CT and MR Imaging Findings of Structural Heart Diseases Associated with Sudden Cardiac Death

Sudden cardiac death is an unexpected death originating from the heart that occurs within an hour of the onset of symptoms. The main cause of sudden cardiac death is arrhythmia; however, diagnosing underlying structural heart disease significantly contributes to predicting the long-term risk. Cardiovascular CT and MR provide important information for diagnosing and evaluating structural heart disease, enabling the prediction and preparation of the risk of sudden cardiac death. Therefore, we would like to focus on the various structural heart diseases that increase the risk of clinically-important sudden cardiac death and the importance of imaging findings.

CT and MR Imaging Findings of Structural Heart Diseases Associated with Sudden Cardiac Death

Sudden cardiac death is an unexpected death originating from the heart that occurs within an hour of the onset of symptoms. The main cause of sudden cardiac death is arrhythmia; however, diagnosing underlying structural heart disease significantly contributes to predicting the long-term risk. Cardiovascular CT and MR provide important information for diagnosing and evaluating structural heart disease, enabling the prediction and preparation of the risk of sudden cardiac death. Therefore, we would like to focus on the various structural heart diseases that increase the risk of clinically-important sudden cardiac death and the importance of imaging findings.

Survival Rates of Breast Cancer Patients Aged 40 to 49 Years according to Detection Modality in Korea: Screening Ultrasound versus Mammography

Objective@#The aim of this study was to compare the survival rates of Korean females aged 40 to 49 years with breast cancer detected by supplemental screening ultrasound (US) or screening mammography alone. @*Materials and Methods@#This single-institution retrospective study included 240 patients with breast cancer (mean age, 45.1 ± 2.8 years) detected by US or mammography who had undergone breast surgery between 2003 and 2008. Medical records were reviewed for clinicopathologic characteristics and detection methods. Disease-free survival (DFS) and overall survival (OS) were compared between patients with breast cancer in the US and mammography groups using the log-rank test. Multivariable cox regression analysis was used to identify independent variables associated with DFS and OS. @*Results@#Among the 240 cases of breast cancer, 43 were detected by supplemental screening US and 197 by screening mammography (mean follow-up: 7.4 years, 93.3% with dense breasts). There were 19 recurrences and 16 deaths, all occurring in the mammography group. While the US group did not differ from the mammography group in tumor stage, the patients in this group were more likely to undergo breast-conserving surgery and radiation therapy than the mammography group.The US group also showed better DFS (p = 0.016); however, OS did not differ between the two groups (p = 0.058). In the multivariable analysis, the US group showed a lower risk of recurrence (hazard ratio, 0.097; 95% confidence interval, 0.001–0.705) compared to the mammography group. @*Conclusion@#Our study found that Korean females aged 40–49 years with US-detected breast cancer showed better DFS than those with mammography-detected breast cancer. However, there were no statistically significant differences in OS.

Application of machine learning to ultrasound images to differentiate follicular neoplasms of the thyroid gland

Purpose@#This study was conducted to evaluate the diagnostic performance of machine learning in differentiating follicular adenoma from carcinoma using preoperative ultrasonography (US). @*Methods@#In this retrospective study, preoperative US images of 348 nodules from 340 patients were collected from two tertiary referral hospitals. Two experienced radiologists independently reviewed each image and categorized the nodules according to the 2015 American Thyroid Association guideline. Categorization of a nodule as highly suspicious was considered a positive diagnosis for malignancy. The nodules were manually segmented, and 96 radiomic features were extracted from each region of interest. Ten significant features were selected and used as final input variables in our in-house developed classifier models based on an artificial neural network (ANN) and support vector machine (SVM). The diagnostic performance of radiologists and both classifier models was calculated and compared. @*Results@#In total, 252 nodules from 245 patients were confirmed as follicular adenoma and 96 nodules from 95 patients were diagnosed as follicular carcinoma. As measures of diagnostic performance, the average sensitivity, specificity, and accuracy of the two experienced radiologists in discriminating follicular adenoma from carcinoma on preoperative US images were 24.0%, 84.0%, and 64.8%, respectively. The sensitivity, specificity, and accuracy of the ANN and SVM-based models were 32.3%, 90.1%, and 74.1% and 41.7%, 79.4%, and 69.0%, respectively. The kappa value of the two radiologists was 0.076, corresponding to slight agreement. @*Conclusion@#Machine learning-based classifier models may aid in discriminating follicular adenoma from carcinoma using preoperative US.

Follow-Up Intervals for Breast Imaging Reporting andData System Category 3 Lesions on Screening Ultrasoundin Screening and Tertiary Referral Centers

Objective@#To assess the appropriate follow-up interval, and rate and timepoint of cancer detection in women with Breast ImagingReporting and Data System (BI-RADS) 3 lesions on screening ultrasonography (US) according to the type of institution. @*Materials and Methods@#A total of 1451 asymptomatic women who had negative or benign findings on screening mammogram,BI-RADS 3 assessment on screening US, and at least 6 months of follow-up were included. The median follow-up interval was30.8 months (range, 6.8–52.9 months). The cancer detection rate, cancer detection timepoint, risk factors, and clinicopathologicalcharacteristics were compared between the screening and tertiary centers. Nominal variables were compared using the chisquareor Fisher’s exact test and continuous variables were compared using the independent t test or Mann-Whitney U test. @*Results@#In 1451 women, 19 cancers (1.3%) were detected; two (0.1%) were diagnosed at 6 months and 17 (1.2%) werediagnosed after 12.3 months. The malignancy rates were both 1.3% in the screening (9 of 699) and tertiary (10 of 752) centers.In the screening center, all nine cancers were invasive cancers and diagnosed after 12.3 months. In the tertiary center, twowere ductal carcinomas in situ and eight were invasive cancers. Two of the invasive cancers were diagnosed at 6 months andthe remaining eight cancers newly developed after 13.1 months. @*Conclusion@#One-year follow-up rather than 6-month follow-up may be suitable for BI-RADS 3 lesions on screening US foundin screening centers. However, more caution is needed regarding similar findings in tertiary centers where 6-month follow-upmay be more appropriate.

Preoperative Magnetic Resonance Imaging FeaturesAssociated with Positive Resection Margins in Patientswith Invasive Lobular Carcinoma

Objective@#To investigate preoperative magnetic resonance imaging (MRI) findings associated with resection margin statusin patients with invasive lobular carcinoma (ILC) who underwent breast-conserving surgery. @*Materials and Methods@#One hundred and one patients with ILC who underwent preoperative MRI were included. MRI(tumor size, multifocality, type of enhancing lesion, distribution of non-mass enhancement [NME], and degree of backgroundparenchymal enhancement) and clinicopathological features (age, pathologic tumor size, presence of ductal carcinoma in situ[DCIS] or lobular carcinoma in situ, presence of lymph node metastases, and estrogen receptor/progesterone receptor/humanepidermal growth factor receptor type 2 status) were analyzed. A positive resection margin was defined as the presence ofinvasive cancer or DCIS at the inked surface. Logistic regression analysis was performed to determine pre- and postoperativevariables associated with positive resection margins. @*Results@#Among the 101 patients, 21 (20.8%) showed positive resection margins. In the univariable analysis, NME,multifocality, axillary lymph node metastasis, and pathologic tumor size were associated with positive resection margins.With respect to preoperative MRI findings, multifocality (odds ratio [OR] = 3.977, p = 0.009) and NME (OR = 2.741, p = 0.063)were associated with positive resection margins in the multivariable analysis, although NME showed borderline significance. @*Conclusion@#In patients with ILC, multifocality and the presence of NME on preoperative breast MRI were associated withpositive resection margins.

Diagnostic Value of CYFRA 21-1 Measurement in Fine-Needle Aspiration Washouts for Detection of Axillary Recurrence in Postoperative Breast Cancer Patients

PURPOSE@#The objective of this study was to evaluate the diagnostic value and threshold levels of cytokeratin fragment 21-1 (CYFRA 21-1) in fine-needle aspiration (FNA) washouts for detection of lymph node (LN) recurrence in postoperative breast cancer patients.@*MATERIALS AND METHODS@#FNA cytological assessments and CYFRA 21-1 measurement in FNA washouts were performed for 64 axillary LNs suspicious for recurrence in 64 post-operative breast cancer patients. Final diagnosis was made on the basis of FNA cytology and follow-up data over at least 2 years. The concentration of CYFRA 21-1 was compared between recurrent LNs and benign LNs. Diagnostic performance and cut-off value were evaluated using a receiver operating characteristic curve.@*RESULTS@#Regardless of the non-diagnostic results, the median concentration of CYFRA 21-1 in recurrent LNs was significantly higher than that in benign LNs (p < 0.001). The optimal diagnostic cut-off value was 1.6 ng/mL. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of CYFRA 21-1 for LN recurrence were 90.9%, 100%, 100%, 98.1%, and 98.4%, respectively.@*CONCLUSION@#Measurement of CYFRA 21-1 concentration from ultrasound-guided FNA biopsy aspirates showed excellent diagnostic performance with a cut-off value of 1.6 ng/mL. These results indicate that measurement of CYFRA 21-1 concentration in FNA washouts is useful for the diagnosis of axillary LN recurrence in post-operative breast cancer patients.

Annual Trends in Ultrasonography-Guided 14-Gauge Core Needle Biopsy for Breast Lesions

OBJECTIVE: To examine time trends in ultrasonography (US)-guided 14-gauge core needle biopsy (CNB) for breast lesions based on the lesion size, Breast Imaging-Reporting and Data System (BI-RADS) category, and pathologic findings.MATERIALS AND METHODS: We retrospectively reviewed consecutive US-guided 14-gauge CNBs performed from January 2005 to December 2016 at our institution. A total of 22,297 breast lesions were included. The total number of biopsies, tumor size (≤ 10 mm to > 40 mm), BI-RADS category (1 to 5), and pathologic findings (benign, high risk, ductal carcinoma in situ [DCIS], invasive cancer) were examined annually, and the malignancy rate was analyzed based on the BI-RADS category.RESULTS: Both the total number of US scans and US-guided CNBs increased while the proportion of US-guided CNBs to the total number of US scans decreased significantly. The number of biopsies classified based on the tumor size, BI-RADS category, and pathologic findings all increased over time, except for BI-RADS categories 1 or 2 and category 3 (odds ratio [OR] = 0.951 per year, 95% confidence interval [CI]: 0.902, 1.002 and odds ratio = 0.979, 95% CI: 0.970, 0.988, respectively). Both the unadjusted and adjusted total malignancy rates and the DCIS rate increased significantly over time. BI-RADS categories 4a, 4b, and 4c showed a significant increasing trend in the total malignancy rate and DCIS rate.CONCLUSION: The malignancy rate in the results of US-guided 14-gauge CNB for breast lesions increased as the total number of biopsies increased from 2005 to 2016. This trend persisted after adjusting for the BI-RADS category.

Core-Needle Biopsy Does Not Show Superior Diagnostic Performance to Fine-Needle Aspiration for Diagnosing Thyroid Nodules

Medical Audit of Screening Mammography at a Tertiary Referral Hospital Using the 5th Edition of Breast Imaging Reporting and Data System

PURPOSE@#The purpose of this study is to analyze medical audit of screening digital mammography at a tertiary hospital and to review changes of medical audit according to newly revised standard.@*MATERIALS AND METHODS@#We analyzed 7764 asymptomatic women who underwent screening mammogram at our hospital from January, 2013 to December, 2014. The family or past history of breast, gynecologic and other cancers was reviewed retrospectively. Analysis 1 defined category 3 as positive result and analysis 2 defined category 3 as negative.@*RESULTS@#The overall cancer detection rate was 4.6 per 1000 cases. The cancer detection rate in patients with non-gynecological and non-thyroid cancer (n = 391, 51.2) was the highest compared to patients with family history of breast cancer (n = 691, 1.4), or gynecological cancer (n = 311, 12.9). In analysis 1, positive predictive value 1 decreased 1.3% (6.0% vs. 7.3%) and recall rate increased 1.3% (7.3% vs. 6.0%) compared with analysis 2. The results were appropriate for newly revised target.@*CONCLUSION@#The results of screening digital mammography in the tertiary medical institution showed excellent results even if category 3 was regarded as positive. In addition, screening tests for secondary cancer are needed in the tertiary hospital.

Comparison of breast tissue markers for tumor localization in breast cancer patients undergoing neoadjuvant chemotherapy

PURPOSE: The purpose of this study was to compare the visibility of breast tissue markers in cases of breast cancer on ultrasonography (US) after neoadjuvant chemotherapy (NAC) and to analyze whether the type of marker affected the choice of localization method after NAC. METHODS: We included 153 tissue markers inserted within breast cancers that showed pathologically complete response (pCR) after NAC from January 2012 to April 2017. One of three types of markers (a surgical clip, Cormark, or UltraClip) was inserted. Medical records and imaging findings were retrospectively reviewed. We compared the visibility of the different types of tissue markers on US after NAC, and also compared the imaging modalities used in the preoperative localization. The chi-square test, Fisher exact test, and multiple logistic regression were used for analysis. RESULTS: Of the 153 tissue markers, 56 were surgical clips, 61 Cormark, and 36 UltraClip. After NAC, residual lesions were not seen on US in 42 cases (27.5%). In multivariate analysis, the visibility of the surgical clips and Cormark markers was better than that of the UltraClip markers (odds ratio [OR], 5.467; 95% confidence interal [CI], 1.717 to 17.410; P=0.004 and OR, 3.045; 95% CI, 1.074 to 8.628; P=0.036, respectively). Among the 131 cases where localization targeting the marker was required, the proportion of US-guided localizations was significantly higher when a surgical clip was used than when an UltraClip marker was used (OR, 5.566; 95% CI, 1.610 to 19.246; P=0.007) in the multivariate analysis. CONCLUSION: The type of breast tissue marker affected its visibility on US in cases with pCR after NAC, which in turn affected the localization methodology.

High Body Mass Index and Thyroid Stimulating Hormone Levels Do Not Affect Thyroid Nodule Selection for Fine-Needle Aspiration Biopsy after Ultrasound Evaluation

BACKGROUND AND OBJECTIVES: This study was to evaluate whether high body mass index (BMI) or thyroid stimulating hormone (TSH) level would affect selecting thyroid nodule for fine-needle aspiration biopsy (FNA) after ultrasound (US) evaluation. MATERIALS AND METHODS: A total of 3155 thyroid nodules (2159 benign and 996 malignant nodules) were included. Four grades of BMI and three levels of TSH were applied for grouping. US features of the thyroid nodules were divided into ‘probably benign’ and ‘suspicious for malignancy’ categories. Patients were grouped according to gender and univariate and multivariate logistic regression analysis were used to find the association between variables and malignancy. RESULTS: TSH levels were significantly higher in the malignant group (p<0.001). The grades of BMI did not show difference between the malignant and benign groups (females, p=0.074 and males, p=0.157). Younger age and ‘suspicious for malignancy’ US category were independent risk factors for malignancy in both genders. In females, a high TSH level (odds ratio=1.010, p<0.001) had significant association with malignancy. Except for younger age (odds ratio=0.998, p<0.001), no variable in nodules with ‘probably benign’ US category was significantly associated with malignancy. CONCLUSION: High TSH levels were more frequent in thyroid malignancy group, but neither high BMI nor high TSH level give additional information for FNA selection after US.

Feasibility of Charcoal Tattooing of Cytology-Proven Metastatic Axillary Lymph Node at Diagnosis and Sentinel Lymph Node Biopsy after Neoadjuvant Chemotherapy in Breast Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Sentinel lymph node biopsy (SLNB) can be performed when node-positive disease is converted to node-negative status after neoadjuvant chemotherapy (NCT). Tattooing nodes might improve accuracy but supportive data are limited. This study aimed to investigate the feasibility of charcoal tattooing metastatic axillary lymph node (ALN) at presentation followed by SLNB after NCT in breast cancers. MATERIALS AND METHODS: Twenty patientswith cytology-proven node metastases prospectively underwent charcoal tattooing at diagnosis. SLNB using dual tracers and axillary surgery after NCT were then performed. The detection rate of tattooed node and diagnostic performance of SLNB were analyzed. RESULTS: All patients underwent charcoal tattooingwithout significant morbidity. Sentinel and tattooed nodes could be detected during surgery after NCT. Nodal pathologic complete response was achieved in 10 patients. Overall sensitivity, false-negative rate (FNR), negative predictive value, and accuracy of hot/blue SLNB were 80.0%, 20.0%, 83.3%, and 90.0%, respectively. Retrieving more nodes and favorable nodal response were associated with improved performance. The best accuracy was observed when excised tattooed node was calculated together (FNR, 0.0%). Cold/non-blue tattooed nodes of five patients were removed during non-sentinel axillary surgery but clinicopathological parameters did not differ compared to patients with hot/blue tattooed node detected during SLNB, suggesting the importance of the tattooing procedure itself to improve performance. CONCLUSION: Charcoal tattooing of cytology-confirmed metastatic ALN at presentation is technically feasible and does not limit SLNB after NCT. The tattooing procedure without additional preoperative localization is advantageous for improving the diagnostic performance of SLNB in this setting.

Evaluating imaging-pathology concordance and discordance after ultrasound-guided breast biopsy

Ultrasound (US)-guided breast biopsy has become the main method for diagnosing breast pathology, and it has a high diagnostic accuracy, approaching that of open surgical biopsy. However, methods for confirming adequate lesion retrieval after US-guided biopsy are relatively limited and false-negative results are unavoidable. Determining imaging-pathology concordance after US-guided biopsy is essential for validating the biopsy result and providing appropriate management. In this review article, we briefly present the results of US-guided breast biopsy; describe general aspects to consider when establishing imaging-pathology concordance; and review the various categories of imaging-pathology correlations and corresponding management strategies.

Associations between Bethesda categories and tumor characteristics of conventional papillary thyroid carcinoma

PURPOSE: The aim of this study was to investigate the associations of Bethesda categories III, V, and VI with the clinical and pathological features of thyroid nodules surgically confirmed as conventional papillary thyroid carcinomas (PTCs). METHODS: We analyzed 1,990 consecutive patients diagnosed with conventional PTC at surgery with preoperative Bethesda categories III, V, or VI. We determined the odds ratio (ORs) of the clinical and pathological variables associated with categories III and V, using category VI as the reference. RESULTS: Category III and V PTCs had a smaller pathological tumor size (OR, 0.934 and OR, 0.969, respectively) and less frequently had central lymph node metastasis (OR, 0.487 and OR, 0.780, respectively) than category VI PTCs. Category III PTCs less frequently showed suspicious ultrasonographic features (OR, 0.296) than category VI PTCs, and category V PTCs less frequently had gross extrathyroidal extension, with borderline significance (OR, 0.643; P=0.059). CONCLUSION: Conventional PTCs with a preoperative Bethesda category of III or V may less frequently exhibit poor prognostic factors than those with malignant cytology.

Ultrasonography-guided 14-gauge core biopsy of the breast: results of 7 years of experience

PURPOSE: This study assessed the outcomes of ultrasound (US)-guided core needle biopsies (CNBs) of breast lesions with at least 2 years of follow-up to determine the false-negative rate and to evaluate the diagnostic accuracy of CNB. METHODS: We retrospectively analyzed 13,254 consecutive US-guided 14-gauge CNBs for breast lesions. We excluded biopsies if non-malignant biopsy result was not confirmed by surgical excision or US-guided vacuum-assisted biopsy, or fewer than 2 years of follow-up data were available. A total of 4,186 biopsies were excluded, and 9,068 breast masses from 7,039 women were included. The pathologic findings from each CNB were assessed using the standard diagnostic reference, defined based on the results of surgical excision, vacuum-assisted biopsy, or at least 2 years of long-term imaging follow-up. The false-negative rate and underestimation rate were calculated. RESULTS: Of the 9,068 CNBs, benign pathology was found in 64.2%, high-risk results in 3.5%, and malignant results in 32.3%. Of the 5,821 benign CNBs, an additional malignancy was found at excision in 63 lesions, leading to a false-negative rate of 2.0% (63 of 3,067). The underestimation rate was 33.6% (111 of 330) for ductal carcinoma in situ and 24.5% (79 of 322) for high-risk results at surgical excision. Most false-negative diagnoses (84.1%, 53 of 63) were recognized through imaging-histology correlations, and immediate rebiopsies were performed. Ten malignancies (15.9%, 10 of 63) had delayed diagnoses and showed progression in follow-up US imaging. CONCLUSION: US-guided 14-gauge CNB provided optimal diagnostic information. Imaging-histology correlations and appropriate imaging follow-up should be performed to avoid delayed diagnoses.

Preoperative High Neutrophil-Lymphocyte Ratio May Be Associated with Lateral Lymph Node Metastasis in Patients with Papillary Thyroid Cancers

BACKGROUND AND OBJECTIVES: The present study investigated the association between preoperative neutrophil-to-lymphocyte ratio (NLR) and poor prognostic outcomes in conventional papillary thyroid carcinomas (cPTCs). MATERIALS AND METHODS: Two hundred and five patients who underwent total thyroidectomy for cPTCs larger than 10 mm were evaluated retrospectively. Patients were classified into the low NLR (n=103) and high NLR (n=102) groups by the median NLR value (1.78) and logistic regression analysis was used to evaluate whether the NLR predicted aggressive PTC features. Patients were also classified into the disease-free (n=183) and persistence/recurrence (n=22) groups and Cox regression analysis was used to investigate factors affecting persistence/recurrence by Cox regression analysis. RESULTS: The high NLR group had a higher presence of lateral lymph node metastasis (p=0.004) and higher radioactive iodine doses (p=0.006) than the low NLR group. High NLR was an independent predictor of lateral lymph node metastasis (LNM) (OR, 2.786; p=0.005) but was not significantly associated with persistence/recurrence. CONCLUSION: Preoperative high NLR was an independent predictor of lateral LNM in cPTCs.

Metastatic renal cell carcinoma in the thyroid gland: ultrasonographic features and the diagnostic role of core needle biopsy

PURPOSE: The aims of this study were to present the ultrasonographic (US) features of metastatic renal cell carcinoma (RCC) in the thyroid gland and to evaluate the diagnostic utility of fineneedle aspiration (FNA) and core needle biopsy (CNB). METHODS: Eight patients with nine metastatic RCC nodules in the thyroid glands who were treated from January 2002 to March 2015 in a single tertiary hospital were consecutively selected and retrospectively reviewed. US features and clinical history were obtained from the institution's medical database. FNA was performed nine times on eight nodules and CNB was performed six times on six nodules. The diagnostic utility of FNA and CNB was evaluated. RESULTS: All nine nodules showed mass formation without diffuse thyroid involvement. On ultrasonography, metastatic RCC nodules were solid (100%), hypoechoic (100%), and oval-shaped nodules with a well-defined smooth margin (88.9%) and increased vascularity (100%, with 55% showing extensive vascularity). No calcifications were noted in any nodules. Lymph node metastasis and direct extension to nearby structures beyond the thyroid gland were not found. One FNA (11%) was able to confirm metastatic RCC, whereas all six CNBs confirmed metastatic RCC. CONCLUSION: Metastatic RCC appears as oval-shaped hypoechoic solid nodules with well-defined smooth margins, no calcifications, and increased vascularity on ultrasonography. Characteristic US features along with a previous history of RCC should raise clinical suspicion, and CNB should be performed to make an accurate diagnosis.

Ultrasonographic evaluation of women with pathologic nipple discharge

Nipple discharge is a common symptom that is alarming for the patient since it can be a presenting symptom of breast cancer. Breast imaging is used to examine women with pathologic nipple discharge in order to detect any lesions that may be present and to assist in the differential diagnosis. The modalities of breast imaging include mammography, breast ultrasonography (US), and magnetic resonance imaging. Breast US is currently considered to be useful for the visualization of ductal structures and intraductal lesions that cause nipple discharge. In this review, we discuss US techniques that assist in the clear visualization of ductal structures and intraductal lesions in patients with nipple discharge. Controversy remains regarding the evaluation and management of patients with nipple discharge, and we summarize the results available in the currently published literature.

Magnetic resonance imaging and pathological characteristics of pure mucinous carcinoma in the breast according to echogenicity on ultrasonography

PURPOSE: The aim of this study was to explore the clinical and pathological characteristics of pure mucinous breast carcinoma (PMBC) according to internal echogenicity on ultrasonography (US). METHODS: Thirty-three patients with PMBC diagnosed at surgery were included in this study. Cases of PMBC were classified according to internal echogenicity on US. The imaging features on magnetic resonance (MR) imaging and clinicohistopathological characteristics were compared between the hypoechogenic and the isoechogenic to hyperechogenic groups. RESULTS: Eleven cases of PMBC (33.3%) exhibited hypoechogenicity on US, while 22 cases (66.7%) exhibited isoechogenicity or hyperechogenicity. Of the isoechogenic to hyperechogenic PMBCs, 95.5% showed a high signal on T2-weighted images, which was a significantly greater percentage than was observed for the hypoechogenic group (54.5%) (P=0.010). Of the hypoechogenic PMBCs, 63.6% showed a washout pattern in the delayed phase, which was substantially more than the result of 23.8% observed for the isoechogenic to hyperechogenic PMBCs (P=0.053). CONCLUSION: PMBCs with isoechogenicity or hyperechogenicity were more likely to show a high signal intensity on T2-weighted images than hypoechogenic PMBCs. However, other MR imaging and clinicohistopathological characteristics were not significantly different between the two groups.