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Background Data are limited regarding the performance of abbreviated screening breast MRI during consecutive years and the characteristics of breast cancers missed and detected with it. Purpose To assess the longitudinal diagnostic performance of abbreviated screening MRI and to determine whether the screening outcomes of abbreviated MRI differed between yearly time periods for 3 consecutive years. Materials and Methods This retrospective study included 1975 consecutive women who underwent abbreviated screening MRI between September 2015 and August 2018. Breast Imaging Reporting and Data System (BI-RADS) categories 3-5 defined positive results, and BI-RADS categories 1-2 defined negative results. Cancer detection rate (CDR), sensitivity, specificity, positive predictive value (PPV), abnormal interpretation rate (AIR), and interval cancer rate were assessed annually. Yearly performance measures were compared with the Fisher exact test by using the permutation method. Clinical-pathologic and imaging characteristics of the missed and detected cancers were compared by using the Fisher exact test and the Wilcoxon rank sum test. Results A total of 1975 women (median age, 49 years; interquartile range, 44-56 years) underwent 3037 abbreviated MRI examinations over 3 years. CDR (year 1 to year 3, 6.9-10.7 per 1000 examinations), positive predictive value for recall (9.7% [six of 62] to 15.6% [12 of 77]), positive predictive value for biopsy (31.6% [six of 19] to 63.2% [12 of 19]), sensitivity (75.0% [six of eight] to 80.0% [12 of 15]), and specificity (93.5% [807 of 863] to 94.1% [1041 of 1106]) were highest in year 3, and AIR (7.1% [62 of 871] to 6.9% [77 of 1121]) was lowest in year 3. However, all outcome measures did not differ statistically between years 1, 2, and 3 (all P > .05). The interval cancer rate was 0.66 per 1000 examinations (two of 3037). Thirty-eight breast cancers were identified in 36 women; 29 were detected with abbreviated MRI, but nine were missed. Of these, seven were detected with other imaging modalities after negative results at the last screening MRI examination, and two were interval cancers. All missed cancers were node-negative early-stage invasive cancers and were smaller (median size, 0.8 cm vs 1.2 cm; P = .01) than detected cancers. Conclusion Screening outcome measures of abbreviated MRI were sustained without significant differences between 3 consecutive years. All cancers missed at abbreviated MRI were node-negative invasive cancers and tended to be smaller than detected cancers. © RSNA, 2021 See also the editorial by Lee in this issue. Online supplemental material is available for this article.

Purpose To evaluate the value of preoperative axillary ultrasonography (US) for preventing unnecessary axillary lymph node dissection after sentinel lymph node (SLN) biopsy in a large series of patients with early-stage breast cancers treated with both breast-conserving surgery and SLN biopsy. Materials and Methods From March 2009 to February 2013, 1802 patients who underwent breast-conserving surgery for clinical T1-2/N0 cancers and SLN biopsy with or without axillary lymph node dissection were included. Preoperative axillary US results and clinical-pathologic variables were compared according to the status of non-SLN metastasis. Multivariate logistic regression analysis was performed to find factors associated with non-SLN metastasis. Results Of 1802 patients, 397 (22.0%) underwent axillary lymph node dissection due to positive SLN biopsy and 76 (4.2%) had non-SLN metastasis at final histopathologic examination. Patients with non-SLN metastasis were younger and showed positive axilla at US and clinical T2 stage more frequently (P < .05). At multivariate analysis, positive axilla at US (P = .001), clinical T2 stage (P = .005), and lymphovascular invasion (P < .001) were significantly associated with non-SLN metastasis. Among 1284 patients with negative axilla at US and clinical T1 stage cancer, 1254 (97.7%) did not have non-SLN metastasis and 30 (2.3%) had non-SLN metastasis. Conclusion Preoperative axillary US results and clinical T stage are associated with the status of non-SLN metastasis in patients with early breast cancer. The results of this study suggest that preoperative axillary US can help select patients at minimal risk of non-SLN metastasis, for whom axillary lymph node dissection can be omitted. © RSNA, 2018 Online supplemental material is available for this article.

Purpose To determine the relationship between tumor heterogeneity assessed by means of magnetic resonance (MR) imaging texture analysis and survival outcomes in patients with primary breast cancer. Materials and Methods Between January and August 2010, texture analysis of the entire primary breast tumor in 203 patients was performed with T2-weighted and contrast material-enhanced T1-weighted subtraction MR imaging for preoperative staging. Histogram-based uniformity and entropy were calculated. To dichotomize texture parameters for survival analysis, the 10-fold cross-validation method was used to determine cutoff points in the receiver operating characteristic curve analysis. The Cox proportional hazards model and Kaplan-Meier analysis were used to determine the association of texture parameters and morphologic or volumetric information obtained at MR imaging or clinical-pathologic variables with recurrence-free survival (RFS). Results There were 26 events, including 22 recurrences (10 local-regional and 12 distant) and four deaths, with a mean follow-up time of 56.2 months. In multivariate analysis, a higher N stage (RFS hazard ratio, 11.15 [N3 stage]; P = .002, Bonferroni-adjusted α = .0167), triple-negative subtype (RFS hazard ratio, 16.91; P.001, Bonferroni-adjusted α = .0167), high risk of T1 entropy (less than the cutoff values [mean, 5.057; range, 5.022-5.167], RFS hazard ratio, 4.55; P = .018), and T2 entropy (equal to or higher than the cutoff values [mean, 6.013; range, 6.004-6.035], RFS hazard ratio = 9.84; P = .001) were associated with worse outcomes. Conclusion Patients with breast cancers that appeared more heterogeneous on T2-weighted images (higher entropy) and those that appeared less heterogeneous on contrast-enhanced T1-weighted subtraction images (lower entropy) exhibited poorer RFS.

Background The relationship between method of breast cancer screening (mammography or US) and survival outcome in patients with screening-detected ductal carcinoma in situ (DCIS) has not been determined. Purpose To investigate whether different methods of breast cancer screening are associated with different survival outcomes in patients with screening-detected DCIS and to evaluate clinical-pathologic and imaging factors associated with second breast cancer. Materials and Methods We retrospectively identified women who underwent surgery to treat DCIS initially detected with screening mammography or US between July 2004 and December 2011 in a single institution. Overall survival (OS) and disease-free survival (DFS) were assessed. Factors associated with second breast cancer (invasive carcinoma or DCIS) were found with multivariable Cox proportional hazards regression analysis. Subgroups were analyzed according to screening method. Results A total of 814 women (median age, 47 years; age range, 25-81 years) were included; 627 underwent treatment for screening mammography-detected DCIS (mammography-detected group), and 187 underwent treatment for screening US-detected DCIS (US-detected group). During follow-up (median, 7 years; interquartile range, 5-8 years), 26 ipsilateral and 26 contralateral second breast cancers (6.4%, 52 of 814) were found, with 44 in the mammography-detected group and eight in the US-detected group. The overall 5-year OS and DFS rates were 100% and 95.3%, respectively. DFS rates did not differ according to screening method (P = .21, 5-year DFS rates were 94.9% in the mammography-detected group and 96.5% in the US-detected group). In the mammography-detected group, higher nuclear grade (intermediate grade: hazard ratio [HR], 5.7; 95% confidence interval [CI]: 1.3, 24.3; P = 0.02) (high grade: HR, 8.0; 95% CI: 1.9, 34.2; P = .01) and dense breast (HR, 3.5; 95% CI: 1.1, 11.4; P = 0.04) were associated with second breast cancer. In the US-detected group, human epidermal growth factor receptor 2 positivity was associated with second breast cancer (HR, 9.2; 95% CI: 2.2, 38.5; P = .002). Conclusion Disease-free survival of patients who underwent treatment for screening-detected ductal carcinoma in situ (DCIS) did not differ according to screening detection method. In patients with screening mammography-detected DCIS, higher nuclear grade and dense breast were associated with second breast cancer, and in patients with screening US-detected DCIS, human epidermal growth factor 2 positivity was associated with second breast cancer. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Fowler in this issue.

Purpose To determine the survival rates and clinical-pathologic and imaging factors associated with recurrence in women with breast cancer detected at screening ultrasonography (US). Materials and Methods This study was approved by the institutional review board, and the requirement to obtain informed consent was waived. A retrospective review of the databases of four institutions identified 501 women (median age, 47 years; range, 27-74 years) with breast cancer (425 invasive cancers and 76 ductal carcinoma in situ) detected at screening US between January 2004 and March 2011. Five-year overall survival (OS) and recurrence-free survival (RFS) rates were estimated, and the clinical-pathologic and imaging data were collected. Multivariate analysis was performed by using Cox proportional hazard regression to determine factors associated with recurrence. Results At a median follow-up of 7.0 years (range, 5.0-12.1 years), 15 (3.0%) recurrences were detected: five in ipsilateral breast and 10 in contralateral breast. The 5-year OS and RFS rates were 100% and 98.0% (95% confidence interval [CI]: 96.8%, 99.2%), respectively. In patients with invasive cancers, age younger than 40 years (hazard ratio: 3.632 [95% CI: 1.099, 11.998]; P = .032), the triple-negative subtype (hazard ratio: 7.498 [95% CI: 2.266, 24.816]; P = .001), and Breast Imaging Reporting and Data System (BI-RADS) category 4A lesions (hazard ratio: 5.113 [95% CI: 1.532, 17.195]; P = .008) were associated with recurrence. Conclusion Women with breast cancers detected at screening US have excellent outcomes, with a 5-year RFS rate of 98.0%. However, in patients with invasive breast cancer, age younger than 40 years, the triple-negative subtype, and BI-RADS category 4A lesions were associated with recurrence. © RSNA, 2017 Online supplemental material is available for this article.

To determine whether apparent diffusion coefficient (ADC) values vary according to tumor-stroma ratio, dominant stroma type, or presence of central fibrosis in estrogen receptor-positive breast cancer.Institutional review board approval was obtained, and patient consent was waived. Sixty-one patients with estrogen receptor-positive invasive ductal carcinoma-not otherwise specified who underwent breast magnetic resonance (MR) imaging with diffusion-weighted (DW) imaging were included in this study. The ADC values of the lesions were measured. Two pathologists evaluated the tumor-stroma ratio, dominant stroma type (collagen, fibroblast, lymphocyte), and central fibrosis. Detectability on DW images was compared between the two groups according to the tumor-stroma ratio (stroma rich or stroma poor). Mean ADC values were retrospectively compared with the tumor-stroma ratio, dominant stroma type, and presence of a central fibrosis. Multiple linear regression analysis was performed to determine variables independently associated with ADC.On DW images, detectability was not significantly different between stroma-rich and stroma-poor groups (P = .244). ADC values were significantly lower in the stroma-poor group (P.001). The mean ADC values in the collagen-dominant type were lower than in fibroblast-dominant or lymphocyte-dominant types (P = .021). In multiple linear regression analysis, tumor-stroma ratio (P = .007), tumor size (P = .007), and dominant stroma type (collagen dominant, P = .029) were independently correlated with ADC.In estrogen receptor-positive breast cancers, ADC values showed significant differences according to the tumor-stroma ratio and dominant stroma type.

To prospectively compare the diagnostic performance of radiologists by using conventional ultrasonography (US) and tissue harmonic imaging for the differentiation of benign from malignant solid breast masses, with histologic results used as the reference standard.The study was approved by the institutional review board, and informed consent was obtained from all patients. Images were obtained with conventional US and tissue harmonic imaging in 88 patients (age range, 25-67 years; mean age, 45 years) with 91 solid breast masses (30 cancers and 61 benign lesions) before excisional or needle biopsy. Three experienced radiologists, who did not perform the examinations, independently analyzed the US findings and provided a level of suspicion to indicate the probability of malignancy. Results were evaluated by using kappa statistics and receiver operating characteristic (ROC) analyses.Regarding the descriptions of US findings, echogenicity (kappa=0.205) was the most discordant between conventional US and tissue harmonic imaging, followed by margin (kappa=0.495), lesion boundary (kappa=0.495), calcifications (kappa=0.537), posterior acoustic transmission (kappa=0.546), echotexture (kappa=0.586), shape (kappa=0.591), and orientation (kappa=0.594). The area under the ROC curve (Az) for conventional US and tissue harmonic imaging was 0.84 and 0.79, respectively, for reader 1; 0.88 and 0.85, respectively, for reader 2; and 0.91 and 0.89, respectively, for reader 3. The overall Az value for the three readers was 0.88 for conventional US and 0.84 for tissue harmonic imaging (95% confidence interval: -0.0950, 0.1646; P=.595).The performance of the radiologists with respect to the characterization of solid breast masses as benign or malignant was not significantly improved with tissue harmonic imaging.

To compare prospectively obtained static two-dimensional (2D) and three-dimensional (3D) ultrasonographic (US) images in the diagnostic performance of radiologists with respect to the differentiation of benign from malignant solid breast masses with histopathologic examination as the reference standard.This study had institutional review board approval, and patient informed consent was obtained. Conventional 2D and 3D US images were obtained from 141 patients (age range, 25-71 years; mean age, 46 years) with 150 solid breast masses (60 cancers and 90 benign lesions) before excisonal or needle biopsy. Four radiologists who had not performed the examinations independently reviewed 2D US images and stored 3D US data and provided a level of suspicion concerning probability of malignancy. The sensitivity, specificity, and negative predictive values of 2D images were compared with those of 3D US images.For all readers, 3D US images were the same as or better than 2D US images in terms of sensitivity (100% vs 100% for reader 1; 100% vs 98% for reader 2; 98% vs 93% for reader 3; 93% vs 92% for reader 4), specificity (58% vs 56% for reader 1; 51% vs 46% for reader 2; 83% vs 72% for reader 3; 86% vs 84% for reader 4), and negative predictive values (100% vs 100% for reader 1; 100% vs 98% for reader 2; 99% vs 94% for reader 3; 95% vs 94% for reader 4). These differences, however, were not statistically significant (P.05).The performance of the radiologists with respect to the characterization of solid breast masses with static 2D US images was similar to that with 3D US data.

To evaluate the causes for localized fat collection that seemed to be within the subdiaphragmatic inferior vena cava (IVC) on axial computed tomographic (CT) scans.Six consecutive patients with presumed intracaval fat collection at routine abdominal CT (n = 2) or thin-section CT of the lung (n = 4) were studied prospectively with helical CT. Three patients had chronic liver diseases. Multi-directional, two-dimensional, reformatted images were obtained from the helical CT data for identification of the relation between the IVC and fat collection. Six patients without intracaval fat collection were studied as control subjects.On axial CT scans, the fat collection had a round or oval shape (in four of six patients) and was located posteromedial to the IVC (in four of six patients). On coronal reformatted images, the fat collection was outside the IVC between the diaphragm and subdiaphragmatic IVC, which was contiguous to the fat around the subdiaphragmatic esophagus. In the fat collection group, the IVC angled toward the right and narrowed to half in diameter as it passed down to the diaphragm. In the control group, the IVC was straight, although the diameter decreased similarly.A localized fat collection adjacent to the subdiaphragmatic IVC that mimics intracaval fat on axial CT scans is due to acute angulation of the IVC, which is probably a result of anatomic variation, chronic liver disease, or both.

To compare prospectively the diagnostic performance of radiologists who used conventional ultrasonography (US) with that of radiologists who used spatial compound imaging for the differentiation of benign from malignant solid breast masses.The study was approved by the institutional review board, and informed consent was obtained. Before excisional or needle biopsy was performed, conventional US and spatial compound images were obtained in 67 patients (age range, 25-67 years; mean age, 45 years) with 75 solid breast masses (21 cancers and 54 benign lesions). Three experienced radiologists who did not perform the examinations independently analyzed US findings and indicated the probability of malignancy. Results were evaluated with kappa statistics and receiver operating characteristic (ROC) analysis.For US findings, the presence of calcifications was the most discordant feature (kappa = 0.372) between conventional US and spatial compound imaging, followed by echotexture (kappa = 0.439), boundary echo (kappa = 0.496), orientation (kappa = 0.518), echogenicity (kappa = 0.523), shape (kappa = 0.526), margin (kappa = 0.569), and posterior acoustic transmission (kappa = 0.669). The area under the ROC curve for conventional US was 0.79 for reader 1, 0.88 for reader 2, and 0.82 for reader 3, and the area under the ROC curve for spatial compound imaging was 0.85 for reader 1, 0.88 for reader 2, and 0.89 for reader 3. The partial area index for conventional US was 0.29 for reader 1, 0.69 for reader 2, and 0.39 for reader 3, and the partial area index for spatial compound imaging was 0.29 for reader 1, 0.65 for reader 2, and 0.39 for reader 3. The difference between the diagnostic performances of the two techniques was not significant (P.05).The performance of the radiologists with respect to the characterization of solid breast masses was not significantly improved with spatial compound imaging.