Gadolinium-enhanced MR angiography of the breast: is breast cancer associated with ipsilateral higher vascularity?

The value of dynamic contrast-enhanced magnetic resonance imaging combined with apparent diffusion coefficient in the differentiation of benign and malignant diseases of the breast

BACKGROUND

The value of combined dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and apparent diffusion coefficient (ADC) histogram analysis for the diagnosis of breast cancer has not been evaluated in previous studies.

PURPOSE

To investigate the diagnostic value of DCE-MRI combined with ADC in benign and malignant breast lesions.

MATERIAL AND METHODS

The clinicopathological imaging data included 168 patients (177 lesions) with breast lesions who underwent convention breast MRI, DCE-MRI, and diffusion-weighted imaging (DWI); they were divided into the benign lesion group (n = 39) and malignant lesion group (n = 129) based on pathology.

RESULTS

Using the type III outflow curve as a diagnostic criterion for malignant breast lesions, the diagnostic sensitivity was 76.9%, the specificity was 80%, the correct rate was 72.2%, and its area under the curve (AUC) was 0.823. Using an enhancement ratio > 100% as a diagnostic criterion for malignant breast lesions, the sensitivity was 61.5%, specificity was 80%, and AUC was 0.723. Using > 3 ipsilateral vessels as a diagnostic criterion for malignant lesions in the breast resulted in a diagnostic sensitivity of 81.6%, a specificity of 80.8%, and an AUC of 0.805.

CONCLUSION

The type of time intensity curve DCE-MRI, the early enhancement rate in the first phase, the number of ipsilateral vessels, and the ADC full volume histogram of the blood supply score and DWI are valuable in the diagnosis of benign and malignant breast lesions.

Vascularity and Dynamic Contrast-Enhanced Breast Magnetic Resonance Imaging

Angiogenesis is a key step in the initiation and progression of an invasive breast cancer. High microvessel density by morphological characterization predicts metastasis and poor survival in women with invasive breast cancers. However, morphologic characterization is subject to variability and only can evaluate a limited portion of an invasive breast cancer. Consequently, breast Magnetic Resonance Imaging (MRI) is currently being evaluated to assess vascularity. Recently, through the new field of radiomics, dynamic contrast enhanced (DCE)-MRI is being used to evaluate vascular density, vascular morphology, and detection of aggressive breast cancer biology. While DCE-MRI is a highly sensitive tool, there are specific features that limit computational evaluation of blood vessels. These include (1) DCE-MRI evaluates gadolinium contrast and does not directly evaluate biology, (2) the resolution of DCE-MRI is insufficient for imaging small blood vessels, and (3) DCE-MRI images are very difficult to co-register. Here we review computational approaches for detection and analysis of blood vessels in DCE-MRI images and present some of the strategies we have developed for co-registry of DCE-MRI images and early detection of vascularization.

Does three-dimensional functional infrared imaging improve breast cancer detection based on digital mammography in women with dense breasts?

Purpose

We aimed to estimate the incremental cancer detection rate achieved by adding three-dimensional functional infrared imaging (3DIRI) to digital mammography in women with dense breasts.

Materials and methods

In this prospective study conducted between December 2014 and April 2016, 1727 women (median age 56) with percentage volumetric breast density > 6% were recruited at routine screening mammography to undergo additional 3DIRI. The 3DIRI findings were classified as negative or positive. Women with a negative mammography but positive 3DIRI were referred to dynamic contrast-enhanced MRI, whereas all other women underwent routine follow-up based on the mammography finding. Diagnosis of breast cancer was verified by histopathologic examination. The number of women diagnosed with a malignancy formed the basis of our statistical analysis.

Results

Mammography detected 7 cancers in 7 women. Of 1692 women with negative mammography, 222 women (13%) had a positive 3DIRI of which 219 underwent MRI. An additional 6 cancers were identified in 5 women, increasing the diagnostic yield from 7 of 1727 (0.41%) to 12 of 1727 (0.69%). The incremental cancer detection rate associated with using 3DIRI to select women for MRI was 5 of 222 (22.5 additional cancers per 1000).

Conclusion

The use of 3DIRI to select women for an additional MRI can result in the detection of additional cancers in women with dense breasts, but at the expense of additional false positives and considerably lower positive predictive value of the combined examinations. Additional studies are necessary to evaluate the role of 3DIRI as an adjunct to mammography.

Key Points

• Use of three-dimensional functional infrared imaging to select women for an MRI in addition to screening mammography has the potential to improve breast cancer detection in women with dense breasts.

Electronic supplementary material

The online version of this article (10.1007/s00330-019-06248-y) contains supplementary material, which is available to authorized users.

Quantitative analysis of vascular properties derived from ultrafast DCE-MRI to discriminate malignant and benign breast tumors

PURPOSE

We propose a novel methodology to integrate morphological and functional information of tumor-associated vessels to assist in the diagnosis of suspicious breast lesions.

THEORY AND METHODS

Ultrafast, fast, and high spatial resolution DCE-MRI data were acquired on 15 patients with suspicious breast lesions. Segmentation of the vasculature from the surrounding tissue was performed by applying a Hessian filter to the enhanced image to generate a map of the probability for each voxel to belong to a vessel. Summary measures were generated for vascular morphology, as well as the inputs and outputs of vessels physically connected to the tumor. The ultrafast DCE-MRI data was analyzed by a modified Tofts model to estimate the bolus arrival time, K^trans (volume transfer coefficient), and v_p (plasma volume fraction). The measures were compared between malignant and benign lesions via the Wilcoxon test, and then incorporated into a logistic ridge regression model to assess their combined diagnostic ability.

RESULTS

A total of 24 lesions were included in the study (13 malignant and 11 benign). The vessel count, K^trans , and v_p showed significant difference between malignant and benign lesions (P = 0.009, 0.034, and 0.010, area under curve [AUC] = 0.76, 0.63, and 0.70, respectively). The best multivariate logistic regression model for differentiation included the vessel count and bolus arrival time (AUC = 0.91).

CONCLUSION

This study provides preliminary evidence that combining quantitative characterization of morphological and functional features of breast vasculature may provide an accurate means to diagnose breast cancer.

Ultrafast dynamic contrast-enhanced mri of the breast using compressed sensing: breast cancer diagnosis based on separate visualization of breast arteries and veins

PURPOSE

To evaluate the feasibility of ultrafast dynamic contrast-enhanced (UF-DCE) magnetic resonance imaging (MRI) with compressed sensing (CS) for the separate identification of breast arteries/veins and perform temporal evaluations of breast arteries and veins with a focus on the association with ipsilateral cancers.

MATERIALS AND METHODS

Our Institutional Review Board approved this study with retrospective design. Twenty-five female patients who underwent UF-DCE MRI at 3T were included. UF-DCE MRI consisting of 20 continuous frames was acquired using a prototype 3D gradient-echo volumetric interpolated breath-hold sequence including a CS reconstruction: temporal resolution, 3.65 sec/frame; spatial resolution, 0.9 × 1.3 × 2.5 mm. Two readers analyzed 19 maximum intensity projection images reconstructed from subtracted images, separately identified breast arteries/veins and the earliest frame in which they were respectively visualized, and calculated the time interval between arterial and venous visualization (A-V interval) for each breast.

RESULTS

In total, 49 breasts including 31 lesions (breast cancer, 16; benign lesion, 15) were identified. In 39 of the 49 breasts (breasts with cancers, 16; breasts with benign lesions, 10; breasts with no lesions, 13), both breast arteries and veins were separately identified. The A-V intervals for breasts with cancers were significantly shorter than those for breasts with benign lesions (P = 0.043) and no lesions (P = 0.007).

CONCLUSION

UF-DCE MRI using CS enables the separate identification of breast arteries/veins. Temporal evaluations calculating the time interval between arterial and venous visualization might be helpful in the differentiation of ipsilateral breast cancers from benign lesions.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018;47:97-104.

Optical Imaging of the Breast: Basic Principles and Clinical Applications

OBJECTIVE

The objective of this article is to summarize the physical principles, technology features, and first clinical applications of optical imaging techniques to the breast.

CONCLUSION

Light-breast tissue interaction is expressed as absorption and scattering coefficients, allowing image reconstruction based on endogenous or exogenous contrast. Diffuse optical spectroscopy and imaging, fluorescence molecular tomography, photoacoustic imaging, and multiparametric infrared imaging show potential for clinical application, especially for lesion characterization, estimation of cancer probability, and monitoring the effect of neoadjuvant therapy.

Breast Contrast Enhanced MR Imaging: Semi-Automatic Detection of Vascular Map and Predominant Feeding Vessel

Purpose

To obtain breast vascular map and to assess correlation between predominant feeding vessel and tumor location with a semi-automatic method compared to conventional radiologic reading.

Methods

148 malignant and 75 benign breast lesions were included. All patients underwent bilateral MR imaging. Written informed consent was obtained from the patients before MRI. The local ethics committee granted approval for this study. Semi-automatic breast vascular map and predominant vessel detection was performed on MRI, for each patient. Semi-automatic detection (depending on grey levels threshold manually chosen by radiologist) was compared with results of two expert radiologists; inter-observer variability and reliability of semi-automatic approach were assessed.

Results

Anatomic analysis of breast lesions revealed that 20% of patients had masses in internal half, 50% in external half and the 30% in subareolar/central area. As regards the 44 tumors in internal half, based on radiologic consensus, 40 demonstrated a predominant feeding vessel (61% were supplied by internal thoracic vessels, 14% by lateral thoracic vessels, 16% by both thoracic vessels and 9% had no predominant feeding vessel—p<0.01), based on semi-automatic detection, 38 tumors demonstrated a predominant feeding vessel (66% were supplied by internal thoracic vessels, 11% by lateral thoracic vessels, 9% by both thoracic vessels and 14% had no predominant feeding vessel—p<0.01). As regards the 111 tumors in external half, based on radiologic consensus, 91 demonstrated a predominant feeding vessel (25% were supplied by internal thoracic vessels, 39% by lateral thoracic vessels, 18% by both thoracic vessels and 18% had no predominant feeding vessel—p<0.01), based on semi-automatic detection, 94 demonstrated a predominant feeding vessel (27% were supplied by internal thoracic vessels, 45% by lateral thoracic vessels, 4% by both thoracic vessels and 24% had no predominant feeding vessel—p<0.01). An excellent agreement between two radiologic assessments (k = 0.81) and between radiologic consensus and semi-automatic assessment (k = 0.80) was found to identify origin of predominant feeding vessel. An excellent reliability for semi-automatic assessment (Cronbach's alpha = 0.96) was reported.

Conclusions

Predominant feeding vessel location was correlated with breast lesion location: internal thoracic artery supplied the highest proportion of breasts with tumor in internal half and lateral thoracic artery supplied the highest proportion of breasts with lateral tumor.

Comparison of diameters of ipsilateral and contralateral internal mammary arteries by breast MRI in patients with unilateral breast cancer

PURPOSE

We compared maximal diameters of ipsilateral (IMA) and contralateral (IMA) internal mammary arteries in patients with unilateral breast cancer and analyze the implications of enlargements of ipsilateral or contralateral IMAs in relation to histopathologic factors.

MATERIALS AND METHODS

Of 568 women who underwent breast magnetic resonance imaging (MRI) examinations from January 2009 to May 2012, 196 had unilateral, histologically proven breast cancer. In 156 women, maximal IMA diameters in the second intercostal space were measured by two blinded radiologists in left and right sides using nonenhanced axial T2-weighted turbo spin-echo sequence images.

RESULTS

In the 156 study patients, mean maximal diameter of ipsilateral IMAs (2.37 ± 0.60 mm) was significantly larger than that of contralateral IMAs (2.03 ± 0.58 mm) (p = 0.00). Ipsilateral IMA enlargement was present in 66.7 % of the patients (104 of 156). Furthermore, ipsilateral IMA enlargement was found to be significantly associated with human epidermal growth factor receptor-2 (HER-2) expression (p = 0.039).

CONCLUSIONS

Maximal IMA diameter was significantly greater in ipsilateral sides in breast cancer patients. Findings suggest ipsilateral IMA enlargement detected by MRI might be a useful additional predictor of HER-2 expression in unilateral breast cancer.

A new algorithm for automatic vascular mapping of DCE-MRI of the breast: Clinical application of a potential new biomarker

BACKGROUND AND OBJECTIVE

Vascularity evaluation on breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) has a potential diagnostic value, but it represents a time consuming procedure, affected by intra- and inter-observer variability. This study tests the application of a recently published method to reproducibly quantify breast vascularity, and evaluates if the vascular volume of cancer-bearing breast, calculated from automatic vascular maps (AVMs), may correlate with pathologic tumor response after neoadjuvant chemotherapy (NAC).

METHODS

Twenty-four patients with unilateral locally advanced breast cancer underwent DCE-MRI before and after NAC, 8 responders and 16 non-responders. A validated algorithm, based on multiscale 3D Hessian matrix analysis, provided AVMs and allowed the calculation of vessel volume before the initiation and after the last NAC cycle for each breast. For cancer bearing breast, the difference in vascular volume before and after NAC was compared in responders and non-responders using the Wilcoxon two-sample test. A radiologist evaluated the vascularity on the subtracted images (first enhanced minus unenhanced), before and after treatment, assigning a vascular score for each breast, according to the number of vessels with length ≥30mm and maximal transverse diameter ≥2mm. The same evaluation was repeated with the support of the simultaneous visualization of the AVMs. The two evaluations were compared in terms of mean number of vessels and mean vascular score per breast, in responders and non-responders, by use of Wilcoxon two sample test. For all the analysis, the statistical significance level was set at 0.05.

RESULTS

For breasts harboring the cancer, evidence of a difference in vascular volume before and after NAC for responders (median=1.71cc) and non-responders (median=0.41cc) was found (p=0.003). A significant difference was also found in the number of vessels (p=0.03) and vascular score (p=0.02) before or after NAC, according to the evaluation supported by the AVMs.

CONCLUSIONS

The encouraging, although preliminary, results of this study suggest the use of AVMs as new biomarker to evaluate the pathologic response after NAC, but also support their application in other breast DCE-MRI vessel analysis that are waiting for a reliable quantification method.

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

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

Breast contrast-enhanced MR imaging: semiautomatic detection of vascular map

BACKGROUND

The diagnostic value of breast vascular maps using contrast-enhanced MR imaging has recently been explored. We propose a semiautomatic method to obtain breast vascular maps and to measure the number of blood vessels in the breast.

METHODS

From January 2011 to December 2013, 188 patients underwent breast contrast-enhanced MRI; patients with unilateral and histopathologically confirmed breast lesions were included in this study; 123 patients had malignant lesions and 65 patients had benign tissue diagnoses. Breast semiautomatic vascular map detection was performed using Hessian matrix-based method and morphologic operators. Blood vessels detection was compared with radiologic interpretation findings to evaluate algorithm goodness. Increase in vascularity associated with ipsilateral cancer was also assessed. Chi square test was used to observe statistically significant difference.

RESULTS

A total of 1315 blood vessels were identified using semiautomatic procedure; 1034 were correctly classified (78.7 %), 261 (19.8 %) were incorrectly classified, and 20 (1.5 %) were missing. A significant association was found between one-sided increased breast vascularity and ipsilateral malignancy (p < 0.001).

CONCLUSIONS

In conclusion, detection of vascularity increase as risk factor for developing breast cancer could be performed with semiautomatic vascular mapping of contrast-enhanced MR imaging.

Effect of taxane-based neoadjuvant chemotherapy on fibroglandular tissue volume and percent breast density in the contralateral normal breast evaluated by 3T MR

The aim of this study was to evaluate the change of breast density in the normal breast of patients receiving neoadjuvant chemotherapy (NAC). Forty-four breast cancer patients were studied. MRI acquisition was performed before treatment (baseline), and 4 and 12 weeks after treatment. A computer-algorithm-based program was used to segment breast tissue and calculate breast volume (BV), fibroglandular tissue volume (FV), and percent density (PD) (the ratio of FV over BV × 100%). The reduction of FV and PD after treatment was compared with baseline using paired t-tests with a Bonferroni-Holm correction. The association of density reduction with age was analyzed. FV and PD after NAC showed significant decreases compared with the baseline. FV was 110.0 ml (67.2, 189.8) (geometric mean (interquartile range)) at baseline, 104.3 ml (66.6, 164.4) after 4 weeks (p < 0.0001), and 94.7 ml (60.2, 144.4) after 12 weeks (comparison with baseline, p < 0.0001; comparison with 4 weeks, p = 0.016). PD was 11.2% (6.4, 22.4) at baseline, 10.6% (6.6, 20.3) after 4 weeks (p < 0.0001), and 9.7% (6.2, 17.9) after 12 weeks (comparison with baseline, p = 0.0001; comparison with 4 weeks, p = 0.018). Younger patients tended to show a higher density reduction, but overall correlation with age was only moderate (r = 0.28 for FV, p = 0.07, and r = 0.52 for PD, p = 0.0003). Our study showed that breast density measured from MR images acquired at 3T MR can be accurately quantified using a robust computer-aided algorithm based on non-parametric non-uniformity normalization (N3) and an adaptive fuzzy C-means algorithm. Similar to doxorubicin and cyclophosphamide regimens, the taxane-based NAC regimen also caused density atrophy in the normal breast and showed reduction in FV and PD. The effect of breast density reduction was age related and duration related.

Bilateral analysis of the cross-sectional area of the internal mammary arteries and veins in patients with and without breast cancer on breast magnetic resonance imaging

OBJECTIVE

To analyse bilateral differences in the cross-sectional area of the internal mammary artery (IMA) and vein (IMV) in breast cancer patients compared to healthy controls.

MATERIALS AND METHODS

On 135 breast MRIs the cross-sectional areas of the IMA and IMV were measured on the left and right side in the second and third intercostal space (ICS) by two independent readers. Differences were analysed using a linear mixed model.

RESULTS

In the healthy control group (n = 91) no significant differences between the cross-sectional areas of the IMA and IMV were observed. Both readers reported a mean adjusted difference of 0.12 mm2 (p = 0.298) and 0.21 mm2 (p = 0.058) for the IMA in the second ICS. In the malignancy group (n = 44) the cross-sectional area was significantly larger on the malignancy side compared to the contralateral side. The largest difference in the IMA was measured in the second ICS with a mean adjusted difference for reader 1 of 1.37 mm2 (p < 0.001) and for reader 2 of 0.81 mm2 (p = 0.003).

CONCLUSIONS

The vascular cross-sectional area of internal mammary vessels was significantly different on the side with breast cancer compared to the contralateral side. This difference was not observed in healthy controls.

MAIN MESSAGES

• MRI has become an important imaging modality in the diagnostic workup of breast cancer. • In healthy persons no significant difference in the size of the left and right IMA is observed. • A significant enlargement of the IMA on the malignant side occurs in most patients.

A novel functional infrared imaging system coupled with multiparametric computerised analysis for risk assessment of breast cancer

OBJECTIVE

We evaluated a functional three-dimensional (3D) infrared imaging system (3DIRI) coupled with multiparametric computer analysis for risk assessment of breast cancer. The technique provides objective risk assessment for the presence of a malignant tumour based on automated parameters derived from a clinically known training set.

METHODS

Following institutional review board approval, we recruited 434 women for this prospective multicentre trial, including 256 healthy woman undergoing routine screening mammography with BI-RADS-1 results and 178 women with newly diagnosed breast cancer. This was a two-phase study: an initial training and calibration phase, followed by a two-armed blinded evaluation phase (52 healthy and 66 with breast cancer). 3DIRI data sets were acquired using a non-contact, no radiation system.

RESULTS

The sensitivity and specificity of functional infrared imaging in providing the correct risk for the presence of breast cancer were 90.9 % and 72.5 %, respectively. The area under the ROC curve was 86 %. Forty-two of the 60 (70 %) cancers in women correctly classified by the system as suspicious were smaller than 20 mm in size.

CONCLUSION

The preliminary blinded results of this novel technology show sufficient performance of functional infrared imaging in providing risk assessment for breast cancer to warrant further clinical studies.

KEY POINTS

• 3D functional infrared imaging (3DIRI) provides new metabolic signatures from breast lesions. • 3DIRI offers high sensitivity for risk assessment of breast cancer. • It also has reasonable specificity. • This initial experience warrants further evaluation in larger clinical trials.

Prognostic role of MRI enhancement features in patients with breast cancer: value of adjacent vessel sign and increased ipsilateral whole-breast vascularity

OBJECTIVE

The purpose of this study was to compare adjacent vessel sign, increased ipsilateral whole-breast vascularity, and various MRI features as described in the American College of Radiology BI-RADS MRI lexicon with histopathologic predictors in patients with unilateral breast cancer.

MATERIALS AND METHODS

We retrospectively evaluated breast MRI examinations of 249 patients with histologically confirmed breast cancer. In addition to the BI-RADS MRI lexicon, the adjacent vessel sign and increased ipsilateral whole-breast vascularity of the cancer-bearing breast were evaluated by two independent observers. MRI features were then correlated with histopathologic prognostic factors.

RESULTS

The adjacent vessel sign was significantly (p=0.023 to p<0.001) associated with tumor size, lymph node metastasis, distant metastasis, nuclear grade, and expression of estrogen and progesterone receptors. Increased ipsilateral whole-breast vascularity was significantly associated with all histopathologic predictors (p=0.017 to p<0.001). In multivariate analysis, the significant and independent predictors were a spiculated margin and rim enhancement for negative estrogen and progesterone receptors, a kinetic curve type for higher histologic grade, and an increased ipsilateral whole-breast vascularity for larger tumor size, lymph node metastasis, distant metastasis, higher nuclear grade, and higher histologic grade.

CONCLUSION

In conjunction with the standard BI-RADS MRI lexicon, the adjacent vessel sign and increased ipsilateral whole-breast vascularity may serve as additional predictors of a poor prognosis.

Contrast-enhanced MR imaging of the breast: association between asymmetric increased breast vascularity and ipsilateral cancer in a consecutive series of 197 patients

PURPOSE

This study was done to estimate the diagnostic performance of an asymmetric increase in breast vascularity (AIBV) for ipsilateral cancer.

MATERIALS AND METHODS

A total of 197 patients without previous breast interventions underwent bilateral contrast-enhanced (gadoterate meglumine, 0.1 mmol/kg) magnetic resonance (MR) imaging. Vessels >-2 mm in diameter and ≥ 3 cm in length were counted on maximum intensity projections: a difference ≥ 2 in number between the two breasts was considered AIBV. Pathology or ≥ 1 year follow-up served as a reference standard. The difference in sensitivity of AIBV between invasive and ductal carcinoma in situ (DCIS) as well as the association between AIBV and the diameter of invasive lesions or the histological grade were evaluated using χ(2) test.

RESULTS

Pathology revealed 82 malignancies and 20 benign lesions: 70 invasive carcinomas (57 ductal, nine lobular, three mucinous, one papillary) and 12 DCIS: 10 fibroadenomas, two papillomas, two atypical ductal hyperplasias and six other benign lesions. The remaining 95 patients were negative at follow-up. Sensitivity of AIBV was 74% (61/82), specificity 94% (108/115), accuracy 86% (169/197), positive predictive value 90% (61/68) and negative predictive value 84% (108/129). Sensitivity for invasive cancers (80%; 56/70) was significantly higher than that for DCIS (42%; 5/12) (p<0.001). For invasive cancers, sensitivity was 40% (2/5) for lesions ≤ 9 mm in diameter, 69% (9/13) for those 10-14 mm, 79% (15/19) for those 15-19 mm and 91% (30/33) for those ≥ 20 mm (p<0.001). The G3 lesion rate was 49% (27/55) among true positives and only 7% (1/14) among false negatives (p=0.009).

CONCLUSIONS

An association between AIBV and ipsilateral cancer exists, particularly for invasive cancers ≥ 20 mm or with high pathologic grade.

Variation of breast vascular maps on dynamic contrast-enhanced MRI after primary chemotherapy of locally advanced breast cancer

OBJECTIVE

The purpose of this article is to assess changes in breast vascular maps on dynamic contrast-enhanced MRI (DCE-MRI) after primary chemotherapy in patients with locally advanced breast cancer (LABC).

SUBJECTS AND METHODS

Thirty-four patients with unilateral LABC underwent DCE-MRI before and after anthracycline- and taxane-based primary chemotherapy. The number of vessels 30 mm or longer in length and 2 mm or larger in maximum transverse diameter were counted on maximum intensity projections of the first subtracted phase for each of the two breasts. Patients achieving pathologic response or small clusters of residual cancer cells after primary chemotherapy were considered as responders, and those with an inferior pathologic response were considered as nonresponders.

RESULTS

The mean (± SD) number of vessels in the breast harboring the cancer and in the contralateral breast was 2.7 ± 1.3 and 1.1 ± 1.0 (p < 0.001), respectively, before primary chemotherapy and 1.3 ± 1.1 and 1.1 ± 1.1 (p = 0.147), respectively, after primary chemotherapy. Overall, primary chemotherapy was associated with a significant reduction in DCE-MRI vascular maps in the breast harboring the cancer only (p < 0.001). Of the 34 patients, 10 were considered responders and 24 were nonresponders. The mean number of vessels in the breast harboring the cancer changed from 2.7 ± 1.1 to 0.6 ± 0.8 for the 10 responders and from 2.7 ± 1.4 to only 1.6 ± 0.9 for the 24 nonresponders. The mean reduction of vascular map in the breast harboring the cancer was significantly higher in responders compared with nonresponders (p = 0.017).

CONCLUSION

Before primary chemotherapy, DCE-MRI vascular maps were asymmetrically increased ipsilaterally to the LABC. After primary chemotherapy, vascular maps significantly changed only in the breast harboring the cancer, with significant differences between responders and nonresponders.

Magnetic resonance imaging of breast vascularity in medial versus lateral breast cancer

OBJECTIVE

Breasts with malignant tumors can demonstrate a general increased vascularity compared to the contralateral breast and a prominent blood vessel adjacent to the tumor on magnetic resonance imaging (MRI). The aim of the study was to further characterize these alterations in blood supply by location of the tumor within the breast using MRI.

MATERIALS AND METHODS

The study group included 105 patients who underwent breast MRI for suspicion of a malignancy over a 2-year period. Fifty-one had pathologically verified malignant tumors (study group), 11 had pathologically verified benign lesions (control), and 43 had negative scans (control). The malignant lesions were distinguished by location, medial or lateral, within the breast. Origin of the vascular supply and vessel diameter was recorded in a blinded manner. When available, MRI scans performed 2 years after treatment were reviewed as well.

RESULTS

Of the 24 medial malignant tumors, 21 (87%) had a predominantly medial vascular supply and 3 (13%), a predominantly lateral supply; of the 23 lateral tumors, 11 (48%) had a predominantly medial vascular supply and 8 (35%), a predominantly lateral supply (p=0.03). In 4 cases, no dominant vessel was noted. Maximum vessel diameter was 3.6+/-1.1mm in the patients with malignancy and 2.6 +/- 0.8mm in the controls (p<0.0005). General increased vascularity was demonstrated in 91% of the medial tumor subgroup and 83% of the lateral tumor subgroup, as opposed to 36-37% in the control groups (p<0.0005). Follow-up MRI, performed in 8 patients in the malignant-tumor group after treatment, revealed a considerable decrease in the prominent vessels, to a size close to that of the controls.

CONCLUSION

Breasts with malignant tumors are characterized by an altered general vascular supply, a prominent feeding vessel, and increased regional vascularity. Both the presence and location of the tumor affect the vascular supply. The vascular change apparently diminishes after treatment, although this finding requires further investigation in a larger sample.

Breast vascular mapping obtained with contrast-enhanced MR imaging: implications for cancer diagnosis, treatment, and risk stratification

The value of breast vascular maps obtained using contrast-enhanced MR imaging has recently been explored. Additional information is obtained only by evaluating maximum intensity projections of the first dynamic subtraction to achieve a form of MR angiography of the breast. No increase in acquisition time and no dedicated contrast injections are needed. Four studies have been performed to evaluate the one-sided (asymmetric) increase in vascularity associated with ipsilateral cancer in a total of 404 patients with a cancer prevalence ranging from 38% to 80%. Sensitivity ranged from 72% to 88%, specificity from 57% to 100%, positive predictive value from 85% to 100%, negative predictive value from 38% to 88%, and overall accuracy from 73% to 87%. An asymmetric increase in breast vascularity ipsilateral to a cancer may be due to reduced flow resistance in the tumour, to a high metabolic rate (more likely in large tumours) or to angiogenic stimulation of the whole breast harbouring the lesion (more likely in small tumours). Tumour size could play a specific role in determining the ipsilaterally increased vascularity, and invasive cancers might be more frequently associated with ipsilaterally increased vascularity than in situ cancers. Moreover, while a reduction in breast vasculature has anecdotically been observed in breasts with locally advanced cancers treated with neoadjuvant chemotherapy, especially when taxanes are used, the higher incidence of breast cancer in patients with size asymmetry between the breasts as determined on screening mammography suggests that a role for breast MR vascular mapping in breast cancer risk stratification should be explored. Finally, arteries and veins might be differentiated with dedicated techniques. High-relaxivity agents may be used with advantage in these future investigations.

Inflammatory breast carcinoma in magnetic resonance imaging: a comparison with locally advanced breast cancer

RATIONALE AND OBJECTIVES

Although inflammatory breast carcinoma (IBC) accounts for 1%-4% of all breast cancer cases, the appearance of this highly malignant tumor in magnetic resonance imaging (MRI) is still not well characterized. The aim of this study was to identify typical imaging features of IBC in comparison with noninflammatory locally advanced breast carcinoma (LABC).

MATERIALS AND METHODS

MRIs of 48 patients with IBC were compared with an equivalent cohort of 52 subjects with LABC. Age and histopathologic subtype were equivalent between the two groups. To delineate characteristic features, a multitude of dynamic and morphologic parameters were evaluated using T1- and T2-weighted sequences.

RESULTS

No significant differences of prevalences could be found for the following criteria: dynamic tumor signal characteristics, prominent vessels, perifocal edema, axillary lymph node involvement, morphology of focal masses, and morphologic pattern of non-mass like enhancement. Otherwise, the quantity of focal masses and the spatial distribution of the tumoral infiltration significantly differed between the two cancer groups. The following parameters occurred more frequently in the IBC cases: edema (cutaneous/subcutaneous 81.3%, perimamillar 70.8%, diffuse 89.6%, prepectoral 72.9%, intramuscular pectoral 41.7%), thickening (75.0%) and pathologic enhancement (60.4%) of Cooper's ligaments, skin thickening (83.3%), punched-out sign (initially strong, focal increase of some dermal or subcutaneous parts followed by slow-continuous enhancement of the surrounding skin; 56.3%).

CONCLUSIONS

Inflammatory breast carcinoma seems to represent a specific biological entity resulting in typical MRI characteristics. Some of the parameters are supposed to visualize the characteristic extensive lymphovascular infiltration and therefore may improve the diagnosis of IBC.

MR imaging and proton spectroscopy of the breast: how to select the images useful to convey the diagnostic message

PURPOSE

The purpose of this study was to propose a short way to summarise a breast magnetic resonance (MR) examination including a precontrast and contrast-enhanced dynamic study and proton spectroscopy (1H-MRS) in order to convey the diagnostic message.

MATERIALS AND METHODS

At the Department of Radiology of the Policlinico San Donato (University of Milan), breast MR is routinely performed at 1.5 T as follows: 36-slice axial 2D short-time inversion-recovery (STIR) sequence; 128-partition 3D gradient-echo coronal sequence (1-mm3 siotropic voxel) before and after rapid automatic intravenous injection of 0.1 mmol/kg of Gd-DOTA (one precontrast and four postcontrast phases). Postprocessing includes temporal subtraction (postcontrast minus precontrast), maximum intensity projections (MIPs), percent enhancement-to-time curves for small regions of interest, and axial and/or sagittal multiplanar reconstructions. Single-voxel 1H-MRS is acquired to characterise focal lesions. Applying this protocol, more than 1,200 images are generated for each examination. We select only four MIPs of an early subtracted dynamic phase: one axial similar to craniocaudal x-ray mammographic views, one coronal, and two lateral similar to lateral 90 degrees x-ray mammographic views. For each lesion described in the report, we select five items, including three images, one graph, and one table: STIR image, precontrast and subtracted postcontrast images (morphology), percent enhancement-to-time curves and a table of raw data generating the curves (dynamics). If 1H-MRS has been performed, we add other five items: two postprocessed spectra (metabolism) and three images localising the volume of interest. Only the selected items are printed on films and attached to the report.

RESULTS

The selected items range usually from four (no detected lesion) to 14 (one lesion, studied also with 1H-MRS), to 44 (five lesions, one of them studied also with 1H-MRS). The percentage of items presented with the report if compared with the total number of generated images is equal to 0.33% (4/1,200), 1.17% (14/1,200), and 2.83% (34/1,200), respectively.

CONCLUSIONS

Breast MR imaging and 1H-MRS can be effectively summarised presenting only a minimal fraction of all generated images.

Contrast-enhanced 3.0-T breast MRI for characterization of breast lesions: increased specificity by using vascular maps

PURPOSE

To assess the diagnostic accuracy of contrast-enhanced 3.0-T breast magnetic resonance imaging (MRI) for differentiating benign from malignant breast masses and subsequently to test if specificity could be further improved by scoring of the overall ipsilateral breast vascularity.

MATERIALS AND METHODS

Fifty-four patients were prospectively enrolled in the study and underwent contrast-enhanced 3.0-T breast MRI. MR images were evaluated and classified according to the MRI BI-RADS lexicon criteria. Lesion size, number of lesions, and localization in the breast were systematically assessed. Maximum intensity projections (MIPS) were obtained by using high-resolution contrast-enhanced (0.1 mmol/kg gadobutrol) fat-saturated T1-weighted images. Breast vascularization was scored according to the methods from Sardanelli et al. by measuring the number, diameter, and length of the vessels on the MIPS. The score ranged from 0 (indicating absent or low breast vascularity) to 3 (indicating high breast vascularity).

RESULTS

Final analysis of 56 lesions revealed 25 (45%) malignant lesions and 31 (55%) benign lesions. Correlation with the MRI BI-RADS classification revealed cancer in none (0%) of the BI-RADS II lesions, in 1 (12%) of the BI-RADS III lesions, in 5 (83%) of the BI-RADS IV lesions, and in 19 (100%) of the BI-RADS V lesions. Based on morphologic and kinetic data analysis, the sensitivity and specificity of 3.0-T breast MRI was 100% (25/25) and 74% (23/31), respectively. After adjustment for the breast vascularity score, specificity significantly (p = 0.048) increased to 87% (27/31) without affecting sensitivity.

CONCLUSION

Diagnostic accuracy of contrast-enhanced 3.0-T breast MRI increased significantly when the vascularity score was added to the standard morphologic and kinetic data analysis, resulting in a specificity of 87% without affecting sensitivity, which remained 100%.

The adjacent vessel on dynamic contrast-enhanced breast MRI

OBJECTIVE

The purpose of this study was to investigate whether an adjacent vessel leading to an enhancing lesion seen on subtraction images can help differentiate malignant from benign breast lesions and therefore increase the specificity of breast MRI.

MATERIALS AND METHODS

The study included 132 histologically verified lesions (71 malignant lesions, 10 pure carcinoma in situ, and 51 benign lesions) enhancing on dynamic breast MRI before biopsy. The lesions were evaluated by three radiologists in a double-blinded manner. The presence of an adjacent vessel was supposed if at least two observers voted positively.

RESULTS

Sixty-one (85.9%) of 71 malignant lesions, six (60%) of 10 carcinomas in situ, and 10 (19.6%) of 51 benign lesions were associated with an adjacent vessel, which differed significantly (p < 0.001) between benign and malignant lesions (the latter with and without including pure carcinoma in situ), leading to a positive predictive value of 85.9% (87% including pure carcinomas in situ), a negative predictive value of 80.4% (74.5% including pure carcinomas in situ), an accuracy of 83.2% (81.6% including pure carcinomas in situ), a sensitivity of 85.9% (82.7% including carcinomas in situ), and a specificity of 80.4% for this sign concerning malignancy.

CONCLUSION

The presence of an adjacent vessel seen on subtraction images promises to be a good marker for malignancy and can therefore help increase the specificity of breast MRI.

MR angiography of tumor-related vasculature: from the clinic to the micro-environment

Angiogenesis is a very important process for tumor growth and proliferation. Given its high temporal and spatial resolution, magnetic resonance (MR) imaging is well suited for use in the assessment of angiogenesis. MR angiography can be used clinically and experimentally for identification of tumor feeding and draining vessels, for tumor characterization, and for treatment planning. The morphologic structure of tumor vessels can be investigated in relation to tumor vessel permeability with use of specific contrast agents. To gain insight into tumor angiogenesis in vivo, the authors compared images obtained with digital photography, high-resolution MR angiography, and intravital microscopy through a dorsal skin-fold window in a rodent model. The close correlation between images obtained with these various modalities, with regard to the depiction of the developing tumor vasculature, indicates that noninvasive quantification of angiogenesis may be possible with MR imaging. Future directions in tumor imaging may include so-called four-dimensional MR angiography, in which high-resolution three-dimensional MR angiography is combined with dynamic contrast-enhanced MR imaging.

Potential MRI Interpretation Model: Differentiation of Benign from Malignant Breast Masses

OBJECTIVE

Our objective was to increase the accuracy of breast MRI using a semiquantitative analysis of typical MRI features and their diagnostic potential. The prevalence of recently reported MRI signs of breast lesions were analyzed and compared with other well-known signs.

CONCLUSION

New MRI features, especially from T2-weighted images, are promising for more reliable and accurate interpretation of breast lesions. Prospective studies of these findings are required to define cut-off values and test clinical practicality.

Further Signs in the Evaluation of Magnetic Resonance Mammography

PURPOSE

To increase accuracy and reliability of magnetic resonance breast imaging, a new evaluation method might be helpful. The recently suggested evaluation method (Fischer U, et al) resulted in a relevant number of equivocal cases (3 or 4 points). Additional morphologic and dynamic signs as an extension of this score were evaluated.

METHOD AND MATERIALS

One hundred thirty-two histologically verified lesions were evaluated by 3 radiologists double-blinded using 2 evaluation methods: 1) method 1 (according to Fischer, et al): 2pt: initial signal increase >100%, washout, centripetal enhancement, 1pt: initial signal increase 50-100%, plateau phenomenon, centrifugal inhomogeneous enhancement, irregular borders, linear, stellar or dendritic structure; and 2) method 2 (according to Malich, et al): 3pt: hook sign (sign of pectoral invasion), 2pt: unifocal edema, blooming. 1pt: hypointensity in T2, lymph nodes >10 mm, skin thickening, adjacent vessels, a lesion's distorted inner architecture, disruption of the mamillary edge; -1pt: isointensity in T2, no edema, enhancing septations; -3pt: hyperintensity in T2, non enhancing septations. Method 1 judged a lesion to be malignant if 5 or more points were given and benign if 2 or less points were given, respectively. Method 2 (mean value of 3 radiologists) was tested in those cases in which a clear possible decision using method 1 was not sufficiently possible.

RESULTS

Method 1 alone resulted in a negative predictive value of 96.8% and a positive predictive value of 90.8% (without carcinoma in situ), a sensitivity of 83.1%, a specificity of 58.8%, and revealed uncertain results (3 and 4 points) in 29 cases (out of 132; 22%). Adding the new scoring system in these 29 equivocal cases and an increase of 2 or more points by using method 2 is supposed to be a sign of malignancy; findings suggest a sensitivity of 90.9% and a specificity of 60% if an increase of maximum 1 is observed in benign lesions. In conclusion, our results show that Göttingen score alone has a sensitivity of 83.1%, a specificity of 58.8%; the second evaluation method reveals a sensitivity of 90.9% and a specificity of 60% in equivocal cases of Göttingen score. Göttingen score then reaches in all cases and second, adding the second evaluation method in equivocal cases, a sensitivity of 97% and a specificity of 76.5%.

CONCLUSION

The application of a second evaluation method in those cases remaining unclear in Göttingen score can lead to a decrease of uncertainty and a higher sensitivity and specificity of diagnosis in MR mammography. In this study, Göttingen score reaches a sensitivity of 83.1% and a specificity of 58.8%, increasing to a sensitivity of 97% and a specificity of 76.5% when being extended by a second evaluation method in unclear cases.

Gadobenate Dimeglumine–enhanced MR Imaging Breast Vascular Maps: Association between Invasive Cancer and Ipsilateral Increased Vascularity

PURPOSE

To retrospectively compare three different doses of gadobenate dimeglumine with a standard dose of gadopentetate dimeglumine for magnetic resonance (MR) imaging evaluation of breast vessels and to evaluate the accuracy of one-sided increased vascularity seen on gadobenate dimeglumine-enhanced MR images as an indicator of ipsilateral breast cancer.

MATERIALS AND METHODS

The original study had local ethics committee approval; informed consent was obtained from all enrolled patients. Ninety-five patients known to have or suspected of having breast cancer were randomly assigned to four groups to receive gadobenate dimeglumine at a dose of 0.05, 0.10, or 0.20 mmol per kilogram of body weight or gadopentetate dimeglumine at a dose of 0.10 mmol/kg. T1-weighted gradient-echo MR images were acquired before and 2 minutes after intravenous contrast material injection. Subtracted images were used to obtain maximum intensity projections (MIPs). Two readers blinded to the type and dose of contrast agent administered scored the MIPs obtained in the dose groups for vessel number, length, and conspicuity from 0, which indicated absent or low breast vascularity, to 3, which indicated high breast vascularity. The sensitivity, specificity, accuracy, positive predictive value (PPV), and negative predictive value (NPV) of one-sided increased vascularity in association with ipsilateral malignancy for 69 histopathologically confirmed lesions (reference standard) were determined after gadobenate dimeglumine-enhanced MR imaging.

RESULTS

The mean MIP scores assigned to the gadobenate dimeglumine groups were significantly higher than those assigned to the gadopentetate dimeglumine group (P < or = .044). Histopathologic analysis revealed malignant lesions in 52 of 69 patients examined with gadobenate dimeglumine MR imaging: invasive ductal carcinoma in 45, invasive lobular carcinoma in four, and invasive mixed ductal-lobular carcinoma in three patients. Seventeen patients had benign lesions. Two cases of bilateral invasive cancer with symmetric breast vascular maps were excluded. Thus, the overall sensitivity, specificity, accuracy, PPV, and NPV of one-sided increased vascularity as a finding associated with ipsilateral malignancy were 88% (44 of 50 patients), 82% (14 of 17 patients), 87% (58 of 67 patients), 94% (44 of 47 patients), and 70% (14 of 20 patients), respectively.

CONCLUSION

Gadobenate dimeglumine is effective for MR imaging evaluation of breast vessels at doses as low as 0.05 mmol/kg. One-sided increased vascularity is an MR imaging finding frequently associated with ipsilateral invasive breast cancer.

Application of an exogenous hyperoxic contrast agent in MR mammography: initial results

There is interest in applying novel methods to dynamic MR mammography (MRM). One such possibility is to administer an exogenous hyperoxic contrast agent, such as carbogen (95-98% O2 and 2-5% CO2) or pure oxygen (100% O2). We report our first experiences with these agents in a patient with an invasive lobular carcinoma. Fourteen dynamic series were acquired with an rf-spoiled 2D multislice gradient echo sequence, including three measurements while breathing air, four measurements with 100% oxygen, three measurements with air and four measurements with carbogen. Afterwards, 0.1 mmol/kg bw of Gd-DTPA was administered to obtain dynamic T1-weighted double-echo 3D axial gradient echo images (TR/TE1/TE2/alpha=7.8 ms/2 ms/4.76 ms/15 degrees) every 90 s up to 4.5 min after injection. The lesion was well delineated on the contrast-enhanced images, contrary to magnitude images reconstructed from the raw data sets acquired during air/oxygen/carbogen breathing. A ROI-based median-filtered signal-time course revealed a tumor signal increase of roughly 15% between scans acquired during air and oxygen breathing. Though preliminary, these first results are encouraging concerning the exploration of these alternative contrast agents in MRM in greater detail.

Gadopentetate dimeglumine-enhanced three-dimensional MR-angiography: dosing, safety, and efficacy

Noninvasiveness, inherent three-dimensionality allowing reformations in any desired plane, and safe contrast agents, coupled with high diagnostic accuracy have driven the rise in popularity of contrast-enhanced MR angiography (CE-MRA) within the medical community. Reflecting its dominant market share as a paramagnetic contrast agent, gadopentetate dimeglumine (Gd-DTPA) has been used for the majority of clinically-performed MRA exams. Over the period January 1994 to February 2002, a total of 172 original studies describing the use of gadolinium-enhanced MRA in more than three human subjects were identified. Of these, 117 described the use of Gd-DTPA as the contrast agent for MRA. A total of 4046 subjects who received Gd-DTPA for MRA are described in these studies. Analysis of these data demonstrate Gd-DTPA to be a safe contrast agent for MRA when applied in a dose ranging from 0.1 to 0.3 mmol/kg of bodyweight. The documented clinical results show Gd-DTPA to be efficacious in the assessment of the arterial system. The effectiveness of Gd-DTPA-enhanced MRA extends beyond the detection, localization, and characterization of arterial disease, and encompasses choice and planning of appropriate therapy, as well as evaluation of therapeutic effectiveness.

A physiologic model of capillary-tissue exchange for dynamic contrast-enhanced imaging of tumor microcirculation

We present a multiple compartment, mammillary distributed-parameter model for capillary-tissue exchange, which can be implemented with dynamic contrast-enhanced imaging to study kinetic heterogeneity in tumors. The proposed n-compartment model consists of a vascular distributed-parameter compartment in direct exchange with a number (n - 1) of interstitial compartments. It is applied to a prostate tumor case study to illustrate the possible co-existence of two kinetically distinct compartments in the tumor, and the estimation of useful physiological parameters (such as perfusion, mean transit time, fractional volumes, and transfer and rate constants) associated with tissue microcirculation. The present model exhibits the convenient property of a separable impulse residue response function in time domain, which can be used to provide further insights and understanding on the physiological basis of tissue enhancement parameters commonly used for correlation studies with tumor histological diagnosis.