Akiko Shimauchi

University of Chicago, Chicago, IL, United States

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Publications (20)53.6 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: To compare magnetic resonance imaging (MRI) and ultrasound (US) for axillary lymph node (LN) staging in breast cancer patients in an observer-performance study. An observer-performance study was conducted with five breast radiologists reviewing 50 consecutive patients of newly diagnosed invasive breast cancer with the use of ipsilateral axillary MRI and US. LN status was pathologically proved in all patients. Each observer reviewed the images in two separate sessions: one for MRI and the other for US. Observers were asked to indicate their confidence of the presence of at least one ipsilateral metastatic LN on a quasi-continuous rating scale and whether they recommend percutaneous biopsy preoperatively. Receiver operating characteristic (ROC) analysis and area under the ROC curve were used to characterize diagnostic performance. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated from whether observers recommended biopsy. There were no statistically significant differences in each observer's performance between MRI and US, or in the performance of all observers as a group, in terms of ROC analysis. There were no statistically significant differences in sensitivity, specificity, PPV, or NPV between MRI and US, but there were statistically significant improvements in specificity and PPV from either MRI or US alone to MRI and US combined. Observer performance on MRI and US are comparable for axillary LN staging. When US and MRI are concordant for positive findings, higher specificity and PPV can be obtained.
    Academic radiology 11/2013; 20(11):1399-1404. · 2.09 Impact Factor
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    ABSTRACT: Inhomogeneously broadened, non-Lorentzian water resonances have been observed in small image voxels of breast tissue. The non-Lorentzian components of the water resonance are probably produced by bulk magnetic susceptibility shifts caused by dense, deoxygenated tumor blood vessels (the 'blood oxygenation level-dependent' effect), but can also be produced by other characteristics of local anatomy and physiology, including calcifications and interfaces between different types of tissue. Here, we tested the hypothesis that the detection of non-Lorentzian components of the water resonance with high spectral and spatial resolution (HiSS) MRI allows the classification of breast lesions without the need to inject contrast agent. Eighteen malignant lesions and nine benign lesions were imaged with HiSS MRI at 1.5 T. A new algorithm was developed to detect non-Lorentzian (or off-peak) components of the water resonance. After a Lorentzian fit had been subtracted from the data, the largest peak in the residual spectrum in each voxel was identified as the major off-peak component of the water resonance. The difference in frequency between these off-peak components and the main water peaks, and their amplitudes, were measured in malignant lesions, benign lesions and breast fibroglandular tissue. Off-peak component frequencies were significantly different between malignant and benign lesions (p < 0.001). Receiver operating characteristic (ROC) analysis was used to assess the diagnostic performance of HiSS off-peak component analysis compared with dynamic contrast-enhanced (DCE) MRI parameters. The areas under the ROC curves for the 'DCE rapid uptake fraction', 'DCE washout fraction', 'off-peak component amplitude' and 'off-peak component frequency' were 0.75, 0.83, 0.50 and 0.86, respectively. These results suggest that water resonance lineshape analysis performs well in the classification of breast lesions without contrast injection and could improve the diagnostic accuracy of clinical breast MR examinations. In addition, this approach may provide an alternative to DCE MRI in women who are at risk for adverse reactions to contrast media. Copyright © 2012 John Wiley & Sons, Ltd.
    NMR in Biomedicine 11/2012; · 3.45 Impact Factor
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    ABSTRACT: The purpose of this research is to evaluate the potential for identifying malignant breast lesions and their margins on large specimen MRI, in comparison to specimen radiography and clinical dynamic contrast enhanced MRI (DCE-MRI). Breast specimens were imaged with an MR scanner immediately after surgery, with an IRB-approved protocol and with the patients' informed consent. Specimen sizes were at least 5 cm in diameter and approximately 1 to 4 cm thick. Coronal and axial gradient echo MR images without fat suppression were acquired over the whole specimens using a 9.4T animal scanner. Findings on specimen MRI were compared with findings on specimen radiograph, and their volumes were compared with measurements obtained from clinical DCE-MRI. The results showed that invasive ductal carcinoma (IDC) lesions were easily identified using MRI and the margins were clearly distinguishable from nearby tissue. However, ductal carcinoma in situ (DCIS) lesions were not clearly discernible and were diffused with poorly defined margins on MRI. Calcifications associated with DCIS were visualized in all specimens on specimen radiograph. There is a strong correlation between the maximum diameter of lesions as measured by radiograph and MRI (r = 0.93), as well as the maximum diameter measured by pathology and radiograph/MRI (r>0.75). The volumes of IDC measured on specimen MRI were slightly smaller than those measured on DCE-MRI. Imaging of excised human breast lumpectomy specimens with high magnetic field MRI provides promising results for improvements in lesion identification and margin localization for IDC. However, there are technical challenges in visualization of DCIS lesions. Improvements in specimen imaging are important, as they will provide additional information to standard radiographic analysis.
    Journal of Applied Clinical Medical Physics 01/2012; 13(6):3802. · 0.96 Impact Factor
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    ABSTRACT: The aims of this study were to evaluate high spectral and spatial resolution (HiSS) magnetic resonance imaging (MRI) for the diagnosis of breast cancer without the injection of contrast media by comparing the performance of precontrast HiSS images to that of conventional contrast-enhanced, fat-suppressed, T1-weighted images on the basis of image quality and in the task of classifying benign and malignant breast lesions. Ten benign and 44 malignant lesions were imaged at 1.5 T with HiSS (precontrast administration) and conventional fat-suppressed imaging (3-10 minutes after contrast administration). This set of 108 images, after randomization, was evaluated by three experienced radiologists blinded to the imaging technique. Breast Imaging Reporting and Data System morphologic criteria (lesion shape, lesion margin, and internal signal intensity pattern) and final assessment were used to measure reader performance. Image quality was evaluated on the basis of boundary delineation and quality of fat suppression. An overall probability of malignancy was assigned to each lesion for HiSS and conventional images separately. On boundary delineation and quality of fat suppression, precontrast HiSS scored similarly to conventional postcontrast MRI. On benign versus malignant lesion separation, there was no statistically significant difference in receiver-operating characteristic performance between HiSS and conventional MRI, and HiSS met a reasonable noninferiority condition. Precontrast HiSS imaging is a promising approach for showing lesion morphology without blooming and other artifacts caused by contrast agents. HiSS images could be used to guide subsequent dynamic contrast-enhanced MRI scans to maximize spatial and temporal resolution in suspicious regions. HiSS MRI without contrast agent injection may be particularly important for patients at risk for contrast-induced nephrogenic systemic fibrosis or allergic reactions.
    Academic radiology 09/2011; 18(12):1467-74. · 2.09 Impact Factor
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    ABSTRACT: To compare the pathology and kinetic characteristics of breast lesions with focus-, mass-, and nonmass-like enhancement. A total of 852 MRI detected breast lesions in 697 patients were selected for an IRB approved review. Patients underwent dynamic contrast enhanced MRI using one pre- and three to six postcontrast T(1)-weighted images. The "type" of enhancement was classified as mass, nonmass, or focus, and kinetic curves quantified by the initial enhancement percentage (E(1)), time to peak enhancement (T(peak)), and signal enhancement ratio (SER). These kinetic parameters were compared between malignant and benign lesions within each morphologic type. A total of 552 lesions were classified as mass (396 malignant, 156 benign), 261 as nonmass (212 malignant, 49 benign), and 39 as focus (9 malignant, 30 benign). The most common pathology of malignant/benign lesions by morphology: for mass, invasive ductal carcinoma/fibroadenoma; for nonmass, ductal carcinoma in situ (DCIS)/fibrocystic change(FCC); for focus, DCIS/FCC. Benign mass lesions exhibited significantly lower E(1), longer T(peak), and lower SER compared with malignant mass lesions (P < 0.0001). Benign nonmass lesions exhibited only a lower SER compared with malignant nonmass lesions (P < 0.01). By considering the diverse pathology and kinetic characteristics of different lesion morphologies, diagnostic accuracy may be improved.
    Journal of Magnetic Resonance Imaging 06/2011; 33(6):1382-9. · 2.57 Impact Factor
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    ABSTRACT: A multiparametric computer-aided diagnosis scheme that combines information from T1-weighted dynamic contrast-enhanced (DCE)-MRI and T2-weighted MRI was investigated using a database of 110 malignant and 86 benign breast lesions. Automatic lesion segmentation was performed, and three categories of lesion features (geometric, T1-weighted DCE, and T2-weighted) were automatically extracted. Stepwise feature selection was performed considering only geometric features, only T1-weighted DCE features, only T2-weighted features, and all features. Features were merged with Bayesian artificial neural networks, and diagnostic performance was evaluated by ROC analysis. With leave-one-lesion-out cross-validation, an area under the ROC curve value of 0.77±0.03 was achieved with T2-weighted-only features, indicating high diagnostic value of information in T2-weighted images. Area under the ROC curve values of 0.79±0.03 and 0.80 ± 0.03 were obtained for geometric-only features and T1-weighted DCE-only features, respectively. When all features were considered, an area under the ROC curve value of 0.85±0.03 was achieved. We observed P values of 0.006, 0.023, and 0.0014 between the geometric-only, T1-weighted DCE-only, and T2-weighted-only features and all features conditions, respectively. When ranked, the P values satisfied the Holm-Bonferroni multiple-comparison test; thus, the improvement of multiparametric computer-aided diagnosis was statistically significant. A computer-aided diagnosis scheme that combines information from T1-weighted DCE and T2-weighted MRI may be advantageous over conventional T1-weighted DCE-MRI computer-aided diagnosis.
    Magnetic Resonance in Medicine 04/2011; 66(2):555-64. · 3.27 Impact Factor
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    ABSTRACT: To evaluate a computer-aided diagnosis (CADx) system for dynamic contrast material-enhanced magnetic resonance (MR) imaging and compare it with a currently used clinical method of interpreting breast MR image findings that includes the use of commercially available automated software for kinetic image data processing and visualization. In this HIPAA-compliant, institutional review board-approved study, a training set of 121 breast lesions (77 malignant, 44 benign) was used to train the CADx system. After practicing with 10 training cases, six breast imaging radiologists assessed the likelihood of malignancy and the need for biopsy with a separate test set of 60 lesions (30 malignant, 30 benign). Their performances in differentiating between benign and malignant breast lesions both without (conventional lesion viewing, output from commercially available breast MR imaging analysis software) and with the aid of the CADx workstation (with classification yielding an estimation of the probability of malignancy for each lesion) were evaluated with receiver operating characteristic analysis. When CADx was used, the average performance of the radiologists was significantly improved, as indicated by increases in mean area under the receiver operating characteristic curve (from 0.80 to 0.84, P = .007), mean sensitivity (from 83% to 88%, P = .001), and average number of biopsy recommendations for malignant cases (1.7 more biopsies for malignant lesions with use of CADx, P = .032). Although the mean specificity improved (from 50% to 53%), the improvement was not significant (P = .2). Use of the CADx system improved the radiologists' performance in differentiating between malignant and benign MR imaging-depicted breast lesions.
    Radiology 03/2011; 258(3):696-704. · 6.34 Impact Factor
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    ABSTRACT: Improvements in the reliable diagnosis of preinvasive ductal carcinoma in situ (DCIS) by dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are needed. In this study, we present a new characterization of early contrast kinetics of DCIS using high temporal resolution (HiT) DCE-MRI and compare it with other breast lesions and normal parenchyma. Forty patients with mammographic calcifications suspicious for DCIS were selected for HiT imaging using T(1)-weighted DCE-MRI with ∼7 s temporal resolution for 90 s post-contrast injection. Pixel-based and whole-lesion kinetic curves were fit to an empirical mathematical model (EMM) and several secondary kinetic parameters derived. Using the EMM parameterized and fitted concentration time curve for subsequent analysis allowed for calculation of kinetic parameters that were less susceptible to fluctuations due to noise. The parameters' initial area under the curve (iAUC) and contrast concentration at 1 min (C(1 min)) provided the highest diagnostic accuracy in the task of distinguishing pathologically proven DCIS from normal tissue. There was a trend for DCIS lesions with solid architectural pattern to exhibit a negative slope at 1 min (i.e. increased washout rate) compared to those with a cribriform pattern (p < 0.04). This pilot study demonstrates the feasibility of quantitative analysis of early contrast kinetics at high temporal resolution and points to the potential for such an analysis to improve the characterization of DCIS.
    Physics in Medicine and Biology 10/2010; 55(19):N473-85. · 2.70 Impact Factor
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    ABSTRACT: To develop and evaluate a computerized segmentation method for breast MRI (BMRI) mass-lesions. A computerized segmentation algorithm was developed to segment mass-like-lesions on breast MRI. The segmentation algorithm involved: (i) interactive lesion selection, (ii) automatic intensity threshold estimation, (iii) connected component analysis, and (iv) a postprocessing procedure for hole-filling and leakage removal. Seven observers manually traced the borders of all slices of 30 mass-lesions using the same tools. To initiate the computerized segmentation, each user selected a seed-point for each lesion interactively using two methods: direct seed-point and robust region of interest (ROI) selections. The manual and computerized segmentations were compared pair-wise using the measured size and overlap to evaluate similarity, and the reproducibility of the computerized segmentation was compared with the interobserver variability of the manual delineations. The observed inter- and intraobserver variations were similar (P > 0.05). Computerized segmentation using the robust ROI selection method was significantly (P < 0.001) more reproducible in measuring lesion size (stDev 1.8%) than either manual contouring (11.7%) or computerized segmentation using directly placed seed-point method (13.7%). The computerized segmentation method using robust ROI selection is more reproducible than manual delineation in terms of measuring the size of a mass-lesion.
    Journal of Magnetic Resonance Imaging 07/2010; 32(1):110-9. · 2.57 Impact Factor
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    ABSTRACT: The objective of our study was to determine the sensitivity of cancer detection at breast MRI using current imaging techniques and to evaluate the characteristics of lesions with false-negative examinations. Two hundred seventeen patients with 222 newly diagnosed breast cancers or highly suspicious breast lesions that were subsequently shown to be malignant underwent breast MRI examinations for staging. Two breast imaging radiologists performed a consensus review of the breast MRI examinations. The absence of perceptible contrast enhancement at the expected site was considered to be a false-negative MRI. Histology of all lesions was reviewed by an experienced breast pathologist. Enhancement was observed in 213 (95.9%) of the 222 cancer lesions. Of the nine lesions without visible enhancement, two lesions were excluded because the entire tumor had been excised at percutaneous biopsy performed before the MRI examination and no residual tumor was noted on the final histology. The overall sensitivity of MRI for the known cancers was 96.8% (213/220); for invasive cancer, 98.3% (176/179); and for ductal carcinoma in situ, 90.2% (37/41). In a population of 220 sequentially diagnosed breast cancer lesions, we found seven (3.2%) MRI-occult cancers, fewer than seen in other published studies. Small tumor size and diffuse parenchymal enhancement were the principal reasons for these false-negative results. Although the overall sensitivity of cancer detection was high (96.8%), it should be emphasized that a negative MRI should not influence the management of a lesion that appears to be of concern on physical examination or on other imaging techniques.
    American Journal of Roentgenology 06/2010; 194(6):1674-9. · 2.90 Impact Factor
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    ABSTRACT: The objective of our study was to assess the clinical utility of MR-directed ("second-look") ultrasound examination to search for breast lesions detected initially on MRI. A retrospective review was performed of the records of 158 consecutive patients (202 lesions) with breast abnormalities initially detected on MRI between July 2003 and May 2006. All lesions were detected as enhancing findings on a dynamic contrast MR study and were subsequently evaluated with ultrasound. Ultrasound was performed using MR images as a guide to lesion location, size, and morphology. Pathology findings were confirmed by subsequent percutaneous biopsy or lesion excision. Imaging follow-up was used for probably benign lesions, which were not biopsied. Of the 202 MRI-detected lesions, ultrasound correlation was made in 115 (57%) including 33 malignant lesions and 82 benign lesions. The remaining 87 lesions were not sonographically correlated and included 11 malignant lesions and 76 nonmalignant lesions. Mass lesions identified on MRI were more likely to have a sonographic correlate than nonmasslike lesions (65% vs 12%, respectively); malignant mass lesions were more likely to show an ultrasound correlation (85%). The malignant lesions with successful sonographic correlation tended to present with subtle sonographic findings. MR-directed ultrasound of MRI-detected lesions was useful for decision making as part of the diagnostic workup. Malignant lesions were likely to have an ultrasound correlate, especially when they presented as masses on MRI. However, the sonographic findings of these lesions were often subtle, and careful scanning technique was needed for successful MRI-ultrasound correlation.
    American Journal of Roentgenology 02/2010; 194(2):370-7. · 2.90 Impact Factor
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    ABSTRACT: The purpose of this paper is to demonstrate that voxels with inhomogeneously broadened water resonances, as revealed by high spectral and spatial resolution (HiSS) MRI, correlate with underlying tumor pathology findings, and thus carry diagnostically useful information. Thirty-four women with mammographically suspicious breast lesions were imaged at 1.5 T, using high-resolution echo-planar spectroscopic imaging. Fourier component images (FCIs) of the off-peak spectral signal were generated, and clusters of voxels with significant inhomogeneous broadening (broadened clusters) were identified and correlated to biopsy results. Inhomogeneously broadened clusters were found significantly more frequently in malignant than in benign lesions. A larger percentage of broadened cluster voxels were found inside the malignant versus benign lesions. The high statistical significance for separation of benign and malignant lesions was robust over a large range of post-processing parameters, with a maximum ROC area under curve of 0.83. In the human breast, an inhomogeneously broadened water resonance can serve as a correlate marker for malignancy and is likely to reflect the underlying anatomy or physiology.
    Physics in Medicine and Biology 10/2009; 54(19):5767-79. · 2.70 Impact Factor
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    ABSTRACT: To quantify the relationship between dose of contrast administered and contrast kinetics of malignant breast lesions. A total of 108 patients with 120 malignant lesions were selected for an institutional review board-approved review. Dynamic magnetic resonance protocol: one pre- and three or five post-contrast (at a fixed volume of 20 mL of 0.5 M gadodiamide) images. Patients were stratified into groups based on dose of contrast administered, after calculation of body weight (kg): Dose Group 1, <0.122 mmol/kg; Dose Group 2, 0.123-0.155 mmol/kg; Dose Group, 3 > 0.155 mmol/kg. Analysis of kinetic curve shape was made according to the Breast Imaging Reporting and Data System lexicon. Several quantitative parameters were calculated including initial and peak enhancement percentage (E(1) and E(peak)). Linear regression was used to model the variation of kinetic parameters with dose. There was no difference found in the qualitative Breast Imaging Reporting and Data System descriptors of curve shape between the three dose groups. There was a trend for E(1) and E(peak) to increase from Dose Group 1 to Dose Group 3 in malignant lesions overall, as well as in invasive ductal carcinoma lesions separately. Each decrement/increment of 0.05 mmol/kg in dose yielded a decrease/increase of 78% and 97% in E(1) for in situ and invasive cancers, respectively. Contrast should be administered at fixed dose to achieve comparable levels of lesion uptake in women of different weights. Our results suggest that reducing the contrast administered to 0.05 mmol/kg, as has been suggested for patients at risk of developing nephrogenic systemic fibrosis, could substantially decrease the observed initial enhancement in some cancers.
    Academic radiology 10/2009; 17(1):24-30. · 2.09 Impact Factor
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    ABSTRACT: The purpose of this study was to compare MRI kinetic curve data acquired with three systems in the evaluation of malignant lesions of the breast. The cases of 601 patients with 682 breast lesions (185 benign, 497 malignant) were selected for review. The malignant lesions were classified as ductal carcinoma in situ (DCIS), invasive ductal carcinoma (IDC), and other. The dynamic MRI protocol consisted of one unenhanced and three to seven contrast-enhanced images acquired with one of three imaging protocols and systems. An experienced radiologist analyzed the shapes of the kinetic curves according to the BI-RADS lexicon. Several quantitative kinetic parameters were calculated, and the kinetic parameters of malignant lesions were compared across the three systems. Imaging protocol and system 1 were used to image 304 malignant lesions (185 IDC, 62 DCIS); imaging protocol and system 2, 107 lesions (72 IDC, 21 DCIS); and imaging protocol and system 3, 86 lesions (64 IDC, 17 DCIS). Compared with those visualized with imaging protocols and systems 1 and 2, IDC lesions visualized with imaging protocol and system 3 had significantly less initial enhancement, longer time to peak enhancement, and a slower washout rate (p < 0.004). Only 47% of IDC lesions imaged with imaging protocol and system 3 exhibited washout type curves, compared with 75% and 74% of those imaged with imaging protocols and systems 2 and 1, respectively. The diagnostic accuracy of kinetic analysis was lowest for imaging protocol and system 3, but the difference was not statistically significant. The kinetic curve data on malignant lesions acquired with one system showed significantly lower initial contrast uptake and a different curve shape in comparison with data acquired with the other two systems. Differences in k-space sampling, T1 weighting, and magnetization transfer effects may be explanations for the difference.
    American Journal of Roentgenology 09/2009; 193(3):832-9. · 2.90 Impact Factor
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    ABSTRACT: High-resolution, single-slice, high spatial and spectral resolution (HiSS) breast magnetic resonance imaging (MRI) provides improved lesion conspicuity, margin definition and internal definition, as compared to conventional clinical MRI - and thus may provide better lesion characterization and increase breast MRI specificity. Volumetric HiSS imaging is highly desirable, but was considered to be time-prohibitive. Specifically, the concern was that faster acquisition times -- necessitating a lower spectral resolution -- could compromise established advantages of HiSS imaging. In this pilot study, we demonstrate for the first time a fast, clinically practical, HiSS-based sequence that achieves full unilateral breast coverage, while preserving essential qualities of full-spectral resolution HiSS imaging. We imaged five patients of varying breast sizes at 1.5 T, with HiSS acquisitions performed after the standard clinical protocol, and lasting an average of 8.5 min. Maximum intensity projection (MIP) images of HiSS data were constructed and compared to MIPs of conventional clinical images. Single-slice images through three lesions were also compared. HiSS images achieved better fat suppression than the clinical fat-saturated sequence (fat signal SNR was reduced by 50% in HiSS images) as well as increased conspicuity, as assessed qualitatively by an experienced radiologist. Thus, we show that volumetric HiSS imaging can conserve the advantages of single-slice HiSS imaging and that further technical development of volumetric HiSS is desirable.
    Magnetic Resonance Imaging 08/2009; 28(1):16-21. · 2.06 Impact Factor
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    ABSTRACT: To retrospectively compare the kinetic and morphologic characteristics of pure ductal carcinoma in situ (DCIS) lesions depicted on dynamic contrast material-enhanced magnetic resonance (MR) images with the nuclear grade and conventional mammographic appearance of these lesions. This HIPAA-compliant retrospective study was institutional review board approved, and informed patient consent was waived. Seventy-eight patients with 79 histologically proved pure DCIS lesions were selected. There were 17 low-nuclear-grade, 26 intermediate-nuclear-grade, 30 high-nuclear-grade, and six unclassified lesions. Sixty-five lesions were classified as fine pleomorphic, fine linear, or fine linear-branching calcifications (n = 31); amorphous or indistinct calcifications (n = 18); noncalcified mass (n = 10); or occult (n = 6) at conventional (x-ray) mammography. One experienced radiologist analyzed lesion morphology and kinetic curve shape according to the Breast Imaging Reporting and Data System lexicon. Initial enhancement percentage, time to peak enhancement (T(peak)), and signal enhancement ratio (a measure of washout) were calculated for each lesion. Of the 79 pure DCIS lesions, 20 (25%) exhibited enhancement plateau curves and 35 (44%) exhibited washout curves. The lesions with a masslike appearance on mammograms exhibited more suspicious kinetic characteristics (mean T(peak) approximately 2 minutes) than did the lesions with amorphous or indistinct calcifications (mean T(peak) = 4.4 minutes). There was no significant difference in enhancement kinetic properties across the nuclear grades. Lesion morphology was predominantly nonmass, with clumped or heterogeneous enhancement in a segmental or linear distribution. The pure DCIS lesions exhibited washout, plateau, and persistent enhancement curves. Enhancement kinetic characteristics varied with mammographic appearance but not with nuclear grade. Supplemental material: http://radiology.rsnajnls.org/cgi/content/full/245/3/684/DC1.
    Radiology 01/2008; 245(3):684-91. · 6.34 Impact Factor
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    ABSTRACT: Axillary lymph node status is an extremely important prognostic factor in the assessment of new breast cancer patients. Sentinel lymph node biopsy is now often performed instead of axillary dissection for lymph node staging but raises numerous issues of practicality. Sentinel lymph node biopsy can be avoided if lymph node metastasis is documented presurgically, making an alternative staging method desirable. Although not widely performed for axillary lymph node staging, ultrasonography (US)-guided core needle biopsy is a well-established procedure for the breast and other organs, with a higher success rate in terms of tissue diagnosis than fine-needle aspiration biopsy. Improvements in US have established it as a valuable method for evaluating lymph nodes. US findings in abnormal lymph nodes include cortical thickening and diminished or absent hilum. In addition, color Doppler US of abnormal axillary lymph nodes often shows hyperemic blood flow in the hilum and central cortex or abnormal (nonhilar cortical) blood flow. US-guided core needle biopsy of axillary lymph nodes in breast cancer patients can yield a high accuracy rate with no significant complications, given the use of a biopsy device with controllable needle action, a clear understanding of anatomy, and good skills for controlling the needle.
    Radiographics 11/2007; 27 Suppl 1:S91-9. · 2.79 Impact Factor
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    ABSTRACT: Dynamic contrast enhanced breast MRI (DCE BMRI) is an emerging tool for breast cancer diagnosis. There is a clear clinical demand for computer-aided diagnosis (CADx) tools to support radiologists in the diagnostic reading process of DCE BMRI studies. A crucial step in a CADx system is the segmentation of tumors, which allows for accurate assessment of the 3D lesion size and morphology. In this paper we propose a semiautomatic segmentation procedure for suspicious breast lesions. The proposed methodology consists of four steps: (1) Robust seed point selection. This interaction mode ensures robustness of the segmentation result against variations in seed-point placement. (2) Automatic intensity threshold estimation in the subtraction image. (3)Connected component analysis based on the estimated threshold. (4) A post-processing step that includes non-enhancing portions of the lesion into the segmented area and removes attached vessels. The proposed methodology was applied to DCE BMRI data acquired at different institutions using different protocols.
    Proc SPIE 03/2007;
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    ABSTRACT: The purpose of our study was to compare the accuracy of MDCT and MRI for evaluating the intraductal component of breast cancer. Sixty-nine patients with histologically proven invasive carcinoma underwent MDCT and MRI. Retrospectively, two radiologists performed a blinded review of the MDCT and MRI. Cases with intraductal component enhancement were classified into two morphologic types: ductal extension and segmental distribution. The lengths of the main tumor and of the intraductal component were measured in cases with ductal extension. For cases with segmental distribution, only the maximum length of the tumor was measured. The sensitivity, specificity, and accuracy in detecting the intraductal component were 61%, 88%, and 71%, respectively, using MDCT; and 75%, 88%, and 80%, respectively, using MRI. MRI revealed the presence of the intraductal component with significantly higher sensitivity than did MDCT (p = 0.031). In the analysis of the length of the intraductal component in cases with ductal extension, which had relatively small intraductal components, underestimation by 15 mm or more was significantly less frequent with MRI than with MDCT (p = 0.008). There was no significant difference between MDCT and MRI in the evaluation of the maximum length of tumors in cases with segmental distribution, which had relatively large intraductal components. Compared with MDCT, MRI revealed the presence of the intraductal component with higher sensitivity and equivalent specificity. In cases with ductal extension, MRI is more precise than MDCT for determination of the margin for surgical removal, with less underestimation of the extent of the intraductal component.
    American Journal of Roentgenology 09/2006; 187(2):322-9. · 2.90 Impact Factor
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    ABSTRACT: We present a retrospective analysis of long-term therapeutic results for patients treated in our institution to evaluate the efficacy of breast-conserving therapy (BCT). The study population was 99 patients (102 breasts) with stage 0, I, and II breast cancer who underwent breast conservation therapy between April 1990 and November 1997. The entire breast was irradiated to a median dose of 50 Gy (range, 50-60 Gy) in 25-30 fractions. An additional 10 Gy in five fractions with 6-12 MeV electrons was given to 23 breasts (23%) with positive surgical margins. The 5-/10-year overall survival, cause-specific survival, relapse-free rate, local recurrence, and regional recurrence rates were 94.6/93.3%, 95.7/94.5%, 88.2/77.5%, 4.2/8.5%, and 2.0/6.3%, respectively. In both uni- and multivariate analyses, age < 40 years was a significant prognostic factor for local recurrence. No severe morbidity was observed. The long-term clinical outcome of BCT for early breast carcinoma patients in our department was favorable. Patient age <40 was the most important factor associated with an increased risk of local recurrence in the ipsilateral breast.
    Radiation Medicine 11/2005; 23(7):485-90.

Publication Stats

215 Citations
53.60 Total Impact Points

Institutions

  • 2007–2012
    • University of Chicago
      • Department of Radiology
      Chicago, IL, United States
  • 2010
    • The University of Chicago Medical Center
      • Section of Breast Imaging
      Chicago, Illinois, United States
  • 2005–2006
    • Tohoku University
      • Department of Diagnostic Radiology
      Sendai-shi, Miyagi-ken, Japan