Non-contrast-enhanced breast MRI for evaluation of tumor volume change after neoadjuvant chemotherapy.

PURPOSE: Three-dimensional contrast-enhanced magnetic resonance imaging (3D-Ce-MRI) is a most powerful tool for evaluation of neoadjuvant chemotherapy (NAC). However, the use of contrast agent is invasive, expensive, and time consuming, Thus, contrast agent-free imaging is preferable. We aimed to investigate the tumor volume change after NAC using maximum intensity projection diffusion-weighted image (MIP-DWI) and 3D-Ce-MRI. METHOD: We finally enrolled 55 breast cancer patients who underwent NAC in 2018. All MRI analyses were performed using SYNAPSE VINCENT® medical imaging system (Fujifilm Medical, Tokyo, Japan). We evaluated the tumor volumes before, during, and after NAC. Tumor volume before NAC on 3D-Ce-MRI was termed Pre-CE and those during and after NAC were termed Post-CE. The observer raised the lower end of the window width until the tumor was clearly visible and then manually deleted the non-tumor tissues. A month thereafter, the same observer who was blinded to the 3D-Ce-MRI results randomly evaluated the tumor volumes (Pre-DWI and Post-DWI) using MIP-DWI with the same method. Tumor volume change between ΔCE (Pre-CE - Post-CE/Pre-CE) and ΔDWI (Pre-DWI - Post-DWI/Pre-DWI) and the processing time for both methods (Time-DWI and Time-CE) were compared. RESULTS: We enrolled 55 patients. Spearman's rho between ΔDWI and ΔCE for pure mass lesions, and non-mass enhancement (NME) was 0.89 (p < 0.01), 0.63(p < 0.01) respectively. Time-DWI was significantly shorter than Time-CE (41.3 ± 21.2 and 199.5 ± 98.3 respectively, p < 0.01). CONCLUSIONS: Non-contrast-enhanced Breast MRI enables appropriate and faster evaluation of tumor volume change after NAC than 3D-Ce-MRI especially for mass lesions.

Can breast MRI and adjunctive Doppler ultrasound improve the accuracy of predicting pathological complete response after neoadjuvant chemotherapy?

BACKGROUND: To examine the accuracy of MRI and Doppler ultrasound (US) for detecting residual tumor after neoadjuvant chemotherapy (NAC) for breast cancer and evaluate whether adjunctive Doppler US improves the MRI accuracy. METHODS: We reviewed 276 invasive breast cancer cases treated with NAC. Tumors were classified into four subtypes based on estrogen receptor and HER2 status. Response to NAC was evaluated using contrast-enhanced MRI and Doppler US. Residual Doppler flow was assumed to indicate a residual tumor. MRI and Doppler findings were compared with the histopathological findings of resected specimens. Pathological complete response (pCR) was defined as neither in situ nor invasive cancer left. RESULTS: Of the 276 tumors, imaging complete responses were observed using MRI and Doppler US in 62 (22%) and 111 (40%), respectively, whereas pCR was achieved in 44 (16%). MRI and Doppler US predicted residual tumor with 88% and 69% sensitivity, 80% and 91% specificity, 87% and 73% accuracy, 96% and 98% PPV, and 56% and 36% NPV, respectively. The accuracies of MRI and Doppler US were significantly higher for HER2-negative than HER2-positive tumors (p < 0.001 and p = 0.043, respectively). Seven (26%) of 27 false-negative cases identified by MRI were correctly diagnosed as positives with adjunctive Doppler US. CONCLUSIONS: Although MRI accurately detected residual tumor with 87% accuracy, this was still not sufficient to meet clinical demands and differed with tumor subtype. Adjunctive Doppler US in cases that appear to show a complete response on MRI might reduce chances of false negatives and increase the NPV of MRI for predicting residual tumor.

Evaluation of Breast Edema Findings at T2-weighted Breast MRI Is Useful for Diagnosing Occult Inflammatory Breast Cancer and Can Predict Prognosis after Neoadjuvant Chemotherapy.

Background Prediction of occult inflammatory breast cancer (IBC) and breast cancer prognosis based on breast edema findings on T2-weighted MRI scans, even for patients without clinical signs of IBC, would be useful in both pretreatment planning and prognosis and may elucidate the underlying biologic mechanisms. Purpose To evaluate whether classification of breast edema on T2-weighted MRI scans is useful for predicting the prognosis of patients with breast cancer treated with neoadjuvant chemotherapy (NAC). Materials and Methods A retrospective evaluation was performed of women with breast cancer who underwent breast MRI and were treated with NAC between January 2011 and December 2018. Breast edema on T2-weighted images was scored on a scale of 1 to 4, as follows: (a) breast edema score (BES) 1, no edema; (b) BES 2, peritumoral edema; (c) BES 3, prepectoral edema; and (d) BES 4, subcutaneous edema (suspicious for occult IBC). Clinically evident IBC was classified as BES 5 (without MRI). The log-rank test was performed, and hazard ratios were calculated using the Cox hazard model to evaluate associations between BES and progression-free survival (PFS) and overall survival (OS). PFS rate at 100 months after initiation of therapy was also evaluated. Results Of 408 patients (median age, 53 years; range, 28-80 years), 65 (16%) had a recurrence and 27 (7%) died. The log-rank test revealed differences in PFS for BES 4 versus 1, BES 5 versus 1, BES 5 versus 2, and BES 5 versus 3 (adjusted P < .05 for all). PFS rates for BES 1-5 were 0.92, 0.85, 0.80, 0.62, and 0.58, respectively, and the corresponding OS rates at 100 months were 0.98, 0.91, 0.92, 0.77, 0.86, respectively. Conclusion Classification of breast edema findings on T2-weighted MRI scans using a breast edema score was related to the prognosis of patients after neoadjuvant chemotherapy. © RSNA, 2021 Online supplemental material is available for this article.

Is the presence of edema and necrosis on T2WI pretreatment breast MRI the key to predict pCR of triple negative breast cancer?

PURPOSE: Given that a pathological complete response (pCR) after neoadjuvant chemotherapy (NAC) is an important prognostic factor, evaluating pretreatment imaging findings is important. Outcomes for triple negative breast cancer (TNBC) vary with the histological classification, indicating that this classification is clinically significant. In this study, we focus on the most common histological subtype of TNBC, invasive carcinoma of no special type (NST), to evaluate whether intramammary edema (intra-E) and intratumoral necrosis (intra-N) on T2-weighted magnetic resonance imaging (T2WI) is a useful predictor of pCR. METHOD: We retrospectively included patients with biopsy-diagnosed TNBC-NST who received NAC between January 2014 and December 2017. Intra-E and intra-N were evaluated on T2WI before NAC. We grouped intra-E into no edema, peritumoral edema, prepectoral edema, and subcutaneous edema, and we defined intra-N as water-like signal intensity without enhancement on T2WI. We also evaluated tumor size, Ki-67 expression, and histological/nuclear grade, as well as their correlation with intra-E and intra-N. RESULTS: Fifty-seven patients with TNBC-NST were enrolled. There was no correlation with the rate of pCR and the presence of either intra-E or intra-N before NAC. Only intra-E and tumor size showed a positive correlation. CONCLUSIONS: In patients with TNBC-NST, intra-E and intra-N did not correlate with pCR, but intra-E did positively correlate with tumor size. NST may exhibit a greater response to NAC, regardless of whether intra-E or intra-N is present or not on the pretreatment MRI. KEY POINTS: • Pathological complete response in TNBC-NST had no correlation with intramammary edema or intratumoral necrosis. • NAC may be justified in TNBC-NST even in the presence of edema or necrosis. • The extension of edema correlated with tumor size of TNBC-NST.

Imaging features of breast cancer with marked hemosiderin deposition: A case report.

A 63-year-old woman was referred to our hospital for breast cancer treatment. She had a large HER2-positive breast tumor on her left breast, and received neoadjuvant chemotherapy. After treatment, a shrunk spiculated mass with calcification-like high density was detected on mammography, and MRI revealed a large strong susceptibility artifact. Surgical specimen analysis attributed these imaging features to a large marked hemosiderin deposition. This case is herein reported due to its rarity and to the importance of acknowledging that this large marked hemosiderin depositions can present as a calcification-like high density on mammography and shows large susceptibility artifact on MRI imaging.

MRI-detected breast lesions: clinical implications and evaluation based on MRI/ultrasonography fusion technology.

Magnetic resonance imaging (MRI) is a highly sensitive imaging modality that frequently reveals additional breast lesions that are occult on mammography and ultrasonography (US) and are thus difficult to diagnose. It is important to investigate these MRI-detected suspicious lesions, which are associated with a fairly high rate of malignancy. In this review, we have discussed MRI/US fusion technology, a magnetic position tracking system that synchronizes real-time US and MRI to improve lesion detection and enables comparisons of MRI and US findings of the detected lesions. This combination increases the precision of second-look US. We hope that our review underscores the importance of understanding the US findings and histopathology of MRI-detected breast lesions, as this will enable radiologists to perform appropriate assessments.

Does breast cancer growth rate really depend on tumor subtype? Measurement of tumor doubling time using serial ultrasonography between diagnosis and surgery.

BACKGROUND: Breast cancer growth is generally expected to differ between tumor subtypes. We aimed to evaluate tumor doubling time (DT) using ultrasonography and verify whether each tumor subtype has a unique DT. METHODS: This retrospective study included 265 patients with invasive breast cancer who received serial ultrasonography between diagnosis and surgery. Tumor diameters were measured in three directions and DTs were calculated according to an exponential growth model using the volume change during serial ultrasonography. We investigated the relationships between DT, tumor subtype, and histopathological factors. RESULTS: Volumes did not change in 95 (36%) of 265 tumors and increased in 170 (64%) tumors during serial ultrasonography (mean interval, 56.9 days). The mean volume increases of all tumors and volume-increased tumors were 22.1% and 34.5%, respectively. Triple-negative tumors had greater volume increases (40% vs. 20%, p = 0.001) and shorter DT (124 vs. 185 days, p = 0.027) than estrogen receptor (ER)+/human epidermal growth factor receptor 2 (HER2)- tumors. Volume-increased tumors had higher Ki-67 indices than those of volume-stable tumors in ER+/HER2- (p = 0.002) and ER+/HER2+ tumors (p = 0.011) and higher histological grades in all tumors except triple-negative tumors (p < 0.001). Triple-negative tumors with DTs < 90 days (short-DT) showed higher Ki-67 indices than those with DTs > 90 days (long-DT) (p = 0.008). In ER+/HER2- tumors, histological grades were higher for short-DT than for long-DT tumors (p = 0.022). CONCLUSION: Differences in tumor DT depending on breast cancer subtype, Ki-67 index, and histological grade were confirmed using serial ultrasonography even during preoperative short interval.

T2-hypointense rim of breast mass lesions on magnetic resonance images: Radiologic-pathologic correlation.

We investigated the radiologic-pathologic correlation of a strong hypointense rim on T2-weighted images (T2-hypo-rim) surrounding breast mass lesions and evaluated its clinical significance. We retrospectively reviewed 3503 consecutive breast magnetic resonance imaging (MRI) examinations. The T2-hypo-rim was defined as a border of strong hypointensity compared with the fat signal on fat-suppressed T2-weighted images. Detected lesions with T2-hypo-rim were classified as a solid or cystic mass with MRI and correlated with histopathologic findings. Sixty-two masses (2%; 34 solid, 28 cystic) with T2-hypo-rim were detected [44 breast cancers, 18 benign lesions, including 15 (24%) papillary tumors]. Patients with cancer were significantly older than those with benign lesions (P = .002). Breast cancers were significantly larger than benign masses (P = .023). In 49 of 62 lesions (24 solid and 16 cystic cancers; three solid and six cystic benign masses), the rims were accurately correlated with the histopathologic findings. All malignant and benign cystic masses exhibited hemosiderin deposits in the cyst walls. However, 22 of 24 solid cancers and no solid benign masses exhibited hemosiderin at the tumor periphery (92% and 0%, respectively, P < .001). In addition, a thick fibrous capsule was present in nine (38%) of 24 solid cancers and none of the solid benign lesions. Strong T2-hypo-rims mostly correlated with hemosiderin deposits and/or sometimes fibrous capsules. Although the rims could not distinguish malignant from benign cystic lesions, they indicated malignancy in solid mass lesions on MRI. Additionally, the rims often indicated papillary tumors.

Comparison of visibility of circumscribed masses on Digital Breast Tomosynthesis (DBT) and 2D mammography: are circumscribed masses better visualized and assured of being benign on DBT?

OBJECTIVE: To compare the visibility of circumscribed masses on digital breast tomosynthesis (DBT) images and 2D mammograms and determine the usefulness of DBT for differentiation between benign and malignant circumscribed masses. METHODS: Seventy-one (19 malignant and 52 benign) mammographic well-circumscribed masses were included. Visibility of the masses and halo signs on DBT images were retrospectively compared with 2D mammograms. The effects of mammographic breast density on mass visibility were also evaluated. RESULTS: For DBT, 83% were superior and 17% were equivalent in visibility of the masses to that of 2D, and superiority of DBT was significantly enhanced in the high breast density group compared with the low breast density group (91% vs 68%, respectively, p = 0.016). Three lesions were only detected on DBT. There was no significant difference in the superiority of DBT for lesion visibility between malignant and benign masses. The halo sign was detected in 58% lesions on DBT and in 4% on 2D (p < 0.001). CONCLUSION: Circumscribed masses were better visualized on DBT than on 2D mammograms, particularly in high-density breasts. The halo sign often appeared on DBT and gave a clearer mass margin. However, circumscribed masses on DBT are not assured of being benign. KEY POINTS: • Circumscribed masses were better visualized on breast tomosynthesis than on 2D mammography. • Tomosynthesis visualized circumscribed masses better than 2D for all breast density categories. • Halo signs often appeared on tomosynthesis and contributed to detect circumscribed margins. • Circumscribed masses on tomosynthesis images are not assured of being benign lesions.