Dynamic Contrast-enhanced Breast MRI Research Articles

SU‐EE‐A4‐04: Accelerating Breast Dynamic Contrast Enhanced MRI with Efficient Multiple Acquisitions by SPEED Using Shared Information

Purpose: The efficient multiple acquisition method using Skipped Phase Encoding and Edge Deghosting (SPEED) has been successfully demonstrated with a dynamic contrast enhanced (CE) mice tumor study; however, it has not been tested with any human subjects. In this work, this technique is further developed to accelerate breast dynamic CE MRI. Method and Materials: In dynamic CE‐MRI, a series of images are acquired within different time frames, which contain highly similar spatial information. The strong structural similarity is used to accelerate imaging by SPEED with factors greater than that achievable with a single acquisition. It was tested in this work with an in vivo breast dynamic CE MRI study. The dynamic CE scan was performed on a GE 1.5T system using a T1‐weighted gradient echo sequence (matrix 256×256, FOV 20cm × 20cm, TR = 5.5 ms, TE = 1.5 ms, flip angle = 30°, slice thickness = 4 mm, the number of frames = 7). Results: Reference images are first reconstructed from full k‐space data. The corresponding deghosted images are then reconstructed from partial data, with undersampling factors of 3/5 for one frame and 2/5 for all other frames, resulting in an acceleration factor of 2. In other words, the total scan time is 3.5 times that of a single acquisition. The images reconstructed from partial data by the proposed method show comparable quality as those reference images. Conclusion: In this work, the technique of efficient multiple acquisitions by SPEED is further developed to accelerate breast dynamic CE MRI. By using shared spatial information, a breast dynamic CE MRI study is accelerated by SPEED with a factor of 2, which is greater than that achievable with a single acquisition. This saving can be used to double the image resolution, or to increase the frame rates of dynamic sequence.

Breast Stromal Enhancement on MRI Is Associated with Response to Neoadjuvant Chemotherapy

Cancerous neovascular changes in histologically normal-appearing breast tissue have been shown to increase risk for local recurrence after breast-conserving therapy. However, the imaging characteristics of this tissue have not been well studied. We hypothesized that signal enhancement ratios from dynamic contrast-enhanced breast MRI could be used to analyze the contrast kinetics of microvasculature in breast stroma beyond the tumor margin and that this information can be developed to improve local treatment options. Signal enhancement ratio analysis of nontumor breast stroma was performed on dynamic contrast-enhanced MRI scans of 42 patients who received neoadjuvant chemotherapy for invasive breast cancer performed before chemotherapy (scan 1) and after one cycle of chemotherapy (scan 2). Stromal signal enhancement ratio values were then correlated to several clinical parameters and to clinical outcome using univariate and multivariate analyses. Median follow-up for the group was 52.1 months. On univariate analysis, factors that were significantly associated (p < 0.05) with disease-free survival included the mean stromal signal enhancement ratio at scan 2 (hazard ratio [HR] = 0.11, 95% CI = 0.013-0.88, p = 0.03), pretreatment tumor size (HR = 1.33, 95% CI = 1.07-1.66, p = 0.012), pretreatment tumor volume (HR = 1.04, 95% CI = 1.01-1.07, p = 0.006), and number of involved axillary lymph nodes (HR = 1.18, 95% CI = 1.05-1.32, p = 0.005). These factors were then analyzed in a multivariate Cox proportional hazards model. The only factor that was associated with disease-free survival was mean stromal signal enhancement ratio at scan 2 (HR = 0.11, 95% CI = 0.012-0.95, p < 0.045). These findings indicate that breast stroma tissue outside the incident tumor can be quantified using signal enhancement ratio analysis on dynamic contrast-enhanced MRI. Stromal signal enhancement ratio is a potential indicator for response to treatment and for overall outcome in patients with breast cancer; however, these results should be validated in a prospective study.

What is the sensitivity of mammography and dynamic MR imaging for DCIS if the whole-breast histopathology is used as a reference standard?

Our purpose was to compare mammography and dynamic contrast-enhanced magnetic resonance imaging (MRI) in the detection of ductal carcinoma in situ (DCIS). Ninety patients (aged 58.6+/-16.1 years) who were candidates for unilateral (n=81) or bilateral (n=9) mastectomy underwent mammography and dynamic contrast-enhanced breast MRI using a coronal three-dimensional gradient-echo sequence with slice thickness < or =3 mm before and after intravenous injection of gadoteridol (0.1 mmol/kg). Mammographic and MR images were evaluated by two offsite readers working in consensus. Pathological examination performed on 5-mm sections covering the whole breast was used as a reference standard. Out of 99 breasts, pathology revealed 26 DCIS in 14 breasts of 14 patients, aged 52.0 +/- 9.6 years. Lesion diameter at pathology was <5 mm (n=4); > or =5 and <10 mm (n=7); > or =10 and <20 mm (n=3); > or =20 mm (n=2); not assessed (n=10). Sensitivity was 35% (9/26) for mammography and 38% (10/26) for MRI (not significant difference, McNemar test). Both mammography and MRI provided a true positive result in seven cases (four of them measured at pathology, with a diameter of 20.0+/-12.9 mm; median 20 mm) and a false negative result in 14 cases (10 of them measured at pathology, with a diameter of 4.2+/-1.9 mm; median 4.6 mm) (p=0.024, Mann-Whitney U test). Only 46% (12/26) of DCIS were detected at mammography and/or MRI; the remaining 54% (14/26) were diagnosed only at pathological examination. When the whole breast is used as the histopathological reference standard, both mammography and MRI show low sensitivity for DCIS.

Effect of Gd-DTPA induCED susceptibility on single-point dixon fat/water separation

A single-point Dixon (SPD) fat/water separation method is proposed for breast dynamic contrast-enhanced MRI (DCE-MRI) in which field inhomogeneities and phase offsets measured prior to the injection of gadopentate dimeglumine (Gd-DTPA) are used to correct the postinjection images. A breast phantom study was conducted to demonstrate this technique, in which varying excess concentrations of Gd-DTPA (0-3 mM) were introduced into a 25-cm(3) breast lesion. The presence of excess Gd-DTPA in the lesion was found to create magnetic field perturbations of up to 0.35 microT per mM excess Gd-DTPA around the lesion. However, these perturbations had a negligible effect on the quality of the fat/water separation for Gd-DTPA concentrations in the range of, and exceeding, those observed in breast tumors following a standard 0.1 mmole/kg injection. Therefore, we conclude that the preinjection phase data is adequate for the correction of the postinjection images in breast exams.

Unsupervised clustering of fMRI and MRI time series

Unsupervised clustering represents a powerful technique for self-organized segmentation of biomedical image time series data describing groups of pixels exhibiting similar properties of local signal dynamics. The theoretical background is presented in the beginning, followed by several medical applications demonstrating the flexibility and conceptual power of these techniques. These applications range from functional MRI data analysis to dynamic contrast-enhanced perfusion MRI and breast MRI. For fMRI, these methods can be employed to identify and separate time courses of interest, along with their associated spatial patterns. When applied to dynamic perfusion MRI, they identify groups of voxels associated with time courses that are clinically informative and straightforward to interpret. In breast MRI, a segmentation of the lesion is achieved and in addition a subclassification is obtained within the lesion with regard to regions characterized by different MRI signal time courses. In the present paper, we conclude that unsupervised clustering techniques provide a robust method for blind analysis of time series image data in the important and current field of functional and dynamic MRI.

Supine Breast MRI Utilizing a Zonal Motion-Adapted Acquisition and Reordering Technique

Dynamic, contrast-enhanced breast MRI (DCE-MRI) has been shown to be more accurate than mammography, ultrasound and clinical breast exam for the identification of tumour extent in the breast. However, DCE breast MRI is not currently utilized for the guidance of breast conservation surgery, primarily due to the differences in breast positioning during the MR imaging compared to the positioning in the surgical theatre. Therefore a supine positioning of the patient during MR imaging is preferred, which should result in a better matching of the images of the preoperative MRI and the later positioning in the operating room.

Dynamic contrast-enhanced MR imaging in screening detected microcalcification lesions of the breast: is there any value?

To prospectively evaluate whether dynamic contrast-enhanced magnetic resonance (MR) imaging findings can help predict the presence of malignancy when screening detected microcalcification lesions, and its contribution to patient management of stereotactic vacuum-assisted breast biopsy (SVAB). Dynamic contrast-enhanced breast MR imaging was performed when screening 100 detected microcalcification lesions not visualized by ultrasonography with 11-gauge SVAB. Definitive surgery was performed on all patients with the biopsy resulting in the diagnosis of breast cancer or atypical ductal hyperplasia (ADH). Positive predictive values (PPVs) and negative predictive values (NPVs) were calculated on the basis of a BI-RADS (Breast Imaging Reporting and Data System) category and the absence or presence of contrast uptake in the area of microcalcification. The BI-RADS mammography category correlated with the diagnosis of breast cancer (ADH excluded): category 3 = 7% (4/55); category 4 = 48% (13/27); category 5 = 94% (17/18). After dynamic contrast-enhanced MR imaging, three of four malignancies with BI-RADS mammography category 3 were diagnosed as true positive. Therefore, the PPV of BI-RADS mammography category 3 with MR imaging was 1.8% (1/55). The PPV of contrast uptake of MR imaging was 86% (32/37), significantly higher than the 67% (30/45) PPV of BI-RADS mammography 4 and 5 (P = 0.033). The NPV of BI-RADS mammography 3 was 93% (51/55) versus 97% (61/63) NPV of MR imaging (P = 0.167). In the evaluation of screening detected microcalcification lesions, dynamic contrast-enhanced breast MR imaging provides additional information with high PPV and NPV, and may therefore offer an alternative to SVAB for women who do not want to undergo SVAB with equivocal findings following full diagnostic mammographic assessment, but breast MR imaging with imperfect PPV and NPV cannot replace SVAB. Dynamic contrast-enhanced breast MR imaging can demonstrate malignant microcalcifications detected by screening mammography and can be recommended in the evaluation of equivocal microcalcifications prior to SVAB.

Rapid fat suppression in MRI of the breast with short binomial pulses

To develop a faster method of fat suppression for use in dynamic contrast enhanced MRI of the breast. A method of fast fat suppression is presented using spatially nonselective rapid binomial pulses. In contrast to conventional binomial frequency-selective pulses, these short pulses are applied without interpulse delay, allowing for very rapid spectrally selective excitation. Effective water excitation and fat suppression were achieved in breast MRI at 3.0 Tesla with total excitation time as low as 160 microsec, which is several times shorter than the excitation time of currently used fat suppression techniques. Rapid fat suppression comes at the expense of increased specific absorption rate (SAR) and mildly degraded quality of suppression. A flexible tradeoff of short imaging time vs. SAR can be made to optimize imaging speed for fat-suppressed breast MRI. Rapid binomial pulses can be used for dynamic contrast enhanced breast MRI with excitation times significantly shorter than currently used fat suppression pulses. Shorter excitation time allows more rapid imaging, allowing greater temporal and spatial resolution for characterization of breast lesions.

Dynamic Contrast-enhanced Breast MR Imaging in Men: Preliminary Results

To prospectively evaluate whether the descriptors of lesion features and the diagnostic criteria that have been established for breast magnetic resonance (MR) imaging in female patients may be used for differential diagnosis with breast MR imaging in male patients as well. The study design was approved by the institutional review board; all patients gave informed consent. The Institutional Review Board and informed consent information applied to the prospective and any retrospective component of the study. Seventeen consecutive male patients (mean age, 53 years +/- 14) were referred for imaging of a palpable breast mass. In addition to mammography and high-frequency breast ultrasonography, patients underwent dynamic breast MR imaging in a prone position with a dedicated double-breast surface coil. The standardized protocol consisted of a T2-weighted turbo spin-echo sequence followed by a dynamic series. Findings were recorded by using the terminology and descriptors and by evaluating the diagnostic criteria (related to morphology and enhancement kinetics) that have been developed for breast MR imaging in female patients. Validation was achieved at biopsy (nine patients) or follow-up with clinical examination and conventional imaging (eight patients). Because of the small size of the patient cohort, statistical significance was not tested. A total of 24 breast abnormalities were diagnosed. Three patients had invasive breast cancer (five tumors), 11 had gynecomastia (six unilateral, five bilateral), two had pseudogynecomastia, and one had a benign solid tumor (angiolipoma). All malignant tumors appeared as irregular masses with heterogeneous internal architecture or rim enhancement and showed rapid initial enhancement (mean value, 137% +/- 23) followed by a washout time course (Breast Imaging Reporting and Data System [BI-RADS] category 5). Diffuse and nodular gynecomastia showed slow initial and persistent enhancement with normal-appearing parenchymal architecture (BI-RADS category 2; 15 of 16 breasts in 10 of 11 patients). In one patient with biopsy-proved bilateral gynecomastia, an area with segmental enhancement was classified as suspicious for ductal carcinoma in situ. Pseudogynecomastia did not enhance at all. The angiolipoma showed benign morphologic features and slow initial and persistent enhancement (BI-RADS category 2). In the small study cohort, the MR imaging features of benign breast diseases and breast cancers in male patients seemed to be comparable to those seen in female patients.

Breast MRI at Highfield

Puropose: Breast MR imaging has an established role for staging primary cancer and for diagnosing recurrent tumor. Recently, it has also been suggested as screening tool in specific high risk cohorts. In particular in a screening setting, a high PPV is mandatory. One way to improve the technique's PPV is by improving morphologic analysis of enhancing lesions by higher matrix imgaing. MR systems operating at stronger magnetic fields (e.g. 3.0T) may offer the higher SNR that is necessary for high-matrix time-resolved MR imaging. On the other hand, high field systems may go along with specific difficulties that are due to stronger susceptibility effects, longer T1 relaxation times, and higher RF deposition. Aim of this study was first, to establish a clinically useful and stable pulse sequence for bilateral dynamic contrast enhanced breast MRI at 3.0T that would provide about the same diagnostic information as breast MRI at 1.5T. Second, we strived to establish pulse sequences that would provide a higher spatial resolution compared to what is currently attainable at 1.5T.

Bilateral open breast coil and compatible intervention device

Dynamic contrast-enhanced breast MRI is an extremely sensitive method for breast lesion detection. For MR-only detected lesions it is essential that needle biopsy or localization prior to surgery is carried out under MR guidance. This work describes a bilateral open breast coil and prototype intervention device, which may be used in these situations. Results demonstrate that the open coil provides images superior to those obtained with a conventional closed breast coil. Initial phantom tests with the intervention device indicate a potential for this system to be used in the MR-guided localization of breast lesions. J. Magn. Reson. Imaging 2000;12:984-990.

Dynamic image interpretation of MRI of the breast.

Dynamic breast MRI provides information on both lesion cross-sectional morphology and functional lesion features such as vascularity/perfusion and vessel permeability. This review gives an overview of the historical background of dynamic contrast-enhanced breast MRI. It explains the technique's pathophysiological basis, describes the various technical approaches that have been pursued and the corresponding interpretation guidelines that have been proposed (including their respective diagnostic accuracies), and presents established and evolving clinical applications of the "dynamic approach" to breast MRI. J. Magn. Reson. Imaging 2000;12:965-974.

Accuracy of T1 measurement in dynamic contrast-enhanced breast MRI using two- and three-dimensional variable flip angle fast low-angle shot.

In vivo T1 measurements, used to monitor the uptake of contrast agent by tissues, are typically performed as a first step in implementing compartmental analysis of contrast-enhanced breast magnetic resonance imaging (MRI) data. We have extended previously described methodology for in vivo T1 measurement (using a variable flip-angle gradient-recalled echo technique) to two-dimensional (2D), fast low-angle shot (FLASH). This approach requires computational modeling of slice-selective radiofrequency (RF) excitation to correct for nonrectangular slice profiles. The accuracy with which breast tissue T1 values can be measured by this approach is examined: T1 measurements from phantom and in vivo image data acquired with 2D and 3D FLASH imaging sequences are presented. Significant sources of error due to imaging pulse sequence quality and RF transmit field nonuniformity in the breast coil device that will have detrimental consequences for compartmental analysis are identified. Rigorous quality assurance programs with calibrated phantoms are thus recommended, to verify the accuracy with which T1 measurements are obtained.

Improved diagnostic accuracy in dynamic contrast enhanced MRI of the breast by combined quantitative and qualitative analysis.

To develop an optimized interpretation strategy of dynamic contrast enhanced breast MRI based on a combination of quantitative and qualitative criteria, the features of 120 histopathologically verified lesions were retrospectively analysed on contrast enhanced dynamically acquired (before and 1, 2, 4 and 7 min following injection of 0.2 mmol kg-1 gadolinium-DOTA) three-dimensional gradient echo images. Quantitative criteria, based on relative signal intensity measurements and qualitative morphological features, including lesion shape, margins and enhancement patterns were analysed in regard to differentiating malignant (n = 70) from benign (n = 50) lesions. Quantitative assessment of enhancement profiles was most accurate when analysis was based on early 1 min measurements. Using a 90% threshold, sensitivity and specificity in detecting breast cancer were 83% and 66%, respectively. When based on qualitative morphological analysis alone, sensitivity and specificity were 83% and 54%. Combined quantitative and qualitative assessment yielded a considerably higher sensitivity, specificity and accuracy of 93%, 74% and 85%, respectively. In conclusion, results from dynamic contrast enhanced breast MRI can be improved by basing the interpretation on both quantitative and qualitative criteria.

Dynamic MR imaging of invasive breast cancer: correlation with tumour grade and other histological factors.

The purpose of this study was to explore the association between dynamic MR enhancement characteristics and histopathological prognostic factors of invasive breast cancer. 53 women with primary invasive breast cancer underwent dynamic contrast enhanced breast MRI. Region of interest (ROI) analysis was performed on synthetic images obtained by kinetic modelling of the dynamic data. Operator-defined, large ROIs and computer-defined, 9-pixel ROIs were selected for each tumour. The relative increase in mean ROI pixel intensity was expressed in the form of enhancement ratios. Univariate and multivariate analyses were performed to explore the association of these ratios with standard histological factors, including tumour size, histopathological classification, histological grade, the presence of extensive in situ component and lymphovascular invasion, multifocal disease, and axillary lymph node status. All enhancement ratios showed significant differences between node-positive and node-negative tumours (max. p = 0.002). However, automated ROI ratios showed less overlap between node-positive and node-negative carcinomas than did large ROI ratios. A strongly significant association was observed between all automated ROI enhancement ratios and histological tumour grade (max. p = 0.001). Based on stepwise multiple regression analysis, node status and histological grade were the only histopathological factors with a significant independent effect on the enhancement characteristics. In summary, there is a strong association between dynamic MR characteristics and two important prognostic markers of invasive breast cancer, namely axillary node status and histological grade. This may allow MRI to be used in pre-operative predictions of tumour behaviour and biological activity.

Breast neoplasms: T2* susceptibility-contrast, first-pass perfusion MR imaging.

To evaluate the differentiation of benign from malignant breast tumors with T2*-weighted perfusion magnetic resonance (MR) imaging (blood volume imaging) versus that with dynamic T1-weighted contrast agent-enhanced MR imaging. Ten healthy adult volunteers and 18 adult patients with benign or malignant lesions underwent both conventional T1-weighted dynamic contrast-enhanced breast MR imaging and repetitive first-pass, single-section, dynamic T2*-weighted perfusion MR imaging. Images were obtained before, during, and after injection of 20 mL of gadopentetate dimeglumine; peak gadopentetate dimeglumine concentrations were calculated from the maximal signal intensity loss on T2*-weighted images. No perfusion effect was detectable in healthy breast parenchyma. A strong susceptibility-mediated signal intensity loss occurred in malignant breast tumors. No or only minor perfusion effects were seen in fibroadenomas, in spite of their rapid enhancement at T1-weighted dynamic imaging. Perfusion imaging was possible after conventional dynamic contrast-enhanced breast MR imaging. T2*-weighted perfusion imaging exploits the susceptibility-mediated signal intensity loss of a first-pass bolus of gadopentetate dimeglumine within the capillary bed. First-pass perfusion imaging of breast lesions is feasible. It is promising in the differentiation of benign from malignant, rapidly enhancing lesions.

Dynamic sequential 3D gadolinium-enhanced MRI of the whole breast.

Dynamic contrast-enhanced 2D MR imaging of the breast has shown high sensitivity and specificity for the detection and characterization of breast lesions. We investigated the ability of a dynamic fast 3D MR imaging technique that repeatedly scans the whole breast in 44-s intervals without an interscan delay time to obtain similar sensitivity and specificity as 2D imaging. Fifty-six patients scheduled for breast biopsy were entered into the study, and 83 lesions detected by 3D dynamic scanning were biopsied. Dynamic 3D contrast-enhanced breast imaging with subtraction detected and correctly classified all 23 cancers, and 44 of the 60 benign lesions yielding a sensitivity of 100%, a specificity of 73%, and a 100% predictive negative value. The enhancement profiles of metastatic lymph nodes were similar to those of primary cancer. This technique allowed detection of multifocal and multicentric lesions and did not require a prior knowledge of lesion location. These results indicate that dynamic contrast-enhanced 3D MRI of the whole breast is a useful and economically feasible method for staging breast cancer, providing a comprehensive noninvasive method for total evaluation of the breast and axilla in patients considering breast conservation surgery or lumpectomy.