Accuracy Of Breast Magnetic Resonance Imaging Research Articles

Abstract P2-10-02: Impact of neoadjuvant treatment on the accuracy of breast MRI and calliper in premenopausal ER-positive, HER2-negative, and node-positive breast cancer patients: Prospective phase III clinical trial

Abstract Background: Improved understanding of factors affecting the accuracy of breast MRI after NST can lead to more tailored use of MRI in deciding surgical extent after NST. Purpose: To investigate whether the accuracy of magnetic resonance imaging (MRI) and caliper predicting residual tumor extent is affected by neoadjuvant treatment in estrogen receptor (ER) positive and HER2-negative, lymph node-positive, premenopausal breast cancer breast cancer. Materials and Methods: We analyzed the imaging and clinicopathologic data of 123 patients in phase 3, randomized clinical trial (NCT01622361), which compared neoadjuvant chemotherapy (NCT) with neoadjuvant endocrine therapy (NET) in estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-), lymph node (LN)-positive, premenopausal breast cancer patients. In this study, we compared the largest size of MRI and Caliper after neoadjuvant treatment with one of pathology. Results: In patient with discrepancy in predicting response to NST, the measurement (MRI or caliper) that predict as non-response (SD or PD) was more accurate in both of NCT and NET group (ICC, Intraclass correlation coefficient, MRI; 0.84, 95% CI 0.616-0.942, Caliper;0.75, 95% CI 0.303-0.931). The accuracy of MRI was better in NCT group than in NET group (ICC 0.86; 95% CI 0.626-0.956 for NCT, 0.47; 95%CI 0.133-0.708 for NET). The mean absolute discrepancies (largest size by MRI or caliper -largest size in pathology) for the MRI and Caliper were, respectively, -0.78cm and -1.04cm in NCT group and -0.44cm and -1.32cm in NET group (p > 0.05). The proportion of discrepancy >1cm or >0.5cm were not significantly difference between NCT and NET groups among MRI and Caliper. Conclusion: In ER-positive, HER2-negative, lymph node-positive breast cancer, both MRI and caliper tend to overestimate residual tumor size than pathology in NET group compare to NCT group. When MRI and caliper show discrepancy in predicting response to NST, the measurement (MRI or caliper) that predict as non-response (SD or PD) was more accurate in both of NCT and NET group. These factors should be considered for deciding the evaluation method of response and surgical decision after NST and surgical decision in this subgroup. REGISTRATION: ClinicalTrials.gov identifier: NCT01622361 Citation Format: Sungchan Gwark, Sei Hyun Ahn, Jong Won Lee, Byung Ho Son, Beom Seok Ko, Jisun Kim, Il-Yong Chung, Sae Byul Lee, Jin-Hee Ahn, Kyung Hae Jung, Sung-Bae Kim, Hee Jin Lee, Gyungyub Gong, Hee Jeong Kim. Impact of neoadjuvant treatment on the accuracy of breast MRI and calliper in premenopausal ER-positive, HER2-negative, and node-positive breast cancer patients: Prospective phase III clinical trial [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-10-02.

Breast MRI for Evaluating Residual Tumor Size Following Neoadjuvant Chemotherapy: Clinicopathologic Factors and MRI Imaging Features Affecting its Accuracy.

The aim of the study was to investigate the accuracy of breast Magnetic Resonance Imaging (MRI) for evaluating residual tumor size following Neoadjuvant Chemotherapy (NAC) and to identify clinicopathologic and MRI features affecting its accuracy. We retrospectively assessed 109 women who underwent preoperative Dynamic Contrast-Enhanced (DCE) MRI following NAC and subsequent surgery between April 2016 and August 2020. Preoperative MRI features, including Breast Imaging Reporting and Data System lexicon characteristics, size of residual enhancing lesion, tumor shrinkage pattern, and clinicopathologic features, were investigated, and MRI and pathology findings were compared. Residual tumor size on MRI showed high agreement with residual invasive tumor size on pathologic examination (ICC, 0.808, p<0.001). The residual tumor size measured by MRI and final pathologic size were concordant in 63/109 cases (57.8%), while MRI overestimated the size in 35/109 cases (32.1%). For estrogen receptor (ER)-positive/human epidermal growth factor receptor 2 (HER2)-negative tumors, MRI tended to underestimate the residual tumor size compared with HER2-positive cancers (p=0.002) and triple-negative cancers (p=0.12). On MRI, tumors with concentric shrinkage patterns after NAC showed less size discrepancy with final pathologic tumor size than those with non-concentric patterns (p=0.026). In ER-positive/HER2-negative cancers, MRI tends to underestimate the residual tumor size, compared to in other subtypes. Tumors with concentric shrinkage patterns after NAC showed less MRI/pathology size discrepancy.

Accuracy of breast MRI in evaluating nodal status after neoadjuvant therapy in invasive lobular carcinoma

Neoadjuvant therapy in breast cancer can downstage axillary lymph nodes and reduce extent of axillary surgery. As such, accurate determination of nodal status after neoadjuvant therapy and before surgery impacts surgical management. There are scarce data on the diagnostic accuracy of breast magnetic resonance imaging (MRI) for nodal evaluation after neoadjuvant therapy in patients with invasive lobular carcinoma (ILC), a diffusely growing tumor type. We retrospectively analyzed patients with stage 1–3 ILC who underwent pre-operative breast MRI after either neoadjuvant chemotherapy or endocrine therapy at our institution between 2006 and 2019. Two breast radiologists reviewed MRIs and evaluated axillary nodes for suspicious features. All patients underwent either sentinel node biopsy or axillary dissection. We evaluated sensitivity, specificity, negative and positive predictive values, and overall accuracy of the post-treatment breast MRI in predicting pathologic nodal status. Of 79 patients, 58.2% received neoadjuvant chemotherapy and 41.8% neoadjuvant endocrine therapy. The sensitivity and negative predictive value of MRI were significantly higher in the neoadjuvant endocrine therapy cohort than in the neoadjuvant chemotherapy cohort (66.7 vs. 37.9%, p = 0.012 and 70.6 vs. 40%, p = 0.007, respectively), while overall accuracy was similar. Upstaging from clinically node negative to pathologically node positive occurred in 28.0 and 41.7%, respectively. In clinically node positive patients, those with an abnormal post-treatment MRI had a significantly higher proportion of patients with ≥4 positive nodes on pathology compared to those with a normal MRI (61.1 versus 16.7%, p = 0.034). Overall, accuracy of breast MRI for predicting nodal status after neoadjuvant therapy in ILC was low in both chemotherapy and endocrine therapy cohorts. However, post-treatment breast MRI may help identify patients with a high burden of nodal disease (≥4 positive nodes), which could impact pre-operative systemic therapy decisions. Further studies are needed to assess other imaging modalities to evaluate for nodal disease following neoadjuvant therapy and to improve clinical staging in patients with ILC.

Accuracy of breast MRI in patients receiving neoadjuvant endocrine therapy: comprehensive imaging analysis and correlation with clinical and pathological assessments

PurposeTo assess the accuracy of magnetic resonance imaging (MRI) measurements in locally advanced oestrogen receptor-positive and human epidermal growth factor receptor 2-negative breast tumours before, during and after neoadjuvant endocrine treatment (NET) for evaluation of tumour response in comparison with clinical and pathological assessments.MethodsThis prospective study enrolled postmenopausal patients treated neoadjuvant with letrozole and exemestane given sequentially in an intra-patient cross-over regimen. Fifty-four patients were initially recruited, but only 35 fulfilled the inclusion criteria and confirmed to participate with a median age of 77. Tumours were scanned with MRI prior to treatment, during the eighth week of treatment and prior to surgery. Additionally, changes in longest diameter on clinical examination (CE) and tumour size at pathology were determined. Pre- and post-operative measurements of tumour size were compared in order to evaluate tumour response.ResultsThe correlation between post-treatment MRI size and pathology was moderate and higher with a correlation coefficient (r) 0.64 compared to the correlation between CE and pathology r = 0.25. Post-treatment MRI and clinical results had a negligible bias towards underestimation of lesion size. Tumour size on MRI and CE had 0.82 cm and 0.52 cm lower mean size than tumour size measured by pathology, respectively.ConclusionsThe higher correlation between measurements of residual disease obtained on MRI and those obtained with pathology validates the accuracy of imaging assessment during NET. MRI was found to be more accurate for estimating complete responses than clinical assessments and warrants further investigation in larger cohorts to validate this finding.

Can breast MRI accurately exclude malignancy in mammographic architectural distortion?

To investigate the diagnostic accuracy of problem-solving breast magnetic resonance imaging (MRI) in excluding malignancy in a cohort of patients diagnosed with mammographic architectural distortion (MAD). The Institutional Review Board approved the study. Imaging database with 40,245 breast MRIs done between January 2008 and September 2018 was retrospectively reviewed. The study included all exams considered problem-solving MRI for MAD. Two radiologists reviewed the imaging data. Outcome was determined by the pathology results of biopsy/surgical excision or at least 1year of clinical and radiological follow-up. Predictors for malignancy were examined, and appropriate statistical tests were applied. One hundred seventy-five patients (median age 53years) fulfilled the inclusion criteria and formed the study cohort. No cancers were diagnosed in 106 patients with a negative MRI. Out of 69 women with positive MRI findings, 48 (70%) had benign outcome defined either by pathology result or by negative follow-up, and 21 (30%) yielded malignancy. Malignancy was significantly associated with positive MRI (p < 0.001) and older age (p = 0.014). Falsely positive MRIs were frequently found in women with radial scars. The sensitivity, specificity, negative predictive value, positive predictive value, and overall accuracy of breast MRI were 100% (95% CI 84 to 100%), 68% (CI 61 to 76%), 100% (CI 95 to 100%), 30% (CI 26 to 36%), and 73% (95% CI 66-79), respectively. A negative breast MRI in patients with MAD was reliable in excluding malignancy in this cohort and may have a role as a precision medicine tool for avoiding unnecessary interventions. • MRI shows a high negative predictive value in MAD cases. • MRI displays low accuracy in differentiating malignancy from RS. • MRI is a reliable non-invasive method to exclude malignancy in women with mammographic architectural distortion, potentially avoiding unnecessary biopsies and surgeries.

Abstract OT2-02-01: Brazilian randomized study - Impact of preoperative magnetic resonance in the evaluation for breast cancer conservative surgery (BREAST-MRI trial)

Abstract Background: A precise preoperative evaluation of the tumor is essential to improve breast cancer surgical management. Currently, mammography associated with ultrasound and clinical exam are the standard techniques for evaluating extension and tumor localization. However, approximately one third of the lesions in patients eligible for conservative surgical treatment are misevaluated by these methods. Breast magnetic resonance imaging (MRI) has a high sensitivity (95-100%) in detecting invasive neoplasms, and is able to detect occult tumors, multifocal and/or multicentric disease, and contralateral breast cancer more accurately than mammography and ultrasound. Until now, there are only three randomized trials assessing the role of preoperative MRI. These trials have different designs and contradictory results. Trial design: BREAST-MRI is a randomized, open label, unblinded trial designed to compare the accuracy of breast MRI in the preoperative planning of surgical treatment of breast cancer to standard protocol (clinical exam of the breast, mammography and/or breast ultrasound) and the impact of breast MRI on breast cancer outcome. Patients are randomized on a 1:1 basis, stratified for mammary density, into two groups: 1)MRI group: patients are submitted to MRI and standard protocol 2)Control group: standard protocol. First phase: patient recruitment and data collection up until surgery. Second phase: follow-up for five years or until death. Eligibility criteria: women aged 18 years or older with breast cancer stages I to III candidates for conservative surgery (CC). Specific aims: The aim of this study is to evaluate the ability of MRI in selecting patients for conservative treatment of breast cancer. Primary outcomes are: false positive rates, false negative rates, positive predictive value and negative predictive value of MRI in breast cancer CC. Secondary outcomes are: rates of positive margins on pathological examination; reoperation rates; number of conversions to mastectomy; accuracy of MRI according to mammographic density, immunohistochemical subtype and histopathology of the tumor; rates of multicentricity, multifocality and bilateralality of tumors; disease-free survival after 3 and 5 years; and cost-effectiveness of breast MRI. Statistical methods: The calculated total case number for this trial is 372, assuming a recurrence rate of 10% for CC and 1% for mastectomies. The Shapiro-Whilks test will be used to verify if distribution of the quantitative variables follows normal distribution. The baseline population will be analyzed using the t-Student test, or the Mann-Whitney test when appropriate. To test the existence of a possible association between outcomes and the categorized characteristics, chi-square and Fisher's exact test will be performed. Disease progression will be reassessed at 3 and 5 years follow-up, in order to produce a log-rank Kaplan-Meier curve of survival. Present accrual and target accrual: In June 2017, randomizations are at approximately 90% of the target sample size. Citation Format: Dória MT, Mota BS, Reis YN, Ricci MD, Piato JRM, Ferreira VCCS, Shimizu C, Barros N, Filassi JR, Baracat EC. Brazilian randomized study - Impact of preoperative magnetic resonance in the evaluation for breast cancer conservative surgery (BREAST-MRI trial) [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT2-02-01.

Role of breast magnetic resonance imaging in predicting malignant invasion of the nipple-areolar complex

In this study, we assessed the diagnostic accuracy of breast magnetic resonance imaging (MRI) for evaluation of malignant invasion of the nipple-areolar complex (NAC).Patients with primary operable breast cancer who underwent preoperative breast MRI and received surgery during January 2011 to December 2013 were collected. The accuracy and potential factors of MRI in predicting nipple invasion were evaluated by comparing preoperative MRI with postoperative histopathologic findings. The consistency of interobservers’ variances across different radiologists was also compared.Totally, 704 patients were enrolled in this study, and 56 (8%) patients have pathologic NAC invasion. Several MRI factors were potential predictors of nipple invasion. Only unilateral nipple enhancement on MRI was the most significant independent predictor of NAC involvement in multivariate analysis. The statistical measures, such as sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and the accuracy of breast MRI were 71.4%, 81.6%, 25.2%, 97.1%, and 80.8%, respectively, in one investigator and 78.6%, 88.1%, 36.4%, 97.9%, and 87.4%, respectively, in the other investigator.MR images showed acceptable accuracy and impressive NPV, but low PPV in evaluation of malignant NAC invasion preoperatively. MRI finding of unilateral nipple enhancement was the most significant predictor of NAC involvement.

The Accuracy of Breast MR Imaging for Measuring the Size of a Breast Cancer: Analysis of the Histopathologic Factors

BackgroundThe objective of the study was to compare the accuracy of different magnetic resonance (MR) sequences for measuring tumor size and to evaluate whether the imaging and histopathologic features affect the accuracy of the tumor size estimation on the MR sequence. Patients and MethodsEight hundred women were included. The maximum diameter of the tumor was measured on T2-weighted (T2W) sequences, early-subtracted dynamic contrast-enhanced (DCE) T1-weighted (T1W) sequences, and maximal intensity projection (MIP) reconstructions. Agreement between the MR imaging and pathology-determined size were analyzed. Using the best MR sequence to measure the tumor size, the relationship between the accuracy and the imaging and histopathologic features were evaluated. ResultsTumor measurement showed a good agreement with the pathology-determined size, and with the best results using MIP (k = 0.805) compared with the early-subtracted DCE T1W sequence (k = 0.802) and the T2W sequence (k = 0.779). On MIP, the tumors of patients with minimal or mild background parenchymal enhancement, a mass, invasive ductal carcinoma (IDC), pathology-determined size < 2 cm, positive estrogen receptor, negative HER2, luminal A type, nuclear and histologic grade 1, negative nodal status, negative lymphovascular invasion, and negative extensive intraductal component were significantly more accurately estimated. The independent factors associated with the accuracy of tumor measurement were a mass, IDC, and the pathology-determined size < 2 cm. ConclusionOur study showed that tumor size is most accurately measured on MIP, especially for IDC appearing as a mass on MR imaging and with the pathology-determined size < 2 cm.

Adjacent vessel sign and breast imaging reporting and data system are valuable for diagnosis of benign and malignant breast lesions

The purpose of this study is to investigate whether an adjacent vessel sign (AVS) observed on the maximum intensity projections (MIPs) from the subtracted images can help distinguish between malignant and benign breast lesions and to test whether the combination of breast imaging reporting and data system (BI-RADS) category and AVS can increase the specificity and diagnostic accuracy of breast magnetic resonance imaging (MRI). The study included 63 histologically verified lesions which underwent dynamic breast MRI before biopsy. All magnetic resonance (MR) images were evaluated by two radiologists in consensus, who were unaware of the histopathological outcome. The MR images of all cases were analyzed according to BI-RADS-MRI assessment category. Levels of suspicion were reported as categories of I–V. The presence of vessels either entering the enhancing lesion or in contact with the lesion edge on MIP images was considered as the presence of AVS. Final analysis of 63 masses revealed 41 malignant lesions (65.1%) and 22 benign lesions (34.9%). Thirty seven out of 41 malignant lesions and 3 out of 22 benign lesions were associated with adjacent vessel, with highly significant difference between benign and malignant lesions (P < 0.001), especially for lesions smaller than 2.0 cm. The corresponding specificity, sensitivity and accuracy of contrast-enhanced 3.0-T breast were 86.4%, 82.9% and 84.1%, respectively. Based on BI-RADS-MRI category, the specificity, sensitivity and accuracy of breast MRI were 54.5%, 100% and 84.1%, respectively. After combining BI-RADS category and AVS, the specificity, sensitivity and accuracy of breast MRI were 90.9%, 82.9% and 85.7%, respectively. AVS can help differentiate malignant from benign breast lesions, especially for the lesions smaller than 2.0 cm. The combination of BI-RADS category and AVS can increase the specificity and the diagnostic accuracy of breast MRI.

P3-14-16: Molecular Phenotype and the Use of HER-2 Targeted Agents Influence the Accuracy of Breast MRI after Neoadjuvant Chemotherapy.

Abstract Background: Improved understanding of factors affecting the accuracy of breast magnetic resonance imaging (MRI) after neoadjuvant systemic therapy (NST) can lead to more tailored use of MRI in deciding surgical extent after NST. Materials and Methods: We analyzed the imaging and clinicopathologic data of 463 patients who underwent NST. We aimed to investigate whether the molecular subtypes, as well as the use of targeted therapies, were associated with changes in the accuracy of MRI predicting residual tumor extent. Results: The accuracy of MRI predicting the residual tumor extent was most accurate in triple negative breast cancer and was least accurate in Luminal A subtype (Pearson's correlation coefficient of 0.754 and 0.531, respectively). Multivariate analysis suggested estrogen receptor status as an independent factor influencing the MRI accuracy. In HER2−amplified tumors, the use of HER2−targeted agents was associated with less accurate MRI prediction. Dual HER2−blockade by using trastuzumab and pertuzumab resulted in lowest MRI accuracy among the patients treated with HER2−targeted agents. Conclusion: The accuracy of MRI in predicting residual tumor extent was lowest in ER positive tumors treated with NST. In HER2 positive tumors, the use of HER2−targeted agents resulted in less accurate MRI after NST. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-14-16.

Breast Cancer: Evaluation of Response to Neoadjuvant Chemotherapy with 3.0-T MR Imaging

To assess how the molecular biomarker status of a breast cancer, including human epidermal growth factor receptor 2 (HER2), hormone receptors, and the proliferation marker Ki-67 status, affects the diagnosis at 3.0-T magnetic resonance (MR) imaging. This study was approved by the institutional review board and was HIPAA compliant. Fifty patients (age range, 28-82 years; mean age, 49 years) receiving neoadjuvant chemotherapy were monitored with 3.0-T MR imaging. The longest dimension of the residual cancer was measured at MR imaging and correlated with pathologic findings. Patients were further divided into subgroups on the basis of HER2, hormone receptor, and Ki-67 status. Pathologic complete response (pCR) was defined as when there were no residual invasive cancer cells. The Pearson correlation was used to correlate MR imaging-determined and pathologic tumor size, and the unpaired t test was used to compare MR imaging-pathologic size discrepancies. Of the 50 women, 14 achieved pCR. There were seven false-negative diagnoses at MR imaging. The overall sensitivity, specificity, and accuracy for diagnosing invasive residual disease at MR imaging were 81%, 93%, and 84%, respectively. The mean MR imaging-pathologic size discrepancy was 0.5 cm ± 0.9 (standard deviation) for HER2-positive cancer and 2.3 cm ± 3.5 for HER2-negative cancer (P = .009). In the HER2-negative group, the size discrepancy was smaller for hormone receptor-negative than for hormone receptor-positive cancers (1.0 cm ± 1.1 vs 3.0 cm ± 4.0, P = .04). The size discrepancy was smaller in patients with 40% or greater Ki-67 expression (0.8 cm ± 1.1) than in patients with 10% or less Ki-67 expression (3.9 cm ± 5.1, P = .06). The diagnostic accuracy of breast MR imaging is better in more aggressive than in less aggressive cancers. When MR imaging is used for surgical planning, caution should be taken with HER2-negative hormone receptor-positive cancers.

The Role of Preoperative Magnetic Resonance Imaging for Detecting the Extent of Disease and Predicting the Prognosis of Ductal Carcinoma In Situ

Purpose: Magnetic Resonance Imaging (MRI) is widely used for the preoperative staging of breast cancer. In this study, we investigated a role of preoperative breast MRI for detecting the extent of disease and predicting the prognosis of ductal carcinoma in situ (DCIS). Methods: From January 2002 to April 2008, preoperative MRI was performed for evaluating the extent of disease in 26 patients with DCIS. The MRI findings, the modified Van Nuys scores and the clinicopathological results were reviewed. The accuracy of breast MRI was analyzed with respect to the detection of tumor multiplicity and disease extending into the nipple, and this was compared with that of mammography. Results: For detecting multiple lesions, the sensitivity and specificity of breast MRI were 25.0% and 86.4%, respectively, and the results of mammography were 0.0% and 86.4%, respectively. The accuracy of breast MRI was 76.9% and that of mammography was 73.1%. For detecting tumor extension into the nipple, the sensitivity and specificity of breast MRI was 100.0% and 80.0%, respectively, and that for mammography was 0.0% and 92.0%. respectively. The accuracy of MRI was 80.8% and that for mammography was 88.5%. The MRI final assessment was not associated with the modified Van Nuys score (p=0.474). Conclusion: For detecting the disease extent of DCIS, preoperative breast MRI is not superior to mammography due to the low specificity and accuracy of MRI. MRI did not show a definite ability to predict the prognosis of DCIS in this study.

The Clinical Significance of Preoperative MRI for Determination of Surgery in Breast Cancer

Purpose: Currently MRI (Magnetic Resonance Imaging) is widely used for the preoperative staging of breast cancer. In this study, we assessed the impact of preoperative breast MRI on the surgical management of breast cancer in women. Methods: From March 2004 to October 2006, 162 cases were enrolled for preoperative MRI for the staging of breast cancer. The MRI findings and clinicopathological results were investigated and the accuracy of breast MRI was analyzed with respect to the detection of multiplicity, nipple involvement and bilaterality of the breast cancers. Results: For detecting multifocal lesions, the sensitivity and specificity of breast MRI were 100% and 48.5%, respectively, and the results of bresat ultrasound were 100% and 63.4%, respectively. For detecting nipple invasion, the sensitivity and specificity of breast MRI was 80% and 74.6%, and for ultrasound was 33.3% and 86.4%. In 27 cases (16.7%) the type of surgery was changed according to the preoperative MRI findings; however, in only 6 cases were the MRI findings in concordance with the pathological findings of the mastectomy specimen. Conclusion: In clinical application of breast MRI for preoperative staging, the decision to undertake surgery for breast cancer based on a MRI findings should be prudent due to its low specificity. (J Breast Cancer 2006;9: 343-348)

Adding in Vivo Quantitative1H MR Spectroscopy to Improve Diagnostic Accuracy of Breast MR Imaging: Preliminary Results of Observer Performance Study at 4.0 T

To determine whether the addition of in vivo quantitative hydrogen 1 (1H) magnetic resonance (MR) spectroscopy can improve the radiologist's diagnostic accuracy in interpreting breast MR images to distinguish benign from malignant lesions. The study was approved by the institutional review board and, where appropriate, was compliant with the Health Insurance Portability and Accountability Act. All patients provided written informed consent. Fifty-five breast MR imaging cases-one lesion each in 55 patients aged 24-66 years with biopsy-confirmed findings-were retrospectively evaluated by four radiologists. Patients were examined with contrast material-enhanced fat-suppressed T1-weighted 4.0-T MR imaging. The concentration of total choline-containing compounds (tCho) was quantified by using single-voxel 1H MR spectroscopy. For each case, the radiologists were asked to give the percentage probability of malignancy, the Breast Imaging and Reporting Data System category, and a recommendation for patient treatment. Two interpretations were performed for each case: The initial interpretation was based on the lesion's morphologic features and time-signal intensity curve, and the second interpretation was based on the lesion's morphologic features, time-signal intensity curve, and tCho concentration. Receiver operating characteristic (ROC), Wilcoxon signed rank, kappa statistic, and accuracy (based on the area under the ROC curve) analyses were performed. Of the 55 lesions evaluated, 35 were invasive carcinomas and 20 were benign. The addition of 1H MR spectroscopy resulted in higher sensitivity, specificity, accuracy, and interobserver agreement for all four radiologists. More specifically, two of the four radiologists achieved a significant improvement in sensitivity (P=.03, P=.03), and all four radiologists achieved a significant improvement in accuracy (P = .01, P = .05, P = .009, P < .001). Current study results suggest that the addition of quantitative 1H MR spectroscopy to the breast MR imaging examination may help to improve the radiologist's ability to distinguish benign from malignant breast lesions.

Accuracy of MR imaging in the work-up of suspicious breast lesions: A diagnostic meta-analysis

The authors performed a systematic, critical review of the literature on magnetic resonance (MR) imaging for primary breast cancer detection in patients with suspicious breast lesions, analyzed MR test performance in the articles meeting study criteria, and used this information to examine the cost-effectiveness of preoperative MR imaging. A structured, predefined MEDLINE search was conducted to identify potentially relevant, peer-reviewed, English-language references from January 1996 through August 1997 on the diagnostic accuracy of breast MR imaging. This information was supplemented by manually searching bibliographies of the retrieved articles for additional potentially relevant references. All studies were independently abstracted by two reviewers using a prospectively designed worksheet. Abstraction results were analyzed with the summary receiver operating characteristic (ROC) method. Of 41 identified studies, 16 met the inclusion criteria. These studies reported sensitivities ranging from 63% to 100% and specificities ranging from 21% to 100%. Maximum joint sensitivity and specificity of the summary ROC curve was 89% (95% confidence interval [CI]: 82%, 93%). At a sensitivity of 95%, specificity was 67%. When test performance values were applied to a previous cost-effectiveness analysis, the cost-effectiveness of preoperative MR imaging relative to that of excisional biopsy was confirmed, but its cost-effectiveness relative to that of needle core biopsy varied widely. For MR imaging to be a cost-effective alternative to excisional biopsy for diagnosis of suspicious breast lesions, its diagnostic test performance must be equal to or better than the best results in recently published studies.