, mammography and sonography was recorded and compared to histopathology. In contrast-enhanced MRI, the degree of BPE was categorised by two readers. The influence of additionally detected CIS and BPE on the rate of repeated surgeries was analysed. RESULTS: Additional CIS was present in 45.4% of the cases (49/108). The degree of BPE was minimal or mild in 80% of the cases and moderate or marked in 20% of the cases. In 17 cases (15.7%) at least one repeated surgery was performed. In n=15 of these cases, repeated surgery was performed after BCT (n=9 re-excisions, n=6 conversions to mastectomy), in n=2 cases after initial mastectomy. The initial surgical procedure (p=0.008) and additional CIS (p=0.046) significantly influenced the rate of repeated surgeries, while tumour size, patient age and BPE did not (p=ns). CONCLUSIONS: Additional CIS was associated with a higher rate of repeated surgeries, whereas BPE had no influence.

Management of breast lesions detectable only on MRI.

UNLABELLED: Breast MR imaging has become established as the most sensitive imaging method for diagnosing breast cancer. As a result of the increasing examination volume and improved image quality, the number of breast lesions detected only on MRI and requiring further clarification has risen in recent years. According to the S3-guideline "Diagnosis, Therapy, and Follow-Up of Breast Cancer" as revised in July 2012, institutions performing breast MRI should provide the option of an MRI-guided intervention for clarification. This review describes the indications, methods and results of MRI-guided interventions for the clarification of breast lesions only visible on MRI. Recent guidelines and study results are also addressed and alternative methods and pitfalls are presented. KEY POINTS: ▶ Up to 57 % of lesions originally visible only on MRI can be sonographically correlated and biopsied. ▶ MRI-guided intervention is necessary for the clarification of BI-RADS® 4 and 5 lesions detectable only on MRI ▶ MRI-guided vacuum-assisted breast biopsy should be preferentially used ▶ MRI-guided localization and surgical excision should be used if MRI-guided vacuum-assisted biopsy is not possible ▶ If BI-RADS® 4 and 5 findings visible only on MRI are not detectable on interventional MRI, a follow-up MRI should be performed within six months.