Elsevier

Medical Image Analysis

Volume 20, Issue 1, February 2015, Pages 265-274
Medical Image Analysis

Automated localization of breast cancer in DCE-MRI

https://doi.org/10.1016/j.media.2014.12.001Get rights and content

Highlights

  • A computer-aided detection system for breast cancer in DCE-MRI is proposed.

  • The system was trained to detect mass-like and non-mass-like malignant lesions.

  • Performance is evaluated on a dataset containing abnormal and normal cases.

  • The CAD system reaches 89% sensitivity at 4 false positives per normal case.

Abstract

Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is increasingly being used for the detection and diagnosis of breast cancer. Compared to mammography, DCE-MRI provides higher sensitivity, however its specificity is variable. Moreover, DCE-MRI data analysis is time consuming and depends on reader expertise. The aim of this work is to propose a novel automated breast cancer localization system for DCE-MRI. Such a system can be used to support radiologists in DCE-MRI analysis by marking suspicious areas. The proposed method initially corrects for motion artifacts and segments the breast. Subsequently, blob and relative enhancement voxel features are used to locate lesion candidates. Finally, a malignancy score for each lesion candidate is obtained using region-based morphological and kinetic features computed on the segmented lesion candidate. We performed experiments to compare the use of different classifiers in the region classification stage and to study the effect of motion correction in the presented system. The performance of the algorithm was assessed using free-response operating characteristic (FROC) analysis. For this purpose, a dataset of 209 DCE-MRI studies was collected. It is composed of 95 DCE-MRI studies with 105 breast cancers (55 mass-like and 50 non-mass-like malignant lesions) and 114 DCE-MRI studies from women participating in a screening program which were diagnosed to be normal. At 4 false positives per normal case, 89% of the breast cancers (91% and 86% for mass-like and non-mass-like malignant lesions, respectively) were correctly detected.

Introduction

Dynamic Contrast-Enhanced Magnetic Resonance Imaging (DCE-MRI) of the breast is employed for breast cancer screening in women with cumulative lifetime breast cancer risk of more than 20–25% (US and EU guideline) (Mann et al., 2008). Other indications include, but are not limited to, preoperative staging, evaluation of women treated with neoadjuvant chemotherapy and problem solving in case of inconclusive findings from other modalities. Compared to mammography, which is the image modality commonly used in regular screening, breast DCE-MRI presents higher sensitivity (Peters et al., 2008), especially in women with dense breasts (Pisano et al., 2008). However, specificity is more variable, both for screening (Mann et al., 2008) and characterization (Peters et al., 2008) purposes, since the examination of breast DCE-MRI depends on many factors such as reader expertise and use of adequate visualization techniques. This fact can lead to a substantial amount of false positive findings. Furthermore, breast MRI analysis requires interpretation of four-dimensional DCE data, as well as correlation to multi-parametric data from other MRI imaging sequences, and is therefore a time consuming task.

In order to help overcome these limitations, dedicated workstations are currently used in clinical practice to assist the radiologist in the detection and classification of breast lesions in DCE-MRI data. These systems mainly provide an automated kinetic assessment by color-coding the intensity changes per voxel during enhancement of the breast tissue. This automated assessment aids in the interpretation of patterns of contrast enhancement (persistent, plateau and washout enhancement) across a series of MRI volumes (Dorrius et al., 2011), but human interaction is still required to identify and characterize suspicious areas, which increases the risk of misinterpreting or overlooking breast lesions (Pages et al., 2012, Yamaguchi et al., 2013) and may cause inter- and intra-observer variability (Newell et al., 2010).

A computer-aided detection (CAD) system that marks the most suspicious locations of the breast can aid radiologists in the analysis of breast DCE-MRI. Such a system can reduce the interpretation time of analyzing breast DCE-MRI data and, as shown when CAD has been applied to other modalities (Li et al., 2008, White et al., 2009, Kligerman et al., 2013, Burhenne et al., 2000), otherwise missed lesions could be detected.

Only a few authors have presented algorithms to automatically detect lesions in breast DCE-MRI (Vignati et al., 2011, Renz et al., 2012, Chang et al., 2014). The method developed by Vignati et al. (2011) used subtracted mean intensity projection images over time, which were normalized using the contrast uptake of the mammary vessel. Renz et al. (2012) evaluated a fully automatic CAD system that segmented lesions with a hierarchical 3D Gaussian pyramid approach. More recently, Chang et al. (2014) combined kinetic and morphological features to identify focal tumor breast lesions. However, in these previous studies, results were reported for relatively small datasets that do not cover the entire spectrum of malignant breast lesions since non-mass-like enhancing lesions, which are lesions with abnormal enhancement larger than focus without space-occupying effect (Morris et al., 2014), and thus without blob-like shape, are not included. Therefore, automatic lesion detection in DCE-MRI is still an open problem. The problem is also clinically relevant since recent studies showed that lesions are regularly overlooked or misinterpreted in breast cancer screening programs with MRI (Pages et al., 2012, Yamaguchi et al., 2013).

In this work, we propose a novel CAD system to automatically detect breast lesions in DCE-MRI. The system is a multi-stage approach that uses blob features in combination with kinetic and morphological information of the lesion in motion corrected data. The performance of the algorithm was assessed using free-response operating characteristic (FROC) analysis, using a dataset composed of 95 studies with manually annotated malignant mass-like and non-mass-like lesions and 114 studies from patients participating in a screening program for high and intermediate risk women that were evaluated as normal.

Section snippets

Study dataset

The dataset used in this study contained 209 T1-weighted coronal DCE-MRI studies from different patients (age: 22–81 years, mean age: 48.5 years). Of the complete dataset, 114 DCE-MRI studies were obtained from patients participating in a high-risk screening program. These MRIs were scored as either BI-RADS 1 (n=87) or BI-RADS 2 (n=27). For each included MRI, at least 2 years of follow up were available with no sign of breast cancer and no previous history of breast cancer or breast surgery was

Results

Results of the first experiment can be observed in Fig. 6, which shows the performance of the proposed CAD system using different classifiers in the final region classification stage. Table 2 shows p-values for the comparisons between the classifiers. For the detection of malignant lesions, LDA, kNN, gentleboost, SVM and random forest obtained mean sensitivity values in the range between 0.1 and 4 FPs/case of 0.48, 0.60, 0.66, 0.64 and 0.72, respectively. The random forests classifier

Discussion

In this work, we developed a CAD system for breast cancer in DCE-MRI that provides automated localization of malignant lesions on motion corrected data. First, relative enhancement and blob features are used to detect suspicious areas. Then, the final malignancy likelihood is obtained using region-based morphological and kinetic information computed on segmented lesion candidates. The use of different classifiers in the final region classification stage and the effect of applying motion

Conclusion

In this paper we have presented a fully automatic algorithm for the detection of breast cancer in DCE-MRI. We introduced blob features in an initial voxel candidate detection stage. Morphological and kinetic features are employed by a second step to reduce false positives. Evaluation on a dataset of 209 DCE-MRI cases, which contained 114 DCE-MRI studies representative for normal patients participating in a screening program, showed that our approach yields high sensitivity for the detection of

Acknowledgments

The research leading to these results has received funding from the European Unions Seventh Framework Programme FP7 under Grant Agreement No. 306088. Albert Gubern-Mérida held a FPU Grant AP2009-2835.

References (45)

  • M.D. Dorrius et al.

    Computer-aided detection in breast MRI: a systematic review and meta-analysis

    Eur. Radiol.

    (2011)
  • B. Efron

    Bootstrap methods: another look at the jackknife

    Ann. Stat.

    (1979)
  • J. Friedman et al.

    Special invited paper. Additive logistic regression: a statistical view of boosting

    Ann. Stat.

    (2000)
  • C. Gallego Ortiz et al.

    Automatic atlas-based segmentation of the breast in MRI for 3D breast volume computation

    Med. Phys.

    (2012)
  • K.G. Gilhuijs et al.

    Computerized analysis of breast lesions in three dimensions using dynamic magnetic-resonance imaging

    Med. Phys.

    (1998)
  • K.G.A. Gilhuijs et al.

    Breast MR imaging in women at increased lifetime risk of breast cancer: clinical system for computerized assessment of breast lesions initial results

    Radiology

    (2002)
  • Gubern-Mérida, A., Wang, L., Kallenberg, M., Martí, R., Hahn, H., Karssemeijer, N., 2013. Breast segmentation in MRI:...
  • A. Gubern-Mérida et al.

    Breast segmentation and density estimation in breast MRI: a fully automatic framework

    IEEE J. Biomed. Health Inform.

    (2014)
  • S. Klein et al.

    elastix: a toolbox for intensity-based medical image registration

    IEEE Trans. Med. Imaging

    (2010)
  • S. Kligerman et al.

    The effect of computer-aided detection on radiologist performance in the detection of lung cancers previously missed on a chest radiograph

    J. Thorac. Imaging

    (2013)
  • C.K. Kuhl

    The coming of age of nonmammographic screening for breast cancer

    JAMA

    (2008)
  • G.D. Leonard et al.

    Ductal carcinoma in situ, complexities and challenges

    J. Natl. Cancer Inst.

    (2004)
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