Comparison of New and Established Full-Field Digital Mammography Systems in Diagnostic Performance

OBJECTIVE: To compare the diagnostic performance of new and established full-field digital mammography (FFDM) systems. MATERIALS AND METHODS: During a 15-month period, 1038 asymptomatic women who visited for mammography were prospectively included from two institutions. For women with routine two-view mammograms from established FFDM systems, bilateral mediolateral oblique (MLO) mammograms were repeated using the new FFDM system. One of the four reviewers evaluated two-sets of bilateral MLO mammograms at 4-week intervals by using a five-point score for the probability of malignancy according to a Breast Imaging Reporting and Data System. The lesion type and breast density were determined by the consensus of two readers at each institution. The dichotomized mammographic results correlated with a final pathologic outcome and follow-up data. Receiver operating characteristic (ROC) curves, sensitivity, and specificity were compared in general and according to the lesion type and breast density. RESULTS: Of the 1038 cases, 193 (18.6%) had cancer. The areas under the ROC curve (AUC), sensitivity, and specificity of the established system were 0.815, 65.3%, and 90.2%, respectively. Those of the new system were 0.839, 68.4%, and 91.7%, respectively. There were no significant differences in the AUCs, sensitivities or the specificities in general between new and established systems (Ps = 0.194, 0.590, 0.322, respectively). We found no significant difference in these parameters according to lesion type or breast density. CONCLUSION: The new FFDM system has a comparable diagnostic performance with established systems.

Feasibility of Sentinel Lymph Node Biopsy in Breast Cancer Patients with Initial Axillary Lymph Node Metastasis after Primary Systemic Therapy / 한국유방암학회지

PURPOSE: Primary systemic therapy (PST) downstages up to 40% of initial documented axillary lymph node (ALN) metastases in breast cancer. The current surgical treatment after PST consists of breast tumor resection and axillary lymph node dissection (ALND). This strategy, however, does not eliminate unnecessary ALND in patients with complete remission of axillary metastases. The aim of this study was to examine the accuracy of sentinel lymph node biopsy (SLNB) after PST among patients with documented ALN metastasis at presentation and to identify the rate of pathologic complete-remission (CR) with ALN after PST. METHODS: We analyzed 66 patients with ALN metastasis that was pathologically proven preoperatively who underwent SLNB and concomitant ALND after PST. Axillary ultrasound (AUS) was used to evaluate the clinical response of initially documented ALN metastasis after PST. Intraoperative lymphatic mapping was performed using blue dye with or without radioisotope. RESULTS: After PST, 34.8% of patients had clinical CR of ALN on AUS and 28.8% patients had pathologic CR of ALN. The overall success rate of SLNB after PST was 87.9%, and the sentinel lymph node identification rate in patients with clinical CR was 95.7%. In patients with successful lymphatic mapping, 70.7% of patients had residual axillary metastases. The overall accuracy and false-negative rate were 87.9% and 17.1% in all patients: 95.5% and 10.0% in patients with clinical CR of ALN, and 83.3% and 19.4% in patients with residual axillary disease after PST. CONCLUSION: Our findings suggest that SLNB may be feasible in patients with initial documented ALN metastasis who have clinical CR for metastatic ALN after PST. Further investigation in a prospective setting should be performed to confirm our results.

Computer-Aided Evaluation of Breast MRI for the Residual Tumor Extent and Response Monitoring in Breast Cancer Patients Receiving Neoadjuvant Chemotherapy

OBJECTIVE: To evaluate the accuracy of a computer-aided evaluation program (CAE) of breast MRI for the assessment of residual tumor extent and response monitoring in breast cancer patients receiving neoadjuvant chemotherapy. MATERIALS AND METHODS: Fifty-seven patients with breast cancers who underwent neoadjuvant chemotherapy before surgery and dynamic contrast enhanced MRI before and after chemotherapy were included as part of this study. For the assessment of residual tumor extent after completion of chemotherapy, the mean tumor diameters measured by radiologists and CAE were compared to those on histopathology using a paired student t-test. Moreover, the agreement between unidimensional (1D) measurement by radiologist and histopathological size or 1D measurement by CAE and histopathological size was assessed using the Bland-Altman method. For chemotherapy monitoring, we evaluated tumor response through the change in the 1D diameter by a radiologist and CAE and three-dimensional (3D) volumetric change by CAE based on Response Evaluation Criteria in Solid Tumors (RECIST). Agreement between the 1D response by the radiologist versus the 1D response by CAE as well as by the 3D response by CAE were evaluated using weighted kappa (k) statistics. RESULTS: For the assessment of residual tumor extent after chemotherapy, the mean tumor diameter measured by radiologists (2.0 +/- 1.7 cm) was significantly smaller than the mean histological diameter (2.6 +/- 2.3 cm) (p = 0.01), whereas, no significant difference was found between the CAE measurements (mean = 2.2 +/- 2.0 cm) and histological diameter (p = 0.19). The mean difference between the 1D measurement by the radiologist and histopathology was 0.6 cm (95% confidence interval: -3.0, 4.3), whereas the difference between CAE and histopathology was 0.4 cm (95% confidence interval: -3.9, 4.7). For the monitoring of response to chemotherapy, the 1D measurement by the radiologist and CAE showed a fair agreement (k = 0.358), while the 1D measurement by the radiologist and 3D measurement by CAE showed poor agreement (k = 0.106). CONCLUSION: CAE for breast MRI is sufficiently accurate for the assessment of residual tumor extent in breast cancer patients receiving neoadjuvant chemotherapy. However, for the assessment of response to chemotherapy, the assessment by the radiologist and CAE showed a fair to poor agreement.

The Interobserver Variability and Diagnostic Performance of 3-Dimensional Breast Ultrasound

PURPOSE: We wanted to evaluate the interobserver variability and diagnostic performance of 3-dimensional (3D) breast ultrasound (US) as compared with that of 2-dimensional (2D) US. MATERIALS AND METHODS: We included 150 patients who received US-guided core biopsy and 3D US between June 2009 and April 2010. Three breast imaging radiologists analyzed the 2D and 3D US images using the Breast Imaging Reporting and Data System (BI-RADS) lexicon. The intra-observer agreement and inter-observer agreement were calculated. The sensitivity and specificity of 2D and 3D US were evaluated. RESULTS: The intra-observer agreement between 2D and 3D US was mostly slight or fair agreement. However, in terms of the final category, there was substantial agreement for all three radiologists. The inter-observer agreement of 3D US was similar to that of 2D US (moderate agreement for shape, orientation, circumscribed margin and boundary; fair agreement for indistinct margin, angular margin, microlobulated margin, echo pattern and final category). The sensitivity of 3D US for breast cancer was higher than that of 2D US for two radiologists (2D vs. 3D for reader 2: 55.8% vs. 61.5%, 2D vs. 3D for reader 3: 59.6% vs. 63.5%), and the specificity of 3D US was lower than that of 2D US for all the readers (2D vs. 3D for reader 1: 90.8% vs. 86.7%, 2D vs. 3D for reader 2: 90.8% vs. 87.8%, 2D vs. 3D for reader 3: 94.9% vs. 90.8%), but the difference was not significant (p > or = 0.05). CONCLUSION: The interobserver variability and diagnostic performance of 3D breast US were similar to those of 2D US.

Limitations of Conventional Contrast-enhanced MRI in Selecting Sentinel Node Biopsy Candidates among DCIS Patients / 한국유방암학회지

PURPOSE: A better predictive model for occult invasive disease in ductal carcinoma in situ (DCIS) patients is essential to guide the tailored use of sentinel node biopsies. We hypothesized that recent improvement of contrast-enhanced breast magnetic resonance imaging (MRI) could provide more accurate information on the presence of occult invasion in DCIS patients. METHODS: From a prospectively maintained database, we identified 143 DCIS patients diagnosed with needle biopsies in whom MRI images were available. RESULTS: Sixty-five patients (45.5%) were upstaged to invasive carcinoma after curative surgery. Ultrasonographic lesion size, mass-appearance on mammography, type of needle used, and the presence of suspicious microinvasive foci were associated with increased likelihood of upstaging. Among the features of MRI, only mass-appearance was significantly associated with the presence of invasive disease (p=0.002). However, up to 50% of masses in MRI cases had massappearance on mammography as well. Other morphologic and pharmacokinetic features of MRI, such as shape, margin, and patterns of enhancement and washout, did not have a significant association. CONCLUSION: Among various morphologic and pharmacokinetic parameters of contrast-enhanced MRI, only mass-appearance was associated with occult invasive disease. Our results show the limitations of current contrast-enhanced MRI in predicting invasive disease in patients with preoperative diagnoses of DCIS.

Usefulness of Ultrasound and Ultrasound-guided Fine-Needle Aspiration Biopsy for Axillary Staging in Breast Cancer: Analysis of 327 patients at a single institution

PURPOSE: To evaluate the accuracy of ultrasound (US) and US-guided fine needle aspiration biopsy (FNAB) for the diagnosis of metastasis in the axillary lymph node (LN) of patients with breast cancer. MATERIALS AND METHODS: A retrospective review of the data was performed on 327 breast cancer patients that underwent axillary US from Jun 2006 to July 2008. US-guided FNAB was performed when a LN indicated suspicious findings. Results of FNAB were compared with those of subsequent surgery. RESULTS: Of the 327 patients, 111 showed suspicious findings on US and underwent FNAB. Among the 111 cases, 73 (66%) were positive for cancer, while 38 (34%) were negative results. A Total of 254 patients who had normal findings on US (n=216) and negative results on FNAB (n=38) underwent SNB, of which 56 (22%) were proven to have metastasis. Sensitivity and specificity of US were 61.9% and 81.8%, respectively, with a positive predictive value (PPV) of 65.8% and negative predictive value (NPV) of 79.2%. Sensitivity and specificity of US-guided FNAB were 86.9% and 100%, respectively, with a PPV of 100% and a NPV of 71.7%. CONCLUSION: US and US-guided FNAB performed for axillary staging are useful methods with a high specificity and positive predictive value in invasive breast cancer patients.

Evaluation of Mammographic Phantom Images Using JPEG2000 Image Compression

PURPOSE: To determine the usefulness of compression standard JPEG2000 for compression of mammographic images. MATERIALS AND METHODS: Image of a mammographic phantom was compressed using JPEG2000 at ratios of 10:1, 20:1, 30:1, 40:1, 50:1 and 60:1. The sizes of the images were compared, and scores were recorded by counting the numbers of fibers, groups of specks and masses seen in each phantom image. More than four fibers, three groups of specks and three masses and a total score of 10 were considered acceptable. RESULTS: The size of a DICOM image was 17,042 KB, a TIFF image was 8,324 KB, the original JPEG image was 1,506 KB and the most compressed image (50:1) above an acceptable total score of 10 was 43 KB. In each category, the compression image of fiber was acceptable up to compression ratio of 50:1 (score of 5), groups of specks was acceptable up to 60:1 (score of 3) and mass was acceptable up to 50:1 (score of 3.5). The total score, which was acquired by adding up the individual scores of all three categories, for a compression ratio of 50:1 was 12 and was acceptable, but the total score for 60:1 was 8 and was not acceptable. CONCLUSION: The compression standard JPEG2000 is an efficient means for compressing mammographic images at high ratios without compromising diagnostic value.