Contrast-enhanced Breast Magnetic Resonance Imaging Research Articles

Breast MRI used as a problem-solving tool reliably excludes malignancy

PurposeTo evaluate the diagnostic performance of breast MRI if used as a problem-solving tool in BI-RADS 0 cases. Material and methodsIn this IRB-approved, single-center study, 687 women underwent high-resolution-3D, dynamic contrast-enhanced breast magnetic resonance imaging (MRI) between January 2012 and December 2012. Of these, we analyzed 111 consecutive patients (mean age, 51±12 years; range, 20–83 years) categorized as BI-RADS 0. Breast MRI findings were stratified by clinical presentations, conventional imaging findings, and breast density. MRI results were compared to the reference standard, defined as histopathology or an imaging follow-up of at least 1 year. ResultsOne hundred eleven patients with BI-RADS 0 conventional imaging findings revealed 30 (27%) mammographic masses, 57 (51.4%) mammographic architectural distortions, five (4.5%) mammographic microcalcifications, 17 (15.3%) ultrasound-only findings, and two palpable findings without imaging correlates. There were 15 true-positive, 85 true-negative, 11 false-positive, and zero false-negative breast MRI findings, resulting in a sensitivity, specificity, PPV, and NPV of 100% (15/15), 88.5% (85/96), 57.7% (15/26), and 100% (85/85), respectively. Breast density and reasons for referral had no significant influence on the diagnostic performance of breast MRI (p>0.05). ConclusionBreast MRI reliably excludes malignancy in conventional BI-RADS 0 cases resulting in a NPV of 100% (85/85) and a PPV of 57.7% (15/26).

A Novel Approach to Contrast-Enhanced Breast Magnetic Resonance Imaging for Screening

The use of breast magnetic resonance imaging (MRI) as screening tool has been stalled by high examination costs. Scan protocols have lengthened to optimize specificity. Modern view-sharing sequences now enable ultrafast dynamic whole-breast MRI, allowing much shorter and more cost-effective procedures. This study evaluates whether dynamic information from ultrafast breast MRI can be used to replace standard dynamic information to preserve accuracy. We interleaved 20 ultrafast time-resolved angiography with stochastic trajectory (TWIST) acquisitions (0.9 × 1 × 2.5 mm, temporal resolution, 4.3 seconds) during contrast inflow in a regular high-resolution dynamic MRI protocol. A total of 160 consecutive patients with 199 enhancing abnormalities (95 benign and 104 malignant) were included. The maximum slope of the relative enhancement versus time curve (MS) obtained from the TWIST and curve type obtained from the regular dynamic sequence as defined in the breast imaging reporting and data system (BIRADS) lexicon were recorded. Diagnostic performance was compared using receiver operating characteristic analysis. All lesions were visible on both the TWIST and standard series. Maximum slope allows discrimination between benign and malignant disease with high accuracy (area under the curve, 0.829). Types of MS were defined in analogy to BIRADS curve types: MS type 3 implies a high risk of malignancy (MS >13.3%/s; specificity, 85%), MS type 2 yields intermediate risk (MS <13.3%/s and >6.4%/s), and MS type 1 implies a low risk (MS <6.4%/s; sensitivity, 90%). This simplification provides a much higher accuracy than the much lengthier BIRADS curve type analysis does (area under the curve, 0.812 vs 0.692; P = 0.0061). Ultrafast dynamic breast MRI allows detection of breast lesions and classification with high accuracy using MS. This allows substantial shortening of scan protocols and hence reduces imaging costs, which is beneficial especially for screening.

Breast Magnetic Resonance Imaging Alters Patient Selection for Accelerated Partial Breast Irradiation

To determine whether pretreatment contrast-enhanced breast magnetic resonance imaging (MRI) alters patient selection for accelerated partial breast irradiation (APBI). Women aged 40 years or older with unifocal invasive or intraductal carcinoma ≤2.5 cm on physical examination, mammography, and ultrasound (US) were evaluated with breast MRI before enrollment on an APBI trial using single-fraction intraoperative radiotherapy (IORT) or fractionated 3-dimensional conformal radiotherapy. Abnormal MRI findings were evaluated with US-guided or MRI-guided biopsy. Between December 2002 and March 2005, 51 women (median age=61 y; range, 40 to 83 y) who met inclusion criteria underwent breast MRI before APBI. MRI demonstrated limited disease in 41 patients (80.4%): 34 received APBI using IORT (22) or 3DCRT (12), whereas 7 elected standard whole-breast radiotherapy. Ten of the 51 patients (19.6%) had indeterminate or suspicious enhancement patterns on MRI. Five of these 10 (9.8% of MRI cohort) underwent US-guided or MRI-guided biopsy revealing normal breast tissue without atypia: 3 were treated with APBI using IORT (5.9% of MRI cohort) and 2 underwent standard breast conservation therapy (3.9% of MRI cohort). The remaining 5 patients (9.8% of MRI cohort) had MRI findings revealing previously unsuspected pectoral fascia involvement (1), multifocal disease (3), or multicentric disease (1): 2 were treated with standard breast conservation therapy, whereas 3 underwent mastectomy without adjuvant radiotherapy. Pretreatment breast MRI altered patient selection for APBI by identifying additional disease in 9.8% of the candidates, all of whom fit into the "cautionary" or "unsuitable" categories as defined by the American Society for Radiation Oncology APBI consensus guidelines. The clinical significance of these findings will be clarified with the results of ongoing randomized trials of APBI that do not incorporate breast MRI as part of the selection criteria.

Dynamic Contrast-Enhanced Magnetic Resonance Imaging of Breast Tumors at 3 and 7 T

The objective of this study was to compare the image quality, contrast enhancement behavior, and diagnostic value of bilateral 3-dimensional dynamic contrast-enhanced breast magnetic resonance imaging (MRI), with high spatial and temporal resolution, at 3 and 7 T, in the same patient group. Twenty-four consecutive patients (mean [SD] age, 57 [17] years) were included in this prospective institutional review board-approved study. Written informed consent was obtained from all patients. T1-weighted 3-dimensional sequences (time-resolved angiography with stochastic trajectories) were optimized at 3 and 7 T, with high temporal (both 14 seconds) and spatial resolution (1.1 × 1.1 × 1.1 mm [3 T], 0.7 × 0.7 × 0.7 mm [7 T]): echo time/repetition time, 2.84/6.01 milliseconds (3 T) and 2.5/4.75 milliseconds (7 T); acquisition time, 9 minutes (3 T/7 T). Dotarem (gadoterate meglumine, Guerbet, Roissy CdG, France) contrast agent was injected intravenously as a bolus (0.2 mL/kg of body weight) after 3 baseline images. The images were rated according to breast imaging-reporting and data system by 2 radiologists in consensus. Signal-to-noise ratio and average enhancement ratios were measured quantitatively by means of region of interest analysis. In addition, B1 mapping was done in the same 5 healthy subjects at both field strengths. Twenty-eight enhancing lesions were detected in the 24 patients at both field strengths (16 malignant, 12 benign). At 7 T, higher contrast than that at 3 T and good image quality were achieved. With the high spatial isotropic resolution of 0.7 mm at 7 T, images with more detailed information could be acquired when compared with those acquired at 3 T. Sensitivity was 93.75% and 100%, at 3 and 7 T, respectively. Specificity was 91.67% at both field strengths. The signal-to-noise ratio at both field strengths was comparable, but at 7 T, the spatial resolution was 3.2-times higher than that at 3 T. A signal-to-noise ratio decrease toward prepectoral breast regions due to B1 inhomogeneities was observed at both field strengths but was stronger at 7 T (51%) than at 3 T (19%)(P = 0.0002). At 7 T, B1+ dropped by 20.7% and 32.8% in the prepectoral and lateral region of the breast in healthy subjects. Our comparison study shows that 7-T DCE-MRI provides simultaneous high temporal and spatial resolution that is significantly improved compared with lower field strengths, but further technical improvements are necessary to overcome B1 inhomogeneity problems at 7 T to fully unfold the potential of breast MRI at 7 T.

Evaluation of Neoadjuvant Chemotherapy Response with Dynamic Contrast Enhanced Breast Magnetic Resonance Imaging in Locally Advanced Invasive Breast Cancer.

The reliability of traditional methods such as physical examination, ultrasonography (US) and mammography is limited in determining the type of treatment response in patients with neoadjuvant chemotherapy (NAC) application for locally advanced breast cancer (LABC). Dynamic contrast-enhanced magnetic resonance imaging (MRI) is gaining popularity in the evaluation of NAC response. This study aimed to compare NAC response as determined by dynamic contrast-enhanced breast MRI in patients with LABC to histopathology that is the gold standard; and evaluate the compatibility of MRI, mammography and US with response types. The US, mammography and MRI findings of 38 patients who received NAC with a diagnosis of locally advanced breast cancer and surgical treatment were retrospectively analyzed and compared to histopathology results. Type of response to treatment was determined according to the "Criteria in Solid Tumors Response Evolution 1.1" by mammography, US and MRI criteria. The relationship between response types as defined by all three imaging modalities and histopathology were evaluated, and the correlation of response type as detected by MRI and pathological response and histopathological type of breast cancer was further determined. For statistical analysis, the chi-square, paired t test, correlation and kappa tests were used. There is a statistical moderate positive correlation between response type according to pathology and MRI (kappa: 0.63). There was a weak correlation between response type according to mammography or US and according to pathology (kappa: 0.2). When the distribution of treatment response by MRI is stratified according to histopathological types, partial response was higher in all histopathological types similar to the type of pathologic response. When compared with pathology MRI detected treatment response accurately in 84.2% of the patients. Dynamic contrast-enhanced breast MRI appears to be a more effective method than mammography or US in the evaluation of response to neoadjuvant chemotherapy. MRI evaluation of LABC is accepted as the appropriate radiological approach.

BI-RADS® 3 lesions at contrast-enhanced breast MRI: is an initial short-interval follow-up necessary?

Magnetic resonance imaging (MRI) BI-RADS® 3 lesions should have a very high probability of being benign. To prove benignity most institutions do follow-up MRI. To evaluate the necessity of initial short-interval follow-up after 6 months as it is suggested for mammographic BI-RADS®3 lesions. We analyzed 163 consecutive MRI-BI-RADS® 3 lesions on follow-up MRI: 75 masses (46%), 67 foci (41.1%), and 21 (12.9%) non-mass-like enhancing lesions (NMLE). During MRI follow-up (mean time, 563 days) 20% of the lesions disappeared, 23% decreased, 52% did not change, and 4.9% showed increase. All increasing lesions were biopsied (5 benign, 2 ductal carcinoma in situ, 1 invasive carcinoma). The rate of malignancy was 1.8%. All malignant lesions (1 mass, 1 focus, 1 NMLE) showed increase at initial follow-up after a mean interval of 190 days. In this study the malignancy rate of MRI-BI-RADS® 3 lesions corresponded to mammographic BI-RADS® 3 lesions. Initial short-interval MRI should be suggested to identify malignant MRI-BI-RADS® 3 lesions.

MR imaging-guided vacuum-assisted breast biopsy: Reduction of false-negative biopsies by short-term control MRI 24–48 h after biopsy

To evaluate whether another contrast-enhanced (CE) magnetic resonance imaging (MRI) examination 24-48h after MRI-guided vacuum-assisted breast biopsy (MRI-VAB) can reduce the rate of false-negative cases. The study included 252 patients who underwent MRI-VAB for the clarification of 299 lesions. The success of MRI-VAB was assessed at interventional MRI and another CE MRI 24-48h after the intervention. In cases of successful MRI-VAB (complete or partial lesion removal) and benign histological results, follow-up breast MRI was performed. In cases of unsuccessful biopsy (unchanged lesion), tissue sampling was repeated. False-negative cases were calculated to assess the diagnostic value of MRI follow-up within 2 days after intervention. Ninety-eight malignant (32.8%) and 201 (67.2%) benign lesions were diagnosed using MRI-VAB. At immediate unenhanced control MRI, all lesions were assessed as successfully biopsied. In 18 benign cases (6%), CE MRI after 24-48h showed an unsuccessful intervention. Further tissue sampling revealed another 13 cancers in these patients. This results in a false-negative rate of 11.7%. Follow-up MRI of the benign lesions presented no further malignancy. MRI-VAB with immediate unenhanced control offers a success rate of 94%. The rate of false-negative biopsies (11.7%) could be reduced to zero by using short-term follow-up MRI. Therefore, a further CE breast MRI 24-48h after benign MRI-VAB to eliminate missed cancers is recommended.

Effects of Tamoxifen and Aromatase Inhibitors on Breast Tissue Enhancement in Dynamic Contrast–enhanced Breast MR Imaging: A Longitudinal Intraindividual Cohort Study

To prospectively investigate the effects of two antihormonal medications, tamoxifen and aromatase inhibitor (AI), on the degree of background enhancement in breast magnetic resonance (MR) imaging. This institutional review board-approved study was performed in 40 postmenopausal women (mean age, 63 years; range, 49-78 years) with unilateral breast cancer between January 2005 and December 2010. Informed consent was obtained from all participants. All patients underwent breast MR imaging before starting any medication, under tamoxifen, and after switching to an AI. Qualitative and quantitative degrees of benign parenchymal enhancement were investigated before treatment, under tamoxifen, and under AI. Data were analyzed by using the Wilcoxon singed-rank test and Student t test for matched pairs. Before treatment, the distribution of background enhancement MR-American College of Radiology (ACR) categories 1, 2, 3, and 4 was 20%, 35%, 33%, and 13%, respectively. With tamoxifen, background enhancement was suppressed, with a distribution of 80%, 15%, 5%, and 0% for MR-ACR categories 1, 2, 3, and 4, respectively. With AI, background enhancement recovered in part, with a distribution of 25%, 53%, 23%, and 0% for categories 1, 2, 3, and 4, respectively. In all 40 women, background enhancement rates were highest before treatment (mean, 51.3% ± 33.3 [standard deviation]). By using tamoxifen, background enhancement rates were significantly reduced (mean, 8.4% ± 9.2), and rose again after the switch to an AI (mean, 22.9% ± 19.1 [P < .001]). Prevalence of benign enhancing foci was 65% (26 of 40) at baseline, 12.5% (five of 40) with tamoxifen, and 40% (16 of 40) with AI. The effects of tamoxifen and AI on benign parenchymal enhancement differ. Whereas tamoxifen leads to a virtually complete suppression of enhancement, the effects of AI are less pronounced. Accordingly, whereas enhancement is unusual and deserves a more careful work-up in a patient in whom tamoxifen is used, this is not necessarily true for women in whom AIs are used. Online supplemental material is available for this article.

7 T versus 3 T contrast-enhanced breast Magnetic Resonance Imaging of invasive ductulolobular carcinoma: First clinical experience

PurposeHere we describe our first experience with contrast-enhanced (CE) MRI of breast cancer at 7tesla (T), compared to 3T and histopathology. Materials and MethodsA 52 year old female patient with a mammographically suspicious breast mass (BI-RADS V) underwent 7T CE-MRI. Results were described according to the BI-RADS-MRI criteria and compared to 3T and histopathology. ResultsAfter contrast administration, a homogeneously enhancing, irregular spiculated mass was depicted at both 3T and 7T; sizes were identical. The most malignant kinetic curve was characterized by a rapid initial rise followed by a wash-out pattern in the delayed phase, i.e. a type 3 curve, at both field strengths. Even though T1-effects of contrast agents are suggested to be reduced at higher fields, quantification of contrast enhancement-to-noise ratio showed a ratio of 4.6 at 7T and 2.8 at 3T when comparing contrast-to-noise of the mass before and after contrast administration. Both examinations, using a single dose of gadolinium-based contrast agent, achieved good image quality. Final histopathological evaluation showed an invasive ductulolobular carcinoma with an intraductal component. ConclusionThis initial experience suggests that clinical contrast-enhanced 7T MRI of the breast is technically feasible and may allow BI-RADS-conform analysis.

Location constrained approximate message passing for compressed sensing MRI

Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization methods for solving large-sized problems in compressed sensing. A novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) is presented for reducing computational complexity and improving reconstruction accuracy when a nonzero location (or sparse support) constraint can be obtained from view shared images. LCAMP modifies the existing approximate message passing algorithm by replacing the thresholding stage with a location constraint, which avoids adjusting regularization parameters or thresholding levels. This work is first compared with other conventional reconstruction methods using random one-dimention signals and then applied to dynamic contrast-enhanced breast magnetic resonance imaging to demonstrate the excellent reconstruction accuracy (less than 2% absolute difference) and low computation time (5-10 s using Matlab) with highly undersampled three-dimentional data (244 × 128 × 48; overall reduction factor = 10).

Updated breast MRI lexicon

The American College of Radiology (ACR) BI-RADS Breast Imaging Lexicon was developed over a 5 year period, initially organized in 1999 by a Breast MRI “Lesion Diagnosis Working Group” and later by the ACR. This work resulted in a lexicon (dictionary) of terms to describe breast lesions on contrast-enhanced breast magnetic resonance imaging studies. The first publication was developed when breast MRI was first being used and referencing the little data available to produce the lexicon of terms in describing lesions seen on breast MRI. Even though the ACR Lexicon has proved robust for the most part, since its publication there have been technical advances in breast MRI hardware, coils and pulse sequences, resulting in new information on breast cancer morphology and kinetic behavior. Publication on MRI studies using the new hardware and software resulted in increases in cancer sensitivity and specificity in published literature. As a result, information is now available on technical parameters required to obtain both high spatial and temporal resolution on breast MRI scans that resulted in high sensitivity and specificity. These advances and scientific data were used in developing and updating the new Lexicon. The new breast MRI Lexicon is chaired by Elizabeth A Morris, M.D and is expected to be published in the fall of 2012. The new ACR Lexicon includes a web-based format (hardcopy is also available), recommends mammography/US/MRI correlation, and has evidence based information with hyperlinks to references. The Lexicon also includes sections on Quality Assessment with technical parameters and kinetic/functional considerations that influence MRI images. There is a new section on audit recommendations. The ACR also lists a separate ACR Breast MRI Accreditation Program that accredits breast MRI facilities in the United States with technical, outcome and personnel credentialing criteria. Breast MRI Lexicon recommendations include adding T2weighted non-contrast sequences, and combined reporting of MRI with mammographic and ultrasound findings. Finally, simultaneous bilateral MRI scans are recommended and are considered standard of care. There is a new section on breast implants, with a lexicon describing the implant type, location, and findings commonly seen in intact and ruptured implants. In silicone breast implant studies, imaging terms include normal radial folds, subcapsular line, linguine and keyhole/teardrop. Importantly, there is a new section describing background parenchymal enhancement (BPE) that describes how much of the normal breast parenchyma enhances, which in turn can influence the sensitivity of breast MRI to detect cancer. The BPE can be described as none, minimal, mild, moderate or marked. Terms that previously were used to describe findings seen on breast MRI such as “diffuse stippled enhancement” may actually represent moderate BPE, which is a normal finding. As before, both morphology and kinetic information is considered important. There are no changes to the kinetic terminology. Morphology terms in the lexicon have been added or deleted, adding terms that were commonly used, and deleting those that were not used in the scientific literature. Deleted terms include central and septal enhancement, and enhancing septations. Morphology additions include clustered ring enhancement in contrast-enhanced studies. Morphology terms that have been revised include “non-masslike” to “non-mass” enhancement, and “irregular” mass margins to “uneven” mass margins in masses that have an irregular shape. Last, the Lexicon recommends a final BIRADS assessment including BIRADS codes 0 – Incomplete, Need Additional Imaging Evaluation, 1 – Negative, 2 – Benign, 3 – Probably Benign, 4 – Suspicious, 5 – Highly Suggestive of Malignancy, and 6 – Known Biopsy Proven Malignancy. The ACR Breast MRI Lexicon publication also includes an atlas that illustrates the key findings described in the lexicon. Because the contributors to the atlas were based both in the USA and around the world, there are a wide variety of techniques and pulse sequences that were used to generate the images. Variability in the examples include axial, sagittal, multi-planar reconstructions, fatsuppressed and non-fat-suppressed images chosen as state-of-theart, providing the reader with the rare chance to view MRI studies of specific findings using high-quality, varying techniques.

Intra-individual randomised comparison of gadobutrol 1.0 M versus gadobenate dimeglumine 0.5 M in patients scheduled for preoperative breast MRI

To demonstrate non-inferiority of gadobutrol versus gadobenate dimeglumine by intra-individually comparing 0.1 mmol/kg body weight doses for contrast-enhanced breast magnetic resonance imaging (MRI) and prospectively evaluating lesion detection and characterisation in a multicentre trial. Two identical breast MRI examinations were performed in 72 patients with biopsy-proven breast cancer, separated by 1-7 days. Gadobutrol 1.0 M or gadobenate 0.5 M were administered in a randomised order. Lesion detection and characterisation were performed by two independent blinded readers. Lesion tracking, which compared on-site readings and histology from surgery or biopsy, was performed by a third reader. Differences in lesion detection and characterisation were compared between the two contrast agents. Among 103 lesions, 96 were malignant and 7 were benign. No difference in lesion detection was identified between the contrast agents (82.33 % for gadobutrol, 81.60 % for gadobenate). Assessment of sensitivity in lesion characterisation and Breast Imaging Reporting and Data Systems showed no difference between gadobutrol (92.63 %) and gadobenate (90.53 %). Regarding morphology, there was more non-focal enhancement for gadobutrol than for gadobenate (P = 0.0057). Non-inferiority of gadobutrol compared with gadobenate was demonstrated for breast lesion detection and sensitivity in lesion characterisation in breast MRI.

Utility of Targeted Sonography in Management of Probably Benign Breast Lesions Identified on Magnetic Resonance Imaging

The purpose of this study was to determine the utility of targeted sonography in the management of probably benign breast lesions detected on magnetic resonance imaging (MRI). A total of 4370 consecutive contrast-enhanced breast MRI examinations from March 1, 2004, to March 1, 2009, were retrospectively reviewed. The study was Health Insurance Portability and Accountability Act compliant and Institutional Review Board approved. When targeted sonography was recommended for a Breast Imaging Reporting and Data System (BI-RADS) category 3 examination, results of the sonography and any subsequent breast pathologic examinations were recorded. The frequency of identifying the MRI-detected lesions and the rate at which the BI-RADS category was changed by sonography were calculated for mass and non-mass-like lesions. Of the 4370 examinations, 349 (8%) had BI-RADS 3 findings in 346 patients. One hundred eighteen lesions underwent targeted sonography for evaluation of 85 masses and 33 areas of non-mass-like enhancement. Of these 118 lesions, 54 (46%) were seen on sonography. No cancers were detected on sonography in the areas of non-mass-like enhancement. Two of the 85 masses (2.4%) evaluated with targeted sonography had a malignant diagnosis before initiation of follow-up. Selective use of targeted sonography, particularly in masses, may help identify some malignancies before initiating short-interval follow-up for MRI-detected BI-RADS 3 lesions.

Characteristics of axillary lymph nodes apparent on dynamic contrast-enhanced breast MRI in healthy women

The study was initiated to characterize and better understand the natural characteristics of axillary lymph nodes (LNs) apparent on dynamic breast magnetic resonance imaging (MRI). The most important finding in 71 subjects that included healthy women was that 41% showed strong enhanced axillary LNs. The dynamic curves of these LNs revealed an initial mean signal increase of 197% (±58%), all of them with a following plateau (34%) or washout (66%). Our study points out that the previous understanding of contrast enhancement in breast lesions should be taken with care when assessing axillary LNs. This has to be considered especially in preoperative breast MRI.

Advanced Imaging Techniques for the Detection of Breast Cancer

Mammography is the only breast imaging examination that has been shown to reduce breast cancer mortality. Population-based sensitivity is 75% to 80%, but sensitivity in high-risk women with dense breasts is only in the range of 50%. Breast ultrasound and contrast-enhanced breast magnetic resonance imaging (MRI) have become additional standard modalities used in the diagnosis of breast cancer. In high-risk women, ultrasound is known to detect approximately four additional cancers per 1,000 women. MRI is exquisitely sensitive for the detection of breast cancer. In high-risk women, it finds an additional four to five cancers per 100 women. However, both ultrasound and MRI are also known to lead to a large number of additional benign biopsies and short-term follow-up examinations. Many new breast imaging tools have improved and are being developed to improve on our current ability to diagnose early-stage breast cancer. These can be divided into two groups. The first group is those that are advances in current techniques, which include digital breast tomosynthesis and contrast-enhanced mammography and ultrasound with elastography or microbubbles. The other group includes new breast imaging platforms such as breast computed tomography (CT) scanning and radionuclide breast imaging. These are exciting advances. However, in this era of cost and radiation containment, it is imperative to look at all of them objectively to see which will provide clinically relevant additional information.

Suspicious Breast Lesions Detected at 3.0 T Magnetic Resonance Imaging: Clinical and Histological Outcomes

To evaluate the imaging features and histological and clinical outcomes of a series of suspicious, mammographically occult breast lesions detected at 3.0 T magnetic resonance imaging (MRI). Approval was obtained from the institutional review board. A Health Insurance Portability and Accountability Act-compliant retrospective review was performed of 121 suspicious, mammographically occult lesions detected on 3.0 T contrast-enhanced breast MRI. All 121 lesions underwent histological sampling. Radiology and clinic reports were reviewed for patient demographics, MRI indication and findings, biopsy and localization details, histological results, and follow-up information. Positive predictive value (PPV) of biopsy recommendations were calculated and compared for screening versus diagnostic cases. Likelihood of malignancy was also compared with lesion size. Statistical analyses were performed using chi-square, Fisher's exact, and two-tail z-tests. Overall 43 malignancies were diagnosed from 121 suspicious, mammographically occult 3.0 T MRI-detected lesions. Seventy-eight (64%) of the 121 were benign. The overall PPV of 3.0 T MRI-detected lesions was 36% (43/121). The PPV for biopsy in the screening setting (22% [10/45]) was statistically significantly less (P = .018) compared to the PPV of a biopsy recommendation in the diagnostic setting (43% [33/76]). There was no correlation between lesion size and the likelihood of detecting malignancy. Our PPV of suspicious, mammographically occult, breast lesions detected at 3.0 T breast MRI is similar to the PPV reported previously for suspicious breast lesions detected at 1.5 T. This study supports the use of 3.0 T breast MRI for both screening and diagnostic breast imaging.

Accuracy of Predicting Axillary Lymph Node Positivity by Physical Examination, Mammography, Ultrasonography, and Magnetic Resonance Imaging

Axillary lymph node status continues to be among the most important prognostic variables regarding breast cancer survival. We were interested in our ability to accurately predict axillary nodal involvement by using physical examination and standard breast imaging studies in combination. A retrospective review was performed of 244 consecutive patients diagnosed with invasive breast carcinoma between May 2008 and December 2010 who underwent physical examination of the axilla, digital mammography, axillary ultrasonography, and contrast-enhanced breast magnetic resonance imaging and who had subsequent histopathologic evaluation of one or more axillary lymph nodes. A total of 62 (25%) of 244 women were found to have positive axillary lymph nodes on final histopathologic examination, 42% of whom were able to be identified preoperatively. The sensitivity for predicting axillary metastasis if any one or more examination modalities were suspicious was 56.5%. The specificity for predicting axillary metastasis if any three or more modalities were suspicious was 100%. Of the patients who had all four modalities negative, 14% were ultimately found to have histologically positive nodes at the time of surgery. Physical examination and multimodal imaging in combination are useful for preoperative axillary staging and treatment planning. However, they remain inadequate definitive predictors of axillary lymph node involvement.

The role of breast magnetic resonance imaging on surgical treatment planning of breast cancer

To determine the frequency by which breast magnetic resonance imaging (MRI) provides information that influences the surgical management of patients with breast cancer. From August 2006 to December 2008, contrast-enhanced bilateral breast MRI was performed on 68 patients, all of whom exhibited highly suspicious imaging findings (BI-RADS category 4 or 5). Patients were grouped according to their histopathological diagnosis and type of breast parenchyma. All of the enrolled patients were believed to be candidates for breast conservation on the basis of physical examination, mammography, and ultrasonography. The patients were reevaluated with the MRI examination as to whether they were still candidates for breast conservation therapy. The MRI findings changed the previous management plans in 19.1% of the 68 patients. With respect to the surgical approach, no statistically significant difference was observed between the histopathology groups (P = 0.403). In terms of the breast parenchymal pattern, however, surgical planning was changed in 53.8% of the patients who exhibited a dense pattern, which was significantly different from the rates of the other groups (P = 0.006). The sensitivity, specificity, positive predictive value, and negative predictive value of the MRI for additional malignant lesion detection and identification were 85%, 98%, 92%, and 96%, respectively. The agreement test revealed 86% agreement (very good) between the additional findings observed on the MRI and the histopathological results. If breast-conserving surgery is planned, an MRI should be performed in all women with suspected breast cancer, especially those exhibiting dense or heterogeneously dense breast parenchyma, for which the sensitivity of both ultrasonography and mammography is low.

P3-14-06: Combined Use of 18F-FDG PET/CT and MRI To Monitor Breast Cancer Response during Neoadjuvant Chemotherapy.

Abstract Background and aim: Contrast-enhanced breast magnetic resonance imaging (MRI) is commonly used for the evaluation of the therapeutic effect of neoadjuvant chemotherapy (NAC). A recent study demonstrated the relevance of breast cancer subtype with regard to the accuracy of MRI to predict response during NAC. The role of 18F-fluorodeoxyglucose (FDG) positron emission tomography (FDG PET/CT) is under investigation, and varying results have been reported. MRI and 18F-FDG PET/CT, visualize different functional characteristics of the tumor (perfusion and glucose metabolism), but it is unclear if they complement one another to monitor response to NAC, and whether breast cancer subtype plays an independent role. Method and material: The study group consisted of 65 women with stage II or III breast cancer and measurable FDG tumor uptake, who were treated with NAC and participated in an ongoing MRI/FDG PET/CT study. MRI and FDG PET/CT scans were acquired prior to and during treatment, using prone patient positioning. Written informed consent was obtained. Prior to the start of NAC a biopsy was taken and tumors were divided into three subtypes, using immunohistochemistry: human epidermal growth factor receptor 2 (HER2) amplified (HER2+) (N=18), estrogen receptor positive/HER2 non-amplified (ER+/HER2−) (N=29), and triple negative (TN) tumors (N=18). MRI interpretation included lesion morphology at baseline, changes in morphology, tumor size, and contrast uptake kinetics (initial and late enhancement). At FDG PET/CT the maximum standardized uptake value (SUVmax) at baseline and during treatment was obtained. Tumor response at pathology was stratified to “incomplete response” (substantial presence of vital invasive tumor cells) and “favourable response” (complete absence of invasive residual tumor or only a small number of scattered tumor cells). Appropriate statistical analyses including T-tests, multivariate logistic regression and receiver operating characteristic (ROC) curves were employed to indentify factors associated with incomplete response at pathology. The following imaging and clinical features were candidates for forward feature selection in the multivariate analysis: lesion morphology, largest tumor diameter, pattern of reduction, absolute and relative change in largest tumor diameter at initial and at late enhancement during NAC, SUVmax at baseline; absolute and relative change in SUVmax during NAC; breast cancer subtype; chemotherapy regimen, and age. Results: At pathology after NAC, 32 tumors (49 %) showed favourable response and 33 (51 %) had residual disease. At multivariate analysis, breast cancer subtype, relative change in the diameter of late enhancement on MRI and relative change in SUVmax on FDG PET/CT were independent markers of tumor response at final pathology. The area under the ROC curve increased from 0.86 for MRI alone to 0.94 (p&amp;lt;0.01) in combination with FDG PET/CT and breast cancer subtype, yielding 84% sensitivity at 95 % specificity. Conclusion: MRI and FDG PET/CT show complementary potential to predict response during NAC, in addition to breast cancer subtype. Ackowledgement: This study was supported by the Center for Translational Molecular Medicine, project Breast CARE (grant ***03O-104). Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-14-06.

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). Two versions of a 3D fast gradient echo TWIST sequence were implemented and applied to patients: First, an ultrafast TWIST acquisition (TA = 5.7 sec) in combination with a routine DCE MRM protocol to allow the extraction of arterial input functions and to resolve the first pass of the contrast agent. Second, a dynamic full coverage TWIST DCE acquisition (TA = 10.6 sec) in a repeat examination, replacing the routine DCE MRM sequence. The ultrafast acquisition enabled extraction of arterial input functions and the monitoring of the contrast agent's first pass through vessels and lesions. The dynamic full coverage TWIST acquisition captured the initial dynamic slope of the signal time curve of lesions accurately, in contrast to the routine protocol. TWIST acquisitions proved very robust and offer high flexibility in protocol timing. The ultrafast protocol achieved 5.7 seconds time resolution with good image quality and can be combined with any established routine protocol. The full dynamics TWIST DCE protocol offers improved time resolution of the CE dynamic time-course and closely matches the image quality of the routine protocol.