Histogram-Based Densitometry Index to Assess the Severity of Interstitial Lung Disease in Systemic Sclerosis in Standard and Low-Dose Computed Tomography.

OBJECTIVE: Mean lung attenuation, skewness, and kurtosis are histogram-based densitometry variables that quantify systemic sclerosis-associated interstitial lung disease (SSc-ILD) and were recently merged into a computerized integrated index (CII). Our work tested the CII in low-dose 9-slice (reduced) and standard high-resolution computed tomography (CT) scans to evaluate extensive SSc-ILD and predict mortality. METHODS: CT scans from patients with SSc-ILD were assessed using the software Horos to compute standard and reduced CIIs. Extensive ILD was determined following the Goh staging system. The association between CIIs and extensive ILD was analyzed with a generalized estimating equation regression model, the predictive ability of CIIs by the area under the receiver-operation characteristic curve (AUC), and the association between CIIs and death by Kaplan-Meier analysis. RESULTS: Among 243 patients with standard and reduced CT scans available, 157 CT scans from 119 patients with SSc-ILD constituted the derivation cohort. The validation cohort included 116 standard and 175 reduced CT scans. Both CIIs from standard (odds ratio [OR] 0.53, 95% CI 0.37-0.75; AUC 0.77, 95% CI 0.68-0.87) and reduced CT scans (OR 0.54, 95% CI 0.35-0.82; AUC 0.78, 95% CI 0.70-0.87) were significantly associated with extensive ILD. A threshold of CII ≤ -0.96 for standard CT scans and CII ≤ -1.85 for reduced CT scans detected extensive ILD with high sensitivity in both derivation and validation cohorts. Extensive ILD according to Goh staging (OR 2.94, 95% CI 1.10-7.82) and standard CII ≤ -0.96 (OR 1.78, 95% CI 1.24-2.56) significantly predicted mortality; a marginal P value was observed for reduced CII ≤ -1.85 (OR 1.27, 95% CI 0.93-1.75). CONCLUSION: Thresholds for both standard and reduced CII to identify extensive ILD were developed and validated, with an additional association with mortality. CIIs might help in clinical practice when radiology expertise is missing.

Prospective measurement of the width of cerebrospinal fluid spaces by cranial ultrasound in neurologically healthy children aged 0-19 months.

BACKGROUND: Ultrasound (US) is often the first method used to look for brain or cerebrospinal fluid (CSF) space pathologies. Knowledge of normal CSF width values is essential. Most of the available US normative values were established over 20 years ago, were obtained with older equipment, and cover only part of the age spectrum that can be examined by cranial US. This prospective study aimed to determine the normative values of the widths of the subarachnoid and internal CSF spaces (craniocortical, minimal and maximal interhemispheric, interventricular, and frontal horn) for high-resolution linear US probes in neurologically healthy infants and children aged 0-19 months and assess whether subdural fluid collections can be delineated. METHODS: Two radiologists measured the width of the CSF spaces with a conventional linear probe and an ultralight hockey-stick probe in neurologically healthy children not referred for cranial or spinal US. RESULTS: This study included 359 neurologically healthy children (nboys = 178, 49.6%; ngirls = 181, 50.4%) with a median age of 46.0 days and a range of 1-599 days. We constructed prediction plots, including the 5th, 50th, and 95th percentiles, and an interactive spreadsheet to calculate normative values for individual patients. The measurements of the two probes and the left and right sides did not differ, eliminating the need for separate normative values. No subdural fluid collection was detected. CONCLUSION: Normative values for the widths of the subarachnoid space and the internal CSF spaces are useful for evaluating intracranial pathology, especially when determining whether an increase in the subarachnoid space width is abnormal.

Multicenter Standardization of Phase-Resolved Functional Lung MRI in Patients With Suspected Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: Detection of pulmonary perfusion defects is the recommended approach for diagnosing chronic thromboembolic pulmonary hypertension (CTEPH). This is currently achieved in a clinical setting using scintigraphy. Phase-resolved functional lung (PREFUL) magnetic resonance imaging (MRI) is an alternative technique for evaluating regional ventilation and perfusion without the use of ionizing radiation or contrast media. PURPOSE: To assess the feasibility and image quality of PREFUL-MRI in a multicenter setting in suspected CTEPH. STUDY TYPE: This is a prospective cohort sub-study. POPULATION: Forty-five patients (64 ± 16 years old) with suspected CTEPH from nine study centers. FIELD STRENGTH/SEQUENCE: 1.5 T and 3 T/2D spoiled gradient echo/bSSFP/T2 HASTE/3D MR angiography (TWIST). ASSESSMENT: Lung signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were compared between study centers with different MRI machines. The contrast between normally and poorly perfused lung areas was examined on PREFUL images. The perfusion defect percentage calculated using PREFUL-MRI (QDPPREFUL ) was compared to QDP from the established dynamic contrast-enhanced MRI technique (QDPDCE ). Furthermore, QDPPREFUL was compared between a patient subgroup with confirmed CTEPH or chronic thromboembolic disease (CTED) to other clinical subgroups. STATISTICAL TESTS: t-Test, one-way analysis of variance (ANOVA), Pearson's correlation. Significance level was 5%. RESULTS: Significant differences in lung SNR and CNR were present between study centers. However, PREFUL perfusion images showed a significant contrast between normally and poorly perfused lung areas (mean delta of normalized perfusion -4.2% SD 3.3) with no differences between study sites (ANOVA: P = 0.065). QDPPREFUL was significantly correlated with QDPDCE (r = 0.66), and was significantly higher in 18 patients with confirmed CTEPH or CTED (57.9 ± 12.2%) compared to subgroups with other causes of PH or with excluded PH (in total 27 patients with mean ± SD QDPPREFUL = 33.9 ± 17.2%). DATA CONCLUSION: PREFUL-MRI could be considered as a non-invasive method for imaging regional lung perfusion in multicenter studies. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 1.

Implementation of artificial intelligence in thoracic imaging-a what, how, and why guide from the European Society of Thoracic Imaging (ESTI).

This statement from the European Society of Thoracic imaging (ESTI) explains and summarises the essentials for understanding and implementing Artificial intelligence (AI) in clinical practice in thoracic radiology departments. This document discusses the current AI scientific evidence in thoracic imaging, its potential clinical utility, implementation and costs, training requirements and validation, its' effect on the training of new radiologists, post-implementation issues, and medico-legal and ethical issues. All these issues have to be addressed and overcome, for AI to become implemented clinically in thoracic radiology. KEY POINTS: • Assessing the datasets used for training and validation of the AI system is essential. • A departmental strategy and business plan which includes continuing quality assurance of AI system and a sustainable financial plan is important for successful implementation. • Awareness of the negative effect on training of new radiologists is vital.

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.

Computed tomography-based radiomics decodes prognostic and molecular differences in interstitial lung disease related to systemic sclerosis.

BACKGROUND: Radiomic features calculated from routine medical images show great potential for personalised medicine in cancer. Patients with systemic sclerosis (SSc), a rare, multiorgan autoimmune disorder, have a similarly poor prognosis due to interstitial lung disease (ILD). Here, our objectives were to explore computed tomography (CT)-based high-dimensional image analysis ("radiomics") for disease characterisation, risk stratification and relaying information on lung pathophysiology in SSc-ILD. METHODS: We investigated two independent, prospectively followed SSc-ILD cohorts (Zurich, derivation cohort, n=90; Oslo, validation cohort, n=66). For every subject, we defined 1355 robust radiomic features from standard-of-care CT images. We performed unsupervised clustering to identify and characterise imaging-based patient clusters. A clinically applicable prognostic quantitative radiomic risk score (qRISSc) for progression-free survival (PFS) was derived from radiomic profiles using supervised analysis. The biological basis of qRISSc was assessed in a cross-species approach by correlation with lung proteomic, histological and gene expression data derived from mice with bleomycin-induced lung fibrosis. RESULTS: Radiomic profiling identified two clinically and prognostically distinct SSc-ILD patient clusters. To evaluate the clinical applicability, we derived and externally validated a binary, quantitative radiomic risk score (qRISSc) composed of 26 features that accurately predicted PFS and significantly improved upon clinical risk stratification parameters in multivariable Cox regression analyses in the pooled cohorts. A high qRISSc score, which identifies patients at risk for progression, was reverse translatable from human to experimental ILD and correlated with fibrotic pathway activation. CONCLUSIONS: Radiomics-based risk stratification using routine CT images provides complementary phenotypic, clinical and prognostic information significantly impacting clinical decision making in SSc-ILD.

Comparison of detection of trauma-related injuries using combined "all-in-one" fused images and conventionally reconstructed images in acute trauma CT.

OBJECTIVES: To compare the accuracy of lesion detection of trauma-related injuries using combined "all-in-one" fused (AIO) and conventionally reconstructed images (CR) in acute trauma CT. METHODS: In this retrospective study, trauma CT of 66 patients (median age 47 years, range 18-96 years; 20 female (30.3%)) were read using AIO and CR. Images were independently reviewed by 4 blinded radiologists (two residents and two consultants) for trauma-related injuries in 22 regions. Sub-analyses were performed to analyze the influence of experience (residents vs. consultants) and body region (chest, abdomen, skeletal structures) on lesion detection. Paired t-test was used to compare the accuracy of lesion detection. The effect size was calculated (Cohen's d). Linear mixed-effects model with patients as the fixed effect and random forest models were used to investigate the effect of experience, reconstruction/image processing, and body region on lesion detection. RESULTS: Reading time of residents was significantly faster using AIO (AIO: 266 ± 72 s, CR: 318 ± 113 s; p < 0.001; d = 0.46) while no significant difference was observed in the accuracy of lesion detection (AIO: 93.5 ± 6.0%, CR: 94.6 ± 6.0% p = 0.092; d = - 0.21). Reading time of consultants showed no significant difference (AIO: 283 ± 82 s, CR: 274 ± 95 s; p = 0.067; d = 0.16). Accuracy was significantly higher using CR; however, the difference and effect size were very small (AIO 95.1 ± 4.9%, CR: 97.3 ± 3.7%, p = 0.002; d = - 0.39). The linear mixed-effects model showed only minor effect of image processing/reconstruction for lesion detection. CONCLUSIONS: Residents at the emergency department might benefit from faster reading time without sacrificing lesion detection rate using AIO for trauma CT. KEY POINTS: • Image fusion techniques decrease the reading time of acute trauma CT without sacrificing diagnostic accuracy.

Old Borders and New Horizons in Multimodality Imaging of Malignant Pleural Mesothelioma.

BACKGROUND: The purpose of this article is to describe the various imaging techniques involved in detection, staging, and preoperative planning in malignant pleural mesothelioma (MPM) focusing on new imaging modalities. METHODS: For this purpose, first a brief summary of the etiology of MPM is given. Second, not only the commonly known, but also novel imaging modalities used in MPM will be discussed. RESULTS: A wide range of imaging methods, from conventional chest radiography, through computed tomography and hybrid imaging to radiomics and artificial intelligence, can be used to evaluate MPM. CONCLUSION: Nowadays multimodality imaging is considered the cornerstone in MPM diagnosis and staging.

[Pulmonary nodules and pneumonia : A diagnostic guideline]. / Pulmonale Rundherde und Pneumonie : Ein diagnostischer Leitfaden.

BACKGROUND: Chest X­ray is one of the most frequent examinations in radiology and its interpretation is considered part of the basic knowledge of every radiologist. OBJECTIVES: The purpose of this article is to recognize common signs and patterns of pneumonias and pseudonodules in chest X­rays and to provide a diagnostic guideline for young radiologists. MATERIALS AND METHODS: Recent studies and data are analyzed and an overview of the most common signs and patterns in chest X­ray is provided. RESULTS: Knowledge about common signs and patterns in chest X­ray is helpful in the diagnosis of pneumonias and can be indicative for the cause of an infection. However, those signs are often unspecific and should, therefore, be set in clinical content. Computed tomography is becoming increasingly important in the primary diagnosis of pulmonary lesions because of its much higher sensitivity. CONCLUSION: Chest X­ray is still the first-line modality in the diagnosis of pneumonia and pulmonary nodules; however, radiologists should be aware of its limitations.

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.

Speed of sound ultrasound: comparison with proton density fat fraction assessed with Dixon MRI for fat content quantification of the lower extremity.

OBJECTIVES: To compare speed of sound (SoS) ultrasound (US) of the calves with Dixon magnetic resonance imaging (MRI) for fat content quantification. MATERIALS AND METHODS: The study was approved by the local ethics committee. Fifty calf muscles of 35 women (age range 22-81 years) prospectively underwent an US and subsequent MRI (Dixon sequence) examination as well as body weight and impedance fat measurements. SoS (in m/s) was calculated positioning a reflector on the opposite side of a conventional US machine probe with the calf in between. Fiducial nitroglycerin markers were placed on the calf at the reflector and US probe end positions for later registration of the US sonification volumetric section. An automatic segmentation algorithm separated MRI adipose tissue, muscle and bone regions. MRI fat fraction of the entire leg slice (total) and intramuscular and adipose tissue fat fraction were calculated and correlation analysis and correlation coefficient comparison were performed. RESULTS: Median SoS demonstrated a very strong (r = - 0.83 (95% CI - 0.90; - 0.72); p < 0.001) correlation with MRI total fat fraction, a strong (r = - 0.61 (95% CI - 0.76; - 0.40); p < 0.001) correlation with MRI adipose tissue fat fraction and a moderate (r = - 0.54 (95% CI - 0.71; - 0.31); p < 0.001) correlation with MRI intramuscular fat fraction. Impedance body fat percentage correlated strongly with SoS (r = - 0.72 (95% CI - 0.85; - 0.51); p < 0.001) and MRI total fat fraction (r = 0.61 (95% CI 0.34; 0.78); p < 0.001). For electrical impedance, significantly lower correlations (p = 0.033) were found for MRI total fat fraction compared with SoS. CONCLUSIONS: Correlations of SoS with Dixon MRI fat fraction measurements were very strong to moderate. KEY POINTS: • Correlations of speed of sound with Dixon MRI fat fraction measurements of the same body location were very strong to moderate. • Speed of sound measurements showed a high repeatability. • Speed of sound provides a sufficient discrimination range for fat fraction estimates.

[Pulmonary nodules - an overview]. / Lungenrundherde ­ Ein Überblick.

Pulmonary nodules - an overview Abstract. Computed tomography (CT) offers fast temporal and high spatial resolution and is increasingly employed for various investigations. Since the 1990s, when multislice computed tomography (CT) technique became commonly available, the detection rate of incidentally detected pulmonary nodules has increased. The aetiology of pulmonary nodules can range from infectious over interstitial lung disease to malignant entities and pose a diagnostic dilemma: Should the incidental finding be dismissed or further investigated? If further investigated which modality and which time frame should be used? Due to the multidisciplinary nature of data required for the complex assessment of an incidental pulmonary nodule, management guidelines are needed in the diagnostic process such as those proposed by the Fleischner Society. The aim of this review is to discuss the different aetiologies pf pulmonary nodules and their potential work-up. Finally, we will also discuss the utility of lung cancer screening.

Visualisation of interstitial lung disease by molecular imaging of integrin αvß3 and somatostatin receptor 2.

OBJECTIVE: To evaluate integrin αvß3 (alpha-v-beta-3)-targeted and somatostatin receptor 2 (SSTR2)-targeted nuclear imaging for the visualisation of interstitial lung disease (ILD). METHODS: The pulmonary expression of integrin αvß3 and SSTR2 was analysed in patients with different forms of ILD as well as in bleomycin (BLM)-treated mice and respective controls using immunohistochemistry. Single photon emission CT/CT (SPECT/CT) was performed on days 3, 7 and 14 after BLM instillation using the integrin αvß3-targeting 177Lu-DOTA-RGD and the SSTR2-targeting 177Lu-DOTA-NOC radiotracer. The specific pulmonary accumulation of the radiotracers over time was assessed by in vivo and ex vivo SPECT/CT scans and by biodistribution studies. RESULTS: Expression of integrin αvß3 and SSTR2 was substantially increased in human ILD regardless of the subtype. Similarly, in lungs of BLM-challenged mice, but not of controls, both imaging targets were stage-specifically overexpressed. While integrin αvß3 was most abundantly upregulated on day 7, the inflammatory stage of BLM-induced lung fibrosis, SSTR2 expression peaked on day 14, the established fibrotic stage. In agreement with the findings on tissue level, targeted nuclear imaging using SPECT/CT specifically detected both imaging targets ex vivo and in vivo, and thus visualised different stages of experimental ILD. CONCLUSION: Our preclinical proof-of-concept study suggests that specific visualisation of molecular processes in ILD by targeted nuclear imaging is feasible. If transferred into clinics, where imaging is considered an integral part of patients' management, the additional information derived from specific imaging tools could represent a first step towards precision medicine in ILD.

Speed of sound ultrasound: a pilot study on a novel technique to identify sarcopenia in seniors.

OBJECTIVES: To measure speed of sound (SoS) with a novel hand-held ultrasound technique as a quantitative indicator for muscle loss and fatty muscular degeneration. METHODS: Both calf muscles of 11 healthy, young females (mean age 29 years), and 10 elderly females (mean age 82 years) were prospectively examined with a standard ultrasound machine. A flat Plexiglas® reflector, on the opposite side of the probe with the calf in between, was used as timing reference for SoS (m/s) and ΔSoS (variation of SoS, m/s). Handgrip strength (kPA), Tegner activity scores, and 5-point comfort score (1 = comfortable to 5 = never again) were also assessed. Ultrasound parameters (muscle/adipose thickness, echo intensity) were measured for comparison. RESULTS: Both calves were assessed in less than two minutes. All measurements were successful. The elderly females showed significantly lower SoS (1516 m/s, SD17) compared to the young adults (1545 m/s, SD10; p < 0.01). The ΔSoS of elderly females was significantly higher (12.2 m/s, SD3.6) than for young females (6.4 m/s, SD1.5; p < 0.01). Significant correlations of SoS with hand grip strength (r = 0.644) and Tegner activity score (rs = 0.709) were found, of similar magnitude as the correlation of hand grip strength with Tegner activity score (rs = 0.794). The average comfort score of the elderly was 1.1 and for the young adults 1.4. SoS senior/young classification (AUC = 0.936) was superior to conventional US parameters. CONCLUSIONS: There were significant differences of SoS and ΔSoS between young and elderly females. Measurements were fast and well tolerated. The novel technique shows potential for sarcopenia quantification using a standard ultrasound machine. KEY POINTS: • Speed of sound ultrasound: a novel technique to identify sarcopenia in seniors. • Measurements were fast and well tolerated using a standard ultrasound machine. • The novel technique shows potential for sarcopenia quantification.

Pre-procedural CT angiography inferior vena cava measurements: a predictor of mortality in patients undergoing transcatheter aortic valve implantation.

OBJECTIVES: To assess the value of pre-procedural computed tomography angiography (CTA) measurements of the suprahepatic inferior vena cava (IVC) to detect elevated central venous pressure (CVP) assessed by right heart catheterisation (RHC), and to predict post-procedural 1-year mortality in a cohort of patients undergoing transcatheter aortic valve implantation (TAVI). METHODS: We retrospectively evaluated 408 consecutive patients undergoing CTA before TAVI between January 2011 and December 2014. Two hundred and five patients were included in the RHC cohort, who underwent RHC and CTA within ≤1 day prior to TAVI. Two hundred and three patients not fulfilling this requirement were included in the validation cohort. Measurements of the IVC were performed between diaphragm and right atrium on axial slices. Receiver operating characteristic (ROC) analyses, Kaplan-Meier analyses and Cox regression analyses were performed. RESULTS: In the RHC cohort, ROC curve analyses for IVC area measurements indicated an AUC of 0.77 (p < 0.001) to detect CVP ≥10mmHg and an area under the ROC curve (AUC) of 0.72 (p < 0.001) to predict 1-year mortality. An IVC area cut-off of ≥665 mm2 predicted 1-year mortality with a specificity of 84% and a sensitivity of 63%. Kaplan-Meier analysis showed that patients with an IVC area ≥665 mm2 had a significantly higher post-procedural 1-year mortality (38% versus 7%, log-rank p < 0.001) with a hazard ratio of 5.5 (95% CI, 2.2-13.6; p < 0.001). Applying this cut-off value to the validation cohort confirmed a significantly higher 1-year mortality after TAVI (34% versus 11%; log-rank p = 0.004) for patients with an IVC area ≥665 mm2. CONCLUSIONS: Pre-procedural enlargement of the suprahepatic IVC is a predictor of post-procedural 1-year mortality in patients evaluated for TAVI. KEY POINTS: • IVC measurements are moderate predictors of an elevated CVP in TAVI patients. • Pre-procedural IVC enlargement is a predictor of 1-year mortality after TAVI. • IVC enlargement is associated with right heart dysfunction in TAVI patients.

Breast-density assessment with hand-held ultrasound: A novel biomarker to assess breast cancer risk and to tailor screening?

OBJECTIVES: To assess feasibility and diagnostic accuracy of a novel hand-held ultrasound (US) method for breast density assessment that measures the speed of sound (SoS), in comparison to the ACR mammographic (MG) categories. METHODS: ACR-MG density (a=fatty to d=extremely dense) and SoS-US were assessed in the retromamillary, inner and outer segments of 106 women by two radiographers. A conventional US system was used for SoS-US. A reflector served as timing reference for US signals transmitted through the breasts. Four blinded readers assessed average SoS (m/s), ΔSoS (segment-variation SoS; m/s) and the ACR-MG density. The highest SoS and ΔSoS values of the three segments were used for MG-ACR whole breast comparison. RESULTS: SoS-US breasts were examined in <2 min. Mean SoS values of densities a-d were 1,421 m/s (SD 14), 1,432 m/s (SD 17), 1,448 m/s (SD 20) and 1,500 m/s (SD 31), with significant differences between all groups (p<0.001). The SoS-US comfort scores and inter-reader agreement were significantly better than those for MG (1.05 vs. 2.05 and 0.982 vs. 0.774; respectively). A strong segment correlation between SoS and ACR-MG breast density was evident (rs=0.622, p=<0.001) and increased for full breast classification (rs=0.746, p=<0.001). SoS-US allowed diagnosis of dense breasts (ACR c and d) with sensitivity 86.2 %, specificity 85.2 % and AUC 0.887. CONCLUSIONS: Using hand-held SoS-US, radiographers measured breast density without discomfort, readers evaluated measurements with high inter-reader agreement, and SoS-US correlated significantly with ACR-MG breast-density categories. KEY POINTS: • The novel speed-of-sound ultrasound correlated significantly with mammographic ACR breast density categories. • Radiographers measured breast density without women discomfort or radiation. • SoS-US can be implemented on a standard US machine. • SoS-US shows potential for a quantifiable, cost-effective assessment of breast density.

Influence of inter-observer delineation variability on radiomics stability in different tumor sites.

BACKGROUND: Radiomics is a promising methodology for quantitative analysis and description of radiological images using advanced mathematics and statistics. Tumor delineation, which is still often done manually, is an essential step in radiomics, however, inter-observer variability is a well-known uncertainty in radiation oncology. This study investigated the impact of inter-observer variability (IOV) in manual tumor delineation on the reliability of radiomic features (RF). METHODS: Three different tumor types (head and neck squamous cell carcinoma (HNSCC), malignant pleural mesothelioma (MPM) and non-small cell lung cancer (NSCLC)) were included. For each site, eleven individual tumors were contoured on CT scans by three experienced radiation oncologists. Dice coefficients (DC) were calculated for quantification of delineation variability. RF were calculated with an in-house developed software implementation, which comprises 1404 features: shape (n = 18), histogram (n = 17), texture (n = 137) and wavelet (n = 1232). The IOV of RF was studied using the intraclass correlation coefficient (ICC). An ICC >0.8 indicates a good reproducibility. For the stable RF, an average linkage hierarchical clustering was performed to identify classes of uncorrelated features. RESULTS: Median DC was high for NSCLC (0.86, range 0.57-0.90) and HNSCC (0.72, 0.21-0.89), whereas it was low for MPM (0.26, 0-0.9) indicating substantial IOV. Stability rate of RF correlated with DC and depended on tumor site, showing a high stability in NSCLC (90% of total parameters), acceptable stability in HNSCC (59% of total parameters) and low stability in MPM (36% of total parameters). Shape features showed the weakest stability across all tumor types. Hierarchical clustering revealed 14 groups of correlated and stable features for NSCLC and 6 groups for both HNSCC and MPM. CONCLUSION: Inter-observer delineation variability has a relevant influence on radiomics analysis and is strongly influenced by tumor type. This leads to a reduced number of suitable imaging features.

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.

Dose Reduction in Tomosynthesis of the Wrist.

OBJECTIVE: The purpose of this study was to quantitatively and qualitatively determine the impact of radiation dose reduction on the image noise and quality of tomosynthesis studies of the wrist. MATERIALS AND METHODS: Imaging of six cadaver wrists was performed with tomosynthesis in anteroposterior position at a tube voltage of 60 kV and tube current of 80 mA and subsequently at 60 or 50 kV with different tube currents of 80, 40, or 32 mA. Dose-area products (DAP) were obtained from the electronically logged protocol. Image noise was measured with an ROI. Two independent and blinded readers evaluated all images. Interreader agreement was measured with a Cohen kappa. Readers assessed overall quality and delineation of soft tissue, cortical bone, and trabecular bone on a 4-point Likert scale. RESULTS: The highest DAP (3.892 ± 0.432 Gy · cm2) was recorded for images obtained with 60 kV and 80 mA; the lowest (0.857 ± 0.178 Gy · cm2) was recorded for images obtained with 50 kV and 32 mA. Noise was highest when a combination of 50 kV and 32 mA (389 ± 26.6) was used and lowest when a combination of 60 kV and 80 mA (218 ± 12.3) was used. The amount of noise on images acquired using 60 kV and 80 mA was statistically significantly different from the amount measured on all other images (p < 0.0001). Interreader agreement was excellent (κ = 0.93). Delineation of anatomy and overall quality were scored best on images obtained with 60 kV and 80 mA and worst on images obtained with 50 kV and 32 mA. The difference in delineation and quality on images obtained using 50 kV and 40 mA was not statistically significantly different compared with images obtained using 60 kV and 80 mA. CONCLUSION: Significant dose reduction for tomosynthesis of the wrist is possible while image quality and delineation of anatomic structures remain preserved.

Economical Sponge Phantom for Teaching, Understanding, and Researching A- and B-Line Reverberation Artifacts in Lung Ultrasound.

This project evaluated a low-cost sponge phantom setup for its capability to teach and study A- and B-line reverberation artifacts known from lung ultrasound and to numerically simulate sound wave interaction with the phantom using a finite-difference time-domain (FDTD) model. Both A- and B-line artifacts were reproducible on B-mode ultrasound imaging as well as in the FDTD-based simulation. The phantom was found to be an easy-to-set up and economical tool for understanding, teaching, and researching A- and B-line artifacts occurring in lung ultrasound. The FDTD method-based simulation was able to reproduce the artifacts and provides intuitive insight into the underlying physics.