ESR Essentials: screening for breast cancer - general recommendations by EUSOBI.

Breast cancer is the most frequently diagnosed cancer in women accounting for about 30% of all new cancer cases and the incidence is constantly increasing. Implementation of mammographic screening has contributed to a reduction in breast cancer mortality of at least 20% over the last 30 years. Screening programs usually include all women irrespective of their risk of developing breast cancer and with age being the only determining factor. This approach has some recognized limitations, including underdiagnosis, false positive cases, and overdiagnosis. Indeed, breast cancer remains a major cause of cancer-related deaths in women undergoing cancer screening. Supplemental imaging modalities, including digital breast tomosynthesis, ultrasound, breast MRI, and, more recently, contrast-enhanced mammography, are available and have already shown potential to further increase the diagnostic performances. Use of breast MRI is recommended in high-risk women and women with extremely dense breasts. Artificial intelligence has also shown promising results to support risk categorization and interval cancer reduction. The implementation of a risk-stratified approach instead of a "one-size-fits-all" approach may help to improve the benefit-to-harm ratio as well as the cost-effectiveness of breast cancer screening. KEY POINTS: Regular mammography should still be considered the mainstay of the breast cancer screening. High-risk women and women with extremely dense breast tissue should use MRI for supplemental screening or US if MRI is not available. Women need to participate actively in the decision to undergo personalized screening. KEY RECOMMENDATIONS: Mammography is an effective imaging tool to diagnose breast cancer in an early stage and to reduce breast cancer mortality (evidence level I). Until more evidence is available to move to a personalized approach, regular mammography should be considered the mainstay of the breast cancer screening. High-risk women should start screening earlier; first with yearly breast MRI which can be supplemented by yearly or biennial mammography starting at 35-40 years old (evidence level I). Breast MRI screening should be also offered to women with extremely dense breasts (evidence level I). If MRI is not available, ultrasound can be performed as an alternative, although the added value of supplemental ultrasound regarding cancer detection remains limited. Individual screening recommendations should be made through a shared decision-making process between women and physicians.

Axillary lymph nodes enlargement after Sars-CoV-2 vaccine in patients undergoing breast examination: a single-centre experience in 285 women.

PURPOSE: To assess the incidence of axillary lymphadenopathy over established time ranges after COVID-19 vaccination and lymph node pathologic features (i.e. size increase and qualitative characteristics) in subjects undergoing axillary evaluation during a breast imaging examination. METHODS AND MATERIALS: The institutional review board approved this prospective study. INCLUSION CRITERIA: women undergoing mammography and breast ultrasound between July and October 2021; information about the COVID-19 vaccine and infection, if any. EXCLUSION CRITERIA: known metastatic lymphadenopathy. Participants were divided into 5 subgroups according to time between vaccine and imaging: < 6 weeks; 7-8 weeks; 9-10 weeks; 11-12 weeks; > 12 weeks. Evaluation of axillary lymph nodes was performed with ultrasound. Descriptive statistical analysis was performed. p < 0.05 was considered significant. RESULTS: A total of 285 women were included. Most of the patients underwent Moderna vaccine (n = 175, 61.4%). 63/285 patients had a previous history of breast cancer (22.1%). 13/17 (76.5%) patients with previous COVID-19 infection had no previous history of cancer, whereas 4/17 had a previous history of cancer (p < .001). 41/285 (14.4%) women showed lymphadenopathy, and they were significantly younger (46.9 ± 11.6 years) than women with borderline (54.0 ± 11.9 years) or no lymphadenopathy (57.3 ± 11.9 years) (p < .001). Lymphadenopathy and borderline lymphadenopathy were more frequently observed in the Moderna-vaccinated women and in the subgroup of patients evaluated < 6 weeks after vaccination (p < 0.001). The most common pathologic feature was cortical thickening, followed by complete or partial effacement of fatty hilum. CONCLUSION: A lymphadenopathy within 12 weeks after vaccination is a common finding particularly in younger women and after Moderna vaccine and no further assessment should be required.

Mammographic calcifications undergoing percutaneous biopsy: outcome in women with and without a personal history of breast cancer.

PURPOSE: To compare the positive predictive values (PPVs) of BI-RADS categories used to assess pure mammographic calcifications in women with and without a previous history of breast cancer (PHBC). MATERIALS AND METHODS: In this retrospective study, all consecutive pure mammographic calcifications (n = 320) undergoing a stereotactic biopsy between 2016 and 2018 were identified. Mammograms were evaluated in consensus by two radiologists according to BI-RADS and blinded to patient history and pathology results. Final pathologic results were used as the standard of reference. PPV of BI-RADS categories were compared between the two groups. Data were evaluated using standard statistics, Mann-Whitney U tests and Chi-square tests. RESULTS: Two hundred sixty-eight patients (274 lesions, median age 54 years, inter-quartile range, 50-65 years) with a PHBC (n = 46) and without a PHBC (n = 222) were included. Overall PPVs were the following: BI-RADS 2, 0% (0 of 56); BI-RADS 3, 9.1% (1 of 11); BI-RADS 4a, 16.2% (6 of 37); BI-RADS 4b, 37.5% (48 of 128); BI-RADS 4c, 47.3% (18 of 38) and BI-RADS 5, 100% (4 of 4). The PPV of BI-RADS categories was similar in patients with and without a PHBC (P = .715). Calcifications were more often malignant in patients with a PHBC older than 10 years (47.3%, 9 of 19) compared to 1-2 years (25%, 1 of 4), 2-5 years (20%, 2 of 10) and 5-10 years (0%, of 13) from the first breast cancer (P = .005). CONCLUSION: PPV of mammographic calcifications is similar in women with or without PHBC when BI-RADS classification is strictly applied. A higher risk of malignancy was observed in patients with a PHBC longer than 10 years.

Fully automatic classification of automated breast ultrasound (ABUS) imaging according to BI-RADS using a deep convolutional neural network.

PURPOSE: The aim of this study was to develop and test a post-processing technique for detection and classification of lesions according to the BI-RADS atlas in automated breast ultrasound (ABUS) based on deep convolutional neural networks (dCNNs). METHODS AND MATERIALS: In this retrospective study, 645 ABUS datasets from 113 patients were included; 55 patients had lesions classified as high malignancy probability. Lesions were categorized in BI-RADS 2 (no suspicion of malignancy), BI-RADS 3 (probability of malignancy < 3%), and BI-RADS 4/5 (probability of malignancy > 3%). A deep convolutional neural network was trained after data augmentation with images of lesions and normal breast tissue, and a sliding-window approach for lesion detection was implemented. The algorithm was applied to a test dataset containing 128 images and performance was compared with readings of 2 experienced radiologists. RESULTS: Results of calculations performed on single images showed accuracy of 79.7% and AUC of 0.91 [95% CI: 0.85-0.96] in categorization according to BI-RADS. Moderate agreement between dCNN and ground truth has been achieved (κ: 0.57 [95% CI: 0.50-0.64]) what is comparable with human readers. Analysis of whole dataset improved categorization accuracy to 90.9% and AUC of 0.91 [95% CI: 0.77-1.00], while achieving almost perfect agreement with ground truth (κ: 0.82 [95% CI: 0.69-0.95]), performing on par with human readers. Furthermore, the object localization technique allowed the detection of lesion position slice-wise. CONCLUSIONS: Our results show that a dCNN can be trained to detect and distinguish lesions in ABUS according to the BI-RADS classification with similar accuracy as experienced radiologists. KEY POINTS: • A deep convolutional neural network (dCNN) was trained for classification of ABUS lesions according to the BI-RADS atlas. • A sliding-window approach allows accurate automatic detection and classification of lesions in ABUS examinations.

Dual energy CT arthrography in shoulder instability: successful iodine removal with virtual non-contrast images and accurate 3D reformats of the glenoid for assessment of bone loss.

OBJECTIVE: To evaluate the image quality of dual energy CT (DECT) of the shoulder after arthrography and of virtual non-contrast (VNC) 3D reformats of the glenoid and to compare glenoid measurements on VNC 3D reformats and on 2D CTs. MATERIALS AND METHODS: DECT arthrography (80 kV/140 kV) was performed in 42 shoulders of 41 patients with instability using diluted iodinated contrast media (80 mg/ml). VNC images and VNC 3D reformats of the glenoid were calculated using image postprocessing. Dose parameters, CT values of intraarticular iodine and muscle, image contrast (iodine/muscle), and image quality (5-point scale: 1 = worst, 5 = best) were evaluated. Two independent readers assessed glenoid morphology and performed glenoid measurements on 2D and 3D images. RESULTS: Calculation of VNC images and VNC 3D reformats was successful in 42/42 shoulders (100%). The effective dose was mean 1.95 mSv (± 0.9 mSv). CT values of iodine and muscle were mean 1014.6 HU (± 235.8 HU) and 64.5 HU(± 8.6 HU), respectively, and image contrast was mean 950.2 HU (± 235.5 HU). Quality of cross-sectional images, VNC images, and VNC 3D reformats was rated good (median 4 (4-5), 4 (3-4), 4 (3-5), respectively). Detection of an osseous defect was equal on 2D and 3D images (13/42, P > 0.99) with no difference for measurement of the glenoid diameter with mean 28.3 mm (± 2.8 mm) vs. 28.4 mm (± 2.9 mm) (P = 0.5), width of the glenoid defect with 3.2 mm (± 2.1 mm) vs. 3.1 mm (± 2.3 mm) (P = 0.84), surface area with 638.5 mm2 (± 127 mm2) vs. 640.8 mm2 (± 129.5 mm2) (P = 0.47), and surface area of the defect with 46.6 mm2 (± 44.3 mm2) vs. 47.2 mm2 (± 48.0 mm2) (P = 0.73), respectively. CONCLUSION: DECT shoulder arthrography is feasible and allows successful iodine removal with generation of VNC images and accurate VNC 3D reformats of the glenoid for assessment of bone loss.

Fully automated breast segmentation on spiral breast computed tomography images.

INTRODUCTION: The quantification of the amount of the glandular tissue and breast density is important to assess breast cancer risk. Novel photon-counting breast computed tomography (CT) technology has the potential to quantify them. For accurate analysis, a dedicated method to segment the breast components-the adipose and glandular tissue, skin, pectoralis muscle, skinfold section, rib, and implant-is required. We propose a fully automated breast segmentation method for breast CT images. METHODS: The framework consists of four parts: (1) investigate, (2) segment the components excluding adipose and glandular tissue, (3) assess the breast density, and (4) iteratively segment the glandular tissue according to the estimated density. For the method, adapted seeded watershed and region growing algorithm were dedicatedly developed for the breast CT images and optimized on 68 breast images. The segmentation performance was qualitatively (five-point Likert scale) and quantitatively (Dice similarity coefficient [DSC] and difference coefficient [DC]) demonstrated according to human reading by experienced radiologists. RESULTS: The performance evaluation on each component and overall segmentation for 17 breast CT images resulted in DSCs ranging 0.90-0.97 and in DCs 0.01-0.08. The readers rated 4.5-4.8 (5 highest score) with an excellent inter-reader agreement. The breast density varied by 3.7%-7.1% when including mis-segmented muscle or skin. CONCLUSION: The automatic segmentation results coincided with the human expert's reading. The accurate segmentation is important to avoid the significant bias in breast density analysis. Our method enables accurate quantification of the breast density and amount of the glandular tissue that is directly related to breast cancer risk.

Atypical ductal hyperplasia: breast DCE-MRI can be used to reduce unnecessary open surgical excision.

PURPOSE: To evaluate the diagnostic performance of dynamic contrast-enhanced (DCE)-MRI in predicting malignancy after percutaneous biopsy diagnosis of atypical ductal hyperplasia (ADH). METHODS AND MATERIALS: In this retrospective study, 68 lesions (66 women) with percutaneous biopsy diagnosis of ADH and pre-operative breast DCE-MRI performed between January 2016 and December 2017 were included. Two radiologists reviewed in consensus mammography, ultrasound, and MR images. The final diagnosis after surgical excision was used as standard of reference. Clinical and imaging features were compared in patients with and without upgrade to malignancy after surgery. The diagnostic performance of DCE-MRI in predicting malignant upgrade was evaluated. RESULTS: A 9-gauge vacuum-assisted biopsy was performed in 40 (58.8%) cases and a 14-gauge core needle biopsy in 28 (41.2%) cases. Upgrade to malignancy was observed in 17/68 (25%) lesions, including 4/17 (23.5%) cases of invasive cancer and 13/17 (76.5%) cases of ductal carcinoma in situ (DCIS). In 16/17 (94.1%) malignant and 20/51 (39.2%) benign lesions, a suspicious enhancement could be recognized in DCE-MRI. The malignant lesion without suspicious enhancement was a low-grade DCIS (4 mm size). Sensitivity, specificity, positive predictive value, and negative predictive value of DCE-MRI on predicting malignancy were respectively 94.1%, 60.7%, 44.4%, and 96.8%. No other clinical or imaging features were significantly different in patients with and without upgrade to malignancy. CONCLUSION: After a percutaneous biopsy diagnosis of ADH, malignancy can be ruled out in most of the cases, if no suspicious enhancement is present in the biopsy area at DCE-MRI. Breast DCE-MRI may be used to avoid surgery in more than half of the patients with final benign diagnosis. KEY POINTS: • Breast DCE-MRI can safely rule out malignancy if no suspicious enhancement is present in the biopsy area after a percutaneous biopsy diagnosis of ADH. • All cases of upgrade to high-grade DCIS and invasive cancers can be identified at breast DCE-MRI after a percutaneous biopsy diagnosis of ADH. • Breast DCE-MRI may be used to avoid surgery in more than half of the patients with final benign diagnosis.

Correction to: Towards clinical grating-interferometry mammography.

The article Towards clinical grating-interferometry mammography, written by Carolina Arboleda, Zhentian Wang, Konstantins Jefimovs, Thomas Koehler, Udo Van Stevendaal, Norbert Kuhn, Bernd David, Sven Prevrhal, Kristina Lång, Serafino Forte, Rahel Antonia Kubik-Huch, Cornelia Leo.

Towards clinical grating-interferometry mammography.

OBJECTIVES: Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, as several research works have demonstrated in a pre-clinical setting, since it is able to provide attenuation, differential phase contrast, and scattering images simultaneously. In order to translate this technique to the clinics, it has to be adapted to cover a large field-of-view within a clinically acceptable exposure time and radiation dose. METHODS: We set up a grating interferometer that fits into a standard mammography system and fulfilled the aforementioned conditions. Here, we present the first mastectomy images acquired with this experimental device. RESULTS AND CONCLUSION: Our system performs at a mean glandular dose of 1.6 mGy for a 5-cm-thick, 18%-dense breast, and a field-of-view of 26 × 21 cm2. It seems to be well-suited as basis for a clinical-environment device. Further, dark-field signals seem to support an improved lesion visualization. Evidently, the effective impact of such indications must be evaluated and quantified within the context of a proper reader study. KEY POINTS: • Grating-interferometry-based mammography (GIM) might facilitate breast cancer detection, since it is sensitive to refraction and scattering and thus provides additional tissue information. • The most straightforward way to do grating-interferometry in the clinics is to modify a standard mammography device. • In a first approximation, the doses given with this technique seem to be similar to those of conventional mammography.

Automatic classification of ultrasound breast lesions using a deep convolutional neural network mimicking human decision-making.

OBJECTIVES: To evaluate a deep convolutional neural network (dCNN) for detection, highlighting, and classification of ultrasound (US) breast lesions mimicking human decision-making according to the Breast Imaging Reporting and Data System (BI-RADS). METHODS AND MATERIALS: One thousand nineteen breast ultrasound images from 582 patients (age 56.3 ± 11.5 years) were linked to the corresponding radiological report. Lesions were categorized into the following classes: no tissue, normal breast tissue, BI-RADS 2 (cysts, lymph nodes), BI-RADS 3 (non-cystic mass), and BI-RADS 4-5 (suspicious). To test the accuracy of the dCNN, one internal dataset (101 images) and one external test dataset (43 images) were evaluated by the dCNN and two independent readers. Radiological reports, histopathological results, and follow-up examinations served as reference. The performances of the dCNN and the humans were quantified in terms of classification accuracies and receiver operating characteristic (ROC) curves. RESULTS: In the internal test dataset, the classification accuracy of the dCNN differentiating BI-RADS 2 from BI-RADS 3-5 lesions was 87.1% (external 93.0%) compared with that of human readers with 79.2 ± 1.9% (external 95.3 ± 2.3%). For the classification of BI-RADS 2-3 versus BI-RADS 4-5, the dCNN reached a classification accuracy of 93.1% (external 95.3%), whereas the classification accuracy of humans yielded 91.6 ± 5.4% (external 94.1 ± 1.2%). The AUC on the internal dataset was 83.8 (external 96.7) for the dCNN and 84.6 ± 2.3 (external 90.9 ± 2.9) for the humans. CONCLUSION: dCNNs may be used to mimic human decision-making in the evaluation of single US images of breast lesion according to the BI-RADS catalog. The technique reaches high accuracies and may serve for standardization of highly observer-dependent US assessment. KEY POINTS: • Deep convolutional neural networks could be used to classify US breast lesions. • The implemented dCNN with its sliding window approach reaches high accuracies in the classification of US breast lesions. • Deep convolutional neural networks may serve for standardization in US BI-RADS classification.

Whole-body adipose tissue and lean muscle volumes and their distribution across gender and age: MR-derived normative values in a normal-weight Swiss population.

PURPOSE: To determine age- and gender-dependent whole-body adipose tissue and muscle volumes in healthy Swiss volunteers in Dixon MRI in comparison with anthropometric and bioelectrical impedance (BIA) measurements. METHODS: Fat-water-separated whole-body 3 Tesla MRI of 80 healthy volunteers (ages 20 to 62 years) with a body mass index (BMI) of 17.5 to 26.2 kg/m2 (10 men, 10 women per decade). Age and gender-dependent volumes of total adipose tissue (TAT), visceral adipose tissue (VAT), total abdominal subcutaneous adipose tissue (ASAT) and total abdominal adipose tissue (TAAT), and the total lean muscle tissue (TLMT) normalized for body height were determined by semi-automatic segmentation, and correlated with anthropometric and BIA measurements as well as lifestyle parameters. RESULTS: The TAT, ASAT, VAT, and TLMT indexes (TATi, ASATi, VATi, and TLMTi, respectively) (L/m2 ± standard deviation) for women/men were 6.4 ± 1.8/5.3 ± 1.7, 1.6 ± 0.7/1.2 ± 0.5, 0.4 ± 0.2/0.8 ± 0.5, and 5.6 ± 0.6/7.1 ± 0.7, respectively. The TATi correlated strongly with ASATi (r > 0.93), VATi, BMI and BIA (r > 0.70), and TAATi (r > 0.96), and weak with TLMTi for both genders (r > -0.34). The VAT was the only parameter showing an age dependency (r > 0.32). The BMI and BIA showed strong correlation with all MR-derived adipose tissue volumes. The TAT mass was estimated significantly lower from BIA than from MRI (both genders P < .001; mean bias -5 kg). CONCLUSIONS: The reported gender-specific MRI-based adipose tissue and muscle volumes might serve as normative values. The estimation of adipose tissue volumes was significantly lower from anthropometric and BIA measurements than from MRI. Magn Reson Med 79:449-458, 2018. © 2017 International Society for Magnetic Resonance in Medicine.

Influence of breast cancer opportunistic screening on aesthetic surgical outcome: A single-center retrospective study in Switzerland.

The aim of this retrospective study is to compare the surgical aesthetic outcome and breast cancer (BC) characteristics in patients with BC detected either by opportunistic screening or clinical diagnosis. 262 women undergoing surgery for BC between 2009 and 2012 were included. The following features were compared in the two groups of patients: (1) age at diagnosis; (2) family history of BC; (3) histology type; (4) tumor diameter; (5) local staging, and (6) type of surgical treatment. In 92/262 (35.1%) cases BC was detected by screening and 170/262 (64.9%) had clinical diagnosis. A positive family history and ductal carcinoma in situ diagnosis were more frequent in patients with clinical diagnosis (P = .001 and P < .0001 respectively). Mean maximum diameter of invasive cancers was significantly greater in symptomatic patients (P < .001). Breast conserving surgery was performed in 76/92 (82.6%) patients with screening and 115/170 (67.6%) with clinical diagnosis. Mastectomy was performed in 16/92 (17.4%) patients with screening and 55/170 (32.3%) with clinical diagnosis. Mastectomy was more frequent in patients with clinical diagnosis of BC (P = .010). No significant group differences were found regarding the other features. This study demonstrated that in opportunistic screening, breast conserving surgery may be applied in a higher number of cases compared to patients presenting with clinical diagnosis, thereby improving life quality of these patients.

Shoulder muscle volume and fat content in healthy adult volunteers: quantification with DIXON MRI to determine the influence of demographics and handedness.

OBJECTIVE: We aimed to provide mean values for fat-fraction and volume for full-length bilateral rotator cuff and deltoid muscles in asymptomatic adults selected on the basis of their good musculoskeletal and systemic health, and to understand the influence of gender, age, and arm dominance. MATERIALS AND METHODS: Seventy-six volunteers aged 20 to 60 years who were screened for normal BMI and high general health were included in the study. MRI was performed at 3 Tesla using three-point DIXON sequences. Volume and fat-signal fraction of the rotator cuff muscles and the deltoid muscle were determined with semi-automated segmentation of entire muscle lengths. Differences according to age, gender, and handedness per muscle were evaluated. RESULTS: Fat-signal fractions were comparable between genders (mean ± 2 SD, 95% CI, women 7.0 ± 3.0; 6.8-7.2%, men 6.8 ± 2.7; 6.7-7.0%) but did not show convincing changes with age. Higher shoulder muscle volume and lower fat-signal fraction in the dominant arm were shown for teres minor and deltoid (p < 0.01) with similar trends shown for the other rotator cuff muscles. CONCLUSIONS: Bilateral fat-signal fractions and volumes based on entire length shoulder muscles in asymptomatic 20-60 year old adults may provide reference for clinicians. Differences shown according to arm dominance should be considered and may rationalize the need for bilateral imaging in determining appropriate management.

Separation of collagen-bound and porous bone-water longitudinal relaxation in mice using a segmented inversion recovery zero-echo-time sequence.

PURPOSE: Cortical bone mechanical properties are related to the collagen-bound water (CBW) and pore water (PW) components of cortical bone. The study evaluates the feasibility of zero-echo-time imaging in mice in vivo for longitudinal relaxation time (T1) measurements in cortical bone and separation of CBW and PW components. METHODS: Zero-echo-time data were acquired at 4.7 Tesla in six mice with 14 different inversion times (0-2,600 ms). Region-of-interest analysis was performed at level of femur diaphysis. The T1 of cortical bone and of CBW (T1cbw) and PW (T1pw) as well as the CBW fraction (cbwf) was computed using a mono-exponential and a bi-exponential fitting approach, respectively. The sum of the squared residuals (Res) to the fit was provided for both approaches. RESULTS: For the mono-exponential model, mean T1 ± standard deviation (SD) was 1,057 ± 160 ms. The bi-exponential approach provided a reliable separation of two different bone-water components, with a mean T1cbw of 213 ± 95 ms, T1pw of 2,152 ± 894 ms, and cbwf of 7.4 ± 2.7 %. Lower Res was obtained with bi-exponential approach (P < 0.001), and Res mean values ± SD were 0.016 ± 0.007 (bi-exponential) and 0.033 ± 0.016 (mono-exponential). CONCLUSION: Zero-echo-time imaging allows for longitudinal relaxation measurements of cortical bone in vivo in mice models, with a reliable separation of PW and CBW components using a bi-exponential curve fitting approach. Magn Reson Med 77:1909-1915, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Separation of collagen-bound and porous bone water transverse relaxation in mice: proposal of a multi-step approach.

The separation and quantification of collagen-bound water (CBW) and pore water (PW) components of the cortical bone signal are important because of their different contribution to bone mechanical properties. Ultrashort TE (UTE) imaging can be used to exploit the transverse relaxation from CBW and PW, allowing their quantification. We tested, for the first time, the feasibility of UTE measurements in mice for the separation and quantification of the transverse relaxation of CBW and PW in vivo using three different approaches for T2 * determination. UTE sequences were acquired at 4.7 T in six mice with 10 different TEs (50-5000 µs). The transverse relaxation time T2 * of CBW (T2 *cbw ) and PW (T2 *pw ) and the CBW fraction (bwf) were computed using a mono-exponential (i), a standard bi-exponential (ii) and a new multi-step bi-exponential (iii) approach. Regions of interest were drawn at multiple levels of the femur and vertebral body cortical bone for each mouse. The sum of the normalized squared residuals (Res) and the homogeneity of variance were tested to compare the different methods. In the femur, approach (i) yielded mean T2 * ± standard deviation (SD) of 657 ± 234 µs. With approach (ii), T2 *cbw , T2 *pw and bwf were 464 ± 153 µs, 15 777 ± 10 864 µs and 57.6 ± 9.9%, respectively. For approach (iii), T2 *cbw , T2 *pw and bwf were 387 ± 108 µs, 7534 ± 2765 µs and 42.5 ± 6.2%, respectively. Similar values were obtained from vertebral bodies. Res with approach (ii) was lower than with the two other approaches (p < 0.007), but T2 *pw and bwf variance was lower with approach (iii) than with approach (ii) (p < 0.048). We demonstrated that the separation and quantification of cortical bone water components with UTE sequences is feasible in vivo in mouse models. The direct bi-exponential approach exhibited the best approximation to the measured signal curve with the lowest residuals; however, the newly proposed multi-step algorithm resulted in substantially lower variability of the computed parameters. Copyright © 2016 John Wiley & Sons, Ltd.

Is there a systematic bias of apparent diffusion coefficient (ADC) measurements of the breast if measured on different workstations? An inter- and intra-reader agreement study.

OBJECTIVES: To evaluate the influence of post-processing systems, intra- and inter-reader agreement on the variability of apparent diffusion coefficient (ADC) measurements in breast lesions. METHODS: Forty-one patients with 41 biopsy-proven breast lesions gave their informed consent and were included in this prospective IRB-approved study. Magnetic resonance imaging (MRI) examinations were performed at 1.5 T using an EPI-DWI sequence, with b-values of 0 and 1000 s/mm(2). Two radiologists (R1, R2) reviewed the images in separate sessions and measured the ADC for lesion, using MRI-workstation (S-WS), PACS-workstation (P-WS) and a commercial DICOM viewer (O-SW). Agreement was evaluated using the intraclass correlation coefficient (ICC), Bland-Altman plots and coefficient of variation (CV). RESULTS: Thirty-one malignant, two high-risk and eight benign mass-like lesions were analysed. Intra-reader agreement was almost perfect (ICC-R1 = 0.974; ICC-R2 = 0.990) while inter-reader agreement was substantial (ICC from 0.615 to 0.682). Bland-Altman plots revealed a significant bias in ADC values measured between O-SW and S-WS (P = 0.025), no further systematic differences were identified. CV varied from 6.8 % to 7.9 %. CONCLUSION: Post-processing systems may have a significant, although minor, impact on ADC measurements in breast lesions. While intra-reader agreement is high, the main source of ADC variability seems to be caused by inter-reader variation. KEY POINTS: • ADC provides quantitative information on breast lesions independent from the system used. • ADC measurement using different workstations and software systems is generally reliable. • Systematic, but minor, differences may occur between different post-processing systems. • Inter-reader agreement of ADC measurements exceeded intra-reader agreement.

Application of a Colored Multiexposure High Dynamic Range Technique to Radiographic Imaging: An Experimental Trial to Show Feasibility.

PURPOSE: The aim of this study was to evaluate the feasibility of applying the high dynamic range (HDR) technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach. MATERIAL AND METHODS: An appropriate study object was repeatedly imaged using a range of different imaging parameters using a standard clinical x-ray unit. An underexposed image (acquired at 80 keV), an intermediate exposed image (110 keV), and an overexposed image (140 keV) were chosen and combined to a 32-bit colored HDR image. To display the resulting HDR image on a regular color display with typically 8 bits per channel, the Reinhard tone mapping algorithm was applied. The source images and the resulting HDR image were qualitatively evaluated by 5 independent radiologists with regard to the visibility of the different anatomic structures using a Likert scale (1, not visible, to 5, excellent visibility). Data were presented descriptively. RESULTS: High dynamic range postprocessing was possible without malalignment or image distortion. Application of the Reinhardt algorithm did not cause visible artifacts. Overall, postprocessing time was 7 minutes 10 seconds for the whole process. Visibility of anatomic structure was rated between 1 and 5, depending on the anatomic structure of interest. Most authors rated the HDR image best before individual source images. CONCLUSIONS: This experimental trial showed the feasibility of applying the HDR technique to radiographic imaging to expand the dynamic range of conventional radiographic images using a colored multiexposure approach.

Magnetization transfer imaging of cortical bone in vivo using a zero echo time sequence in mice at 4.7 T: a feasibility study.

OBJECTIVE: To investigate the feasibility of magnetization transfer (MT) imaging in mice in vivo for the assessment of cortical bone. MATERIALS AND METHODS: MT-zero echo time data were acquired at 4.7 T in six mice using MT preparation pulses with two different flip angles (FAs) and a series of ten different off-resonance frequencies (500-15000 Hz). Regions of interest were drawn at multiple levels of the femoral cortical bone. The MT ratio (MTR) was computed for each combination of FAs and off-resonance frequencies. T1 measurements were used to estimate the direct saturation (DS) using a Bloch equation simulation. Estimation of the absorption line width of cortical bone from T2* measurements was also performed. RESULTS: MTR values were higher using 3000° FA than 1000° FA. MTR values decreased toward higher off-resonance frequencies. Maximum mean MTR ± standard deviation (SD) of 58.57 ± 5.22 (range 50.44-70.61) was measured with a preparation pulse of 3000° and off-resonance frequency of 500 Hz. Maximum "true" MT effect was estimated at around 2-3 and 5 kHz, respectively, for 1000° and 3000° FA. Mean full width at half maximum ± SD of 577 ± 91 Hz was calculated for the absorption spectral line of the cortical bone. CONCLUSION: MT imaging can be used for the assessment of cortical bone in mice in vivo. DS effects are negligible using preparation pulses with off-resonance frequencies greater than 3 kHz.

Normative values for volume and fat content of the hip abductor muscles and their dependence on side, age and gender in a healthy population.

OBJECTIVE: To determine normative values for volume and fat content of the gluteus medius (GMed) and minimus (GMin) muscle in healthy volunteers and to evaluate their dependence on age, gender and leg dominance. MATERIALS AND METHODS: The IRB approval was obtained for this study. 80 healthy volunteers (females, 40; males, 40; age range 20-62 years), divided into four age groups, were included. Fat- and water-signal-separated MR images of the pelvis were acquired on a 3.0 T MR with a 3-point mDIXON sequence. Normalized volume and fat-signal fraction (FSF) of the GMed (ViGMed, FSFGMed) and GMin (ViGMin, FSFGMin) muscles were determined. RESULTS: The overall mean volumes (normalized) and FSF ± SD: ViGMed 105.13 ± 16.30 cm(3); ViGMin 30.24 ± 5.15 cm(3); FSFGMed 8.13 ± 1.70 % and FSFGMin 9.89 ± 2.72 %. Comparing different age subgroups within each gender no significant differences were found concerning the volumes and FSFs (except FSFGMin in male subgroup aged 20-29 versus 50-62 years, P = 0.014). Comparing FSFs differences between the two genders, only in 20-29 years subgroup, FSFGMed (P =0.003) and FSFGMin (P =0.002) were greater in female. Volume differences between the two legs were not significant (P > 0.077); FSFGMed and FSFGMin (P =0.005 for both) were significantly lower in the dominant leg in female but not in male group (P = 0.454 for FSFGMed and P = 0.643 for FSFMin). CONCLUSION: No age dependency was evident for volume normative data for GMed and GMin and normative data for FSF values showed no age- or gender dependency.