External fixation in distal radius fractures

Background: Distal radius fractures are frequent in emergency departments, treatment is generally conservative, but there are patients who meet certain criteria of instability who need surgical treatment, including external fixation. Aim: To update on the most important elements regarding the use of external fixation in unstable fractures of the distal radius. Methods: The search and analysis of the information was carried out in a period of 30 days (from April 1 to April 30, 2021) and the following words were used: distal radius fractures, distal radius fractures and external fixation and unstable radius fractures from the information obtained, a bibliographic review of a total of 809 articles published in the PubMed databases, Hinari, SciELO and Medline was carried out using the search manager and EndNote reference manager, of which 44 selected citations were used to perform the review, 37 from the last five years. Development: The criteria to be taken into account for the instability described by various authors are indicated, as well as the imaging parameters. The two most used classification systems are mentioned. Reference is made to general surgical indications, external fixation, and placement of additional wires. Complications are discussed and a comparison is made between external fixation and blocked volar plates.

Multi-parametric PET/MRI With FDG and RGD for Enhanced Tumor Characterization of Patients With Cervical Cancer

Aim: The concept of personalized medicine has brought increased awareness to the importance of inter- and intra-tumor heterogeneity for cancer treatment. The aim of this study was to explore simultaneous multi-parametric PET/MRI prior to chemoradiotherapy for cervical cancer for characterization of tumors and tumor heterogeneity. Methods: Ten patients with histologically proven primary cervical cancer were examined with multi-parametric 68Ga-NODAGA-E[c(RGDyK)]2-PET/MRI for radiation treatment planning after diagnostic 18F-FDG-PET/CT. Standardized uptake values (SUV) of RGD and FDG, diffusion weighted MRI and the derived apparent diffusion coefficient (ADC), and pharmacokinetic maps obtained from dynamic contrast-enhanced MRI with the Tofts model (iAUC60, Ktrans, ve, and kep) were included in the analysis. The spatial relation between functional imaging parameters in tumors was examined by a correlation analysis and joint histograms at the voxel level. The ability of multi-parametric imaging to identify tumor tissue classes was explored using an unsupervised 3D Gaussian mixture model-based cluster analysis.Results: Functional MRI and PET of cervical cancers appeared heterogeneous both between patients and spatially within the tumors, and the relations between parameters varied strongly within the patient cohort. The strongest spatial correlation was observed between FDG uptake and ADC (median r=-0.7). There was moderate voxel-wise correlation between RGD and FDG uptake, and weak correlations between all other modalities. Distinct relations between the ADC and RGD uptake as well as the ADC and FDG uptake were apparent in joint histograms. A cluster analysis using the combination of ADC, FDG and RGD uptake suggested tissue classes which could potentially relate to tumor sub-volumes. Conclusion: A multi-parametric PET/MRI examination of patients with cervical cancer integrated with treatment planning and including estimation of angiogenesis and glucose metabolism as well as MRI diffusion and perfusion parameters is feasible. A combined analysis of functional imaging parameters indicates a potential of multi-parametric PET/MRI to contribute to a better characterization of tumor heterogeneity than the modalities alone. However, the study is based on small patient numbers and further studies are needed prior to the future design of individually adapted treatment approaches based on multi-parametric functional imaging.

Early Response Prediction of Multiparametric Functional MRI and 18F-FDG-PET in Patients with Head and Neck Squamous Cell Carcinoma Treated with (Chemo)Radiation

Background: Patients with locally-advanced head and neck squamous cell carcinoma (HNSCC) have variable responses to (chemo)radiotherapy. A reliable prediction of outcomes allows for enhancing treatment efficacy and follow-up monitoring. Methods: Fifty-seven histopathologically-proven HNSCC patients with curative (chemo)radiotherapy were prospectively included. All patients had an MRI (DW,-IVIM, DCE-MRI) and 18F-FDG-PET/CT before and 10 days after start-treatment (intratreatment). Primary tumor functional imaging parameters were extracted. Univariate and multivariate analysis were performed to construct prognostic models and risk stratification for 2 year locoregional recurrence-free survival (LRFFS), distant metastasis-free survival (DMFS) and overall survival (OS). Model performance was measured by the cross-validated area under the receiver operating characteristic curve (AUC). Results: The best LRFFS model contained the pretreatment imaging parameters ADC_kurtosis, Kep and SUV_peak, and intratreatment imaging parameters change (Δ) Δ-ADC_skewness, Δ-f, Δ-SUV_peak and Δ-total lesion glycolysis (TLG) (AUC = 0.81). Clinical parameters did not enhance LRFFS prediction. The best DMFS model contained pretreatment ADC_kurtosis and SUV_peak (AUC = 0.88). The best OS model contained gender, HPV-status, N-stage, pretreatment ADC_skewness, D, f, metabolic-active tumor volume (MATV), SUV_mean and SUV_peak (AUC = 0.82). Risk stratification in high/medium/low risk was significantly prognostic for LRFFS (p = 0.002), DMFS (p < 0.001) and OS (p = 0.003). Conclusions: Intratreatment functional imaging parameters capture early tumoral changes that only provide prognostic information regarding LRFFS. The best LRFFS model consisted of pretreatment, intratreatment and Δ functional imaging parameters; the DMFS model consisted of only pretreatment functional imaging parameters, and the OS model consisted ofHPV-status, gender and only pretreatment functional imaging parameters. Accurate clinically applicable risk stratification calculators can enable personalized treatment (adaptation) management, early on during treatment, improve counseling and enhance patient-specific post-therapy monitoring.

Global Longitudinal Strain as a Predictor of Chemotherapy-Induced Cardiotoxicity

Background Chemotherapy-induced cardiotoxicity (ChC) is an important complication among patients receiving anthracyclines. Biomarkers and imaging parameters have been studied for their ability to identify patients at risk of developing this complication. Left ventricle global longitudinal strain (LV-GLS) has been described as a sensitive parameter for detecting systolic dysfunction, even in the presence of preserved left ventricle ejection fraction (LVEF). Objective to evaluate the role of the LV-GLS as a predictor of ChC. Methods This study is a post-hoc analysis of CECCY trial (Carvedilol for Prevention of Chemotherapy-Related Cardiotoxicity) that evaluated the primary prevention of cardiotoxicity with carvedilol during doxorubicin chemotherapy in a population with breast cancer. Cardiotoxicity was defined as a reduction ≥10% in LVEF. LV-GLS was obtained before chemotherapy in patients with no prior cardiovascular disease or echocardiogram abnormalities. Results Thirty-one patients who had a complete echocardiography study including measurement of LV-GLS before chemotherapy were included in this analysis. An absolute LV-GLS <16.9% before chemotherapy showed 100% sensitivity and 73% specificity for predicting cardiotoxicity (AUC=0.85; 95%CI 0.680 – 0.959, p<0.001). In this population, LVEF values before chemotherapy did not predict ChC (95%CI 0.478 to -0.842, p=0.17). The association of low LV-GLS (<17%) and BNP serum levels (>17 pg/mL) two months after chemotherapy increased the accuracy for detecting early onset ChC (100% sensitivity, 88% specificity, AUC=0.94; 95%CI 0.781 – 0.995, p<0.0001). Conclusions Our data suggest that LV-GLS is a potential predictor of chemotherapy-induced cardiotoxicity. Larger studies are needed to confirm the clinical relevance of this echocardiographic parameter in this clinical setting.

Sequential Organ Failure Assessment Outperforms Quantitative Chest CT Imaging Parameters for Mortality Prediction in COVID-19 ARDS

(1) Background: Respiratory insufficiency with acute respiratory distress syndrome (ARDS) and multi-organ dysfunction leads to high mortality in COVID-19 patients. In times of limited intensive care unit (ICU) resources, chest CTs became an important tool for the assessment of lung involvement and for patient triage despite uncertainties about the predictive diagnostic value. This study evaluated chest CT-based imaging parameters for their potential to predict in-hospital mortality compared to clinical scores. (2) Methods: 89 COVID-19 ICU ARDS patients requiring mechanical ventilation or continuous positive airway pressure mask ventilation were included in this single center retrospective study. AI-based lung injury assessment and measurements indicating pulmonary hypertension (PA-to-AA ratio) on admission CT, oxygenation indices, lung compliance and sequential organ failure assessment (SOFA) scores on ICU admission were assessed for their diagnostic performance to predict in-hospital mortality. (3) Results: CT severity scores and PA-to-AA ratios were not significantly associated with in-hospital mortality, whereas the SOFA score showed a significant association (p < 0.001). In ROC analysis, the SOFA score resulted in an area under the curve (AUC) for in-hospital mortality of 0.74 (95%-CI 0.63–0.85), whereas CT severity scores (0.53, 95%-CI 0.40–0.67) and PA-to-AA ratios (0.46, 95%-CI 0.34–0.58) did not yield sufficient AUCs. These results were consistent for the subgroup of more critically ill patients with moderate and severe ARDS on admission (oxygenation index <200, n = 53) with an AUC for SOFA score of 0.77 (95%-CI 0.64–0.89), compared to 0.55 (95%-CI 0.39–0.72) for CT severity scores and 0.51 (95%-CI 0.35–0.67) for PA-to-AA ratios. (4) Conclusions: Severe COVID-19 disease is not limited to lung (vessel) injury but leads to a multi-organ involvement. The findings of this study suggest that risk stratification should not solely be based on chest CT parameters but needs to include multi-organ failure assessment for COVID-19 ICU ARDS patients for optimized future patient management and resource allocation.

NI-18 A Quantitative Analysis of Intraoperative 3T-Diffusion Tensor Imaging parameters for Functional Prediction with Motor Eloquent Glioma Patients

OBJECTIVE: In motor eloquent glioma surgery, the value of intraoperative diffusion tensor (iDT) imaging was not established to preserve motor function. This study aimed to investigate a relationship between postoperative motor function and iDT imaging parameters, including fractional anisotropy (FA), mean diffusivity (MD), and shortest distance (SD) from resected tumor margin to the corticospinal tract (CST) of gliomas in motor eloquent areas. METHODS: This retrospective study enrolled 20 patients with newly diagnosed supratentorial glioma who underwent surgery and intraoperative magnetic resonance imaging at our hospital. Patients were divided into two groups (i.e., worsening and non-worsening groups) based on their manual muscle test scores before and three months after surgery. We obtained the mean FA and MD values bilaterally, along with identification of the CST and determined the ratios (the affected side / the contralateral side). The SD was measured between the CST and the resected margin of the tumor. We evaluated the quantitative analysis of these parameters related to motor functional outcomes. Moreover the correlation was measured between these parameters and the maximum reduction rate of cortical motor evoked potentials (MEPs) during surgery. RESULTS: In the worsening group (n = 5), the mean FA ratio was lower and the mean MD ratio was higher compared with the non-worsening group (n = 15; P &lt; 0.001 and P &lt; 0.01, respectively). Cut-off values were 0.87 for FA and 1.08 for MD. SD was 7.95 mm in the non-worsening group and 0.44 mm in the worsening group (P &lt; 0.01). These iDT based parameters, the mean FA ratio and the SD, were well correlated with the maximum reduction rate in MEP (R = 0.72 and 0.80, respectively). CONCLUSIONS: The mean ratio of FA, MD, and SD using iDT imagings predict postoperative motor function and help in optimal surgical planning in patients with motor eloquent glioma.

Machine Learning Classification of Mild Traumatic Brain Injury Using Whole-Brain Functional Activity: A Radiomics Analysis

Objectives. To investigate the classification performance of support vector machine in mild traumatic brain injury (mTBI) from normal controls. Methods. Twenty-four mTBI patients (15 males and 9 females; mean age, 38.88 ± 13.33 years) and 24 age and sex-matched normal controls (13 males and 11 females; mean age, 40.46 ± 11.4 years) underwent resting-state functional MRI examination. Seven imaging parameters, including amplitude of low-frequency fluctuation (ALFF), fractional amplitude of low-frequency fluctuation (fALFF), regional homogeneity (ReHo), degree centrality (DC), voxel-mirrored homotopic connectivity (VMHC), long-range functional connectivity density (FCD), and short-range FCD, were entered into the classification model to distinguish the mTBI from normal controls. Results. The ability for any single imaging parameters to distinguish the two groups is lower than multiparameter combinations. The combination of ALFF, fALFF, DC, VMHC, and short-range FCD showed the best classification performance for distinguishing the two groups with optimal AUC value of 0.778, accuracy rate of 81.11%, sensitivity of 88%, and specificity of 75%. The brain regions with the highest contributions to this classification mainly include bilateral cerebellum, left orbitofrontal cortex, left cuneus, left temporal pole, right inferior occipital cortex, bilateral parietal lobe, and left supplementary motor area. Conclusions. Multiparameter combinations could improve the classification performance of mTBI from normal controls by using the brain regions associated with emotion and cognition.

Two dynamic modes to streamline challenging atomic force microscopy measurements

The quality of topographic images obtained using atomic force microscopy strongly depends on the accuracy of the choice of scanning parameters. When using the most common scanning method – semicontact amplitude modulation (tapping) mode, the choice of scanning parameters is quite complicated, since it requires taking into account many factors and finding the optimal balance between them. A researcher’s task can be significantly simplified by introducing new scanning techniques. Two such techniques are described: vertical and dissipation modes. Significantly simplified and formalized choice of the imaging parameters in these modes allows addressing a wide range of formerly challenging tasks – from scanning rough samples with high aspect ratio features to molecular resolution imaging.

Electron Microscopy of Bubbles and Dislocations in Helium Implanted Metals

<p>The theoretical contrast in transmission electron microscope of a superlattice of helium gas bubbles in copper is computed using the two-beam and many-beam dynamical theories of electron diffraction with the aim the aim of measuring the density and size of dislocation loops associated with the bubble array. A wide range of parameters (foil thickness, diffraction vector, excitation error, defocus, and depth, radius, and strain-field of the bubble) is considered to considered to construct a library of theoretical images and intensity profiles for a single, isolated bubble. Various criteria are applied to obtain a measurement of the bubble radius from the simulations but the results are inaccurate because of the sensitive dependence of the intensity profile on the imaging parameters. A better measurement is profiles from a single stack of bubbles are modeled and electron diffraction from superlattices simulated. The results obtained suggest that the bubble ordering is of limited extent. A library is made of the theoretical contrast when imaging a system of dislocation loops punched out along the <110> directions by the growth of gas bubbles ordered on a superlattice aligned with the host fcc matrix. These image simulations use the displacement fields surrounding loops and bubbles predicted by isotropic elasticity theory. For a variety of structures involving loops and bubbles, the following imaging parameters were investigated: beam direction, foil normal, diffracting vector, excitation error, number of beams, and defocus, These simulations indicate that it should be possible to image the small dislocations at high density thought to be present in the bubble lattice, provided well focused micrographs taken under strong two-beam conditions can be obtained. In Practice it proved difficult to tilt specimens containing superlattices to strong two-beam conditions because of the deterioration in crystallinity resulting from the implantation. However, the lower concentrations by low dose implantations.</p>

Electron Microscopy of Bubbles and Dislocations in Helium Implanted Metals

<p>The theoretical contrast in transmission electron microscope of a superlattice of helium gas bubbles in copper is computed using the two-beam and many-beam dynamical theories of electron diffraction with the aim the aim of measuring the density and size of dislocation loops associated with the bubble array. A wide range of parameters (foil thickness, diffraction vector, excitation error, defocus, and depth, radius, and strain-field of the bubble) is considered to considered to construct a library of theoretical images and intensity profiles for a single, isolated bubble. Various criteria are applied to obtain a measurement of the bubble radius from the simulations but the results are inaccurate because of the sensitive dependence of the intensity profile on the imaging parameters. A better measurement is profiles from a single stack of bubbles are modeled and electron diffraction from superlattices simulated. The results obtained suggest that the bubble ordering is of limited extent. A library is made of the theoretical contrast when imaging a system of dislocation loops punched out along the <110> directions by the growth of gas bubbles ordered on a superlattice aligned with the host fcc matrix. These image simulations use the displacement fields surrounding loops and bubbles predicted by isotropic elasticity theory. For a variety of structures involving loops and bubbles, the following imaging parameters were investigated: beam direction, foil normal, diffracting vector, excitation error, number of beams, and defocus, These simulations indicate that it should be possible to image the small dislocations at high density thought to be present in the bubble lattice, provided well focused micrographs taken under strong two-beam conditions can be obtained. In Practice it proved difficult to tilt specimens containing superlattices to strong two-beam conditions because of the deterioration in crystallinity resulting from the implantation. However, the lower concentrations by low dose implantations.</p>