MRI of histologically confirmed mammary carcinoma: clinical relevance of diagnostic procedures for detection of multifocal or contralateral secondary carcinoma

Correlation between Magnetic Resonance Imaging and Histopathological Tumor Response after Neoadjuvant Chemotherapy in Breast Cancer

Aim

To evaluate the accuracy of magnetic resonance imaging in assessing tumor response following neoadjuvant chemotherapy in patients with locally advanced breast cancer.

Materials and Methods

Twenty-six patients entered a phase II study of neoadjuvant chemotherapy, undergoing bilateral breast magnetic resonance imaging before therapy and before surgery. Tumor response was classified using RECIST criteria, using tumor size at magnetic resonance imaging. The latter was then compared to residue found at histopathological examination.

Results

Magnetic resonance imaging showed 6 (23%) complete responses, 17 (65%) partial responses, 3 (11.5%) disease stabilizations and no disease progressions. Twenty-three tumors (88.5%) were considered responsive and 3 (11.5%) unresponsive. Pathological tumor response was: 6 complete responses (23%), 17 partial responses (65%), 2 stable disease (8%), 1 progression (4%). When results of the preoperative magnetic resonance imaging were compared to pathological tumor response, magnetic resonance imaging overestimated tumor size in 12 cases (46%) and underestimated it in 9 (35%). However, preoperative magnetic resonance imaging failed to detect invasive tumor in 2 false-negative cases (8%), 1 of which was multifocal. Mastectomy was performed in 12 cases: 1 case of disease progression even though the neoplasm appeared smaller at magnetic resonance imaging, 3 cases with stable disease, and 4 cases with T3 or T4 disease. The 9th patient was T2N2 with initial retroareolar disease and negative magnetic resonance imaging after chemotherapy. The 10th patient, affected by lobular cancer, was in partial remission but was T3N1. The 11th patient was 57 years old but was not interested in conservative surgery. The 12th patient requested bilateral prophylactic mastectomy due to her positive family history of breast cancer.

Conclusions

Magnetic resonance imaging of the breast allowed conservative surgery in 54% of the patients. This low value is primarily due to overestimation of tumor size, with a negative predictive value of 67% in our population. However, surgeons were able to choose conservative surgery with relative safety in cases of small residual disease.

Society of Surgical Oncology Breast Disease Working Group Statement on Prophylactic (Risk-Reducing) Mastectomy

Over the past several years, there has been an increasing rate of bilateral prophylactic mastectomy (BPM) and contralateral prophylactic mastectomy (CPM) surgeries. Since publication of the 2007 SSO position statement on the use of risk-reducing mastectomy, there have been significant advances in the understanding of breast cancer biology and treatment. The purpose of this manuscript is to review the current literature as a resource to facilitate a shared and informed decision-making process regarding the use of risk-reducing mastectomy.

Factors Associated with Preoperative Magnetic Resonance Imaging Use among Medicare Beneficiaries with Nonmetastatic Breast Cancer

Preoperative breast magnetic resonance imaging (MRI) use among Medicare beneficiaries with breast cancer has substantially increased from 2005 to 2009. We sought to identify factors associated with preoperative breast MRI use among women diagnosed with ductal carcinoma in situ (DCIS) or stage I-III invasive breast cancer (IBC). Using Surveillance, Epidemiology, and End Results and Medicare data from 2005 to 2009 we identified women ages 66 and older with DCIS or stage I-III IBC who underwent breast-conserving surgery or mastectomy. We compared preoperative breast MRI use by patient, tumor and hospital characteristics stratified by DCIS and IBC using multivariable logistic regression. From 2005 to 2009, preoperative breast MRI use increased from 5.9% to 22.4% of women diagnosed with DCIS and 7.0% to 24.3% of women diagnosed with IBC. Preoperative breast MRI use was more common among women who were younger, married, lived in higher median income zip codes and had no comorbidities. Among women with IBC, those with lobular disease, smaller tumors (<1 cm) and those with estrogen receptor negative tumors were more likely to receive preoperative breast MRI. Women with DCIS were more likely to receive preoperative MRI if tumors were larger (>2 cm). The likelihood of receiving preoperative breast MRI is similar for women diagnosed with DCIS and IBC. Use of MRI is more common in women with IBC for tumors that are lobular and smaller while for DCIS MRI is used for evaluation of larger lesions.

Evaluation of tissue sampling methods used for MRI-detected contralateral breast lesions in the American College of Radiology Imaging Network 6667 trial

OBJECTIVE

The purpose of our study was to evaluate tissue sampling methods used for MRI-detected suspicious contralateral breast lesions in the American College of Radiology Imaging Network (ACRIN) 6667 trial.

MATERIALS AND METHODS

Breast MRI was performed at 25 institutions in 969 women who had a recent diagnosis of unilateral breast cancer and negative contralateral mammography and clinical breast examinations. Biopsy was recommended for MRI findings in 135 women, and 121 underwent sampling. Frequencies and positive biopsy rates of sampling methods used for initial diagnosis and imaging guidance techniques were calculated and compared.

RESULTS

Sampling yielded 30 malignant and 91 benign results. Initial sampling used needle biopsy in 88 of 121 (72.7%) and surgical biopsy in 30 of 121 (24.8%) women. Surgical biopsy was excisional biopsy in 28 of 30 (93.3%) and mastectomy in two of 30 (6.7%). The remaining three of 121 (2.5%) women underwent mastectomy, but it was not documented whether this represented initial tissue sampling. Of imaging-guided procedures, 56 of 106 (52.8%) used MRI; 49 of 106 (46.2%), ultrasound; and one of 106 (1.0%), stereotaxis. MRI-guided sampling was with needle biopsy rather than wire-localized surgical biopsy in 33 of 56 (58.9%) women, whereas ultrasound used needle biopsy in 47 of 49 (95.9%). Positive biopsy rates of sampling methods were 20.5% for needle biopsy, 46.2% for excisional biopsy, and 0% for mastectomy.

CONCLUSION

The majority of initial biopsies for MRI-detected contralateral breast lesions used needle biopsy rather than surgical biopsy. Contralateral surgery could have been avoided in most cases had needle biopsy been performed because most excisional biopsy and all mastectomy results were benign. MRI-guided biopsy was significantly more likely than ultrasound-guided sampling to use wire-localized surgical biopsy rather than needle biopsy.

Time for a re-evaluation of mammography in the young? Results of an audit of mammography in women younger than 40 in a resource restricted environment

Mammography in younger women is considered to be of limited value. In a resource restricted environment without access to magnetic resonance imaging (MRI) and with a high incidence of breast cancer in the young, mammography remains an important diagnostic tool. Recent technical advances and better regulation of mammography make a reassessment of its value in these conditions necessary. Data of all the mammograms performed at a tertiary hospital and private breast clinic between January 2003 and July 2009 in women less than 40 years of age were collected. Indications were the presence of a mass, follow-up after primary cancer therapy, and screening for patients perceived at high risk due to a family history or the presence of atypical hyperplasia. Data acquired were as follows: Demographics, prior breast surgery, indication for mammography, outcome of mammography, diagnostic procedures, and their results. Of 2,167 mammograms, 393 were performed for a palpable mass, diagnostic mammography. In these, the overall cancer detection rate was 40%. If the mammography was reported as breast imaging reporting and data system (BIRADS(®)) 5 versus BIRADS(®) 3 and 4 versus BIRADS(®) 1 and 2, a final diagnosis of malignancy was established in 96, 48, and 5%, respectively. Of 367 mammograms done for the follow-up after primary treatment of breast cancer, seven cancers were diagnosed for a detection rate of 1.9%. Of 1,312 mammograms performed for screening, the recall rate was 4%; the biopsy rate 2%, and the cancer diagnosis rate 3/1,000 examinations. In contrast to past series, this series has shown that recent advances in mammography have made it a useful tool in the management of breast problems in young women, notably in a resource-restricted environment. Women for screening should be selected carefully.

Breast MRI in community practice: equipment and imaging techniques at facilities in the Breast Cancer Surveillance Consortium

PURPOSE

MRI is increasingly used for the detection of breast carcinoma. Little is known about breast MRI techniques among community practice facilities. The aim of this study was to evaluate equipment and acquisition techniques used by community facilities across the United States, including compliance with minimum standards by the ACRIN® 6667 Trial and the European Society of Breast Imaging.

METHODS

Breast Cancer Surveillance Consortium facilities performing breast MRI were identified and queried by survey regarding breast MRI equipment and technical parameters. Variables included scanner field strength, coil type, acquisition coverage, slice thickness, and the timing of the initial postcontrast sequence. Results were tallied and percentages of facilities meeting ACRIN® and European Society of Breast Imaging standards were calculated.

RESULTS

From 23 facilities performing breast MRI, results were obtained from 14 (61%) facilities with 16 MRI scanners reporting 18 imaging parameters. Compliance with equipment recommendations of ≥1.5-T field strength was 94% and of a dedicated breast coil was 100%. Eighty-three percent of acquisitions used bilateral postcontrast techniques, and 78% used slice thickness≤3 mm. The timing of initial postcontrast sequences ranged from 58 seconds to 8 minutes 30 seconds, with 63% meeting recommendations for completion within 4 minutes.

CONCLUSIONS

Nearly all surveyed facilities met ACRIN and European Society of Breast Imaging standards for breast MRI equipment. The majority met standards for acquisition parameters, although techniques varied, in particular for the timing of initial postcontrast imaging. Further guidelines by the ACR Breast MRI Accreditation Program will be of importance in facilitating standardized and high-quality breast MRI.

Probability of malignancy for lesions detected on breast MRI: a predictive model incorporating BI-RADS imaging features and patient characteristics

OBJECTIVES

To predict the probability of malignancy for MRI-detected breast lesions with a multivariate model incorporating patient and lesion characteristics.

METHODS

Retrospective review of 2565 breast MR examinations from 1/03-11/06. BI-RADS 3, 4 and 5 lesions initially detected on MRI for new cancer or high-risk screening were included and outcomes determined by imaging, biopsy or tumor registry linkage. Variables were indication for MRI, age, lesion size, BI-RADS lesion type and kinetics. Associations with malignancy were assessed using generalized estimating equations and lesion probabilities of malignancy were calculated.

RESULTS

855 lesions (155 malignant, 700 benign) were included. Strongest associations with malignancy were for kinetics (washout versus persistent; OR 4.2, 95% CI 2.5-7.1) and clinical indication (new cancer versus high-risk screening; OR 3.0, 95% CI 1.7-5.1). Also significant were age > = 50 years, size > = 10 mm and lesion-type mass. The most predictive model (AUC 0.70) incorporated indication, size and kinetics. The highest probability of malignancy (41.1%) was for lesions on MRI for new cancer, > = 10 mm with washout. The lowest (1.2%) was for lesions on high-risk screening, <10 mm with persistent kinetics.

CONCLUSIONS

A multivariate model shows promise as a decision support tool in predicting malignancy for MRI-detected breast lesions.

Incidental enhancing lesions found on preoperative breast MRI: management and role of second-look ultrasound

PURPOSE

This study prospectively assessed second-look ultrasound (US) for the evaluation of incidental enhancing lesions identified on preoperative breast magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Between 2004 and 2007, 182 patients with malignant breast lesions detected on US and/or X-ray mammography and confirmed by cytology/histology underwent preoperative breast contrast-enhanced (CE)-MRI. Patients with incidental lesions on breast MRI underwent second-look high-resolution US directed at the site of the incidental finding. Diagnosis of incidental lesions was based on biopsy or 24-month follow-up.

RESULTS

Breast MRI detected 55 additional lesions in 46/182 (25.2%) patients. Forty-two of 55 (76.3%) lesions were detected on second-look US in 38/46 (82.6%) patients. Malignancy was confirmed for 24/42 (57.1%) correlate lesions compared with 7/13 (53.8%) noncorrelate lesions. Second-look US depicted 8/9 (88.8%) Breast Imaging Reporting and Data System (BI-RADS) 5, 16/22 (72.7%) BI-RADS 4 and 18/24 (75%) BI-RADS 3 lesions. Sensitivity, specificity, accuracy and positive and negative predictive values for lesion detection/diagnosis was 100%, 88.9%, 94.6%, 90.3% and 100% for MRI and 64.3%, 70.4%, 67.3%, 69.2% and 65.5% for second-look US. Improved performance for US was obtained when masslike lesions only were considered.

CONCLUSIONS

Second-look US is a confirmatory method for incidental findings on breast MRI, particularly for mass-like lesions.

In newly diagnosed breast cancer, screening MRI of the contralateral breast detects mammographically occult cancer, even in elderly women: the mayo clinic in Florida experience

The role of magnetic resonance imaging (MRI) in patients with newly diagnosed breast cancer is somewhat controversial. The purpose of this study was to evaluate the prevalence of synchronous, occult contralateral breast cancer detected by MRI but not by mammography or clinical breast examination in women with newly diagnosed breast cancer, including those aged 70 years or older at our institution. MRI results for women with newly diagnosed breast cancer who underwent bilateral breast MRI after negative mammography and clinical examination between February 2003 and November 2007 at Mayo Clinic in Florida were reviewed. The prevalence of pathologically confirmed contralateral carcinoma diagnosed solely by MRI was determined and analyzed in the context of age, family history, menopausal status, breast density, and primary-tumor characteristics. Logistic regression was used to explore the association between contralateral carcinoma and potential patient risk factors. A total of 425 women were evaluated, of whom 129 (30%) were aged 70 years or older. A contralateral biopsy was recommended and performed solely on the basis of MRI in 72 of the 425 women (17%). Sixteen of these 72 women (22%) had pathologically confirmed carcinoma, including seven in the older subgroup. The prevalence of clinically and mammographically occult contralateral carcinoma detected by MRI was 3.8% (16/425) overall and 5.4% (7/129) in the group of older women. When potential risk factors for contralateral breast cancer were evaluated, postmenopausal status was the only significant predictor of contralateral cancer detected by MRI (p = 0.016). We concluded that contralateral breast screening with MRI should be considered in postmenopausal women with newly diagnosed breast cancer, even those aged 70 years or older at diagnosis.

Magnetic resonance imaging screening of the contralateral breast in women with newly diagnosed breast cancer: systematic review and meta-analysis of incremental cancer detection and impact on surgical management

PURPOSE

Preoperative magnetic resonance imaging (MRI) is increasingly used for staging women with breast cancer, including screening for occult contralateral cancer. This article is a review and meta-analysis of studies reporting contralateral MRI in women with newly diagnosed invasive breast cancer.

METHODS

We systematically reviewed the evidence on contralateral MRI, calculating pooled estimates for positive predictive value (PPV), true-positive:false-positive ratio (TP:FP), and incremental cancer detection rate (ICDR) over conventional imaging. Random effects logistic regression examined whether estimates were associated with study quality or clinical variables.

RESULTS

Twenty-two studies reported contralateral malignancies detected only by MRI in 131 of 3,253 women. Summary estimates were as follows: MRI-detected suspicious findings (TP plus FP), 9.3% (95% CI, 5.8% to 14.7%); ICDR, 4.1% (95% CI, 2.7% to 6.0%), PPV, 47.9% (95% CI, 31.8% to 64.6%); TP:FP ratio, 0.92 (95% CI, 0.47 to 1.82). PPV was associated with the number of test positives and baseline imaging. Few studies included consecutive women, and few ascertained outcomes in all subjects. Where reported, 35.1% of MRI-detected cancers were ductal carcinoma in situ (mean size = 6.9 mm), 64.9% were invasive cancers (mean size = 9.3 mm), and the majority were stage pTis or pT1 and node negative. Effect on treatment was inconsistently reported, but many women underwent contralateral mastectomy.

CONCLUSION

MRI detects contralateral lesions in a substantial proportion of women, but does not reliably distinguish benign from malignant findings. Relatively high ICDR may be due to selection bias and/or overdetection. Women must be informed of the uncertain benefit and potential harm, including additional investigations and surgery.

The importance of preoperative breast MRI for patients newly diagnosed with breast cancer

The use of preoperative breast magnetic resonance imaging (bMRI) for patients newly diagnosed with breast cancer has been criticized for increasing the number of therapeutic mastectomies performed, as well as increasing the cost of treatment. The purpose of this report is to examine one surgeon's practice and to describe the MRI findings for patients with breast cancer to determine if those findings changed the therapeutic options for those patients in. Data were collected prospectively between August 2003 and January 2006 for patients newly diagnosed with breast cancer. Diagnoses were made by core biopsy or fine-needle aspiration; all lesions were intact at the time of MRI. Twenty-five percent of patients were found to have previously occult, but suspicious lesions on MRI that required additional diagnostic evaluation, including ultrasound, core biopsy, excisional biopsy, or any combination; for approximately half of these patients a separate cancer was confirmed. For most of these patients, the new lesion was ipsilateral and multicentric, and most required mastectomy. For the remaining 75% of patients, MRI confirmed the index lesion was the only area of concern, and appropriate surgical treatment was completed. Preoperative bMRI for patients newly diagnosed with breast cancer identified previously occult and separate tumors in 13% of patients, resulting in surgical treatment change for many.

Gadobenate dimeglumine as a contrast agent for dynamic breast magnetic resonance imaging: effect of higher initial enhancement thresholds on diagnostic performance

RATIONALE AND OBJECTIVE

Gadobenate dimeglumine (Gd-BOPTA), a high-relaxivity contrast agent, has been recently proposed for dynamic MR imaging of the breast. The objective of this study was to optimize the diagnostic performance of Gd-BOPTA-enhanced dynamic breast MR imaging by using adjusted initial enhancement thresholds.

METHODS

Thirty-four patients with 36 breast lesions (malignant/benign = 28/8) underwent dynamic breast MRI with 0.1 mmol/kg Gd-BOPTA and 120-second time resolution. A score system based on shape (round/oval/lobular = 0; linear/dendritic/stellate = 1), margins (defined = 0; undefined = 1), pattern (homogeneous = 0; inhomogeneous = 1; rim = 2), kinetics (continuous = 0; plateau = 1; washout = 2), and initial enhancement was used. Initial enhancement was determined with standard (<50% = 0; 50%-100% = 1; >100% = 2) and adjusted (<100% = 0; 100%-240% = 1; >240% = 2) thresholds. Scores of 0 to 3 indicated benign lesions and scores of 4 to 8 malignant lesions. Diagnostic performance was assessed in terms of sensitivity, specificity, positive and negative predictive values, and overall accuracy.

RESULTS

The initial enhancement was >100% for 26 malignant and 7 benign lesions and >240% for 16 and 1 lesions, respectively. The overall score was 5.89 +/- 1.34 with standard thresholds and 5.50 +/- 1.53 with adjusted thresholds (P = 0.003) for cancers, 4.00 +/- 1.93 and 3.25 +/- 1.75 (P = 0.028) for benign lesions, respectively. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy was 96%, 13%, 79%, 50%, and 78%, respectively, with standard thresholds and 96%, 75%, 93%, 86%, and 92%, respectively, with adjusted thresholds. A ductal carcinoma in situ was false negative whereas a fat necrosis and a papilloma were false positive with both thresholds. Three fibroadenomas, 1 adenosis, and 1 fibrosis were false positive with standard thresholds but true negatives with adjusted thresholds.

CONCLUSIONS

Lesion characterization with Gd-BOPTA requires higher thresholds for initial enhancement than those used with conventional Gd-chelates, leading to improved specificity, predictive values, and accuracy.

[Magnetic resonance imaging in preoperative staging for breast cancer: pros and contras]

In oncologic patients, staging of the disease extent is of paramount importance. Imaging studies are used to decide whether the patient is a surgical candidate; if this is the case, imaging is used for detailed planning of the surgical procedure itself. Even in patients with limited prognosis, the first priority is always to achieve clear margins. Due to the widespread use of screening mammography, breast cancers are among the few cancers that are almost always diagnosed in an operable stage and are operated on with curative intention. It is well established that magnetic resonance imaging (MRI) is far superior to mammography (with and without concomitant ultrasound) for mapping the local extent of breast cancer. Accordingly, there is good reason to suggest that a pre-operative breast MRI should be considered an integral part of breast conserving treatment. Still, it is only rarely used in clinical practice. Arguments against its use are: Its high costs, allegedly high number of false positive findings, lack of MR-guided breast biopsy facilities, lack of evidence from randomized prospective trials and, notably, fear of "overtreatment". This paper discusses the reservations against staging MRI and weighs them against its clinical advantages. The point is made that radiologists as well as breast surgeons should be aware of the possibility of overtreatment, i.e. unnecessary mastectomy for very small, "MRI-only" multicentric cancer foci that would indeed be sufficiently treated by radiation therapy. There is a clear need to adapt the guidelines established for treatment of mammography-diagnosed multicentric breast cancer to account for the additional use of MRI for staging. Until these guidelines are available, the management of additional, "MRI-only" diagnosed small multicentric cancer manifestations must be decided on wisely and with caution. MRI for staging may only be done in institutions that can also offer an MR-guided tissue sampling, preferably by MR-guided vacuum assisted biopsy, to provide pre-operative histological proof of lesions visible by breast MRI alone.

A review of current evidence-based clinical applications for breast magnetic resonance imaging

Magnetic resonance imaging (MRI) is an important new tool for imaging of the breast. MRI has now been demonstrated to be the most sensitive imaging method for detecting breast carcinoma, allowing depiction of cancers that are occult on mammography, ultrasound, and clinical breast examination. This is tempered by imperfect specificity due to overlap in the features of benign and malignant lesions, and by higher examination cost and more limited availability compared to other breast imaging tests. This article describes the current evidence-based clinical indications for use of breast MRI. Specifically, MRI has been shown to be advantageous for cancer assessment for screening patients at high risk, evaluating patients with a new breast cancer diagnosis, monitoring patients undergoing neoadjuvant chemotherapy, and evaluating patients with metastatic axillary adenocarcinoma and unknown primary site. This tool has also been shown to be useful for the evaluation of silicone breast implant integrity. Employment of breast MRI as a problem solving technique for equivocal mammographic or clinical findings is controversial. For each of these clinical applications, the evidence regarding the diagnostic accuracy of breast MRI will be reviewed. An understanding of the current evidence will facilitate the most appropriate utilization of this important medical resource.

Accuracy and surgical impact of magnetic resonance imaging in breast cancer staging: systematic review and meta-analysis in detection of multifocal and multicentric cancer

PURPOSE We review the evidence on magnetic resonance imaging (MRI) in staging the affected breast to determine its accuracy and impact on treatment. METHODS Systematic review and meta-analysis of the accuracy of MRI in detection of multifocal (MF) and/or multicentric (MC) cancer not identified on conventional imaging. We estimated summary receiver operating characteristic curves, positive predictive value (PPV), true-positive (TP) to false positive (FP) ratio, and examined their variability according to quality criteria. Pooled estimates of the proportion of women whose surgery was altered were calculated. Results Data from 19 studies showed MRI detects additional disease in 16% of women with breast cancer (N = 2,610). MRI incremental accuracy differed according to the reference standard (RS; P = .016) decreasing from 99% to 86% as the quality of the RS increased. Summary PPV was 66% (95% CI, 52% to 77%) and TP:FP ratio was 1.91 (95% CI, 1.09 to 3.34). Conversion from wide local excision (WLE) to mastectomy was 8.1% (95% CI, 5.9 to 11.3), from WLE to more extensive surgery was 11.3% in MF/MC disease (95% CI, 6.8 to 18.3). Due to MRI-detected lesions (in women who did not have additional malignancy on histology) conversion from WLE to mastectomy was 1.1% (95% CI, 0.3 to 3.6) and from WLE to more extensive surgery was 5.5% (95% CI, 3.1 to 9.5). CONCLUSION MRI staging causes more extensive breast surgery in an important proportion of women by identifying additional cancer, however there is a need to reduce FP MRI detection. Randomized trials are needed to determine the clinical value of detecting additional disease which changes surgical treatment in women with apparently localized breast cancer.

Breast MRI for cancer detection and characterization: a review of evidence-based clinical applications

RATIONALE AND OBJECTIVES

Breast MRI is an important new tool in the imaging armamentarium for the detection and characterization of breast carcinoma. Understanding the evidence-supported benefits and potential harms of breast MRI is important to ensure the appropriate utilization of this medical resource.

MATERIALS AND METHODS

This article reviews the clinical settings in which MRI for breast cancer assessment has been shown to be advantageous. The evidence regarding the diagnostic accuracy of MRI and the impact of this imaging tool on clinical outcomes are described. Novel breast MRI techniques which may lead to future improvements in performance are discussed.

RESULTS

Breast MRI has been shown in multiple studies to be advantageous for screening patients at high risk, evaluating patients with a new breast cancer diagnosis, monitoring treatment response in patients undergoing neoadjuvant chemotherapy and evaluating patients with metastatic axillary adenocarcinoma and unknown primary site. Among the limitations of MRI are its high cost and modest specificity resulting in false positive examinations.

CONCLUSIONS

When used in evidence-supported clinical settings, the high sensitivity of MRI results in earlier cancer detection or greater accuracy of detection compared to existing tests for breast carcinoma. Further scientific endeavors are crucial to optimize the future performance and application of breast MRI.

Bilateral synchronous breast cancer in an Asian population: mammographic and sonographic characteristics, detection methods, and staging

OBJECTIVE

This study was performed to compare the clinical and radiologic findings and pathologic staging between index cancer and contralateral synchronous breast cancers and to determine the roles of mammography and sonography in their detection.

CONCLUSION

Additional contralateral breast cancers in bilateral synchronous breast cancers are apt to be small and less palpable and to have less suspicious imaging findings and less advanced cancer staging than the index cancer. Bilateral whole-breast sonography with mammography is useful in the early detection of contralateral synchronous breast cancer.

Current Status of Breast MR Imaging Part 2. Clinical Applications

Magnetic resonance (MR) imaging is emerging as the most sensitive modality that is currently available for the detection of primary or recurrent breast cancer. Although this technique has been shown to be an extremely powerful diagnostic tool, it is still relatively rarely used in clinical practice, as compared with other applications of MR imaging such as for musculoskeletal or brain and spine imaging. This is the second of a two-part series on the current status of breast MR. Part two provides an overview of the use of breast MR imaging in clinical patient care, the body of evidence that supports its use. A discussion is provided on the many controversies that exist regarding breast MR imaging for preoperative staging and for screening.

The use of magnetic resonance imaging in breast cancer screening

Screening mammography is a powerful tool for reducing breast cancer mortality. Mammography can often detect clinically occult, early-stage breast cancer that is amenable to successful treatment. However, mammography is not a perfect test and has lower sensitivity in young women and in those with dense breasts. Magnetic resonance imaging (MRI) has been shown to depict breast cancers that are occult to other forms of detection, including mammography. This has generated interest in the use of MRI for breast cancer screening. Although preliminary studies in highly selected populations show promise for the potential efficacy of breast cancer screening with MRI, there are many questions that should be addressed before this technique is offered to the general population.

Contrast-enhanced MR mammography for evaluation of the contralateral breast in patients with diagnosed unilateral breast cancer or high-risk lesions

PURPOSE

To prospectively evaluate accuracy of gadobenate dimeglumine-enhanced magnetic resonance (MR) mammography for depiction of synchronous contralateral breast cancer in patients with newly diagnosed unilateral breast cancer or high-risk lesions, with histologic analysis or follow-up as reference.

MATERIALS AND METHODS

The study had ethics committee approval; all patients provided written informed consent. One hundred eighteen consecutive women (mean age, 52 years) with unilateral breast cancer or high-risk lesions and negative findings in the contralateral breast at physical examination, ultrasonography, and conventional mammography underwent gadobenate dimeglumine-enhanced 1.5-T MR mammography. Transverse three-dimensional T1-weighted gradient-echo images were acquired before and at 0, 2, 4, 6, and 8 minutes after gadobenate dimeglumine administration (0.1 mmol per kilogram body weight). Breast Imaging Reporting and Data System (BI-RADS) was used to categorize breast density and the level of suspicion for malignant contralateral breast lesions. Results were compared with histologic findings. Sensitivity, specificity, accuracy, and positive and negative predictive values for contrast-enhanced MR mammography were evaluated.

RESULTS

Contrast-enhanced MR mammography revealed contralateral lesions in 28 (24%) of 118 patients. Twenty-four lesions were detected in patients with dense breasts (BI-RADS breast density category III or IV). Lesions in eight (29%) of 28 patients were BI-RADS category 4; patients underwent biopsy. Lesions in 20 (71%) patients were BI-RADS category 5; patients underwent surgery. At histologic analysis, 22 lesions were confirmed as malignant; six lesions were fibroadenomas. No false-negative lesions were detected; none of the fibroadenomas were BI-RADS category 5. The sensitivity, specificity, accuracy, and positive and negative predictive values of contrast-enhanced MR mammography for depiction of malignant or high-risk contralateral lesions were 100%, 94%, 95%, 79%, and 100%, respectively. Follow-up findings (12-24 months) confirmed absence of contralateral lesions in 90 of 118 patients with negative contrast-enhanced MR mammographic findings in the contralateral breast.

CONCLUSION

Contrast-enhanced MR mammography is accurate for detection of synchronous contralateral cancer or high-risk lesions in patients with newly diagnosed breast cancer or high-risk lesions.

Role of pre-surgical breast MRI in the management of invasive breast carcinoma

The purpose of the study was to assess the role of preoperative breast magnetic resonance imaging (MRI) as a complementary tool to routine imaging methods in the management of women affected by invasive breast carcinoma. Mammograms, sonograms and biopsy results of 121 breasts in 118 women affected by invasive breast carcinoma, who underwent pre-surgical breast MR, were re-examined to identify patients theoretically eligible for conservative surgery instead of radical mastectomy. Surgery effectively performed was evaluated to identify cases for which MRI determined a change in management. The gold standard was the final pathology. Breast MRI determined an overall change in management in 22 out of 121 breasts (18.2%), and in two out of 87 breasts (25.3%) in patients eligible for conservative surgery. In the evaluation of single breasts, MRI resulted in true-positive in 22 out of 29 breasts (75.9%), false-positive in 7 out of 29 breasts (24.1%), leading to over-treatment in women whose treatment was changed from conservative surgery to radical mastectomy. MRI sensitivity in the detection of additional foci not seen on conventional imaging was 57.4%, overall sensitivity 87.4%, sensitivity for invasive cancers 93.1%, while for ductal carcinoma in situ it was 58.8%. In conclusion, breast MRI determines a significant change in the management of patients affected by invasive breast carcinoma, particularly in patients eligible for conservative surgery after standard breast examination.

MRI evaluation of the contralateral breast in women with recently diagnosed breast cancer

BACKGROUND

Even after careful clinical and mammographic evaluation, cancer is found in the contralateral breast in up to 10% of women who have received treatment for unilateral breast cancer. We conducted a study to determine whether magnetic resonance imaging (MRI) could improve on clinical breast examination and mammography in detecting contralateral breast cancer soon after the initial diagnosis of unilateral breast cancer.

METHODS

A total of 969 women with a recent diagnosis of unilateral breast cancer and no abnormalities on mammographic and clinical examination of the contralateral breast underwent breast MRI. The diagnosis of MRI-detected cancer was confirmed by means of biopsy within 12 months after study entry. The absence of breast cancer was determined by means of biopsy, the absence of positive findings on repeat imaging and clinical examination, or both at 1 year of follow-up.

RESULTS

MRI detected clinically and mammographically occult breast cancer in the contralateral breast in 30 of 969 women who were enrolled in the study (3.1%). The sensitivity of MRI in the contralateral breast was 91%, and the specificity was 88%. The negative predictive value of MRI was 99%. A biopsy was performed on the basis of a positive MRI finding in 121 of the 969 women (12.5%), 30 of whom had specimens that were positive for cancer (24.8%); 18 of the 30 specimens were positive for invasive cancer. The mean diameter of the invasive tumors detected was 10.9 mm. The additional number of cancers detected was not influenced by breast density, menopausal status, or the histologic features of the primary tumor.

CONCLUSIONS

MRI can detect cancer in the contralateral breast that is missed by mammography and clinical examination at the time of the initial breast-cancer diagnosis. (ClinicalTrials.gov number, NCT00058058 [ClinicalTrials.gov].).

MRI compared to conventional diagnostic work-up in the detection and evaluation of invasive lobular carcinoma of the breast: a review of existing literature

Purpose

The clinical diagnosis and management of invasive lobular carcinoma (ILC) of the breast presents difficulties. Magnetic resonance imaging (MRI) has been proposed as the imaging modality of choice for the evaluation of ILC. Small studies addressing different aspects of MRI in ILC have been presented but no large series to date. To address the usefulness of MRI in the work-up of ILC, we performed a review of the currently published literature.

Materials and methods

We performed a literature search using the query “lobular AND (MRI OR MR OR MRT OR magnetic)” in the Cochrane library, PubMed and scholar.google.com, to retrieve all articles that dealt with the use of MRI in patients with ILC. We addressed sensitivity, morphologic appearance, correlation with pathology, detection of additional lesions, and impact of MRI on surgery as different endpoints. Whenever possible we performed meta-analysis of the pooled data.

Results

Sensitivity is 93.3% and equal to overall sensitivity of MRI for malignancy in the breast. Morphologic appearance is highly heterogeneous and probably heavily influenced by interreader variability. Correlation with pathology ranges from 0.81 to 0.97; overestimation of lesion size occurs but is rare. In 32% of patients, additional ipsilateral lesions are detected and in 7% contralateral lesions are only detected by MRI. Consequently, MRI induces change in surgical management in 28.3% of cases.

Conclusion

This analysis indicates MRI to be valuable in the work-up of ILC. It provides additional knowledge that cannot be obtained by conventional imaging modalities which can be helpful in patient treatment.

Multicentric granulocytic sarcoma of the breast: mammographic, sonographic, and MR findings

A rare case of granulocytic sarcoma (GS) of the bilateral breasts after complete remission of acute myelogenous leukemia is reported. Mammogram showed multiple irregular high-density masses, and sonogram demonstrated multiple irregular low-echoic masses with a posterior shadow in the bilateral mammary glands. Contrast-enhanced MR images showed multiple irregular enhancing masses. None of those findings were pathognomonic of GS. However, MR image was useful to evaluate the response of the chemotherapy and detect the nonpalpable relapse tumor and determine the introduction of the radiation therapy early.

Magnetic resonance imaging of breast lesions--a pathologic correlation

Magnetic resonance imaging of the breast is useful in assessing breast lesions. An understanding of the pathologic characteristics of the tumors may help to understand these magnetic resonance imaging observations.Large lesional size (>10 mm), ill-defined margin, and irregular outlines are associated with malignancy. These correlate with the pathological features of breast tumor, characterized by rapid growth rate, large size, and infiltrative growth pattern, invasion into stroma resulting in desmoplasia, and hence irregular outline and margin. The detection and estimation of tumor extent of invasive lobular carcinoma is problematic, even with magnetic resonance imaging, which is considered the most sensitivity. This inaccuracy likely derives from the characteristic linear, single cells infiltration growth pattern of the tumor, which is also often underestimated by clinical examination. Estimation of tumor extent after neoadjuvant chemotherapy is also essential but problematic by imaging, as the shrunken tumor becomes fibrotic, with stromal hyalinization, diminished microvasculature and tumor break up causing size underestimation. Non-enhancement of breast tumors occurs in about 8% of cases correlates with diffuse growth pattern, particularly of infiltrative lobular carcinoma. The observation of disproportionately high non-enhancing ductal carcinoma in situ remains an enigma. Finally, early rim enhancement correlates with small cancer nests, low ratio of peripheral to central fibrosis and high ratio of peripheral to central microvessel density. These may be related to increased vascular endothelial growth factor mediated increased microvessel density as well as increased permeability, which manifest as increased rapid contrast uptake and dissipation.

Overall Breast Density in MR Mammography

The objective of this study was to assess the efficacy of MR mammography (MRM) in evaluating breast cancer extent in women with fatty or dense breasts, and its contribution to the therapeutic approach. The authors reviewed 97 carcinomas detected in 93 women (both symptomatic and from screening) that were classified in two groups according to breast density pattern. Mammography, ultrasound (US), and MRM were performed to evaluate size, extension of the in situ component, presence of multifocal/multicentric disease, and contralateral involvement. Results obtained on mammography plus US were balanced against MRM, considering pathologic analysis as the gold standard. For fatty breasts (n=47), exact measurement was found on mammography plus US and on MRM alone in 70%, underestimation on mammography plus US 23.5% and on MRM 11% (P=0.005). For dense breasts (n=50), exact measurement was found on mammography plus US in 40% and on MRM alone 68%, underestimation on mammography plus US 52% and on MRM 10% (P=0.005). Overall, good correlation (R>0.71) was found between pathologic and clinical size with all imaging methods; nevertheless, when evaluating multifocal/multicentric disease, a poor correlation was observed between histologic assessment and mammography plus US (R=0.52), but it was excellent with regard to MRM (R=0.99). In fatty breasts, the combination of mammography and US allows for a precise assessment of tumoral extension. However, these results show that in dense breasts, MRM is superior to mammography plus US, suggesting that its systematic use in this group of patients is justifiable.

Added cancer yield of MRI in screening the contralateral breast of women recently diagnosed with breast cancer: results from the International Breast Magnetic Resonance Consortium (IBMC) trial

OBJECTIVE

To estimate the added cancer yield of magnetic resonance imaging (MRI) over mammography in the contralateral breast of patients with a recent diagnosis of breast cancer.

METHODS

We conducted a prospective, international study of mammography and MRI in women with a recent diagnosis of unilateral breast cancer. Each subject received a mammogram, clinical breast exam (CBE), and MRI of the unaffected breast within a 90 day time period. Definitive diagnosis of suspicious findings was determined through biopsy and central pathology review.

RESULTS

Of the 103 eligible women included in study analyses, MRI detected 4 cancers in the contralateral breast while mammography detected none. MRI resulted in 12% (95% CI, 6%-20%) of women recommended for biopsy and 10% of women undergoing additional biopsy. The added cancer yield of MRI was 4% (95% CI, 1%-10%) and the positive predictive value of an abnormal MRI was 33% (95% CI, 10%-65%). Forty percent (4/10) of the biopsies performed based on the MRI recommendation were positive for malignancy.

CONCLUSION

In women with a recent breast cancer diagnosis, approximately 4% will have an otherwise occult invasive breast cancer detected in the opposite breast by MRI alone.

The role of magnetic resonance imaging in diagnosis and management of breast cancer

A review of the literature on the current applications of breast magnetic resonance imaging (MRI) indications, their rationale and their place in diagnosis and management of breast cancer was given. Contrast-enhanced breast MRI is developing as a valuable adjunct to mammography and sonography. Its high sensitivity for invasive breast cancer establishes its superiority in evaluation of multifocality/multicentricity, tumor response to neoadjuvant chemotherapy, detection of recurrence, and staging. Emerging applications include spectroscopy, usage of new contrast agents, and MRI-guided interventions, including noninvasive treatment of breast cancer. Its potential benefit in screening high-risk women has yet to be established with prospective studies, particularly with regard to false positive results.

ADC Mapping of Benign and Malignant Breast Tumors

PURPOSE

The purpose of this study was to investigate the utility of diffusion-weighted imaging (DWI) and the apparent diffusion coefficient (ADC) value in differentiating benign and malignant breast lesions and evaluating the detection accuracy of the cancer extension.

MATERIALS AND METHODS

We used DWI to obtain images of 191 benign and malignant lesions (24 benign, 167 malignant) before surgical excision. The ADC values of the benign and malignant lesions were compared, as were the values of noninvasive ductal carcinoma (NIDC) and invasive ductal carcinoma (IDC). We also evaluated the ADC map, which represents the distribution of ADC values, and compared it with the cancer extension.

RESULTS

The mean ADC value of each type of lesion was as follows: malignant lesions, 1.22+/-0.31 x 10(-3) mm2/s; benign lesions, 1.67+/-0.54 x 10(-3) mm2/s; normal tissues, 2.09+/-0.27 x 10(-3) mm2/s. The mean ADC value of the malignant lesions was statistically lower than that of the benign lesions and normal breast tissues. The ADC value of IDC was statistically lower than that of NIDC. The sensitivity of the ADC value for malignant lesions with a threshold of less than 1.6 x 10(-3) mm2/s was 95% and the specificity was 46%. A full 75% of all malignant cases exhibited a near precise distribution of low ADC values on ADC maps to describe malignant lesions. The main causes of false negative and underestimation of cancer spread were susceptibility artifact because of bleeding and tumor structure. Major histologic types of false-positive lesions were intraductal papilloma and fibrocystic diseases. Fibrocystic diseases also resulted in overestimation of cancer extension.

CONCLUSIONS

DWI has the potential in clinical appreciation to detect malignant breast tumors and support the evaluation of tumor extension. However, the benign proliferative change remains to be studied as it mimics the malignant phenomenon on the ADC map.

Sensitivity of MRI versus mammography for detecting foci of multifocal, multicentric breast cancer in Fatty and dense breasts using the whole-breast pathologic examination as a gold standard

OBJECTIVE

Our aim was to compare the effectiveness of mammography and MRI in the detection of multifocal, multicentric breast cancer.

SUBJECTS AND METHODS

Ninety patients with planned mastectomies (nine bilateral) underwent mammography and dynamic gadolinium-enhanced MRI. Off-site reviewers aware of the entry criterion (planned mastectomy) evaluated both examinations for the presence of malignant foci, recording the density pattern on mammography. The gold standard was pathologic examination of the whole excised breast (slice thickness, 5 mm).

RESULTS

Of 99 breasts, pathologic findings revealed 52 unifocal, 29 multifocal, and 18 multicentric cancers for a total of 188 malignant foci (158 invasive and 30 in situ). Overall sensitivity was 66% (124/188) for mammography and 81% (152/188) for MRI (p < 0.001); 72% (113/158) and 89% (140/158) for invasive foci (p < 0.001); and 37% (11/30) and 40% (12/30) for in situ foci (p > 0.05, not significant), respectively. Mammography and MRI missed 64 and 36 malignant foci, respectively, with median diameters of 8 and 5 mm (p = 0.033) and an invasive-noninvasive ratio of 2.4:1 (45:19) and 1.0:1 (18:18) (p = 0.043), respectively. The overall positive predictive value (PPV) was 76% (124/164) for mammography and 68% (152/222) for MRI (not significant). In breasts with an almost entirely fatty pattern, sensitivity was 75% for mammography and 80% for MRI (not significant), and the PPV was 73% and 65% (not significant), respectively. In breasts with fibroglandular or dense pattern, the sensitivity was 60% and 81% (p < 0.001), and the PPV was 78% and 71% (not significant), respectively.

CONCLUSION

MRI was more sensitive than mammography for the detection of multiple malignant foci in fibroglandular or dense breasts. Mammography missed larger and more invasive cancer foci than MRI. A relatively low PPV was a problem for both techniques.

Diagnostic accuracy of mammography, clinical examination, US, and MR imaging in preoperative assessment of breast cancer

PURPOSE

To prospectively assess accuracy of mammography, clinical examination, ultrasonography (US), and magnetic resonance (MR) imaging in preoperative assessment of local extent of breast cancer.

MATERIALS AND METHODS

Institutional review board approval and informed patient consent were obtained. Results of bilateral mammography, US, and contrast-enhanced MR imaging were analyzed from 111 consecutive women with known or suspected invasive breast cancer. Results were correlated with histopathologic findings.

RESULTS

Analysis included 177 malignant foci in 121 cancerous breasts, of which 89 (50%) foci were palpable. Median size of 139 invasive foci was 18 mm (range, 2-107 mm). Mammographic sensitivity decreased from 100% in fatty breasts to 45% in extremely dense breasts. Mammographic sensitivity was highest for invasive ductal carcinoma (IDC) in 89 of 110 (81%) cases versus 10 of 29 (34%) cases of invasive lobular carcinoma (ILC) (P < .001) and 21 of 38 (55%) cases of ductal carcinoma in situ (DCIS) (P < .01). US showed higher sensitivity than did mammography for IDC, depicting 104 of 110 (94%) cases, and for ILC, depicting 25 of 29 (86%) cases (P < .01 for each). US showed higher sensitivity for invasive cancer than DCIS (18 of 38 [47%], P < .001). MR showed higher sensitivity than did mammography for all tumor types (P < .01) and higher sensitivity than did US for DCIS (P < .001), depicting 105 of 110 (95%) cases of IDC, 28 of 29 (96%) cases of ILC, and 34 of 38 (89%) cases of DCIS. In anticipation of conservation or no surgery after mammography and clinical examination in 96 breasts, additional tumor (which altered surgical approach) was present in 30. Additional tumor was depicted in 17 of 96 (18%) breasts at US and in 29 of 96 (30%) at MR, though extent was now overestimated in 12 of 96 (12%) at US and 20 of 96 (21%) at MR imaging. After combined mammography, clinical examination, and US, MR depicted additional tumor in another 12 of 96 (12%) breasts and led to overestimation of extent in another six (6%); US showed no detection benefit after MR imaging. Bilateral cancer was present in 10 of 111 (9%) patients; contralateral tumor was depicted mammographically in six and with both US and MR in an additional three. One contralateral cancer was demonstrated only clinically.

CONCLUSION

In nonfatty breasts, US and MR imaging were more sensitive than mammography for invasive cancer, but both MR imaging and US involved risk of overestimation of tumor extent. Combined mammography, clinical examination, and MR imaging were more sensitive than any other individual test or combination of tests.

Problem solving MR imaging of the breast

MR imaging is emerging as a valuable adjunct to mammography and ultrasound for the evaluation of the breast. Breast MR imaging has high sensitivity for the detection of breast cancer but suffers from a relatively low specificity. There is growing experience with this imaging modality as applied to breast diseases and more standardization in obtaining and interpreting these examinations is occurring, including the introduction ofa reporting lexicon similar to that for mammography. Breast MR imaging can be used for problem solving in determination of the local extent of disease in women with newly diagnosed breast cancer and for the evaluation of cases that remain inconclusive despite thorough mammographic and sonographic evaluation.

Contrast-enhanced MR imaging of breast lesions and effect on treatment

PURPOSE

To assess the value of local staging with preoperative magnetic resonance imaging (MRI) in patients with suspect breast lesions and the effect on therapeutic approach.

MATERIALS AND METHODS

Two hundred and four consecutive women with suspect breast lesions on clinical examination (CE) and/or mammography (MX) and/or ultrasound (US) underwent preoperative contrast-enhanced MRI. Detection of multifocal, multicentric and bilateral breast cancer by all three imaging modalities was evaluated. Results of preoperative breast MRI were discussed with the treating surgeons. The type of therapeutic change after preoperative MRI was marked on a questionnaire (none, additional fine needle aspiration, core biopsy, open biopsy, wider excision, mastectomy) and considered 'necessary' or 'unnecessary' using final histopathological results as gold standard.

RESULTS

In 170 patients, breast cancer was diagnosed. MRI detected 96% of multifocal disease and 95% of multicentric disease, whereas MX depicted 37 and 18%, and US 41 and 9% of them, respectively. All bilateral breast cancers were seen on MRI; both MX and US detected 56%. Findings of more extensive disease and unsuspected multiple breast cancer foci identified on MRI only, changed the therapeutic approach correctly in 30.6% of breast cancer patients. Nine unnecessary wider excisions and three unnecessary FNA/core biopsies were performed because MRI overestimated the number or size of malignant lesions.

CONCLUSION

Preoperative breast MRI is an important adjunct to conventional imaging in the loco-regional staging of breast cancer and a useful tool in treatment planning.

Locally advanced breast cancer: comparison of mammography, sonography and MR imaging in evaluation of residual disease in women receiving neoadjuvant chemotherapy

The accuracy of mammography, sonography and magnetic resonance imaging (MRI) in identifying residual disease after neoadjuvant chemotherapy is evaluated and imaging findings are correlated with pathologic findings. Fifteen patients enrolled in an experimental protocol of preoperative neoadjuvant chemotherapy underwent clinical examination, mammography, sonography and dynamic MRI, performed in this order, before and respectively after 2 and 4 cycles of neoadjuvant chemotherapy. Four radiologists, two for mammography, one for sonography and one for MR, examined the images, blinded to the results of the other examinations. All patients underwent radical or conservative surgery, and imaging findings were compared with pathologic findings. MRI identified 2/15 (13.3.%) clinically complete response (CR), 9/15 (60%) partial response (PR), 3/15 (20%) stable disease (SD) and 1/15 (6.7%) progressive disease. Mammography identified 1/15 (6.7%) clinically CR, 8/15 (53.3%) PR and 4/15 (27%) SD, and was not able to evaluate the disease in 2/15 (13%) cases. Sonography presented the same results as MRI. Therefore, MRI and sonography compared to mammography correctly identified residual disease in 100 vs. 86%. MRI resulted in two false-negative results because of the presence of microfoci of in situ ductal carcinoma (DCIS) and invasive lobular carcinoma (LCI). MRI was superior to mammography in cases of multifocal or multicentric disease (83 vs. 33%). Sonography performed after MRI improves the accuracy in evaluation of uncertain foci of multifocal disease seen on MR images with an increase of diagnostic accuracy from 73 to 84.5%. MRI assesses response to neoadjuvant chemotherapy better than traditional methods of physical examination and mammography.

Breast MR imaging in a patient with unilateral axillary lymphadenopathy and unknown primary malignancy

Bilateral invasive breast cancers were detected on MR imaging in a patient with left unilateral axillary lymphadenopathy and normal findings at physical examination, mammography, and ultrasound of both breasts. One spiculated and a second ill-defined enhancing lesion in the left breast as well as a superficial circumscribed lesion in the right breast were proven to be invasive malignancies. In patients with isolated axillary lymph nodes and occult primary malignancy, breast MRI can identify or exclude the breast as primary site, which proves the superiority and diagnostic benefit of this imaging method and also its contribution to the therapeutic approach.

Outcome analysis and rational management of enhancing lesions incidentally detected on contrast-enhanced MRI of the breast

OBJECTIVE

The purpose of our study was to assess the prevalence, characteristics, and clinical consequence of incidentally detected enhancing lesions on MRI of the breast. SUBJECTS AND METHODS. MRI of the breast (1.0-T scanner, dynamic gadolinium-enhanced T1-weighted three-dimensional gradient-echo sequence, double breast coil) was performed on 1273 women for different indications. Enhancing incidental lesions were defined as enhancing lesions on MRIs that were not expected from findings on the previous conventional imaging. They were classified in five assessment categories using a scoring system based on morphologic and kinetic enhancement characteristics. Detection of enhancing incidental lesions resulted in a review of mammograms and sonograms with the aim of also localizing these lesions on conventional imaging. The lesions were either biopsied or followed up.

RESULTS

Twenty-five percent (274/1086) of all enhancing lesions detected in the study population were enhancing incidental lesions. Enhancing incidental lesions were found in 16% (210/1273) of all study patients. Forty-one percent (113/274) of the enhancing incidental lesions were histologically confirmed. Forty-eight percent (54/113) of the biopsied and 20% (54/274) of all enhancing incidental lesions were malignant. Eleven percent (54/508) of all malignant lesions occurring in the 1273 women were detected solely through additional MRI. Fifty-seven percent (31/54) of these MRI-detected malignant lesions could be identified on a reevaluation of sonograms and mammograms.

CONCLUSION

Detection of enhancing incidental lesions should lead to a thorough reevaluation of mammograms and sonograms. If not reidentified, suspicious enhancing incidental lesions should be biopsied, and enhancing incidental lesions that are probably benign should be carefully followed up. Indeterminate enhancing incidental lesions should be histologically examined by minimally invasive techniques or, if they are small, followed up by another MRI 6 months later.

MR imaging screening of the contralateral breast in patients with newly diagnosed breast cancer: preliminary results

PURPOSE

To investigate the role of screening magnetic resonance (MR) imaging in the detection of synchronous contralateral breast cancer in patients with newly diagnosed breast cancer.

MATERIALS AND METHODS

Between January 1999 and July 2001, 182 patients with newly diagnosed breast cancer (after either core or excisional biopsy with positive or close margins of resection) underwent bilateral contrast material-enhanced MR imaging at 1.5 T with a dedicated bilateral breast multicoil array. The contralateral breast was imaged for cancer screening. Family history of breast cancer, index cancer histology, breast density, and age at diagnosis of first breast cancer were assessed as potential risk factors for synchronous contralateral breast cancer.

RESULTS

Fifteen patients (8.2%) had a suspicious enhancing lesion depicted in the contralateral breast. Seven patients (3.8%) had malignant results: ductal carcinoma in situ (DCIS) in four, invasive ductal carcinoma with DCIS in two, and invasive ductal carcinoma in one. Eight patients (4.4%) had benign results: fibrocystic changes in four, atypical ductal hyperplasia in two, atypical lobular hyperplasia and focal lobular carcinoma in situ in one, and ductal hyperplasia in one. Six patients with negative MR findings underwent prophylactic mastectomy; no malignancy was found. No significant differences were noted among patients with true-positive (n = 7), false-positive (n = 8), or negative (n = 167) MR findings with regard to family history of breast cancer (P <.27), index cancer histology (P <.19), breast density (P <.34), or age at diagnosis of first breast cancer (P <.10).

CONCLUSION

The preliminary results demonstrate the feasibility of using MR imaging of the breast in a screening role, specifically to evaluate the contralateral breast in patients with newly diagnosed breast cancer to detect mammographically and clinically occult synchronous breast cancer.

Preoperative assessment of breast cancer: sonography versus MR imaging

OBJECTIVE

The purposes of our study were to compare the diagnostic value of whole-breast sonography and MR imaging as adjunctive techniques to mammography and to determine whether MR imaging should be used routinely in the preoperative assessment of patients with suspected breast cancer.

SUBJECTS AND METHODS

. One hundred four women (age range, 34-84 years; mean age, 60 years) with findings highly suggestive of malignancy in the breast were examined with mammography, sonography, and dynamic MR imaging before undergoing surgery. All visualized suspicious lesions were correlated histologically. The diagnostic relevance of sonographic and MR imaging findings was compared with the diagnostic value of the findings of clinical examination and mammography alone.

RESULTS

. Twenty-seven tumors showed multifocal or multicentric invasive growth at pathology. Of these 27, 48% were correctly diagnosed via mammography alone; 63%, via the combination of mammography and sonography; and 81%, via MR imaging. Nine of the index tumors were invisible on mammography but were detected on sonography. Use of sonography benefited 13 patients and produced two studies with false-positive findings. Use of MR imaging benefited seven patients and produced eight studies with false-positive findings. In summary, 93% of all patients gained no advantage from MR imaging. Relevant additional findings were significantly more frequent in patients with dense breasts.

CONCLUSION

Although MR imaging is most sensitive for the detection of small tumors, routine preoperative MR imaging appears to be unnecessary for most patients if a combination of mammography and whole-breast sonography is used. Additional MR imaging can be restricted to problematic cases in women with dense breast parenchyma.