Akiko Shimauchi

University of Chicago, Chicago, IL, United States

Are you Akiko Shimauchi?

Claim your profile

Publications (37)53.6 Total impact

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE Can aggressive MRI characteristics and receptor profile of invasive breast cancers be used to predict clinical outcome and metastases/recurrence rates? METHOD AND MATERIALS 54 patients (mean age 56 yo) with biopsy-proven invasive breast cancer and staging MRI (1.5T Phillips) at University of Chicago from 2002-2003 were included in a HIPAA-compliant retrospective study. Patients with prior history of invasive or in-situ breast cancer or distant metastases at time of breast cancer diagnosis were excluded. Imaging and clinical notes were reviewed to identify local recurrence or distant metastases. Average follow up time was 7.8 years. All breast cancers were measured on MRI as maximum diameter in axial dimension. Aggressive MRI morphologic features such as non-mass enhancement (NME), rim or heterogeneous enhancement and multifocality were analyzed in consensus by two board-certified fellowship-trained radiologists. Receptor profiles of all cancers were obtained from pathology reports. RESULTS Histology yielded IDC 46/54 (85%) and ILC 8/54 (15%). 9/54 (17%) of the total patients developed distant metastases. Average time to metastases was 2.8 years, range 0.7 to 6.8 yrs. Histology of all metastatic cancers was IDC. 33% of cancers were grade 2 and 37% were grade 3. Grade 3 tumors metastasized in (6/20) 30% of cases and grade 2 in (1/18) 6%; tumor grade was not included in the pathology report in 2 cases. Cancers were categorized based on receptor profile as triple negative (9/54; 17%), Her2+ (12/54; 22%), and ER+Her2- (33/54; 61%). ER+ Her2- cancers metastasized in 9% (3/33) and all were unifocal. Her+ cancers metastasized in 25% (3/12) (1 unifocal, 2 multifocal) and triple negative cancers in 33% (3/9) (1 unifocal, 2 multifocal). Analysis of the MRI morphologic features showed that 25% of rim-enhancing tumors, 22% with NME, 18% of multifocal and 16% of unifocal cancers metastasized. CONCLUSION Pilot data shows that grade 3, triple negative, NME and multifocal IDC have higher rates of metastases compared to unifocal, low grade, and ILC. Distant metastases presented as late as 6.8 yrs after diagnosis. We intend to analyze a total of 200 patients in our final study. CLINICAL RELEVANCE/APPLICATION To determine the group of patients that can benefit from close follow up and metastatic work up to prevent or detect local recurrence/distant metastases.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE/AIM To review the influence of receptor profile and residual cellularity on MRI findings in breast cancer patients undergoing neoadjuvant chemotherapy (NAC). To better identify patients showing residual invasive cancer post-NAC despite no or minimal enhancement on MRI and to understand factors influencing this rad-path discrepancy. To better delineate extent of residual disease and determine appropriate surgical treatment post NAC. CONTENT ORGANIZATION 10 cases of breast cancer will be shown with pre- and post-NAC MRI and histopathologic images. Differences in imaging response associated with different receptor profiles and patterns of pathologic response to therapy will be reviewed. Pathologic staging of post-NAC breast cancers will be discussed. SUMMARY Major teaching points: Some breast cancers become less cellular post NAC without significantly decreasing in size. These cancers may have no or minimal contrast enhancement on MRI. Evaluation of non-subtracted contrast and delayed images is of increased importance in order to evaluate the extent of residual tumor. ER+Her2- cancers more often have subtle imaging findings after treatment as compared to triple negative and Her2+ cancers. Evaluation of different tumor morphologies and patterns of response to NAC can be helpful in surgical planning.
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To investigate the change of breast parenchymal enhancement (BPE) on MRI, in the contralateral normal breast of patients who received neoadjuvant chemotherapy (NAC) for breast cancer. METHOD AND MATERIALS 20 patients with breast cancer (mean age, 57 years; age range, 35-87 years) treated with NAC who had pre-chemo and post-chemo (pre-surgery) MRI between Jan 2010 and Jan 2012 were reviewed retrospectively. BPE of the contralateral normal breast was analyzed using Dynacad. Regions of interest (ROIs) were traced manually on pre and 5 dynamic T1WI post contrast series , at the same 4 locations of the normal breast on pre-NAC and post-NAC scans. Average relative increase in intensity (%) compared to the intensity on precontrast images within the ROIs was obtained at each of the 5 post contrast time points, and the values from the 4 ROIs were averaged to give a single mean relative signal increase per scan. The effect of NAC on the change of BPE was evaluated using the student t test. Change in categorical scales (minimal, mild, moderate or marked) to rate BPE by radiologists was also evaluated, using the Chi-square test. Subgroup analysis based on menopausal status (premenopausal (n=8), postmenopausal (n=12)) was performed. RESULTS The average relative signal increase at the 5 time points were 15.2, 31.1, 39.7, 46.2 and 50.5% on pre-NAC scans, and 5.7, 14.9, 20.1, 23.4 and 26.2% on post-NAC scans. Statistically significant differences were found at all time points (p=0.013, 0.002, 0.001, <0.001, <0.001 at each time point respectively). The numbers of cases categorized into minimal, mild, moderate, and marked BPE were 4, 10, 6, and 0 on pre-NAC scans, and 17, 3, 0, and 0 cases respectively on post-NAC scans, with a statistically significant difference (p<0.001) in the distribution. In both premenopausal and post menopausal subgroups, a statistically significant decrease in average relative signal increase was found at the 2nd through 5th time points. CONCLUSION BPE in the contralateral normal breast showed a statistically significant decrease after NAC compared to pre-NAC scans, both in early and delayed postcontrast images. The significant decrease was seen regardless of menopausal status. CLINICAL RELEVANCE/APPLICATION Evaluation of functional changes in breast tissue due to NAC may improve the understanding of the influence of NAC on hormonal levels and hemodynamics in pre and post menopausal breast cancer patients
    Radiological Society of North America 2013 Scientific Assembly and Annual Meeting; 12/2013
  • [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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE To evaluate the visibility of breast tumors on large specimen MRI, in comparison to specimen radiography and clinical dynamic contrast enhanced MRI (DCE-MRI). METHOD AND MATERIALS Breast specimens (n=15) were imaged with a MR scanner immediately after surgery, with an IRB approved protocol and with the patient’s informed consent. Specimen sizes were at least 5 cm in diameter and about 1 to 4 cm thick. Coronal and axial gradient echo MRI with and/or without fat suppression were acquired over the whole specimen using a 9.4T animal scanner with 72 mm birdcage volume coil. The lesions detected on MRI were compared with specimen radiograph and their volumes were compared with measurements obtained from clinical DCE-MRI. RESULTS Invasive ductal carcinoma (IDC) lesions were easily identified using MRI and the margins were clearly distinguishable from adjacent tissue. However, ductal carcinoma in situ (DCIS) lesions were not clearly discernible and were diffused with poorly defined margins on MRI. All calcifications associated with DCIS were visualized on specimen radiograph. The calcifications are only visible on MRI when the DCIS component is surrounded by an IDC lesion. The volumes of IDC measured on specimen MRI were not significantly different from those measured on DCE-MRI. CONCLUSION 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 is a technical challenge in visualization of DCIS lesions. Further improvement is necessary in visualization of DCIS lesions in order to aid pathologists in routine assessment of specimens, thus contributing to better treatment of breast cancer patients. CLINICAL RELEVANCE/APPLICATION High magnetic field specimen MRI provides better visualization of IDC lesions than radiography. Protocols and techniques developed in this study could be used to aid pathologists in routine analysis.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 12/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: PURPOSE For lymph node staging in breast cancer patients, ultrasound (US) and MRI are commonly used. The purpose of this study is to compare these two imaging modalities in accuracy of axillary lymph node (LN) staging for breast cancer patients. METHOD AND MATERIALS Observer performance test was conducted by dedicated breast radiologists. Consecutive 50 patients with newly diagnosed invasive breast cancer who underwent staging MRI, ipsilateral axillary US in 2009 were used. LN status of all patients were pathologically proven by surgery (sentinel LN biopsy and/or axillary lymph node dissection). MR images for the observers consisted of axial and sagittal T2 weighted images and axial post contrast T1 weighted images (slice thickness was 1 mm and in-plane resolution was 0.8 mm for all images) and US images consisted of all available static US images of the ipsileteral axilla. No information about primary cancers were provided. Confidence rating for presence of at least one positive lymph node in ipsilateral axilla was made using continuous rating scale. Observers were also asked to indicate if percutaneous biopsy was recommended preoperatively. These results were compared with final pathology results. The Az values, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) for each modality were obtained. RESULTS Our preliminary results are followings. Average sensitivity and specificity were 58% and 80% for US and 69% and 74% for MRI. PPV and NPV were 59% and 80 % for US and 56% and 83% for MRI. When US and MRI findings were concordant, PPV was 76% and NPV was 80%. Average Az values of MR and US are comparable and there was no significant difference between them. Sensitivity of MR is significantly higher than that of US, and no significant difference in specificity, PPV and NPV between US and MR. CONCLUSION Observers’ performance with MR and US are comparable in detecting metastatic lymph node in Az value, however; when they were forced to make an alternative decision, MR was more sensitive. CLINICAL RELEVANCE/APPLICATION MRI and US are comparable for staging lymph node in breast cancer patient.
    Radiological Society of North America 2011 Scientific Assembly and Annual Meeting; 11/2011
  • Source
    [Show abstract] [Hide abstract]
    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
  • Source
    [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • Source
    [Show abstract] [Hide abstract]
    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
  • [Show abstract] [Hide abstract]
    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
  • Source
    [Show abstract] [Hide abstract]
    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
  • Source
    [Show abstract] [Hide abstract]
    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

Publication Stats

228 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