Volume Maps Research Articles

Assessment of Brain Tumour Perfusion Using Early-Phase 18F-FET PET: Comparison with Perfusion-Weighted MRI

PurposeMorphological imaging using MRI is essential for brain tumour diagnostics. Dynamic susceptibility contrast (DSC) perfusion-weighted MRI (PWI), as well as amino acid PET, may provide additional information in ambiguous cases. Since PWI is often unavailable in patients referred for amino acid PET, we explored whether maps of relative cerebral blood volume (rCBV) in brain tumours can be extracted from the early phase of PET using O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET).ProcedureUsing a hybrid brain PET/MRI scanner, PWI and dynamic 18F-FET PET were performed in 33 patients with cerebral glioma and four patients with highly vascularized meningioma. The time interval from 0 to 2 min p.i. was selected to best reflect the blood pool phase in 18F-FET PET. For each patient, maps of MR-rCBV, early 18F-FET PET (0–2 min p.i.) and late 18F-FET PET (20–40 min p.i.) were generated and coregistered. Volumes of interest were placed on the tumour (VOI-TU) and normal-appearing brain (VOI-REF). The correlation between tumour-to-brain ratios (TBR) of the different parameters was analysed. In addition, three independent observers evaluated MR-rCBV and early 18F-FET maps (18F-FET-rCBV) for concordance in signal intensity, tumour extent and intratumoural distribution.ResultsTBRs calculated from MR-rCBV and 18F-FET-rCBV showed a significant correlation (r = 0.89, p < 0.001), while there was no correlation between late 18F-FET PET and MR-rCBV (r = 0.24, p = 0.16) and 18F-FET-rCBV (r = 0.27, p = 0.11). Visual rating yielded widely agreeing findings or only minor differences between MR-rCBV maps and 18F-FET-rCBV maps in 93 % of the tumours (range of three independent raters 91–94%, kappa among raters 0.78–1.0).ConclusionEarly 18F-FET maps (0–2 min p.i.) in gliomas provide similar information to MR-rCBV maps and may be helpful when PWI is not possible or available. Further studies in gliomas are needed to evaluate whether 18F-FET-rCBV provides the same clinical information as MR-rCBV.

Prostate MR image quality of apparent diffusion coefficient maps versus fractional intracellular volume maps from VERDICT MRI using the PI-QUAL score and a dedicated Likert scale for artefacts

PurposeThis study aimed to assess the image quality of apparent diffusion coefficient (ADC) maps derived from conventional diffusion-weighted MRI and fractional intracellular volume maps (FIC) from VERDICT MRI (Vascular, Extracellular, Restricted Diffusion for Cytometry in Tumours) in patients from the INNOVATE trial. The inter-reader agreement was also assessed. MethodsTwo readers analysed both ADC and FIC maps from 57 patients enrolled in the INNOVATE prospective trial. Image quality was assessed using the Prostate Imaging Quality (PI-QUAL) score and a subjective image quality Likert score (Likert-IQ). The image quality of FIC and ADC were compared using a Wilcoxon Signed Ranks test. The inter-reader agreement was assessed with Cohen’s kappa. ResultsThere was no statistically significant difference between the PI-QUAL score for FIC datasets compared to ADC datasets for either reader (p = 0.240 and p = 0.614). Using the Likert-IQ score, FIC image quality was higher compared to ADC (p = 0.021) as assessed by reader-1 but not for reader-2 (p = 0.663). The inter-reader agreement was ‘fair’ for PI-QUAL scoring of datasets with FIC maps at 0.27 (95% confidence interval; 0.08–0.46) and ADC datasets at 0.39 (95% confidence interval 0.22–0.57). For Likert scoring, the inter-reader agreement was also ‘fair’ for FIC maps at 0.38 (95% confidence interval; 0.10–0.65) and substantial for ADC maps at 0.62 (95% confidence interval; 0.39–0.86). ConclusionImage quality was comparable for FIC and ADC. The inter-reader agreement was similar when using PIQUAL for both FIC and ADC datasets but higher for ADC maps compared to FIC maps using the image quality Likert score.

Absence of long-term structural and functional cardiac abnormalities on multimodality imaging in a multi-ethnic group of COVID-19 survivors from the early stage of the pandemic.

Many patients with coronavirus disease-2019 (COVID-19), particularly from the pandemic's early phase, have been reported to have evidence of cardiac injury such as cardiac symptoms, troponinaemia, or imaging or ECG abnormalities during their acute course. Cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE) have been widely used to assess cardiac function and structure and characterize myocardial tissue during COVID-19 with report of numerous abnormalities. Overall, findings have varied, and long-term impact of COVID-19 on the heart needs further elucidation. We performed TTE and 3 T CMR in survivors of the initial stage of the pandemic without pre-existing cardiac disease and matched controls at long-term follow-up a median of 308 days after initial infection. Study population consisted of 40 COVID-19 survivors (50% female, 28% Black, and 48% Hispanic) and 12 controls of similar age, sex, and race-ethnicity distribution; 35% had been hospitalized with 28% intubated. We found no difference in echocardiographic characteristics including measures of left and right ventricular structure and systolic function, valvular abnormalities, or diastolic function. Using CMR, we also found no differences in measures of left and right ventricular structure and function and additionally found no significant differences in parameters of tissue structure including T1, T2, extracellular volume mapping, and late gadolinium enhancement. With analysis stratified by patient hospitalization status as an indicator of COVID-19 severity, no differences were uncovered. Multimodal imaging of a diverse cohort of COVID-19 survivors indicated no long-lasting damage or inflammation of the myocardium.

Identification of non-ischaemic fibrosis in male veteran endurance athletes, mechanisms and association with premature ventricular beats

Left ventricular fibrosis can be identified by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) in some veteran athletes. We aimed to investigate prevalence of ventricular fibrosis in veteran athletes and associations with cardiac arrhythmia. 50 asymptomatic male endurance athletes were recruited. They underwent CMR imaging including volumetric analysis, bright blood (BB) and dark blood (DB) LGE, motion corrected (MOCO) quantitative stress and rest perfusion and T1/T2/extracellular volume mapping. Athletes underwent 12-lead electrocardiogram (ECG) and 24-h ECG. Myocardial fibrosis was identified in 24/50 (48%) athletes. All fibrosis was mid-myocardial in the basal-lateral left ventricular wall. Blood pressure was reduced in athletes without fibrosis compared to controls, but not athletes with fibrosis. Fibrotic areas had longer T2 time (44 ± 4 vs. 40 ± 2 ms, p < 0.0001) and lower rest myocardial blood flow (MBF, 0.5 ± 0.1 vs. 0.6 ± 0.1 ml/g/min, p < 0.0001). On 24-h ECG, athletes with fibrosis had greater burden of premature ventricular beats (0.3 ± 0.6 vs. 0.05 ± 0.2%, p = 0.03), with higher prevalence of ventricular couplets and triplets (33 vs. 8%, p = 0.02). In veteran endurance athletes, myocardial fibrosis is common and associated with an increased burden of ventricular ectopy. Possible mechanisms include inflammation and blood pressure. Further studies are needed to establish whether fibrosis increases risk of malignant arrhythmic events.

Differential Cortical Volume and Surface Morphometry in Youth With Chronic Health Conditions.

Up to 1 in 3 youth in the United States have a childhood-onset chronic health condition (CHC), which can lead to neurodevelopmental disruptions in cognitive functioning and brain structure. However, the nature and extent of structural neurobiomarkers that may be consistent across a broad spectrum of CHCs are unknown. Thus, the purpose of this study was to identify potential differences in brain structure in youth with and without chronic physical health conditions (e.g., diabetes, hemophilia). Here, 49 T1 structural magnetic resonance imaging (MRI) images were obtained from youth with (n = 26) and without (n = 23) CHCs. Images were preprocessed using voxel-based morphometry (VBM) to generate whole-brain voxel-wise gray matter volume maps and whole-brain extracted estimates of cortical surface area and cortical thickness. Multi-scanner harmonization was implemented on surface-based estimates and linear models were used to estimate significant main effects of the group. We detected widespread decreases in brain structure in youth with CHCs as compared to controls in regions of the prefrontal, cingulate, and visual association areas. The insula exhibited the opposite effect, with cases having increased surface area as compared to controls. To our knowledge, these findings identify a novel structural biomarker of childhood-onset CHCs, with consistent alterations identified in gray matter of regions in the prefrontal cortex and insula involved in emotion regulation and executive function. These findings, while exploratory, may reflect an impact of chronic health stress in the adolescent brain, and suggest that more comprehensive assessment of stress and neurodevelopment in youth with CHCs may be appropriate.

VOLMAP: a Large Scale Benchmark for Volume Mappings to Simple Base Domains

AbstractCorrespondences between geometric domains (mappings) are ubiquitous in computer graphics and engineering, both for a variety of downstream applications and as core building blocks for higher level algorithms. In particular, mapping a shape to a convex or star‐shaped domain with simple geometry is a fundamental module in existing pipelines for mesh generation, solid texturing, generation of shape correspondences, advanced manufacturing etc. For the case of surfaces, computing such a mapping with guarantees of injectivity is a solved problem. Conversely, robust algorithms for the generation of injective volume mappings to simple polytopes are yet to be found, making this a fundamental open problem in volume mesh processing. VOLMAP is a large scale benchmark aimed to support ongoing research in volume mapping algorithms. The dataset contains 4.7K tetrahedral meshes, whose boundary vertices are mapped to a variety of simple domains, either convex or star‐shaped. This data constitutes the input for candidate algorithms, which are then required to position interior vertices in the domain to obtain a volume map. Overall, this yields more than 22K alternative test cases. VOLMAP also comprises tools to process this data, analyze the resulting maps, and extend the dataset with new meshes, boundary maps and base domains. This article provides a brief overview of the field, discussing its importance and the lack of effective techniques. We then introduce both the dataset and its major features. An example of comparative analysis between two existing methods is also present.

Radiotherapy-induced diffuse myocardial fibrosis in early-stage breast cancer patients – multimodality imaging study with six-year follow-up

BackgroundBreast radiotherapy (RT) induces diffuse myocardial changes, which may increase the incidence of heart failure with preserved ejection fraction. This study aimed to evaluate the early signs of diffuse fibrosis after RT and their evolution during a six-year follow-up.MethodsThirty patients with early-stage left-sided breast cancer were studied with echocardiography and electrocardiography (ECG) at baseline, after RT, and at three-year and six-year follow-up visits. Echocardiography analysis included an off-line analysis of integrated backscatter (IBS). ECG was analysed for fragmented QRS (fQRS). In addition, cardiac magnetic resonance (CMR) imaging was performed at the six-year control. The left ventricle 16-segment model was used in cardiac imaging, and respective local radiation doses were analysed.ResultsRegional myocardial reflectivity in inferoseptal segments increased by 2.02 (4.53) dB (p = 0.026) and the percentage of leads with fQRS increased from 9.2 to 16.4% (p = 0.002) during the follow-up. In CMR imaging, abnormal extracellular volume (ECV) and T1 mapping values were found with anteroseptal and apical localization in a median of 3.5 (1.00–5.75) and 3 (1.25–4.00) segments, respectively. A higher left ventricle radiation dose was associated with an increased likelihood of having changes simultaneously in CMR and echocardiography (OR 1.26, 95% Cl. 1.00–1.59, p = 0.047).ConclusionsAfter radiotherapy, progressive changes in markers of diffuse myocardial fibrosis were observed in a multimodal manner in ECG and echocardiography. Changes in echocardiography and abnormal values in CMR were localized in the septal and apical regions, and multiple changes were associated with higher radiation doses.

Subcortical Brain Alterations in Carriers of Genomic Copy Number Variants.

Copy number variants (CNVs) are well-known genetic pleiotropic risk factors for multiple neurodevelopmental and psychiatric disorders (NPDs), including autism (ASD) and schizophrenia. Little is known about how different CNVs conferring risk for the same condition may affect subcortical brain structures and how these alterations relate to the level of disease risk conferred by CNVs. To fill this gap, the authors investigated gross volume, vertex-level thickness, and surface maps of subcortical structures in 11 CNVs and six NPDs. Subcortical structures were characterized using harmonized ENIGMA protocols in 675 CNV carriers (CNVs at 1q21.1, TAR, 13q12.12, 15q11.2, 16p11.2, 16p13.11, and 22q11.2; age range, 6-80 years; 340 males) and 782 control subjects (age range, 6-80 years; 387 males) as well as ENIGMA summary statistics for ASD, schizophrenia, attention deficit hyperactivity disorder, obsessive-compulsive disorder, bipolar disorder, and major depression. All CNVs showed alterations in at least one subcortical measure. Each structure was affected by at least two CNVs, and the hippocampus and amygdala were affected by five. Shape analyses detected subregional alterations that were averaged out in volume analyses. A common latent dimension was identified, characterized by opposing effects on the hippocampus/amygdala and putamen/pallidum, across CNVs and across NPDs. Effect sizes of CNVs on subcortical volume, thickness, and local surface area were correlated with their previously reported effect sizes on cognition and risk for ASD and schizophrenia. The findings demonstrate that subcortical alterations associated with CNVs show varying levels of similarities with those associated with neuropsychiatric conditions, as well distinct effects, with some CNVs clustering with adult-onset conditions and others with ASD. These findings provide insight into the long-standing questions of why CNVs at different genomic loci increase the risk for the same NPD and why a single CNV increases the risk for a diverse set of NPDs.

Tracking multi-organ treatment response in systemic AL amyloidosis with cardiac magnetic resonance derived extracellular volume mapping

Abstract Funding Acknowledgements Type of funding sources: None. Background Systemic light-chain (AL) amyloidosis commonly involves the liver, spleen and heart. Cardiac magnetic resonance (CMR) with extracellular volume (ECV) mapping has demonstrated accuracy in measuring cardiac, hepatic and splenic amyloid infiltration. Purpose We sought to: (1) assess the association between baseline multi-organ ECVs and prognosis (2) assess the multi-organ response to treatment using ECV mapping, and (3) assess the association between multi-organ treatment response and prognosis. Methods We identified 351 patients with a confirmed diagnosis of systemic AL amyloidosis who underwent baseline serum amyloid P component (SAP) scintigraphy and CMR at diagnosis, of which 171 had follow-up imaging. We also recruited 20 healthy volunteers who underwent CMR with ECV mapping, without corresponding SAP scintigraphy, to allow calculation of the ECV normal ranges. Results At diagnosis, ECV mapping demonstrated that 304(86.7%) had cardiac involvement, 114(32.5%) significant hepatic involvement and 147(41.9%) significant splenic involvement. Baseline myocardial and liver ECV independently predict mortality (myocardial: HR=1.05,95CI%[1.03–1.07],P&amp;lt;0.001; liver: HR=1.03,95%CI[1.01–1.05],P&amp;lt;0.001). Liver and spleen ECV correlated with amyloid load assessed by SAP scintigraphy (R=0.751,P&amp;lt;0.001; R=0.765,P&amp;lt;0.001, respectively). Serial multi-organ ECV measurements accurately tracked treatment response as validated against serial SAP scintigraphy (the current reference standard). Multi-organ ECV regression was observed as early as 6-months in patients with a good haematological response (liver=15%, spleen=15%, heart=5%). The remaining patients with a good haematological response had stable liver and spleen ECVs, but 20% had cardiac progression. By 12-months more patients with a good haematological response demonstrated cardiac regression (liver=30%, spleen=36%, heart=32%), and this trend was maintained at 24-months. Multi-variable analysis adjusting for haematological response, change in myocardial, liver and spleen ECV demonstrated that haematological response, change in myocardial ECV (HR=1.11, 95%CI[1.02–1.19], P=0.011) and liver ECV (HR=1.06, 95%CI[1.01–1.11], P=0.015) remained independent predictors of prognosis at 6-months. Conclusions Multi-organ ECV quantification accurately tracks treatment response, and demonstrates different rates of organ regression, with the liver and spleen regressing more rapidly than the heart. A good haematological response alone is likely to induce visceral organ stabilisation/regression, but may not be sufficient to induce myocardial stabilisation/regression. Liver and myocardial ECV at diagnosis and changes in ECV at 6-months independently predict mortality. ECV mapping offers a comprehensive multi-organ assessment of treatment response and accurate prognostication.

Tracking treatment response in cardiac AL amyloidosis with native-T1 mapping

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac magnetic resonance (CMR) derived extracellular volume (ECV) mapping has demonstrated utility in determining the cardiac response to chemotherapy in systemic AL amyloidosis, but concomitant renal dysfunction is a common contraindication for the required gadolinium contrast. Objectives To assess the ability of native-T1 mapping to measure the cardiac response to treatment, and assess the association between changes in native-T1 and prognosis. Methods We studied 221 patients who underwent cardiac magnetic resonance (CMR) scans at diagnosis and a repeat scan following chemotherapy. Results At 6-months a reduced native-T1 of ≥50ms occurred in 8(4%) patients, all of whom had a good haematological response; by contrast an increased native-T1 of ≥50ms occurred in 42(23%) patients, most of whom had a poor haematological response (n=27,68%). At 12-months, a reduced native-T1 occurred in 24(15%) patients, all of whom had a good haematological response, and was associated with a reduction in median N-terminal pro-brain natriuretic peptide (NT-proBNP) (2638ng/L vs 432ng/L,P&amp;lt;0.001) and E/e’ (14.9±6.8 vs 12.0±5.2, P=0.007), improved longitudinal strain (−14.8±4.0 vs −16.7±4.0, P=0.004) and reduction in both T2 (52.3±2.9 vs 49.4±2.0, P&amp;lt;0.001) and ECV (0.47±0.07 vs 0.42±0.08, P&amp;lt;0.001); increased native-T1 occurred in 24(15%) patients, most of whom had a poor haematological response (n=17,71%) and was associated with an increased median NT-proBNP (1622ng/L vs 3150ng/L, P=0.007), reduced ejection fraction (65.8±11.4% vs 61.5±12.4%, P=0.009) and both increased T2 (52.5±2.7 vs 55.3±4.2, P&amp;lt;0.001) and ECV (0.48±0.09 vs 0.56±0.09, P&amp;lt;0.001). Change in native-T1 at 6-months predicted mortality even after adjusting for haematological response and NT-proBNP response (HR=2.41,95%CI[1.36–4.27],P=0.003). Conclusion Changes in myocardial native-T1 in response to treatment, are reflected in changes in the traditional markers of the cardiac response provide a powerful independent predictor of mortality. Change in native-T1 represents an important addition to the standard armamentarium of amyloid assessment, and provides an alternative measure of the cardiac treatment response, that not only limits exposure of patients to contrast but could also have implications on clinical workflow by reducing scan time.

GEOPHYSICAL STUDIES OF ROCK DISTORTION IN MINING OPERATIONS IN COMPLEX GEOLOGICAL CONDITIONS

Abstract. Geophysical methods of rock mass survey are one of the most effective ways of solving various problems in mining and are widely used in mining, gas and oil industries, as well as in science. They allow carrying out prospecting and evaluation works remotely, to reveal structural heterogeneities, cavities, contact zones of different media in rock mass with rather high accuracy. At the stage of designing a mining enterprise and making major decisions, it is necessary to have reliable information about the tectonic structure of the undermined and adjacent massif and parameters of its geodynamic activity. For this purpose, special studies of the tectonic structure of the rock massif must be carried out and the parameters of modern geodynamic movements must be determined. The most complete information about tectonic disturbances, identification of gliding surfaces, zones of macrofracturing are provided by geophysical methods of rock mass survey.In the article analysis of study of structural-tectonic structure of ore areas, separation and specification of ore-controlling structures, detection and depth mapping of ore-controlling faults, volume mapping of intrusive massifs based on previously conducted geophysical research in Zhezkazgan syncline area carried out. Geological and geophysical conditions of the central ore field (presence of rich bodies with high electric conductivity, considerable thicknesses of ore bodies, etc.) were favorable for application of various geophysical methods to search and trace rich ore bodies occurring at low depths.Moreover, possibilities of application of seismic works are considered at the solution of problems of ore geology in difficult mining-geological conditions of Kazakhstan.

Calibration of a Dust Scattering Instrument Using Tomographic Techniques and Its Application to a Dust Sensor Instrument.

The characterization of suspended dust near the Martian surface is extremely relevant to understand the climate of Mars. In this frame, a Dust Sensor instrument, an infrared device designed to obtain the effective parameters of Martian dust using the scattering properties of the dust particles, was developed. The purpose of this article is to present a novel methodology to calculate, from experimental data, an instrumental function of the Dust Sensor that allows solving the direct problem and providing the signal that this instrument would provide given a distribution of particles. The experimental method is based on recording the signal measured when a Lambertian reflector is gradually introduced into the interaction volume at different distances from the detector and source and applying tomography techniques (inverse Radon transform) to obtain the image of a section of the interaction volume. This method provides a complete mapping of the interaction volume experimentally, which determines the Wf function. The method was applied to solve a specific case study. Among the advantages of this method, it should be noted that it avoids assumptions and idealizations of the dimensions of the volume of interaction and reduces the time required to carry out simulations.

Prostate perfusion mapping using Fourier-transform based velocity-selective arterial spin labeling: Choice of cutoff velocity and comparison with brain.

To develop velocity selective arterial spin labeling (VSASL) protocols for prostate blood flow (PBF) and prostate blood volume (PBV) mapping. Fourier-transform based velocity-selective inversion and saturation pulse trains were utilized in VSASL sequences to obtain blood flow and blood volume weighted perfusion signal, respectively. Here four cutoff velocities (Vcut = 0.25, 0.50, 1.00, and 1.50 cm/s) for PBF and PBV mapping sequences were evaluated with a parallel implementation in brain for measuring cerebral blood flow (CBF) and cerebral blood volume (CBV) with identical 3D readout. This study was performed at 3T on eight young and middle-aged healthy subjects comparing both perfusion weighted signal (PWS) and temporal SNR (tSNR). In contrast to CBF and CBV, the PWS of PBF and PBV were rather unobservable at Vcut of 1.00 or 1.50 cm/s and both PWS and tSNR of PBF and PBV considerably increased at the lower Vcut , indicating that blood moves much slower in prostate than in brain. Similar to the brain results, the tSNR of PBV-weighted signal was about two to four times over the corresponding values of PBF-weighted signal. The results also suggested a trend of reduced vascularity within prostate during aging. For prostate, a low Vcut of 0.25-0.50 cm/s seemed necessary for both PBF and PBV measurements to obtain adequate perfusion signal. As in brain, PBV mapping yielded a higher tSNR than PBF.

Minimally Invasive Intracerebral Hemorrhage Evacuation Improves Pericavity Cerebral Blood Volume.

Cerebral blood volume mapping can characterize hemodynamic changes within brain tissue, particularly after stroke. This study aims to quantify blood volume changes in the perihematomal parenchyma and pericavity parenchyma after minimally invasive intracerebral hemorrhage evacuation (MIS for ICH). Thirty-two patients underwent MIS for ICH with pre- and post-operative CT imaging and intraoperative perfusion imaging (DynaCT PBV Neuro, Artis Q, Siemens). The pre-operative and post-operative CT scans were segmented using ITK-SNAP software to calculate hematoma volumes and to delineate the pericavity tissue. Helical CT segmentations were registered to cone beam CT data using elastix software. Mean blood volumes were computed inside subvolumes by dilating the segmentations at increasing distances from the lesion. Pre-operative perihematomal blood volumes and post-operative pericavity blood volumes (PBV) were compared. In 27 patients with complete imaging, post-operative PBV significantly increased within the 6-mm pericavity region after MIS for ICH. The mean relative PBV increased by 21.6 and 9.1% at 3 mm and 6 mm, respectively (P = 0.001 and 0.016, respectively). At the 9-mm pericavity region, there was a 2.83% increase in mean relative PBV, though no longer statistically significant. PBV analysis demonstrated a significant increase in pericavity cerebral blood volume after minimally invasive ICH evacuation to a distance of 6 mm from the border of the lesion.

Tracking Multiorgan Treatment Response in Systemic AL-Amyloidosis With Cardiac Magnetic Resonance Derived Extracellular Volume Mapping

BackgroundSystemic light chain amyloidosis is a multisystem disorder that commonly involves the heart, liver, and spleen. Cardiac magnetic resonance with extracellular volume (ECV) mapping provides a surrogate measure of the myocardial, liver, and spleen amyloid burden. ObjectivesThe purpose of this study was to assess multiorgan response to treatment using ECV mapping, and assess the association between multiorgan treatment response and prognosis. MethodsThe authors identified 351 patients who underwent baseline serum amyloid-P-component (SAP) scintigraphy and cardiac magnetic resonance at diagnosis, of which 171 had follow-up imaging. ResultsAt diagnosis, ECV mapping demonstrated that 304 (87%) had cardiac involvement, 114 (33%) significant hepatic involvement, and 147 (42%) significant splenic involvement. Baseline myocardial and liver ECV independently predict mortality (myocardial HR: 1.03 [95% CI: 1.01-1.06]; P = 0.009; liver HR: 1.03; [95% CI: 1.01-1.05]; P = 0.001). Liver and spleen ECV correlated with amyloid load assessed by SAP scintigraphy (R = 0.751; P < 0.001; R = 0.765; P < 0.001, respectively). Serial measurements demonstrated ECV correctly identified changes in liver and spleen amyloid load derived from SAP scintigraphy in 85% and 82% of cases, respectively. At 6 months, more patients with a good hematologic response had liver (30%) and spleen (36%) ECV regression than myocardial regression (5%). By 12 months, more patients with a good response demonstrated myocardial regression (heart 32%, liver 30%, spleen 36%). Myocardial regression was associated with reduced median N-terminal pro-brain natriuretic peptide (P < 0.001), and liver regression with reduced median alkaline phosphatase (P = 0.001). Changes in myocardial and liver ECV, 6 months after initiating chemotherapy, independently predict mortality (myocardial HR: 1.11 [95% CI: 1.02-1.20]; P = 0.011; liver HR: 1.07 [95% CI: 1.01-1.13]; P = 0.014). ConclusionsMultiorgan ECV quantification accurately tracks treatment response and demonstrates different rates of organ regression, with the liver and spleen regressing more rapidly than the heart. Baseline myocardial and liver ECV and changes at 6 months independently predict mortality, even after adjusting for traditional predictors of prognosis.

Evaluation of 3D stack-of-spiral turbo FLASH acquisitions for pseudo-continuous and velocity-selective ASL-derived brain perfusion mapping.

The most-used 3D acquisitions for ASL are gradient and spin echo (GRASE)- and stack-of-spiral (SOS)-based fast spin echo, which require multiple shots. Alternatively, turbo FLASH (TFL) allows longer echo trains, and SOS-TFL has the potential to reduce the number of shots to even single-shot, thus improving the temporal resolution. Here we compare the performance of 3D SOS-TFL and 3D GRASE for ASL at 3T. The 3D SOS-TFL readout was optimized with respect to fat suppression and excitation flip angles for pseudo-continuous ASL- and velocity-selective (VS)ASL-derived cerebral blood flow (CBF) mapping as well as for VSASL-derived cerebral blood volume (CBV) mapping. Results were compared with 3D GRASE readout on healthy volunteers in terms of perfusion quantification and temporal SNR (tSNR) efficiency. CBF and CBV mapping derived from 3D SOS-TFL-based ASL was demonstrated on one stroke patient, and the potential for single-shot acquisitions was exemplified. SOS-TFL with a 15° flip angle resulted in adequate tSNR efficiency with negligible image blurring. Selective water excitation was necessary to eliminate fat-induced artifacts. For pseudo-continuous ASL- and VSASL-based CBF and CBV mapping, compared to the employed four-shot 3D GRASE with an acceleration factor of 2, the fully sampled 3D SOS-TFL delivered comparable performance (with a similar scan time) using three shots, which could be further undersampled to achieve single-shot acquisition with higher tSNR efficiency. SOS-TFL had reduced CSF contamination for VSASL-CBF. 3D SOS-TFL acquisition was found to be a viable substitute for 3D GRASE for ASL with sufficient tSNR efficiency, minimal relaxation-induced blurring, reduced CSF contamination, and the potential of single-shot, especially for VSASL.

A Computational Evaluation of the Steric and Electronic Contributions in Stereoselective Olefin Polymerization with Pyridylamido-Type Catalysts.

A density functional theory (DFT) study combined with the steric maps of buried volume (%VBur) as molecular descriptors and an energy decomposition analysis through the ASM (activation strain model)-NEDA (natural energy decomposition analysis) approach were applied to investigate the origins of stereoselectivity for propene polymerization promoted by pyridylamido-type nonmetallocene systems. The relationships between the fine tuning of the ligand and the propene stereoregularity were rationalized (e.g., the metallacycle size, chemical nature of the bridge, and substituents at the ortho-position on the aniline moieties). The DFT calculations and %VBur steric maps reproduced the experimental trend: substituents on the bridge and on the ortho-positions of aniline fragments enhance the stereoselectivity. The ASM-NEDA analysis enabled the separation of the steric and electronic effects and revealed how subtle ligand modification may affect the stereoselectivity of the process.

Cardioprotective effects of shock wave therapy: A cardiac magnetic resonance imaging study on acute ischemia-reperfusion injury.

Cardioprotection strategies remain a new frontier in treating acute myocardial infarction (AMI), aiming at further protect the myocardium from the ischemia-reperfusion damage. Therefore, we aimed at investigating the mechano-transduction effects induced by shock waves (SW) therapy at time of the ischemia reperfusion as a non-invasive cardioprotective innovative approach to trigger healing molecular mechanisms. We evaluated the SW therapy effects in an open-chest pig ischemia-reperfusion (IR) model, with quantitative cardiac Magnetic Resonance (MR) imaging performed along the experiments at multiple time points (baseline (B), during ischemia (I), at early reperfusion (ER) (∼15 min), and late reperfusion (LR) (3 h)). AMI was obtained by a left anterior artery temporary occlusion (50 min) in 18 pigs (32 ± 1.9 kg) randomized into SW therapy and control groups. In the SW therapy group, treatment was started at the end of the ischemia period and extended during early reperfusion (600 + 1,200 shots @0.09 J/mm2, f = 5 Hz). The MR protocol included at all time points LV global function assessment, regional strain quantification, native T1 and T2 parametric mapping. Then, after contrast injection (gadolinium), we obtained late gadolinium imaging and extra-cellular volume (ECV) mapping. Before animal sacrifice, Evans blue dye was administrated after re-occlusion for area-at-risk sizing. During ischemia, LVEF decreased in both groups (25 ± 4.8% in controls (p = 0.031), 31.6 ± 3.2% in SW (p = 0.02). After reperfusion, left ventricular ejection fraction (LVEF) remained significantly decreased in controls (39.9 ± 4% at LR vs. 60 ± 5% at baseline (p = 0.02). In the SW group, LVEF increased quickly ER (43.7 ± 11.4% vs. 52.4 ± 8.2%), and further improved at LR (49.4 ± 10.1) (ER vs. LR p = 0.05), close to baseline reference (LR vs. B p = 0.92). Furthermore, there was no significant difference in myocardial relaxation time (i.e. edema) after reperfusion in the intervention group compared to the control group: ΔT1 (MI vs. remote) was increased by 23.2±% for SW vs. +25.2% for the controls, while ΔT2 (MI vs. remote) increased by +24.9% for SW vs. +21.7% for the control group. In conclusion, we showed in an ischemia-reperfusion open-chest swine model that SW therapy, when applied near the relief of 50' LAD occlusion, led to a nearly immediate cardioprotective effect translating to a reduction in the acute ischemia-reperfusion lesion size and to a significant LV function improvement. These new and promising results related to the multi-targeted effects of SW therapy in IR injury need to be confirmed by further in-vivo studies in close chest models with longitudinal follow-up.

Distinct imaging features of cerebral small vessel disease are related to rare NOTCH3 variants (S36.002)

<h3>Objective:</h3> To investigate the longitudinal imaging features of cerebral small vessel disease (SVD) in relation to rare <i>NOTCH3</i> variants, including spatial patterns, dynamic patterns, and the interaction between the cortical atrophy and white matter lesions. <h3>Background:</h3> Previous studies reported that rare <i>NOTCH3</i> variants were identified in over 10% of the general population and the carriers have a susceptibility to heavy SVD burden. The correlating imaging characteristics deserve in-depth investigation to uncover the important genetic predisposition in age-related SVD in the general population. <h3>Design/Methods:</h3> Rare <i>NOTCH3</i> variants were identified through Whole-Exome Sequencing. The White matter hyperintensities (WMH) volume and WMH probability maps were assessed through quantitative segmentation. Brain structural volumes and vertex-wise cortex maps were obtained from the longitudinal FreeSurfer analysis suite. Between-group differences were compared through data statistical analysis of global measurements, and voxel/vertex-wise analysis of WMH maps or cortex maps. <h3>Results:</h3> A total of 1054 patients were included in the baseline analysis (13.56% rare <i>NOTCH3</i> variant carriers), while 661 included in the longitudinal analysis (13.76% rare <i>NOTCH3</i> variant carriers). We found that rare <i>NOTCH3</i> variant carriers had heavier WMH burden (1.65 vs 0.85ml, P=0.025) and more presence of lacunes (23.78% vs 14.84, P=0.010). More importantly, rare <i>NOTCH3</i> variant carriers had a distinct WMH distribution and progression pattern in periventricular areas. These features appeared more prominent in the EGFr-involving subgroup. Also, we found that rare <i>NOTCH3</i> variant carriers showed susceptibility to worse cortical atrophy (β=−0.004, SE=0.002, adjusted for age and sex). Of most interest, the progressing of frontal brain atrophy is related to WMH progression, which indicated the role of rare <i>NOTCH3</i> variant in age-related SVD and a structural network disconnection phenomenon. <h3>Conclusions:</h3> Our findings posed a distinct MRI profile of age-related SVD in rare <i>NOTCH3</i> variant carriers and shed new light on the pathogenic mechanisms of rare <i>NOTCH3</i> SNPs. <b>Disclosure:</b> Zi-Yue Liu has nothing to disclose. Feifei Zhai has nothing to disclose. Jing-Yi Liu has nothing to disclose. Yi-Jun Zhou has nothing to disclose. Mei-jun Shu has nothing to disclose. Xiaohong Huang has nothing to disclose. Fei Han has nothing to disclose. Mingli Li has nothing to disclose. Lixin Zhou has nothing to disclose. Jun Ni has nothing to disclose. Ming Yao has nothing to disclose. Shuyang Zhang has nothing to disclose. Liying Cui has nothing to disclose. Zhengyu Jin has nothing to disclose. Yi-Cheng Zhu has nothing to disclose.

Symmetric Volume Maps: Order-invariant Volumetric Mesh Correspondence with Free Boundary

Although shape correspondence is a central problem in geometry processing, most methods for this task apply only to two-dimensional surfaces. The neglected task of volumetric correspondence—a natural extension relevant to shapes extracted from simulation, medical imaging, and volume rendering—presents unique challenges that do not appear in the two-dimensional case. In this work, we propose a method for mapping between volumes represented as tetrahedral meshes. Our formulation minimizes a distortion energy designed to extract maps symmetrically, i.e., without dependence on the ordering of the source and target domains. We accompany our method with theoretical discussion describing the consequences of this symmetry assumption, leading us to select a symmetrized ARAP energy that favors isometric correspondences. Our final formulation optimizes for near-isometry while matching the boundary. We demonstrate our method on a diverse geometric dataset, producing low-distortion matchings that align closely to the boundary.