Stress Imaging Research Articles

Stress distribution of cementless stems with unique flanges in a rectangular cross-section: thermoelastic stress imaging study.

Objective: In this study, thermoelastic stress analysis was conducted to clarify the surface stress distribution of a femur in which a BiCONTACT E stem was inserted. The contact sites between the stem and femur were examined to investigate the association with the range of stress distribution.Materials and Methods: BiCONTACT E was set up using two synthetic femurs that mimic the morphology and mechanical properties of living bone. Preoperative planning was performed using three-dimensional imaging software. The synthetic bone was placed in a sample holder. After the stem was implanted into the synthetic bone, computed tomography imaging was performed. The contact sites between the stem and the cortical part of the synthetic bone were examined using the imaging software. Subsequently, thermoelastic stress measurements were performed on the sample.Results: The results of thermoelastic stress analysis indicated a minimum change in the sum of principal stresses [Δ (σ1+σ2)] on the medial side and a maximum change in the sum of principal stresses on the lateral side. Thus, no minimum change was observed in the sum of the principal stresses at the maximum proximal part. It is reasonable to assume that the use of a cementless stem can inevitably lead to bone atrophy in the proximal part of the femur. The contact sites between the stem and femur were also investigated, and the results of the study clearly and quantitatively demonstrated the correlation of the contact sites with a range of stress distributions.Conclusion: The surface stress distribution of a femur, in which a BiCONTACT E stem was inserted, was clarified. The contact sites between the stem and femur were also investigated. Furthermore, the correlation between these results and clinical bone response was investigated in this study.

Automated Segmental Analysis of Fully Quantitative Myocardial Blood Flow Maps by First-Pass Perfusion Cardiovascular Magnetic Resonance.

First pass gadolinium-enhanced cardiovascular magnetic resonance (CMR) perfusion imaging allows fully quantitative pixel-wise myocardial blood flow (MBF) assessment, with proven diagnostic value for coronary artery disease. Segmental analysis requires manual segmentation of the myocardium. This work presents a fully automatic method of segmenting the left ventricular myocardium from MBF pixel maps, validated on a retrospective dataset of 247 clinical CMR perfusion studies, each including rest and stress images of three slice locations, performed on a 1.5T scanner. Pixel-wise MBF maps were segmented using an automated pipeline including region growing, edge detection, principal component analysis, and active contours to segment the myocardium, detect key landmarks, and divide the myocardium into sectors appropriate for analysis. Automated segmentation results were compared against a manually defined reference standard using three quantitative metrics: Dice coefficient, Cohen Kappa and myocardial border distance. Sector-wise average MBF and myocardial perfusion reserve (MPR) were compared using Pearson’s correlation coefficient and Bland-Altman Plots. The proposed method segmented stress and rest MBF maps of 243 studies automatically. Automated and manual myocardial segmentation had an average (± standard deviation) Dice coefficient of 0.86 ± 0.06, Cohen Kappa of 0.86 ± 0.06, and Euclidian distances of 1.47 ± 0.73 mm and 1.02 ± 0.51 mm for the epicardial and endocardial border, respectively. Automated and manual sector-wise MBF and MPR values correlated with Pearson’s coefficient of 0.97 and 0.92, respectively, while Bland-Altman analysis showed bias of 0.01 and 0.07 ml/g/min. The validated method has been integrated with our fully automated MBF pixel mapping pipeline to aid quantitative assessment of myocardial perfusion CMR.

Cardiac evaluation of the kidney or liver transplant candidate.

As the field of transplant has advanced, cardiac events have become the leading cause of morbidity and mortality after liver and kidney transplantation ahead of graft failure and infection. This trend has been bolstered by the transplantation of older and sicker patients who have a higher burden of cardiovascular risk factors, accentuating the need to determine which patients should undergo more extensive cardiac evaluation prior to transplantation. Computed tomography coronary angiography with or without coronary artery calcium scoring is now preferred over stress imaging in most transplant candidates for assessment of coronary artery disease. Assessment of cardiac structure and function using transthoracic echocardiography with tissue doppler imaging and strain imaging is recommended, particularly in liver transplant candidates who are at high risk of cirrhotic cardiomyopathy, for which new diagnostic criteria were recently published in 2019. Cardiac evaluation of liver and kidney transplant candidates requires a global assessment for both short and long-term risk for cardiac events. Imaging of cardiac structure and function using transthoracic echocardiography with tissue doppler imaging and strain imaging is recommended. Risk stratification should consider both the anatomic and functional consequences of coronary artery disease in transplant candidates. http://links.lww.com/MOT/A27.

Prediction Method of Three‐Dimensional Crack Propagation Path Based on Deep Learning Application

In engineering, most structural components suffer from local damage in service or fabrication. Under different loading conditions, such local damage will further expand to large cracks and structural collapse. For ensuring longevity and reliability, the study of brittle crack growth is important. In structural damage prediction, various methodologies are commonly used and have demonstrated success in the past. Most traditional simulation methods, however, have the problems of large calculation quantities and long calculation times. At the same time, the mutual influence of crack opening stress and crack image on crack widening is rarely considered in existing works based on the deep learning framework. Herein, a deep learning model is developed to predict the spread of fracture of brittle materials under stress to improve the aforementioned problems. By developing a nonlinear relationship between crack stress and damage effects, this approach predicts crack growth, thus avoiding the loss of required information on crack growth behavior. The model emphasizes repeatability and extensibility, which is verified using extended finite element method (XFEM) Abaqus software through multiple sets of material crack data generated. This model's potential applications are material design and evaluation of residual life.

Can QT dispersion improves stress imaging accuracy in detecting ischemia?

Background and Aims: QT dispersion (QTd) is related to regional variations in myocardial repolarization. As exercise-induced ischemia causes heterogeneity in the ventricular repolarization, QTd could be used to assess the resulting ischemia. Aim: To assess the value of QTd in prediction of myocardial ischemia and its severity during stress imaging.

Impaired perfusion in the myocardial microcirculation in asymptomatic patients with Stages 1-4 chronic kidney disease with intrarenal arterial lesions.

Even mild renal disease is a powerful cardiovascular risk factor. However, the association between these pathophysiologic processes (especially in the early asymptomatic stage) is not known. We recruited 243 asymptomatic patients with Stages 1-4 chronic kidney disease (CKD) without obstructive coronary artery disease (CAD). We distinguished different degrees of severity of intrarenal arterial lesions (IALs) according to the Oxford classification. Myocardial microcirculation perfusion was measured using single-photon emission computed tomography (SPECT). Summed scores of 17 stress and rest image segments produced the summed stress score (SSS) and summed rest score (SRS), respectively. The summed difference score (SDS) was calculated as the difference between the SSS and SRS. Coronary microvascular disease (CMD) was defined as abnormal SPECT (SSS ≥4 or SDS ≥2) in the absence of obstructive CAD. Participants showed a stepwise increase in CMD severity with IAL aggravation. SSS of no/mild/moderate/severe IALs was 1.64 ± 1.08, 2.56 ± 1.35, 4.42 ± 2.17 and 6.48 ± 3.52, respectively (P < 0.05 for all). SDS of no/mild/moderate/severe IALs was 1.29 ± 0.49, 1.75 ± 0.56, 3.06 ± 1.12 and 4.16 ± 1.85, respectively (P < 0.05 for all). The percentage of subclinical CMD in CKD patients with IALs was significantly higher than in those without IALs (69.57% versus 14.71%; P = 0.01). Multiple regression analysis showed that renal arteriolar hyalinization (odds ratio = 1.578, P = 0.009) was associated independently with subclinical CMD. We demonstrated, for the first time, that impaired perfusion in the myocardial microcirculation in asymptomatic patients with Stages 1-4 CKD with IALs. Renal arteriolar hyalinization may be a useful marker of CMD in CKD.

Utility of nuclear stress imaging in predicting long-term outcomes one-year post CABG Surgery

BackgroundEarly MPI after CABG is currently considered rarely appropriate in asymptomatic patients. This study aimed to identify prognostic value of nuclear stress-imaging post-CABG. MethodsThis was a single center prospective study looking at long-term outcomes post-CABG. Per protocol participants underwent SPECT-MPI stress testing and coronary angiogram on the same day, 1-year following CABG. Defect size was semi-quantified. The primary outcomes were the composite of death and congestive heart failure. ResultsEighty-four participants underwent nuclear stress-imaging and angiography, with a median follow-up of 11.1 years. Three separate stress findings predicted the primary outcome: inability to reach stage 3 of a Bruce protocol (OR 7.3, CI 2.4-22.1, P < 0.001), LVEF < 45% (OR 4.0, CI 1.1-15.3, P = 0.041) and a moderate-large stress defect size (HR 2.31, CI 1.1-1.5, P = 0.04). These findings appear to be additive and strongest among patients who underwent exercise stress testing (HR 10.6, CI 3.6-30.6, P < 0.001). Graft disease was identified in 39 (46%) patients and compared to those individuals with no graft disease, did not predict long-term adverse outcomes (P = 0.29). ConclusionIn clinically stable patients early after revascularization with CABG, SPECT-MPI can identify patients at higher risk of heart failure and death.

Epidemiology and pathophysiologic insights of coronary atherosclerosis relevant for contemporary non-invasive imaging.

In the past few years significant changes have taken place in the diagnostic and therapeutic approach to patients with coronary artery disease (CAD) and/or ischemic heart disease (IHD). New discoveries about the development and progression of coronary atherosclerosis have changed the clinical landscape. At the same time a marked decrease in cardiovascular (CV) mortality and CAD incidence have been observed in many Countries but particularly in the most industrialized ones. This fall has been also observed in the incidence of stroke, sudden death, myocardial ischemia, myocardial infarction (MI), and prevalence of CAD. As a consequence, an increasing number of patients with chest pain exhibits non-significant stenosis at both invasive and non-invasive coronary angiography and the rate of coronary vessels revascularizations has greatly reduced. Coronary atherosclerosis and its characteristics have shown to be both diagnostic and therapeutic targets beyond obstructive CAD. The decreased prevalence of CAD in the general population has modified the pre-test probability (PTP) of disease. In this landscape the conventional stress imaging tests appear to have limited accuracy making the diagnosis of obstructive CAD very challenging. These diagnostic tests have been introduced and tested in a population with a much higher probability of disease and therefore the contemporary accuracy of these old tests appear much lower than in the past. In addition, in the past few years the relevance of the traditional ischemia guided coronary intervention strategy has been questioned. Given the low CV events granted by an optimal medical therapy in CAD the major attention has been directed on detecting coronary atherosclerosis. The earlier the better. At the same time, a growing number of data from clinical studies have shown a significant prognostic role for non-obstructive CAD and coronary atherosclerosis. All these facts have shifted the clinicians' attention from the functional evaluation of the coronary circulation to the anatomic burden of disease.

Abstract 17014: Cardiologist Assessment and Approval Was the Primary Predictor of Kidney Transplant Candidacy and Transplantation Among Patients With Reduced Left Ventricular Ejection Fraction

Introduction: End stage renal disease (ESRD) patients with concomitant heart failure (HF) are often denied kidney transplantation (KTx). The aims of this study were to explore factors predictive of suitability for KTx and to assess cardiovascular (CV) outcomes in patients with impaired left ventricular ejection fraction (LVEF) presenting for KTx evaluation. Methods: We evaluated 109 consecutive adults with LVEF≤40% at the time of initial KTx evaluation between 2013 and 2018. Post-transplant CV outcomes were defined as non-fatal MI, admission for HF, CV death and all-cause mortality. Results: Mean age was 58.2 years (SD11.9), 78% were male, 58% had diabetes, 70% had history of CV events and 42% had ischemic cardiomyopathy. Mean LVEF was 31.5% (SD 6.47). Eighty patients had nuclear stress imaging; 10% were positive for reversible ischemia and 43% for prior infarct. Mean VO2max was 14.4(SD 5.71)ml/kg/min (31 patients). A cardiologist evaluated 93% of patients and was present at 58% of selection committee meetings. Twenty-four patients (22%) were denied by a cardiologist for KTx and 59 (54%) were denied by the selection committee, of whom 43 were due to CV risk. On univariate analysis, the variables associated with denial for KTx were: cardiologist denial, denial due to CV risk, Native American race (6% of cohort), higher NT-pro-BNP, prior MI, coronary intervention, positive stress study, anemia, lower EF and lower VO2max (all p&lt;0.05). On multivariate analysis, cardiologist denial was the only significant predictor of denial for KTx (OR: 29.4, p=0.0007). At median follow-up of 15 months, 5 (5%) suffered non-fatal MI, 13 (12%) were hospitalized for HF exacerbation and 17 (16%) died. Only 22 (20%) underwent KTx. Post-KTx, there was one death, one non-fatal MI and 3 hospitalizations for HF. Mean LVEF improvement was 16% (SD12.9). Conclusions: Only 38% of ESRD patients with LVEF≤40% presenting for KTx evaluation were approved and of those, only 52% received KTx. Cardiologist approval was the primary predictor of suitability for KTx. Despite careful selection, prevalence of CV events and mortality after KTx was 23%. There is need for a consistent multidisciplinary approach during KTx evaluation, including cardiologist input, to improve CV outcomes.

Impact of early post-stress LV Dis-sinchrony assessed by TC99m GSPECT myocardial perfusion: ischemic patients vs. normal subjects

Abstract Purpose We aimed to determine the value of early post-stress Tc99msestamibi gated SPECT imaging for detecting changes in the two phase analysis synchrony parameters: Histogram bandwidth (HB) and Standard deviation (SD) in ischemic patients compared to normal subjects. Methods We prospectively included normal subjects and consecutive patients who had a positive stress test (angina or ST deviation during stress test). Both groups followed the same GSPECT protocol: an early stress image (acquired at maximum 10 minutes after the tracer injection), a delayed stress image (after 45 min of tracer injection) and the rest image. Phase analysis indices HB and SD were compared from early stress/ rest images and delayed stress/rest images in both groups. We compared the change of SD and HB indices (stress minus rest) for early and delayed images. The ischemic group was divided into mild ischemia (SDS≤3), moderate ischemia (SDS&amp;gt;3 and&amp;lt;8), and severe ischemia (SDS≥8) Results Twenty nine normal subjects and 57 ischemic patients were included. Thirty per cent of the ischemic group had mild ischemia, 32% moderate ischemia and 37% severe ischemia. SD and HB values decreased in early and delayed-stress images compared to those of rest images in normal subjects (all p&amp;lt;0,05). In the ischemic group early-stress SD increased compared to rest SD (p&amp;lt;0,05) while delayed- stress SD did not change. Early-stress HB did not change in comparison to rest HB while delayed-stress HB decrease compared to rest HB.The figure shows the comparison of SD and HB between early-stress, delayed-stress and rest images in normal subjects and ischemic patients. The Table shows the comparison of the change of SD and HB indices (stress minus rest) for early and delay images. Conclusion LVMS indices obtained by phase analysis of Tc99sestamibi GSPECT imaging, HB and SD decrease significantly when derived from early and delayed stress images compared to rest images in normal subjects. A progressive significant increase in SD and HB values in delayed and early stress images was observed in this population what could be an expression of post-ischemic LV dis-synchrony. Larger amounts of ischemia are related to progressive higher changes in SD and HB from early and delayed stress images versus rest images. Funding Acknowledgement Type of funding source: None

Live Cell Imaging of Oxidative Stress in Human Airway Epithelial Cells Exposed to a Secondary Organic Aerosol

Live Cell Imaging of Oxidative Stress in Human Airway Epithelial Cells Exposed to a Secondary Organic Aerosol

Diagnostic accuracy of Instantaneous Wave-Free Ratio (iFR) for the assessment of myocardial ischaemia: a comparison with non-invasive stress imaging

Abstract Background Instantaneous Wave-Free Ratio (iFR) allows for the assessment of the haemodynamic effects of epicardial coronary stenoses without the need for hyperaemia; iFR is currently recommended as a means to evaluate myocardial ischaemia. Purpose To assess the diagnostic accuracy of iFR with respect to the identification of coronary epicardial stenoses causing ischemia. Therefore, we combined anatomical (% stenosis at invasive coronary angiography, ICA) and functional (non-invasive imaging stress test, NIST) information to obtain a “gold standard” for the identification of stenoses causing ischaemia. Methods We enrolled 71 patients (52 male, 19 female; age mean 68.4±8.1 years) with chronic coronary syndrome or low-risk acute coronary syndrome without ST segment elevation who had at least a NIST and who had at least one vessel with a 50%-85% stenosis at ICA. iFR was measured in all coronary arteries with stenosis &amp;gt;50% and categorised according to the 0.89 threshold for ischaemia. Results iFR was assessed in 122 vessels. In a per-vessel analysis, in 56.7% ischaemia was present both at iFR and NIST, in 21.3% ischaemia was absent in both, while in 23.0% ischaemia was found at NIST but not confirmed by iFR. The overall accuracy of iFR with respect to NIST was 90.1%. However, when considering as the “gold standard” for coronary disease causing ischaemia the contemporary presence of an epicardial stenosis &amp;gt;70% at ICA and a positive NIST, the diagnostic accuracy of iFR greatly improved. The sensibility, specificity, PPV, NPV and accuracy were 96.5%, 75.0%, 73.3%, 96.7% and 84.4%, respectively. In case of discordance between NIST and iFR, revascularization was based on iFR. At a mean follow-up of 23±18 months, the composite endpoint of MACE (major adverse cardiac events, defined as the composite of all-cause death, nonfatal MI and unplanned coronary revascularization) occurred in 16.4%, while death/MI occurred in 11.9%. Stratification according to the per-patient concordance between iFR and NIST showed no significant differences in rates of MACE (p=0.50) and death/MI (p=0.20). Stratification based on iFR showed a higher death/MI rate in iFR-positive patients (11.9% vs. 0%, p=0.047) and a trend to higher MACE rate (11.9% vs. 4.47% p=0.14), Conclusions The diagnostic accuracy of iFR is low when compared with NIST as the reference for myocardial ischaemia, but it is very high when compared with the combined presence of epicardial stenosis and positive NIST. Therefore, iFR can accurately guide the decision to treat or defer revascularization of intermediate coronary stenoses, being most useful in patients with multivessel CAD and when non-invasive functional data are lacking or discordant with anatomy. Funding Acknowledgement Type of funding source: None

Role of diesel exhaust particles in the induction of allergic asthma to low doses of soybean

IntroductionExposure to environmental pollutants such as diesel exhaust particles (DEP) increases the risk of asthma and asthma exacerbation. However, the exact mechanisms inducing asthma to low doses of allergens remain poorly understood. The present study aimed to analyse the immunomodulatory effect of the inhalation of DEP in a mouse model exposed to non-asthmagenic doses of soybean hull extract (SHE). Material and methodsBALB/c ByJ mice were randomly divided into four experimental groups. Two groups received nasal instillations of saline and the other two groups received 3 mg ml−1 SHE during 5 days per week for 3 weeks. One group in each pair also received 150 μg of DEP in the same instillations 3 days per week. SHE-specific IgE levels, oxidative stress, leukocyte pattern and optical projection tomography (OPT) imaging studies were assessed. ResultsInhalation of SHE and/or DEP increased levels of H2O2 in BAL, while coexposure to SHE and DEP increased SHE-specific IgE levels in serum. Inhalation of SHE alone increased eosinophils, B cells, total and resident monocytes and decreased levels of NK cells, while inhalation of DEP increased neutrophils and decreased total monocytes. Regarding dendritic cells (DC), the inhalation of SHE and/or DEP increased the total population, while the inhalation of SHE alone increased Th2-related DCs (CD11b + Ly6C-) and decreased tolerogenic DCs (CD11b-Ly6C-). However, coexposure to SHE and DEP increased oxidative stress-sensitive DCs (CD11b-Ly6C+) and decreased Th1-related DCs (CD11b + Ly6C+). As regards macrophages, inhalation of SHE and DEP decreased total and alveolar populations. DEP deposition in lung tissue did not differ between groups. ConclusionCoexposure to DEP activates the asthmatic response to low doses of soy by triggering the immune response and oxidative stress.

Application of PEG-CdSe@ZnS quantum dots for ROS imaging and evaluation of deoxynivalenol-mediated oxidative stress in living cells

Deoxynivalenol (DON), a trichothecene mycotoxin, has attracted global attention due to its prevalence and substantial effects on animal and human health. DON induces the upregulation of intracellular reactive oxygen species (ROS) by disrupting the normal mitochondrial functionality, which causes oxidative stress, cell apoptosis, and even severe disorders. The aim of present work is to develop a simple, convenient, and in situ method for monitoring ROS and evaluating DON-mediated oxidative stress. Herein, polyethylene glycol-modified CdSe@ZnS quantum dots (QDs) were employed as simple and convenient nanoprobe for ROS imaging and oxidative stress evaluating induced by DON in living cells. The results demonstrated 5 ppm QDs nanoprobe can be easily loaded into cells via endocytosis without readily observable oxidative effects. Once in presence of DON, the augmented ROS directly oxidize the QDs nanoprobe, which leads to the destruction of the QDs structure and quenched fluorescence. According to the weakened fluorescence intensity (FI), the oxidative damage mediated by DON can be rapidly monitored and found that the oxidative stress was the most severe when the DON concentration exceeded 10 ppm. The developed QDs nanoprobe is also suitable for assessing other mycotoxins and chemicals. We hope it will be beneficial for the early screening of toxic and harmful substances in in vitro toxicology.

Evolution of CFRP stress cracks observed by in-situ X-ray refractive imaging

Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in-situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An in-house designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations. Imaging and the tensile test are run at the highest possible frame rate (0.7 s−1) and the lowest possible strain rate (5.5·10−4 s−1). For 0°/90° non-crimp fabrics, the first inter-fiber cracks occur at 380 MPa (strain 0.8 %). Prior to failure at about 760 MPa (strain 2.0 %), we observe the evolution of nearly equidistant (1 mm distance) cracks running across the entire sample in the fully damaged state.

Relationship between negative affect, stress and body image in adolescent girls

Abstract&#x0D; In recent decades, concerns about body image and dissatisfaction with it, especially significant increase in adolescents (Mousa, Mashal, Al-Domi HA, Jibril MA, 2010). According to studies, concerns about body image dissatisfaction has become a global phenomenon (Swami, Smith, 2012).&#x0D; The aim of the study was to determine differences of body image satisfaction in adolescent girls with regard to stress and negative affect. The respondents were 80 adolescents from Kaunas city, who were enrolled in grades 8 and 10 (mean age =15.57 years;). Respondents completed the The Multidimensional Body-Self Relations Questionnaire (MBSRQ), PANAS-X Negative Affect scale and Reeder Stress inventory.&#x0D; The results of this study showed that participants with higher stress were more dissatisfied with their body areas and less satisfied with their appearance compared to those who reported feeling less stressed. Girls with higher negative affect were more dissatisfied with their body areas, tended to invest less in their appearance, they also thought they weight is bigger, furthermore were more concerned with their weight and in general were less satisfied with their appearance.&#x0D; The result of the present study demonstrate that as well as examining negative affect, it is also important to investigate other emotional components, which could be related to body image dissatisfaction, such as perceived stress.

PET Imaging for Oxidative Stress in Neurodegenerative Disorders Associated with Mitochondrial Dysfunction.

Oxidative stress based on mitochondrial dysfunction is assumed to be the principal molecular mechanism for the pathogenesis of many neurodegenerative disorders. However, the effects of oxidative stress on the neurodegeneration process in living patients remain to be elucidated. Molecular imaging with positron emission tomography (PET) can directly evaluate subtle biological changes, including the redox status. The present review focuses on recent advances in PET imaging for oxidative stress, in particular the use of the Cu-ATSM radioligand, in neurodegenerative disorders associated with mitochondrial dysfunction. Since reactive oxygen species are mostly generated by leakage of excess electrons from an over-reductive state due to mitochondrial respiratory chain impairment, PET with 62Cu-ATSM, the accumulation of which depends on an over-reductive state, is able to image oxidative stress. 62Cu-ATSM PET studies demonstrated enhanced oxidative stress in the disease-related brain regions of patients with mitochondrial disease, Parkinson’s disease, and amyotrophic lateral sclerosis. Furthermore, the magnitude of oxidative stress increased with disease severity, indicating that oxidative stress based on mitochondrial dysfunction contributes to promoting neurodegeneration in these diseases. Oxidative stress imaging has improved our insights into the pathological mechanisms of neurodegenerative disorders, and is a promising tool for monitoring further antioxidant therapies.

Imaging of Carpal Instabilities.

The term "carpal instability" describes different debilitating wrist conditions, in which the carpus is unable to maintain its physiological range of motion and load transfer. Depending on the cause and location of the dysfunction, four groups can be defined: dissociative, non-dissociative, complex, and adaptive carpal instability. As the most common form by far, dissociative carpal instability can further be categorized as dorsal or palmar intercalated segment instability, contingent on the afflicted interosseous ligament. This review article outlines the different entities of carpal instability, their pathophysiology, and their clinical presentation. It further discusses the diagnostic significance of different imaging methods as well as the established treatment options for each form of instability in context with the current literature. Early detection and treatment of carpal instability are essential for preventing carpal osteoarthritis. Traumatic lesions of the scapholunate interosseous ligament are the most frequent cause of instability. They can occur in an isolated fashion or in context with other carpal injuries. While stress imaging and fluoroscopy facilitate the differentiation between dynamic and static forms of carpal instability, only MRI and CT/MR arthrography can directly reveal the extent of ligament discontinuity. · Carpal instability can manifest only in motion (dynamic) or at rest (static).. · Dissociative forms must be distinguished from non-dissociative, adaptive, or complex entities.. · Most instabilities are related to traumatic injuries or CPPD arthropathy.. · Fluoroscopy, stress imaging, and MR and CT arthrography are helpful for diagnosis.. · Grunz JP, Gietzen CH, Grunz K et al. Imaging of Carpal Instabilities. Fortschr Röntgenstr 2021; 193: 139 - 150.

Association of Prefrontal-Striatal Functional Pathology With Alcohol Abstinence Days at Treatment Initiation and Heavy Drinking After Treatment Initiation.

Alcohol use disorder (AUD) is associated with neuroadaptations in brain stress and reward circuits. It is not known whether such neuroadaptations are affected by number of days of alcohol abstinence and whether they influence heavy drinking during the early treatment phase. The authors used a novel functional MRI (fMRI) approach to assess brain responses during sustained exposure to standardized visual stimuli of stressful, alcohol cue, and neutral control images combined with prospective assessment of drinking outcomes during early outpatient treatment, in two related studies. In study 1, 44 treatment-entering patients with AUD and 43 demographically matched healthy control subjects participated in the fMRI experiment to identify dysfunctional responses associated with chronic alcohol abuse. In study 2, 69 treatment-entering patients with AUD were assessed for whether fMRI responses at treatment initiation were influenced by alcohol abstinence and were prospectively predictive of early heavy drinking outcomes. Relative to control subjects, patients with AUD showed significant hyperreactivity in the ventromedial prefrontal cortex (vmPFC) in response to neutral images, but significant hypoactivation in the vmPFC and ventral striatum in response to stress images and to alcohol cues relative to response to neutral images. In study 2, this specific prefrontal-ventral striatal dysfunction was associated with fewer days of alcohol abstinence and also predicted greater number heavy drinking days during the subsequent 2 weeks of treatment engagement. Number of days of alcohol abstinence at treatment initiation significantly affected functional disruption of the prefrontal-striatal responses to stress images and to alcohol cues in patients with AUD, and the severity of this disruption in turn predicted greater heavy drinking during early treatment. Treatments that target this functional prefrontal-striatal pathology could improve early treatment outcomes in AUD.

Galuminox: Preclinical validation of a novel PET tracer for non-invasive imaging of oxidative stress in vivo

Overproduction of reactive oxygen species (ROS) is a well-established indicator of ongoing tissue inflammation. However, there is a scarcity of molecular imaging probes capable of providing noninvasive sensitive detection of ROS for allowing longitudinal studies of disease pathology and/or monitoring therapeutic efficacy of ROS scavengers. Herein, we report synthesis and chemical characterization of a novel metalloprobe, Galuminox, a moderately fluorescent agent that detects superoxide and hydrogen peroxide generation. Using live-cell fluorescence imaging analysis, Galuminox demonstrates ability to detect superoxide and monitor effects of ROS-attenuating agents, such as Carvedilol, Dexrazoxane, and mitoTempo in lung epithelial A549 cells. Furthermore, LPS stimulation of A549 cells that either express the mitochondria targeted fluorescent protein Keima or are stained with MitoSOX, a mitochondria-specific superoxide probe, indicates preferential co-localization of Galuminox with mitochondria producing elevated amounts of superoxide. Dynamic PET/CT scans 45 min post tail-vein administration of 68Ga-Galuminox show 4-fold higher uptake and stable retention in lungs of LPS treated mice compared to their saline-only treated counterparts. Post preclinical PET imaging, quantitative biodistribution studies also correlate with 4-fold higher retention of the radiotracer in lungs of LPS treated mice compared with their saline-only treated control counterparts. Consistent with these observations, lung cells isolated from LPS-treated mice demonstrated elevated ROS production deploying CellROX, the ROS probe. Finally, Galuminox uptake correlates with histological and physiological evidence of acute lung injury as evident by polynuclear infiltration, thickening of the alveolar epithelial membranes and increased bronchioalveolar lavage protein content. Taken collectively, these data indicate that 68Ga-Galuminox tracer uptake is a measure of ROS activity in acutely injured lungs and suggests its potential utility in monitoring oxidative stress in other diseases.