Contrast-enhanced Magnetic Resonance Mammography Research Articles

Role of Magnetic Resonance Mammography in the Evaluation of Indeterminate Breast Lesions.

Background: Malignancy of the breast is one of the most common cancers among females worldwide. Magnetic resonance mammography (MRM) is a valuable complement to conventional methods for the early diagnosis of disease, thereby providing patients with a better prognosis. The number of unnecessary biopsies and repeated excisions in cases of indeterminate breast lesions detected on conventional imaging is high. Aims: The purpose of this study was to evaluate the role of MRM in the evaluation of indeterminate breast lesions [Breast Imaging Reporting and Data System (BIRADS) 3/4] found in conventional mammography and ultrasonography (USG), taking the histopathological examination (HPE) as the gold standard. Materials and methods: A total of 38 patients with conventional radiological imaging diagnosis of indeterminate breast lesions (BIRADS 3/4) were included in this study and evaluated using contrast-enhanced MRM according to the MR-BIRADS lexicon (5th edition). Morphological characteristics of lesions were evaluated to determine the probability of malignancy. Histopathology was kept as the gold standard for comparing all the statistical parameters. Results: There were a total of 40 lesions, 35 masses, and five nonmass enhancement (NME) available for evaluation out of the 38 patients. The sensitivity of margins to detect malignancy approached 100%; however, it had a slightly lower specificity of 66.67%. Magnetic resonance imaging (MRI) showed good diagnostic performance with sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of 85, 90, 89.47, 85.71, and 87.50%, respectively. Conclusion: The MRI has been shown to be useful as a problem-solving tool in breast cancer screening, clarifying indeterminate findings and avoiding unnecessary short follow-ups and percutaneous biopsies. How to cite this article: Mishra E, Kaur N, Kaur R, et al. Role of Magnetic Resonance Mammography in the Evaluation of Indeterminate Breast Lesions. J Assoc Physicians India 2023;71(11):76-84.

Diagnostic Accuracy of MR Mammography in Comparison with Digital Mammography and Sonomammography

Background. Even though the sensitivity of contrast-enhanced breast magnetic resonance mammography (CE-MRM) is consistently high in the range of 94-100%, conventionally, digital mammography and sonomammography continue as standard imaging modalities for the detection and evaluation of breast disease.
 The objective of the study was to detect additional lesions that go undetected by routine digital mammography and sonomammography using CE-MRM.
 Materials and Methods. In a prospective study, 68 patients who came for screening diagnostic mammogram and had breast lesions of Breast Imaging-Reporting and Data System category 3-6 were evaluated. All patients underwent bilateral digital mammography and targeted high-frequency sonomammography of the primary lesion. Those patients who were thought to possibly have breast cancer and to be candidates for surgical management were offered bilateral CE-MRM.
 Results. In this prospective study, we included 68 patients (mean age - 50.6 years, range - 30-73 years). A total of 74 lesions were evaluated. In detecting these lesions, digital mammography had a sensitivity of 40.0%, specificity of 100% and diagnostic accuracy of 63.5%. CE-MRM sensitivity was found to be 71.7%, specificity - 96.6% and diagnostic accuracy - 83.7%. Among the 27 additional lesions detected by CE-MRM, histopathological evaluation confirmed only 19, indicating the sensitivity of 100%, specificity of 85.4%, positive predictive value of 67.8%, negative predictive value of 100%, diagnostic accuracy of 89.2%.
 Conclusions. The diagnostic accuracy of CE-MRM was found to be 83.7%, with a specificity of 96.6%. CE-MRM detected 19 additional lesions that were undetected by either digital mammography or ultrasonography. CE-MRM is sensitive in detecting additional malignant lesions which are not detected by other imaging modalities.

THE ROLE OF MAGNETIC RESONANCE MAMMOGRAPHY AND MAGNETIC RESONANCE SPECTROSCOPY IN THE DIFFERENTIAL DIAGNOSIS OF BREAST TUMORS

Objective: to investigate the possibility of enhancing the efficiency of complex magnetic resonance (MR) imaging, including MR mammography with dynamic contrast-enhanced MRI and MR spectroscopy for the differential diagnosis of breast tumors. Material and methods. The investigation enrolled 87 patients with breast tumors and 15 healthy volunteers. The mean age of the examinees was 55.7±3.5 years. MR mammography with dynamic contrast-enhanced MRI and subsequent morphological diagnosis verification were performed in 100% of cases. MR spectroscopy was carried out in 93.1% of the patients with breast tumors. Results. There were 189 breast tumors, including 154 (81.5%) and 35 (18.5%) hypervascular and avascular ones, respectively. MR mammography could reveal only 36% of the hypervascular masses. The sensitivity of contrast-enhanced MR mammography was 97.1%, and the specificity was variable. Its specificity was 96.9% for BIRADS 2 and BIRADS 5 and 45% and 55% for BIRADS 4 and BIRADS 3, respectively. MR spectroscopy in addition to MR mammography could increase the overall specificity of the technique up to 98.3%. Conclusion. Comprehensive MR examination that involves MR mammography with dynamic contrast-enhanced MRI and MR spectroscopy makes it possible to visualize breast tissues, to identify additional masses, to investigate not only the morphological, but also chemical structure of the identified tumors, which allows the most precise differential diagnosis between benign and malignant lesions.

Role of diffusion weighted imaging and dynamic contrast enhanced MR mammography to detect recurrence in breast cancer patients after surgery

ObjectiveTo assess role of Diffusion weighted imaging (DWI) in addition to dynamic contrast-enhanced magnetic resonance mammography (DCE-MRM) in detection of breast cancer recurrence after surgery. Patients and methodsSixty female patients who underwent breast surgery were included in this prospective study. Patients were examined by sonomammography followed by DCE-MRI to exclude recurrence. DWI was performed using b values of 0, 50, and 850s/mm2. Patients with suspected recurrence were subjected to histopathological confirmation. ResultsTwenty seven patients had pathologically proven recurrence and thirty three patients showed spectrum of post operative changes. DCE-MRI was superior to DWI with 2 false positive (FP) cases and no false negative (FN) cases, while DWI showed 3 (FN) cases and 4 (FP) cases. DCE-MRI & DWI showed sensitivity (100%, 88.9%), specificity (93.9%, 87.9%), positive predictive value (PPV) (93.1%, 88.9%), negative predictive value (NPV) (100%, 90.6%) & accuracy (96.7%, 88.3%) respectively. ConclusionOur study showed better diagnostic performance for DCE-MRI compared to DWI in post operative breast assessment. However, DWI can provide an alternative diagnostic tool to contrast administration “if interpreted in association with conventional MR sequences” thus can be used when contrast media is contraindicated.

Response to neoadjuvant treatment of invasive ductal breast carcinomas including outcome evaluation: MRI analysis by an automatic CAD system in comparison to visual evaluation

Background. The aim of this study was to evaluate imaging-based response to standardized neoadjuvant chemotherapy (NACT) regimen by dynamic contrast-enhanced magnetic resonance mammography (DCE-MRM), whereas MR images were analyzed by an automatic computer-assisted diagnosis (CAD) system in comparison to visual evaluation. MRI findings were correlated with histopathologic response to NACT and also with the occurrence of metastases in a follow-up analysis. Patients and methods. Fifty-four patients with invasive ductal breast carcinomas received two identical MRI examinations (before and after NACT; 1.5T, contrast medium gadoteric acid). Pre-therapeutic images were compared with post-therapeutic examinations by CAD and two blinded human observers, considering morphologic and dynamic MRI parameters as well as tumor size measurements. Imaging-assessed response to NACT was compared with histopathologically verified response. All clinical, histopathologic, and DCE-MRM parameters were correlated with the occurrence of distant metastases. Results. Initial and post-initial dynamic parameters significantly changed between pre- and post-therapeutic DCE-MRM. Visually evaluated DCE-MRM revealed sensitivity of 85.7%, specificity of 91.7%, and diagnostic accuracy of 87.0% in evaluating the response to NACT compared to histopathology. CAD analysis led to more false-negative findings (37.0%) compared to visual evaluation (11.1%), resulting in sensitivity of 52.4%, specificity of 100.0%, and diagnostic accuracy of 63.0%. The following dynamic MRI parameters showed significant associations to occurring metastases: Post-initial curve type before NACT (entire lesions, calculated by CAD) and post-initial curve type of the most enhancing tumor parts after NACT (calculated by CAD and manually). Conclusions. In the accurate evaluation of response to neoadjuvant treatment, CAD systems can provide useful additional information due to the high specificity; however, they cannot replace visual imaging evaluation. Besides traditional prognostic factors, contrast medium-induced dynamic MRI parameters reveal significant associations to patient outcome, i.e. occurrence of distant metastases.

Pharmacokinetic Approach for Dynamic Breast MRI to Indicate Signal Intensity Time Curves of Benign and Malignant Lesions by Using the Tumor Flow Residence Time

The objective of this study was to evaluate a novel pharmacokinetic approach integrating a tumor model in a whole-body pharmacokinetic model to simulate contrast media-induced signal intensity time curves of breast tumors on dynamic contrast-enhanced magnetic resonance mammography. A recently developed, whole-body pharmacokinetic model, which describes the distribution and excretion of renally discharged contrast media, has been expanded by integrating a tumor model. The parameters of the general approach including exchange between plasma and interstitium were set as fixed values; only 2 tumor-specific parameters, blood volume fraction Vblood and blood flow kt, were varied. These parameters were adjusted with regard to signal intensity time course data of histologically verified benign and malignant mass-like breast lesions on clinical magnetic resonance imaging examinations (1.5 T) using 2 different contrast media (gadopentetate dimeglumine and gadoterate meglumine) and 2 application doses (0.1 and 0.2 mmol kg body weight). Thus, measured signal intensity time curves were compared with simulated gadolinium (Gd) concentration time curves calculated by the pharmacokinetic model. Benign lesions showed continuous signal increase; malignant tumors presented fast initial signal increase followed by washout effect. According to the pharmacokinetic approach, the variation of the Vblood/kt ratio, which defined the tumor flow residence time τr, led to Gd concentration time curves congruent with the shapes of the measured signal intensity time curves. Low values of τr were characteristic for malignant tumors, and high values were typical for benign lesions; τr of 200 seconds best separated malignant from benign tumors. Thus, the dynamic magnetic resonance imaging data can be well approximated by the pharmacokinetic model considering 2 contrast media and application doses. The calculated Gd concentration time curves of 0.1 mmol kg body weight gadopentetate dimeglumine and gadoterate meglumine overlapped for benign lesions; the curve of gadoterate meglumine was by a factor of 0.8 below the curve of gadopentetate dimeglumine for malignant tumors. Doubling the application dose of gadopentetate dimeglumine from 0.1 to 0.2 mmol kg led to an increase in the Gd concentration time curves for benign lesions but not for malignant tumors. High Gd concentrations with values greater than 1 mmol L were calculated in the vessels of the malignant tumors, outside the determined range of the linear relationship between Gd concentration and signal intensity due to saturation effects. On the basis of this pharmacokinetic model, the contrast media-induced time curves on dynamic contrast-enhanced magnetic resonance mammography can be classified by a single kinetic parameter, the tumor flow residence time τr, into benign (τr >200 seconds) and malignant (τr <200 seconds) curve shapes. Possible clinical application of this model is to create pharmacokinetic maps, displaying tumor flow residence times, for computer-assisted diagnosis, which may be integrated into clinical routine for the diagnosis of breast lesions.

Normal Breast Parenchyma: Contrast Enhancement Kinetics at Dynamic MR Mammography—Influence of Anthropometric Measures and Menopausal Status

To study T1 baseline signal intensity (SI) and contrast material enhancement kinetics of normal breast parenchyma by using dynamic contrast-enhanced (DCE) magnetic resonance (MR) mammography and to determine the influence of anthropometric measures and menopausal status on the variability of these features. Institutional review board approval and written informed consent were obtained. Between June 2008 and September 2011, 345 women (age range, 26-81 years; mean age, 51.3 years ± 11.6 [standard deviation]) underwent DCE MR mammography, with T1-weighted three-dimensional MR images (repetition time msec/echo time msec, 8.86/4.51; flip angle, 25°) acquired with a 1.5-T whole-body MR unit before and 1, 2, 3, 4, and 5 minutes after a gadobutrol bolus injection of 0.1 mmol per kilogram of body weight. Regions of interest were traced manually, and T1 SI of parenchyma was recorded. The influence of different predictors of T1 baseline SI and contrast enhancement was studied by using random-effects models. T1 baseline SI varied considerably between women, with a mean of 167.7 ± 49.2 (71.4-424.7 [range]) and 175.9 ± 48.9 (51.8-458.3) in the right and the left breast, respectively (P < .01). T1 baseline SI increased linearly with age (P < .0001) and body weight (P < .0001). After contrast material delivery, relative percentage of enhancement was 8.1%, 13.8%, 18.2%, 22.1%, and 24.6% at 1, 2, 3, 4, and 5 minutes, respectively, but varied considerably between women. Contrast enhancement was 9.3% in the lowest quintile and 47.4% in the highest. Contrast enhancement increased with body weight (P < .01) but decreased in postmenopausal women (P < .01). Women with higher baseline T1 SI tended to have a higher contrast enhancement slope. Anthropometric measures and menopausal status contribute to a large variability in contrast enhancement of normal breast parenchyma. This might influence the interpretation of contrast enhancement kinetics of breast lesions and current strategies for determining contrast medium dose for breast MR imaging.

Fusion of dynamic contrast-enhanced magnetic resonance mammography at 3.0 T with X-ray mammograms: Pilot study evaluation using dedicated semi-automatic registration software

Rationale and objectives To evaluate the semi-automatic image registration accuracy of X-ray-mammography (XR-M) with high-resolution high-field (3.0 T) MR-mammography (MR-M) in an initial pilot study. Material and methods MR-M was acquired on a high-field clinical scanner at 3.0 T (T1-weighted 3D VIBE ± Gd). XR-M was obtained with state-of-the-art full-field digital systems. Seven patients with clearly delineable mass lesions >10 mm both in XR-M and MR-M were enrolled (exclusion criteria: previous breast surgery; surgical intervention between XR-M and MR-M). XR-M and MR-M were matched using a dedicated image-registration algorithm allowing semi-automatic non-linear deformation of MR-M based on finite-element modeling. To identify registration errors (RE) a virtual craniocaudal 2D mammogram was calculated by the software from MR-M (with and w/o Gadodiamide/Gd) and matched with corresponding XR-M. To quantify REs the geometric center of the lesions in the virtual vs. conventional mammogram were subtracted. The robustness of registration was quantified by registration of X-MRs to both MR-Ms with and w/o Gadodiamide. Results Image registration was performed successfully for all patients. Overall RE was 8.2 mm (1 min after Gd; confidence interval/CI: 2.0–14.4 mm, standard deviation/SD: 6.7 mm) vs. 8.9 mm (no Gd; CI: 4.0–13.9 mm, SD: 5.4 mm). The mean difference between pre- vs. post-contrast was 0.7 mm (SD: 1.9 mm). Conclusion Image registration of high-field 3.0 T MR-mammography with X-ray-mammography is feasible. For this study applying a high-resolution protocol at 3.0 T, the registration was robust and the overall registration error was sufficient for clinical application.

Size assessment of breast lesions by means of a computer-aided detection (CAD) system for magnetic resonance mammography

The aim of this study was to investigate the efficacy of a dedicated software tool for automated volume measurement of breast lesions in contrast-enhanced (CE) magnetic resonance mammography (MRM). The size of 52 breast lesions with a known histopathological diagnosis (three benign, 49 malignant) was automatically evaluated using different techniques. The volume of all lesions was measured automatically (AVM) from CE 3D MRM examinations by means of a computer-aided detection (CAD) system and compared with the size estimates based on maximum diameter measurement (MDM) on MRM, ultrasonography (US), mammography and histopathology. Compared with histopathology as the reference method, AVM understimated lesion size by 4% on average. This result was similar to MDM (3% understimation, not significantly different) but significantly better than US and mammographic lesion measurements (24% and 33% size underestimation, respectively). AVM is as accurate as MDM but faster. Both methods are more accurate for size assessment of breast lesions compared with US and mammography.

Optimized density‐weighted imaging for dynamic contrast‐enhanced 3D‐MR mammography

To increase the spatial coverage and to reduce slice crosstalk combined with an optimal signal-to-noise ratio (SNR) in 3D dynamic contrast-enhanced (DCE) magnetic resonance (MR) mammography. Asymmetric sampling schemes and a new reconstruction strategy based on virtual coils are presented for density-weighted (DW) 3D imaging. Additionally, for MR mammography an alternating DW (ADW) sampling along the k(y) direction shifts the undersampling artifacts out of the signal reception region. Virtual coils for effective DW (VIDED) imaging suppresses the aliasing in undersampled DW imaging. VIDED and ADW were compared to the conventional Cartesian imaging in phantom and in vivo MR mammography studies. The slice crosstalk was significantly reduced by VIDED and compared to Cartesian imaging the SNR increased by 16%. Additionally, VIDED and ADW provided a substantially increased field of view (FOV) in the slice direction and allowed the spatial resolution to be improved (up to 60% for ADW and 30% for VIDED) without lengthening the scan time. VIDED and ADW improve the image quality in 3D DCE MR mammography by enhancing the spatial resolution, reducing the slice crosstalk at nearly optimal SNR, and increasing the FOV in the slice direction. For VIDED no lengthening of the scan time or usage of multichannel receiver coils is necessary.

Breast cancer preoperative staging: does contrast-enhanced magnetic resonance mammography modify surgery?

Women with newly diagnosed breast cancer may have lesions undetected by conventional imaging. Recently contrast-enhanced magnetic resonance mammography (CE-MRM) showed higher sensitivity in breast lesions detection. The present analysis was aimed at evaluating the benefit of preoperative CE-MRM in the surgical planning. From 2005 to 2009, 525 consecutive women (25–75 years) with breast cancer, newly diagnosed by mammography, ultrasound, and needle-biopsy, underwent CE-MRM. The median invasive tumour size was 19 mm. In 144 patients, CE-MRM identified additional lesions. After secondlook, 119 patients underwent additional biopsy. CE-MRM altered surgery in 118 patients: 57 received double lumpectomy or wider excision (41 beneficial), 41 required mastectomy (40 beneficial), and 20 underwent contra lateral surgery (18 beneficial). The overall false-positive rate was 27.1% (39/144). CE-MRM contributed significantly to the management of breast cancer, suggesting more extensive disease in 144/525 (27.4%) patients and changing the surgical plan in 118/525 (22.5%) patients (99/525, 18.8% beneficial).

The value of dynamic MRI in the evaluation of the breast following conservative surgery and radiotherapy

ObjectiveTo assess the value of dynamic contrast-enhanced magnetic resonance mammography (DCE-MRM) in breast cancer patients treated by conservation breast surgery and radiotherapy. Materials and methodsThis prospective study were performed on 20 consecutive female patients, from January 2008 till January 2010 at Zagazig university hospitals. All cases had undergone breast conservative therapy (BCT) at least 9–12months since the end of radiation therapy up to 5years. All cases were suspected for either recurrence or post-operative complications by clinical examination in conjunction with mammography or/and US. DCE-MRM was performed at 1.5 T. The findings were correlated with the histopathology in all cases. ResultsWe found that DCE-MRM accurately revealed the presence or absence, location, and extent of recurrent tumor more accurately than mammography or US. US had high sensitivity and specificity (85.7% and 76.8%) compared to mammography (71.4% and 38.4%, respectively). Seven recurrent cases were found, two of them were multifocal. False-positive contrast enhancement was seen in only one patient pathologically proved as granuloma. MRI showed 95% accuracy, 100% sensitivity, 92.3% specificity with 83% positive predictive value and 100% negative predictive value. ConclusionThe conventional imaging was insufficient to detect the recurrent lesions after BCT, so DCE-MRI should be the imaging modality of choice in detection of the tumoral recurrence, and differentiating it from other complications. One limitation of the DCE-MRM is the persistent false-positive enhancement due to granulation tissue.

Accuracy of MRI volume measurements of breast lesions: comparison between automated, semiautomated and manual assessment

The aim of this study was to investigate the efficacy of a dedicated software tool for automated and semiautomated volume measurement in contrast-enhanced (CE) magnetic resonance mammography (MRM). Ninety-six breast lesions with histopathological workup (27 benign, 69 malignant) were re-evaluated by different volume measurement techniques. Volumes of all lesions were extracted automatically (AVM) and semiautomatically (SAVM) from CE 3D MRM and compared with manual 3D contour segmentation (manual volume measurement, MVM, reference measurement technique) and volume estimates based on maximum diameter measurement (MDM). Compared with MVM as reference method MDM, AVM and SAVM underestimated lesion volumes by 63.8%, 30.9% and 21.5%, respectively, with significantly different accuracy for benign (102.4%, 18.4% and 11.4%) and malignant (54.9%, 33.0% and 23.1%) lesions (p < 0.05). Inter- and intraobserver reproducibility was best for AVM (mean difference +/- 2SD, 1.0 +/- 9.7% and 1.8 +/- 12.1%) followed by SAVM (4.3 +/- 25.7% and 4.3 +/- 7.9%), MVM (2.3 +/- 38.2% and 8.6 +/- 31.8%) and MDM (33.9 +/- 128.4% and 9.3 +/- 55.9%). SAVM is more accurate for volume assessment of breast lesions than MDM and AVM. Volume measurement is less accurate for malignant than benign lesions.

Practical application of contrast-enhanced magnetic resonance mammography [CE-MRM] by an algorithm combining morphological and enhancement patterns

The purpose of this article is to report our practical utilization of dynamic contrast-enhanced magnetic resonance mammography [DCE-MRM] in the diagnosis of breast lesions. In many European centers, was preferred a high-temporal acquisition of both breasts simultaneously in a large FOV. We preferred to scan single breasts, with the aim to combine the analysis of the contrast intake and washout with the morphological evaluation of breast lesions. We followed an interpretation model, based upon a diagnostic algorithm, which combined contrast enhancement with morphological evaluation, in order to increase our confidence in diagnosis. DCE-MRM with our diagnostic algorithm has identified 179 malignant and 41 benign lesions; final outcome has identified 178 malignant and 42 benign lesions, 3 false positives and 2 false negatives. Sensitivity of CE-MRM was 98.3%; specificity, 95.1%; positive predictive value, 98.9%; negative predictive value, 92.8% and accuracy, 97.7%.

Diagnosis of ductal carcinoma in situ using contrast-enhanced magnetic resonance mammography compared with conventional mammography

Purpose The objective of this study is to compare mammography with magnetic resonance mammography (MRM) in the diagnosis of histopathologically verified subtypes of ductal carcinoma in situ (DCIS). Materials and Methods All patients with verified pure DCIS lesions (no signs of invasion or microinvasion) after surgery were identified between 2004 and 2006. Selection criteria were performed mammography and MRM at our institute prior to surgery resulting in a cohort of 33 patients (mean patient age, 60 years; mean lesion size, 15 mm). Results Magnetic resonance mammography enabled identification of DCIS in 29 of 33 patients with histopathologically verified pure DCIS (7 G1, 13 G2, and 9 G3 subtypes), giving an overall sensitivity of 87.9% for this patient cohort. Four DCIS lesions (two G1 and two G2) up to 5 mm diameter or smaller were not detected by MRM. In mammography, 21 of the 33 patients revealed suspicious outcome (including all lesions not detected by MRM), demonstrating an overall sensitivity of 63.6%. The remaining 12 mammographically occult DCIS lesions (three G1 subtypes, four G2 subtypes, five G3 subtypes) were all identified in MRM. Conclusion Magnetic resonance mammography can diagnose mammographically visible and also occult DCIS lesions without microcalcifications. Only small DCIS foci with microcalcifications could additionally be verified by mammography supposing MRM as a diagnostic approach.

Contrast-enhanced MR Mammography for Evaluation of the Contralateral Breast in Patients with Diagnosed Unilateral Breast Cancer or High-Risk Lesions1

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. 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. 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. 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.

Improved Lesion Detection in MR Mammography: Three-Dimensional Segmentation, Moving Voxel Sampling, and Normalized Maximum Intensity–Time Ratio Entropy

The objective of this work was to develop a quantitative method for improving lesion detection in dynamic contrast-enhanced magnetic resonance mammography (DCEMRM). For this purpose, we segmented and analyzed suspicious regions according to their contrast enhancement dynamics, generated a normalized maximum intensity-time ratio (nMITR) projection, and explored it to extract important features, to improve accuracy and reproducibility of detection. A novel automated method is introduced to segment and analyze lesions in three dimensions. It consists of four consecutive stages: volume of interest selection, nMITR projection generation using a voxel sampling method based on a moving 3 x 3 mask, three-dimensional lesion segmentation, and feature extraction. The nMITR projection of the detected lesion is used to extract six features: mean, maximum, standard deviation, kurtosis, skewness, and entropy, and their diagnostic significance is studied in detail. High-resolution MR images of 52 breast masses from 46 women are analyzed using the technique developed. Entropy, standard deviation, and the maximum and mean value features were found to have high significance (P < 0.001) and diagnostic accuracy (0.86-0.97). The kurtosis and skewness were not significant. Automated analysis of DCEMRM using nMITR was shown to be feasible. The lesion detection method described is efficient and leads to improved, accurate, reproducible diagnoses. It is reliable in terms of observer variability and may allow for a better standardization of clinical evaluations. The findings demonstrate the usefulness of nMITR based features; nMITR-entropy shows the best performance for quantitative diagnosis.

Contrast-enhanced magnetic resonance mammography: does it affect surgical decision-making in patients with breast cancer?

Diagnostic imaging in women with suspected breast cancer should accurately detect and diagnose malignant tumors and facilitate the correct choice of therapy. Contrast-enhanced magnetic resonance mammography (CE-MRM) is potentially the imaging modality of choice for accurate patient management decisions. A total of 164 women with suspected breast cancer based on clinical examination, conventional mammography and/or ultrasound each underwent preoperative bilateral CE-MRM using an axial 3D dynamic T1-weighted gradient-echo sequence and gadobenate dimeglumine as contrast agent. Images were evaluated by two readers in consensus. Histological evaluation of detected lesions was performed on samples from core biopsy or surgery. Determinations were made of the sensitivity, accuracy and positive predictive value of CE-MRM compared to mammography/ultrasound for the detection of malignant lesions and of the impact of CE-MRM for surgical decision-making. Conventional mammography/ultrasound detected 175 lesions in the 164 evaluated patients. CE-MRM revealed 51 additional lesions in 34/164 patients; multifocal and multicentric cancer was detected in 7 and 4 additional patients, respectively, contralateral foci in 21 additional patients and pectoral muscle infiltration in 2 additional patients. CE-MRM also confirmed the absence or benignity of 3 and 1 lesions suspected of malignancy on mammography/ultrasound. The sensitivity and accuracy for malignant lesion detection and identification was 100% and 93.4%, respectively, for CE-MRM compared to 77.3% and 72.1% for mammography/ultrasound, respectively. Patient management was altered for 32/164 (19.5%) patients as a result of CE-MRM. CE-MRM positively impacts patient management decisions and should be performed in all women with suspected breast cancer based on clinical examination, mammography and/or ultrasound.

Spatial and temporal resolution effects on dynamic contrast-enhanced magnetic resonance mammography

We tested the hypothesis that partial volume effects due to poor in-plane resolution and/or low temporal resolution used in clinical dynamic contrast-enhanced magnetic resonance imaging results in erroneous diagnostic information based on inaccurate estimates of tumor contrast agent extravasation and tested whether reduced encoding techniques can correct for dynamic data volume averaging. Image spatial resolution was reduced from 469 x 469 microm2 to those reported below by selecting a subset of k-space data. We then compared the top five K(trans)/V(T) "hot spots" obtained from the original data set, 469 x 469-microm in-plane spatial resolution and an 18-s temporal resolution processed by fast Fourier transform (FFT), with values obtained from data sets having in-plane spatial resolutions of 938 x 938, 1875 x 1875 and 2500 x 2500 microm2 and a temporal resolution of 18 s, or data sets with temporal resolutions of 36, 54 and 72 and a spatial resolution of 469 x 469 microm2, and found them to statistically differ from the parent data sets. We then tested four different post processing methods for improving the spatial resolution without sacrificing temporal resolution: zero-filled FFT, keyhole, reduced-encoding imaging by generalized-series reconstruction (RIGR) and two-reference RIGR (TRIGR). The top five values of K(trans)/V(T) obtained from data sets, the in-plane spatial resolutions of which were improved to 469 x 469 microm2 by zero-filling FFT, Keyhole and RIGR, statistically differed from those obtained from the original 469 x 469 microm2 FFT parent image data set. Only the 938 x 938 and 1875 x 1875 microm2 data sets reconstructed to 469 x 469 microm2 with TRIGR reconstruction method yielded values of the top five K(trans)/V(T) hot spots statistically the same as the original parent data set, 469 x 469 microm2 in-plane spatial and 18-s temporal-resolution FFT. That is, partial volume effects from data sets of different in-plane spatial resolution resulted in statistically different values of the top five K(trans)/V(T) hot spots relative to a high spatial and temporal resolution data set, and TRIGR reconstruction of these low resolution data sets to high resolution images provided statistically similar values with a savings in temporal resolution of 2 to 4 times.

Evaluation of quantitative parametric analysis for characterization of breast lesions in contrast-enhanced MR mammography

Our aim was to evaluate quantitative parametric analysis for characterization of breast lesions in contrast-enhanced magnetic resonance (MR) mammography. In 62 patients, contrast-enhanced MR mammography revealed 75 suspicious lesions, of which 18 were benign and 57 were malignant. The quantitative parametric analysis delineates signal intensity changes of contrast-enhanced lesions on a pixel-by-pixel basis. The initial rate of enhancement is coded by color intensity: a slow rate is coded to dark; a fast rate, bright. The postinitial enhancement change is coded by color hue: blue for increasing signal intensity, green for plateau, and red for decrease in signal intensity. Malignant lesions showed a significantly higher number of bright-red (P = 0.004) and medium-red (P < 0.001) pixels than benign lesions. Benign lesions showed significantly more blue pixels than did malignant lesions (P = 0.010). Of the 75 lesions, 72 (96%) showed heterogeneous distribution of pixel color hue. Quantitative parametric analysis of contrast kinetics in lesions can replace the subjective manual region of interest (ROI) method and makes a step toward standardization of MR mammography. It allows quantitative evaluation of different contrast kinetics parameters in contrast-enhanced breast lesions.