Pascal A. Baltzer

Breast MRI: EUSOBI recommendations for women's information.

AbstractThis paper summarizes information about breast MRI to be provided to women and referring physicians. After listing contraindications, procedure details are described, stressing the need for correct scheduling and not moving during the examination. The structured report including BI-RADS® categories and further actions after a breast MRI examination are discussed. Breast MRI is a very sensitive modality, significantly improving screening in high-risk women. It also has a role in clinical diagnosis, problem solving, and staging, impacting on patient management. However, it is not a perfect test, and occasionally breast cancers can be missed. Therefore, clinical and other imaging findings (from mammography/ultrasound) should also be considered. Conversely, MRI may detect lesions not visible on other imaging modalities turning out to be benign (false positives). These risks should be discussed with women before a breast MRI is requested/performed. Because breast MRI drawbacks depend upon the indication for the examination, basic information for the most important breast MRI indications is presented. Seventeen notes and five frequently asked questions formulated for use as direct communication to women are provided. The text was reviewed by Europa Donna–The European Breast Cancer Coalition to ensure that it can be easily understood by women undergoing MRI.Key Points• Information on breast MRI concerns advantages/disadvantages and preparation to the examination • Claustrophobia, implantable devices, allergic predisposition, and renal function should be checked • Before menopause, scheduling on day 7–14 of the cycle is preferred • During the examination, it is highly important that the patient keeps still • Availability of prior examinations improves accuracy of breast MRI interpretation

Improved diagnostic accuracy with multiparametric magnetic resonance imaging of the breast using dynamic contrast-enhanced magnetic resonance imaging, diffusion-weighted imaging, and 3-dimensional proton magnetic resonance spectroscopic imaging.

IntroductionThe purpose of this study was to compare the diagnostic accuracy of dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) as a single parameter to multiparametric (MP) MRI with 2 (DCE MRI and diffusion-weighted imaging [DWI]) and 3 (DCE MRI, DWI, and 3-dimensional proton magnetic resonance spectroscopic imaging [3D 1H-MRSI]) parameters in breast cancer diagnosis. Materials and MethodsThis prospective study was approved by the institutional review board. Written informed consent was obtained in all patients. One hundred thirteen female patients (mean age, 52 years; range, 22–86 years) with an imaging abnormality (Breast Imaging Reporting and Data System 0, 4–5) were included in this study. Multiparametric MRI of the breast at 3 T with DCE MRI, DWI, and 3D 1H-MRSI was performed. The likelihood of malignancy was assessed for DCE MRI and MP MRI with 2 (DCE MRI and DWI) and 3 (DCE MRI, DWI, and 3D 1H-MRSI) parameters separately. Histopathology was used as the standard of reference. Appropriate statistical tests were used to assess sensitivity, specificity, and diagnostic accuracy for each assessment combination. ResultsThere were 74 malignant and 39 benign breast lesions. Multiparametric MRI with 3 MRI parameters yielded significantly higher areas under the curve (0.936) in comparison with DCE MRI alone (0.814) (P < 0.001). Multiparametric MRI with just 2 parameters at 3 T did not yield higher areas under the curve (0.808) than did DCE MRI alone (0.814). Multiparametric MRI with 3 parameters resulted in elimination of false-negative lesions and significantly reduced the false-positives ones (P = 0.002). ConclusionsMultiparametric MRI with 3 parameters increases the diagnostic accuracy of breast cancer in comparison with DCE-MRI alone and MP MRI with 2 parameters.

Diagnostic Utility of Second-Look US for Breast Lesions Identified at MR Imaging: Systematic Review and Meta-Analysis

PURPOSE To evaluate the diagnostic utility of second-look ultrasonography (US) in the assessment of lesions identified at breast magnetic resonance (MR) imaging. MATERIALS AND METHODS A systematic review of the PubMed database for articles published up to January 6, 2013, was performed by using predefined search terms applied in a standardized manner. Second-look US studies for the assessment of breast lesions identified at MR imaging were eligible for this meta-analysis. Two independent reviewers performed the literature review and data extraction. Eligible studies presented data on the number of lesions examined and the number of lesions detected at second-look US. The reference standard for lesion diagnosis was either histopathologic or follow-up examination. Sources of bias were assessed by using the Quality Assessment of Diagnostic Accuracy Studies 2, or QUADAS-2 Quality Assessment of Diagnostic Accuracy Studies 2 , tool. Statistical analysis included data pooling, heterogeneity testing, and meta-regression. RESULTS Seventeen studies that included benign and malignant lesions met the inclusion criteria. The general lesion detection rate at second-look US was very heterogeneous and ranged between 22.6% and 82.1% (pooled rate, 57.5% [1266 of 2201]; 95% confidence interval [ CI confidence interval ]: 50.0%, 64.1% [random-effects model]; I(2) = 90.9%; P < .0001). The highest second-look US detection rates were observed for mass lesions (as opposed to nonmass lesions) and malignant (vs benign) lesions (P < .001 for both). Pooled positive and negative predictive values (positive or negative second-look US correlates of MR imaging-detected malignant or benign lesions) were calculated as 30.7% (95% CI confidence interval : 25.3%, 36.4%; I(2) = 75.4%; P < .0001) and 87.8% (95% CI confidence interval : 82.0%, 92.7%; I(2) = 82.1%; P < .0001), respectively, by using random-effects models. CONCLUSION The results of this study demonstrated variable utility of second-look US in MR imaging-detected lesions, as lesion detection rates were very heterogeneous. Subgroup analysis showed that malignant and mass lesions were more likely to be detected at second-look US. Furthermore, malignancy was not excluded if a lesion was not detected at second-look US.

Breast MRI as an adjunct to mammography: Does it really suffer from low specificity? A retrospective analysis stratified by mammographic BI-RADS classes.

Background: Reports on the specificity of breast MRI are heterogeneous, depending on the respective setting of the performed study. Purpose: To retrospectively estimate the sensitivity and especially the specificity of breast MRI in the non-screening setting as an adjunct to mammography sorted by breast density and to estimate the accuracy of breast MRI in cases rated BI-RADS 0 and 3 mammographically. Material and Methods: A total of 216 consecutive patients with referral to breast MRI and previously acquired mammography were enrolled in this analysis. Negative findings were followed up with a mean time of 26.7 months. The loss to follow-up was 10.8%. The single breast was regarded as the study subject (n=399, 364 cases were eligible for calculation of diagnostic accuracy). BI-RADS 1 and 2 were rated as benign, 4 and 5 as malignant. BI-RADS 0 and 3 were analyzed separately. The 95% confidence intervals (CIs) were calculated from the normally approximated binomial distribution and taken to represent significant differences for the two imaging modalities if they did not overlap. Results: Among the study population, 62 malignant neoplasms were detected. For cases rated BI-RADS 1, 2, 4, and 5 (n=251), the sensitivity of breast MRI was 95.7% (95% CI 89.9–100.0%) and 74.5% (95% CI 62.0–87.0%) for mammography, respectively. The specificity of breast MRI was 96.1% (95% CI 93.4–98.8%) and 92.2% (95% CI 88.5–95.9%) for mammography, respectively. The diagnostic accuracy of breast MRI did not depend on breast density. In cases rated BI-RADS 0, n=57 (3, n=56), breast MRI achieved a sensitivity of 100% (90.9%) and a specificity of 98.1% (88.9%). There was a significant (P< 0.01) accumulation of dense breast tissue (ACR IV) in breasts rated BI-RADS 0 in mammography. Breast MRI missed three malignant lesions, two of them being smaller than 3 mm. Conclusion: There is no rationale to criticize the low specificity of breast MRI when used as an adjunct to mammography. The independency of the diagnostic accuracy of breast MRI from breast density makes it a worthwhile choice in mammographic BI-RADS 0 cases.

Automatic multimodal 2D/3D breast image registration using biomechanical FEM models and intensity-based optimization.

Due to their different physical origin, X-ray mammography and Magnetic Resonance Imaging (MRI) provide complementary diagnostic information. However, the correlation of their images is challenging due to differences in dimensionality, patient positioning and compression state of the breast. Our automated registration takes over part of the correlation task. The registration method is based on a biomechanical finite element model, which is used to simulate mammographic compression. The deformed MRI volume can be compared directly with the corresponding mammogram. The registration accuracy is determined by a number of patient-specific parameters. We optimize these parameters--e.g. breast rotation--using image similarity measures. The method was evaluated on 79 datasets from clinical routine. The mean target registration error was 13.2mm in a fully automated setting. On basis of our results, we conclude that a completely automated registration of volume images with 2D mammograms is feasible. The registration accuracy is within the clinically relevant range and thus beneficial for multimodal diagnosis.

Improved Differentiation of Benign and Malignant Breast Tumors with Multiparametric 18Fluorodeoxyglucose Positron Emission Tomography Magnetic Resonance Imaging: A Feasibility Study

Purpose: To assess whether multiparametric 18fluorodeoxyglucose positron emission tomography magnetic resonance imaging (MRI) (MP 18FDG PET-MRI) using dynamic contrast-enhanced MRI (DCE-MRI), diffusion-weighted imaging (DWI), three-dimensional proton MR spectroscopic imaging (3D 1H-MRSI), and 18FDG-PET enables an improved differentiation of benign and malignant breast tumors. Experimental Design: Seventy-six female patients (mean age, 55.7 years; range, 25–86 years) with an imaging abnormality (BI-RADS 0, 4–5) were included in this Institutional Review Board (IRB)-approved study. Patients underwent fused PET-MRI of the breast with 18FDG-PET/CT and MP MRI at 3T. The likelihood of malignancy was assessed for all single parameters, for MP MRI with two/three parameters, and for MP 18FDG PET-MRI. Histopathology was used as the standard of reference. Appropriate statistical tests were used to assess sensitivity, specificity, and diagnostic accuracy for each assessment combination. Results: There were 53 malignant and 23 benign breast lesions. MP 18FDG PET-MRI yielded a significantly higher area under the cure (AUC) of 0.935 than DCE-MRI (AUC, 0.86; P = 0.044) and the combination of DCE-MRI and another parameter (AUC, 0.761–0.826; P = 0.013–0.020). MP 18FDG PET-MRI showed slight further improvement to MP MRI with three parameters (AUC, 0.925; P = 0.317). Using MP 18FDG PET-MRI there would have been a reduction of the unnecessary breast biopsies recommended by MP imaging with one or two parameters (P = 0.002–0.011). Conclusion: This feasibility study shows that MP 18FDG PET-MRI enables an improved differentiation of benign and malignant breast tumors when several MRI and PET parameters are combined. MP 18FDG PET-MRI may lead to a reduction in unnecessary breast biopsies. Clin Cancer Res; 20(13); 3540–9. ©2014 AACR.

Quantitative apparent diffusion coefficient as a noninvasive imaging biomarker for the differentiation of invasive breast cancer and ductal carcinoma in situ.

ObjectivesThe objective of this study was to evaluate whether apparent diffusion coefficient (ADC) obtained through diffusion-weighted imaging magnetic resonance imaging at 3 T can be used as an imaging biomarker to differentiate invasive breast cancer from noninvasive ductal carcinoma in situ (DCIS). Materials and MethodsOne hundred seventy-six histopathologically verified primary malignant breast tumors were retrospectively evaluated in 170 patients. All patients had undergone a standardized 3-T magnetic resonance imaging protocol, containing a diffusion-weighted sequence with 2 b values and a series of dynamic contrast-enhanced T1-weighted sequences. Apparent diffusion coefficient was measured manually by a reader blinded to the histopathological results. The ADC values were correlated with histopathological results. Mean ADC values were compared between invasive cancers and DCIS as well as between different tumor grades. Receiver operating characteristics curves were used to calculate diagnostic performance. ResultsThere were 155 invasive cancers and 21 noninvasive DCIS. Mean (SD) values differed significantly between the invasive cancers (0.9 [0.15] ×10−3 mm2/s) and the DCIS (1.24 [0.23] ×10−3 mm2/s, P < 0.001). Area under the receiver operating characteristics curve was 0.895 (95% confidence interval [CI], 0.840–0.936). A threshold of 1.01 ×10−3 mm2/s or less allowed an identification of invasive cancers with a sensitivity of 78.06% (95% CI, 70.7%–84.3%) and a specificity of 90.5% (95% CI, 69.6%–98.8%). No significant ADC differences were found among different tumor grades (P > 0.05). ConclusionsApparent diffusion coefficient could be used as an imaging biomarker for the diagnosis of breast cancer. It seems to be a valuable noninvasive quantitative biomarker to assess breast cancer invasiveness. Thus, ADC measurements provide the potential to reduce overdiagnosis and subsequent overtreatment.

Bilateral Diffusion-weighted MR Imaging of Breast Tumors with Submillimeter Resolution Using Readout-segmented Echo-planar Imaging at 7 T

PURPOSE To evaluate the image quality, robustness, and diagnostic performance of submillimeter in-plane resolution diffusion-weighted ( DW diffusion-weighted ) magnetic resonance (MR) imaging at 7 T in the assessment of breast tumors. MATERIALS AND METHODS Institutional review board approval and written informed consent of five volunteers and 33 patients with 33 breast lesions (31 with histopathologic confirmation, two with confirmation at follow-up) were obtained. Image quality optimization and comparisons of readout-segmented echo-planar imaging ( rs-EPI readout-segmented echo-planar imaging ) and single-shot echo-planar imaging ( ss-EPI single-shot echo-planar imaging ) with or without parallel imaging were performed in volunteers. In all patients, bilateral DW diffusion-weighted imaging was performed in 3 minutes 35 seconds by using combined rs-EPI readout-segmented echo-planar imaging and parallel imaging with 0.9 × 0.9 mm in-plane resolution with a 7-T whole-body MR imager. Image quality, lesion conspicuity, and image properties (ie, signal-to-noise ratio, contrast-to-noise ratio) were assessed. Regions of interest were drawn in the largest lesion in each patient (23 malignant lesions, 10 benign lesions) by two independent readers. Apparent diffusion coefficient ( ADC apparent diffusion coefficient ) values were used to differentiate between benign and malignant breast tumors. RESULTS DW diffusion-weighted imaging with combined parallel imaging and rs-EPI readout-segmented echo-planar imaging reduced artifacts (ie, blurring and geometric distortions) by a calculated factor of seven when compared with DW diffusion-weighted imaging with ss-EPI single-shot echo-planar imaging , and it improved image quality from a score of 1 of 10 to a score of 8 of 10. The rs-EPI readout-segmented echo-planar imaging sequence with a b value of 0 sec/mm(2) yielded high-spatial-resolution T2-weighted MR images. An ADC apparent diffusion coefficient threshold of 1.275 × 10(-3) mm(2)/sec enabled differentiation between benign and malignant breast lesions, with sensitivity and specificity of 96% and 100%, respectively, for both independent readers. CONCLUSION At 7 T, one DW diffusion-weighted imaging examination of less than 4 minutes yielded high-quality ADC apparent diffusion coefficient maps and high-spatial-resolution T2-weighted MR images that were used to assess tumor and breast morphology. ADC apparent diffusion coefficient quantification alone enabled excellent differentiation of benign and malignant breast lesions.

Utility and limitations of 3-Tesla diffusion-weighted magnetic resonance imaging for differentiation of renal tumors

OBJECTIVE To investigate utility and limitations of 3-Tesla diffusion-weighted (DW) magnetic resonance imaging (MRI) for differentiation of benign versus malignant renal lesions and renal cell carcinoma (RCC) subtypes. MATERIALS AND METHODS Sixty patients with 71 renal lesions underwent 3 Tesla DW-MRI of the kidney before diagnostic tissue confirmation. The images were retrospectively evaluated blinded to histology. Single-shot echo-planar imaging was used as the DW imaging technique. Apparent diffusion coefficient (ADC) values were measured and compared with histopathological characteristics. RESULTS There were 54 malignant and 17 benign lesions, 46 lesions being small renal masses ≤ 4 cm. Papillary RCC lesions had lower ADC values (p=0.029) than other RCC subtypes (clear cell or chromophobe). Diagnostic accuracy of DW-MRI for differentiation of papillary from non-papillary RCC was 70.3% resulting in a sensitivity and specificity of 64.3% (95% CI, 35.1-87.2) and 77.1 (95% CI, 59.9-89.6%). Accuracy increased to 83.7% in small renal masses (≤ 4 cm diameter) and sensitivity and specificity were 75.0% and 88.5%, respectively. The ADC values did not differ significantly between benign and malignant renal lesions (p=0.45). CONCLUSIONS DW-MRI seems to distinguish between papillary and other subtypes of RCCs especially in small renal masses but could not differentiate between benign and malignant renal lesions. Therefore, the use of DW-MRI for preoperative differentiation of renal lesions is limited.

Resolving arterial phase and temporal enhancement characteristics in DCE MRM at high spatial resolution with TWIST acquisition

To investigate the potential of a view‐sharing 3D fast gradient‐echo sequence using pseudo random trajectories (TWIST) to achieve very short acquisition times with high in‐plane resolution and good volume coverage and its application to dynamic contrast‐enhanced (DCE) breast magnetic resonance imaging (MRI).