Combined Resonance Research Articles

Intranasal oxytocin modulates brain responses to voice-identity recognition in typically developing individuals, but not in ASD

Faces and voices are prominent cues for person-identity recognition. Face recognition behavior and associated brain responses can be enhanced by intranasal administration of oxytocin. It is unknown whether oxytocin can also augment voice-identity recognition mechanisms. To find it out is particularly relevant for individuals who have difficulties recognizing voice identity such as individuals diagnosed with autism spectrum disorder (ASD). We conducted a combined behavioral and functional magnetic resonance imaging (fMRI) study to investigate voice-identity recognition following intranasal administration of oxytocin or placebo in a group of adults diagnosed with ASD (full-scale intelligence quotient > 85) and pairwise-matched typically developing (TD) controls. A single dose of 24 IU oxytocin was administered in a randomized, double-blind, placebo-controlled and cross-over design. In the control group, but not in the ASD group, administration of oxytocin compared to placebo increased responses to recognition of voice identity in contrast to speech in the right posterior superior temporal sulcus/gyrus (pSTS/G) — a region implicated in the perceptual analysis of voice-identity information. In the ASD group, the right pSTS/G responses were positively correlated with voice-identity recognition accuracy in the oxytocin condition, but not in the placebo condition. Oxytocin did not improve voice-identity recognition performance at the group level. The ASD compared to the control group had lower right pSTS/G responses to voice-identity recognition. Since ASD is known to have atypical pSTS/G, the results indicate that the potential of intranasal oxytocin to enhance mechanisms for voice-identity recognition might be variable and dependent on the functional integrity of this brain region.

Enhanced nonlinear energy harvesting using combined primary and parametric resonances: Experiments with theoretical verifications

Presented in this paper is harvested nonlinear energy from a vibration energy harvester device; the device has been designed, manufactured, and tested successfully – the device performance is verified theoretically to some extent. The design concept is on the basis of merging the nonlinearities of the building block (i.e. a beam) and those induced by the motion limiters, which for some design parameters leads to the combination of parametric and primary resonances of the device; these two resonances increase the operational frequency bandwidth by 118%. By introducing motion limiters to the proposed system, the overall frequency bandwidth of the primary and parametric resonances is able to be broadened even more -- up to 178%. By varying the angle between the base (ambient) excitation and the length of the core element; the optimal angle for the largest possible frequency bandwidth is obtained. Theoretical investigations including the finite element method (FEM) using ANSYS and an averaging perturbation technique have been performed to verify the experimental results for few cases. An experimental parametric study on the performance of the device has also been conducted to highlight the limiter gap and type as well as orientation angle effects.

Disrupted Coupling Between NAA and Functional Connectivity in Ventromedial Prefrontal Cortex of Drug-Naïve First-Episode Psychosis.

Ventromedial prefrontal cortex (vmPFC) is an important brain region involved in many psychological functions. Previous neuroimaging studies have shown disrupted function and altered metabolic level within vmPFC of schizophrenia (SCZ) patients. However, the linkage between the functional connectivity and its underlying neurobiological mechanism in SCZ remains unclear. In this study, we aimed to investigate the altered relationship between the functional connectivity strength (FCS) and metabolic concentrations within vmPFC in drug-naïve first-episode psychosis (FEP) patients using a combined functional magnetic resonance imaging (fMRI) and single-voxel proton magnetic resonance spectroscopy (1H- MRS) technique. There were 26 drug-naïve FEP patients and 27 matched healthy controls participated this study. We have found altered correlation between FCS and N-acetylaspartate (NAA) in drug-naïve FEP patients. In addition, the glutamate and glutamine compounds (Glx) and NAA concentrations were positively correlated with Positive and Negative Symptoms Scale (PANSS) total scores. Our findings revealed the disrupted functional-metabolic coupling within vmPFC in drug-naïve FEP patients and provided useful insights in understanding the etiology of SCZ.

Nonlinear Parametric Vibration of the Geometrically Imperfect Pipe Conveying Pulsating Fluid

In this paper, the novel model of fluid-conveying imperfect pipe supported at both ends is established by considering the geometric imperfection and the geometric nonlinearity induced by mid-plane stretching. The integral-partial differential equation is discretized by the Galerkin method and solved by a fourth-order Runge–Kutta integration algorithm. Compared with the supercritical pitchfork bifurcation of the perfect pipe conveying fluid, the results show that the cusp bifurcation occurs in the imperfect pipe when increasing the flow velocity. Excellent agreement is observed between the numerical results and the analytical results. The two stable asymmetry bifurcation branches bring interesting phenomena in the post-buckling state. The global nonlinear dynamic behaviors of the imperfect pipe are studied by establishing the bifurcation diagrams. The influence of the geometric imperfection amplitude on the nonlinear response is leading to cusp bifurcation comparing with pitchfork bifurcation of the perfect pipe. When pulsation frequency is set as the bifurcation parameter, there are clear nonresonance ranges, low energy resonance ranges and high energy resonance ranges. In the high energy resonance ranges, the first mode vibration coexisting with the sub-harmonic resonance and combination resonance occurs. As the mean flow velocity and pulsation amplitude are set as bifurcation parameters, the vibration of the imperfect pipe becomes more and more complicated. The vibration exhibits far richer dynamic behaviors including periodic, multi-periodic, quasi-periodic, and chaotic motions. The viscoelastic damping can effectively suppress the vibration response and transfer the high energy resonance to the low energy resonance state. The improved model and corresponding results provide useful information for further studying the dynamic behaviors of fluid-conveying pipe with geometric imperfections.

Biomarkers and antithrombotic treatment in cervical artery dissection - Design of the TREAT-CAD randomised trial.

The type of antithrombotic treatment in cervical artery dissection patients is still a matter of debate. Most physicians prefer anticoagulants over antiplatelet agents for stroke prevention. However, this approach is not evidence-based and antiplatelets might be as safe and as effective. The 'Biomarkers and Antithrombotic Treatment in Cervical Artery Dissection' ('TREAT-CAD') trial (clinicaltrials.gov: NCT02046460) compares Aspirin to oral anticoagulants (vitamin K antagonists) with regard to efficacy and safety by using both clinical and imaging surrogate outcome measures. TREAT-CAD tests the hypothesis, that aspirin is as safe and effective as vitamin K antagonists. TREAD-CAD is a Prospective, Randomised controlled, Open-labelled, multicentre, non-inferiority trial with Blinded assessment of outcome Events (PROBE-design). Key eligibility criteria are (i) clinical symptoms attributable to cervical artery dissection and (ii) verification of the cervical artery dissection diagnosis by established magnetic resonance imaging criteria. Patients are randomised to receive either Aspirin 300 mg daily or vitamin K antagonists for 90 days. Primary outcomes are assessed at 14 ± 10 days (magnetic resonance imaging and clinical examination) and at 90 ± 30 days (clinical examinations). The primary endpoint is a composite outcome measure - labelled Cerebrovascular Ischemia, major Hemorrhagic events or Death (CIHD) - and includes (i) occurrence of any stroke (including retinal infarction), (ii) new ischaemic lesions on diffusion-weighted magnetic resonance imaging, (iii) any major extracranial haemorrhage, (iv) any symptomatic intracranial haemorrhage, (v) any new haemorrhagic lesion visible on paramagnetic-susceptible sequences and (vi) death. After database closure, (i) central verification of cervical artery dissection diagnosis will be done by two experienced raters, (ii) adjudication of outcome events will be performed by independent adjudication committees, separately for clinical and imaging outcomes. The primary analysis will be done on the per protocol data set. The targeted sample size consists of 169 evaluable patients in the per protocol data set. TREAT-CAD is testing the non-inferiority of Aspirin versus vitamin K antagonists treatment in patients with symptomatic cervical artery dissection by combined clinical and magnetic resonance imaging outcomes.

Quantitative Analysis of Doping-Induced Polarons and Charge-Transfer Complexes of Poly(3-hexylthiophene) in Solution.

The mechanism and the nature of the species formed by molecular doping of the model polymer poly(3-hexylthiophene) (P3HT) in its regioregular (rre-) and regiorandom (rra-) forms in solution are investigated for three different dopants: the prototypical π-electron acceptor 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane (F4TCNQ), the strong Lewis acid tris(pentafluorophenyl)borane (BCF), and the strongly oxidizing complex molybdenum tris[1-(methoxycarbonyl)-2-(trifluoromethyl)ethane-1,2-dithiolene] (Mo(tfd-CO2Me)3). In a combined optical and electron paramagnetic resonance study, we show that the doping of rreP3HT in solution occurs by integer charge transfer, resulting in formation of P3HT radical cations (polarons) for all of the dopants considered here. Remarkably, despite the different chemical nature of the dopants and dopant-polymer interaction, the formed polarons exhibit essentially identical optical absorption spectra. The situation is very different for the doping of rraP3HT, where we observe formation of a charge-transfer complex with F4TCNQ and of a "localized" P3HT polaron on nonaggregated chains upon doping with BCF, while there is no indication of dopant-induced species in the case of Mo(tfd-CO2Me)3. We estimate the ionization efficiency of the respective dopants for the two polymers in solution and report the molar extinction coefficient spectra of the three different species. Finally, we observe increased spin delocalization in regioregular compared to regiorandom P3HT by electron nuclear double resonance, suggesting that the ability of the charge to delocalize on aggregates of planarized polymer backbones plays a significant role in determining the doping mechanism.

Highlights of Selected Articles July 2020.

Highlights of Selected Articles July 2020.

Arterial culprit plaque characteristics revealed by magnetic resonance Vessel Wall imaging in patients with single or multiple infarcts

PurposeTo investigate characteristics of intra- and extracranial arterial culprit plaques between patients with single infarct and multiple-infarcts by a head-neck combined high resolution magnetic resonance vessel wall imaging (HR-MRVWI). Materials and methodsForty-three patients with recent ischemic stroke due to large artery atherosclerosis were enrolled. The head-neck combined HR-MRVWI was performed in all patients both pre- and post-contrast administration. Based on diffusion weighted imaging findings, patients were divided into single-infarction and multiple-infarction groups. For patients with anterior circulation ischemic stroke, they were also divided into perforating artery infarction (PAI) and non-PAI groups. Patient demographics, number and location of culprit plaques, artery stenosis percentage, intraplaque hemorrhage, and plaque enhancement were evaluated and compared between single-infarction and multiple-infarction groups, as well as between PAI and non-PAI groups. ResultsA total of 83 culprit plaques were identified. The artery stenosis degree was more severe and plaque enhancement more prominent in multiple-infarction group than in single-infarction group. Patients with multiple infarcts also had more culprit plaques per patient than those with single infarct, which contributed to the occurrence of multiple infarcts. For comparison of PAI and non-PAI groups, a higher artery stenosis percentage was observed in non-PAI group, and patients with non-PAI had more culprit plaques per patient, which contributed to a variety of infarct manifestations. ConclusionA higher stenosis grade and higher number of culprit plaques seem to be associated with a higher number of cerebral infarcts in patients with large artery atherosclerosis.

317-OR: Assessing Sarcopenia in T2D: Results from the Large UK Biobank Imaging Study

Background: A recent study on UK Biobank showed today’s sarcopenia definitions (using functional measures and muscle quantity) are highly BMI dependent and consequently underestimates sarcopenia within obesity. As obesity is common in T2D, this should also affect sarcopenia diagnosis and management in T2D patients. In addition, combined magnetic resonance imaging (MRI) based muscle assessment including sex and body size adjusted fat-free muscle volume (FFMV) and muscle fat infiltration (MFI) showed high diagnostic performance for detecting individuals with low function across BMI classes. Methods: 9724 participants were included. Prevalence of low functional performance and sarcopenia was assessed using hand grip strength, dual energy X-ray absorptiometry and questionnaire data in T2D (N=434) and controls (N=9154 without diabetes). FFMV and MFI were quantified using MRI. For each participant, a matched virtual control group (VCG) was created to calculate an individualized z-score (sex and body size specific) for FFMV (FFMVVCG). Adverse muscle composition was defined as low FFMVVCG (below 25th percentile, whole cohort) and high MFI (above 75th percentile (sex specific), whole cohort). Results: Although prevalence of sarcopenia was not different comparing T2D to controls (3.5 vs. 2.4 %, p=0.24), prevalence of low functional performance was higher in T2D: low hand grip strength 10.6 vs. 6.1 %, slow walking pace 14.8 vs. 3.9 %, no stair climbing 11.8 vs. 7.7 %, more than one fall last year 8.1 vs. 4.7 %, (all p<.003). FFMVVCG was lower, mean -0.31 (SD 1.03) vs. 0.02 (0.98) SDs from sex and body size matched reference VCG, MFI higher 8.62 (2.37) vs. 7.34 (1.81) % (1.66 (2.24) pp from sex matched reference) and adverse muscle composition more common in T2D (26.0 vs. 9.5 %) (all p<.001). Conclusion: Sarcopenia related problems were much more common in T2D as compared to controls. This was not reflected in higher prevalence of sarcopenia within T2D but more accurately described using MRI-based muscle composition. Disclosure J. Linge: Employee; Self; AMRA Medical. O. Dahlqvist Leinhard: Employee; Self; AMRA Medical. Stock/Shareholder; Self; AMRA Medical.

LC-QTOF-MS and 1H NMR Metabolomics Verifies Potential Use of Greater Omentum for Klebsiella pneumoniae Biofilm Eradication in Rats.

Bacterial wound infections are a common problem associated with surgical interventions. In particular, biofilm-forming bacteria are hard to eradicate, and alternative methods of treatment based on covering wounds with vascularized flaps of tissue are being developed. The greater omentum is a complex organ covering the intestines in the abdomen, which support wound recovery following surgical procedures and exhibit natural antimicrobial activity that could improve biofilm eradication. We investigated changes in rats’ metabolome following Klebsiella pneumoniae infections, as well as the greater omentum’s ability for Klebsiella pneumoniae biofilm eradication. Rats received either sterile implants or implants covered with Klebsiella pneumoniae biofilm (placed in the peritoneum or greater omentum). Metabolic profiles were monitored at days 0, 2, and 5 after surgery using combined proton nuclear magnetic resonance (1H NMR) and high performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (LC–QTOF-MS) measurements of urine samples followed by chemometric analysis. Obtained results indicated that grafting of the sterile implant to the greater omentum did not cause major disturbances in rats’ metabolism, whereas the sterile implant located in the peritoneum triggered metabolic perturbations related to tricarboxylic acid (TCA) cycle, as well as choline, tryptophan, and hippurate metabolism. Presence of implants colonized with Klebsiella pneumoniae biofilm resulted in similar levels of metabolic perturbations in both locations. Our findings confirmed that surgical procedures utilizing the greater omentum may have a practical use in wound healing and tissue regeneration in the future.

Multi-Modal PET and MR Imaging in the Hen’s Egg Test-Chorioallantoic Membrane (HET-CAM) Model for Initial In Vivo Testing of Target-Specific Radioligands

The validation of novel target-specific radioligands requires animal experiments mostly using mice with xenografts. A pre-selection based on a simpler in vivo model would allow to reduce the number of animal experiments, in accordance with the 3Rs principles (reduction, replacement, refinement). In this respect, the chick embryo or hen’s egg test–chorioallantoic membrane (HET-CAM) model is of special interest, as it is not considered an animal until day 17. Thus, we evaluated the feasibility of quantitative analysis of target-specific radiotracer accumulation in xenografts using the HET-CAM model and combined positron emission tomography (PET) and magnetic resonance imaging (MRI). For proof-of-principle we used established prostate-specific membrane antigen (PSMA)-positive and PSMA-negative prostate cancer xenografts and the clinically widely used PSMA-specific PET-tracer [68Ga]Ga-PSMA-11. Tracer accumulation was quantified by PET and tumor volumes measured with MRI (n = 42). Moreover, gamma-counter analysis of radiotracer accumulation was done ex-vivo. A three- to five-fold higher ligand accumulation in the PSMA-positive tumors compared to the PSMA-negative tumors was demonstrated. This proof-of-principle study shows the general feasibility of the HET-CAM xenograft model for target-specific imaging with PET and MRI. The ultimate value for characterization of novel target-specific radioligands now has to be validated in comparison to mouse xenograft experiments.

Early exit from neonatal therapeutic hypothermia: A single institution experience using MRI to guide decision-making.

To evaluate the feasibility of a protocol using combined magnetic resonance imaging (MRI), clinical data, and electroencephalogram (EEG) to identify neonates with mild neonatal encephalopathy (NE) treated with therapeutic hypothermia (TH) who are eligible for "early exit". Retrospective chart review of TH cases at a single Level III NICU over a 5-year period was used to describe the demographic, clinical, and outcome data in neonates that received early exit in contrast to 72 hour TH treatment. Two hundred and eight TH cases, including 18 early exit cases (9%) and 9 cases (4%) evaluated for early exit with MRI but continued on 72 hours of TH, were identified. Early exit and 72 hour treatment groups did not differ in demographics or cord gas measures, although early exit neonates had a shorter length of stay (p < 0.05). Consistent with the early exit protocol, no early exit infants had evidence of moderate or severe encephalopathy on EEG or evidence of hypoxic ischemic injury on MRI at 24 hours of life. Neurology follow up between age 1 and 18 months was available for 10 early exit infants, 8 of whom had a normal examination. Early MRI at 24 hours of age, alongside clinical and EEG criteria, is feasible as part of a protocol to identify neonates eligible for early exit from therapeutic hypothermia.

Subharmonic and Combination Resonance of Rotating Pre-deformed Blades Subjected to High Gas Pressure

The present paper deals with the investigation of dynamic responses of a rotating pre-deformed blade in four cases of resonance, including two subharmonic resonances and two combination resonances. The dimensionless gas excitation amplitude is assumed to share the same order with the dimensionless vibration displacement. Four cases of resonance are confirmed by examining the secular terms. The theoretical analysis framework is established for each resonance case based on the method of multiple scales. The original dynamic system is integrated numerically by the Runge–Kutta method. The frequency components and phases obtained from fast Fourier transform of the numerical response are used to verify the theoretical results. For the purpose of contrast, modulation equations are also integrated numerically. In all four resonance cases, the theoretical results agree well with the numerical simulation. Parameter studies are conducted to clarify the effects of system parameters on the perturbation curves. Various results are obtained for the rotating blade. A quasi-saturation phenomenon occurs in both combination resonances of summed type and difference type, and the corresponding limit value of the second-mode response can be reduced by decreasing the external detuning parameter. The quasi-saturation phenomenon of rotating blade only appears with high gas pressure. The subharmonic resonance of second mode and the combination resonance of summed type are hard to excite in practice compared with the other two cases.

Hippocampal Dysconnectivity and Altered Glutamatergic Modulation of the Default Mode Network: A Combined Resting-State Connectivity and Magnetic Resonance Spectroscopy Study in Schizophrenia

BackgroundConverging lines of evidence point to hippocampal dysfunction in schizophrenia. It is thought that hippocampal dysfunction spreads across hippocampal subfields and to cortical regions by way of long-range efferent projections. Importantly, abnormalities in the excitation/inhibition balance could impair the long-range modulation of neural networks. The goal of this project was twofold. First, we sought to identify replicable patterns of hippocampal dysconnectivity in patients with a psychosis spectrum disorder. Second, we aimed to investigate a putative link between glutamatergic metabolism and hippocampal connectivity alterations. MethodsWe evaluated resting-state hippocampal functional connectivity alterations in two cohorts of patients with a psychosis spectrum disorder. The first cohort consisted of 55 medication-naïve patients with first-episode psychosis and 41 matched healthy control subjects, and the second cohort consisted of 42 unmedicated patients with schizophrenia and 41 matched control subjects. We also acquired measurements of glutamate + glutamine in the left hippocampus using magnetic resonance spectroscopy for 42 patients with first-episode psychosis and 37 healthy control subjects from our first cohort. ResultsWe observed a pattern of hippocampal functional hypoconnectivity to regions of the default mode network and hyperconnectivity to the lateral occipital cortex in both cohorts. We also show that in healthy control subjects, greater hippocampal glutamate + glutamine levels predicted greater hippocampal functional connectivity to the anterior default mode network. Furthermore, this relationship was reversed in medication-naïve subjects with first-episode psychosis. ConclusionsThese results suggest that an alteration in the relationship between glutamate and functional connectivity may disrupt the dynamic of major neural networks.

Modulation of the longitudinal pumping in quantum spin systems

The effect of the modulation of a high-frequency ac magnetic field parallel to the dc one (longitudinal pumping) by the lower-frequency ac field acting on quantum spin systems is considered for closed and open systems. For most magnetically ordered spin systems, the modulation causes the oscillation of the threshold of the parametric instability of spin waves as a function of the amplitude and the frequency of the modulation. On the other hand, our results for quantum spin systems with fermionic eigenstates imply that the modulating field causes the combined resonance and the modulation of the magnitude of time-dependent oscillations of the magnetization and the absorbed by the system power of the ac field for the closed system and for the open system in the dynamical and the steady-state regimes.

Aeroelastic responses of airfoil under dynamic stall forced to oscillate by cyclic pitch input

The helicopter blades are involved in a nonlinear aeroelastic system in which unsteady dynamic stall flow and flexible structure are coupled. This problem can be reduced to a 2D aeroelastic problem in which airfoil is forced to oscillate through cyclic pitch input. In this paper, a modified dynamic stall model which focuses on revising the modeling of aerodynamic loads in reattachment stage is adopted in the numerical simulation to predict the aeroelastic responses of the above-mentioned system. The results are validated against experiments, after which parametric studies are performed to investigate the complex aeroelastic responses. In single Degree-Of-Freedom (DOF) system, secondary resonances happen in specific ratios of natural frequency to forcing frequency, which are found in both experiments and simulation. Moreover, as free-stream velocity varies, the aerodynamic stiffness has an apparent influence on the pitching natural frequency of system with low structural frequency. The varying pitching natural frequency brings about different aeroelastic responses including 1/2 subharmonic resonances and quenching phenomenon in single-DOF system as well as internal resonances and combination resonances in 2-DOF system. The aeroelastic system with low structural frequency is further investigated through multiple scale method, which provides an illustration for the mechanism of those phenomena found in the aeroelastic simulation adopting a semi-empirical aerodynamic model.

Whole-Body Atherosclerosis Imaging by Positron Emission Tomography/Magnetic Resonance Imaging: From Mice to Nonhuman Primates.

Cardiovascular disease due to atherosclerosis is still the main cause of morbidity and mortality worldwide. This disease is a complex systemic disorder arising from a network of pathological processes within the arterial vessel wall, and, outside of the vasculature, in the hematopoietic system and organs involved in metabolism. Recent years have seen tremendous efforts in the development and validation of quantitative imaging technologies for the noninvasive evaluation of patients with atherosclerotic cardiovascular disease. Specifically, the advent of combined positron emission tomography and magnetic resonance imaging scanners has opened new exciting opportunities in cardiovascular imaging. In this review, we will describe how combined positron emission tomography/magnetic resonance imaging scanners can be leveraged to evaluate atherosclerotic cardiovascular disease at the whole-body level, with specific focus on preclinical animal models of disease, from mouse to nonhuman primates. We will broadly describe 3 major areas of application: (1) vascular imaging, for advanced atherosclerotic plaque phenotyping and evaluation of novel imaging tracers or therapeutic interventions; (2) assessment of the ischemic heart and brain; and (3) whole-body imaging of the hematopoietic system. Finally, we will provide insights on potential novel technical developments which may further increase the relevance of integrated positron emission tomography/magnetic resonance imaging in preclinical atherosclerosis studies.

Diagnostic yield of the combined Magnetic Resonance Imaging and Magnetic Resonance Spectroscopy to predict malignant brain tumor

Introduction: Brain tumor is a neoplasm originating from various type of intracranial tissue. Histopathology is the gold standard to diagnose brain tumor. However, due to its invasive nature, the biopsy procedure poses a substantial risk. Therefore, advanced imaging, such as conventional Magnetic Resonance Imaging (MRI) and Magnetic Resonance Spectroscopy (MRS), has been widely developed to determine brain tumor type. Conventional MRI has been a routine examination for a suspected brain tumor in Indonesia, and with the utilization of MRS, could theoretically improve the diagnostic yield. This study aims to find diagnostic properties of conventional MRI, Choline/Creatine and Choline/NAA ratio extracted from MRS, and as a combined parameter to differentiate brain tumor type.Methods: This cross-sectional study involved 52 patients who underwent conventional MRI, MRS, and histopathology examination for a suspected brain tumor. The cut-off from Dean Criteria of conventional MRI, Choline/Creatine and Choline/NAA ratio to classify tumor type was determined from the ROC curve and then the diagnostic parameters were calculated from cross-tabulation. Also, a novel approach was made with logical-mathematical equation (disjunction/ ˅ / “or” and conjunction/ ˄ / “and”) to combined parameter obtained from MRI and MRS to predict histopathological brain tumor type.Results: Conventional MRI combined with MRS improve diagnostic yield compared to a single parameter with a sensitivity of 87.5%, a specificity of 88.6%, accuracy of 88.5%, PPV of 58.3%, NPV of 97.5%, LR+ of 7.68, dan LR- of 0.1.Conclusion: Combination of conventional MRI and MRS parameter could improve the diagnostic yield in differentiating the type of brain tumor.

Human Melanoma-Cell Metabolic Profiling: Identification of Novel Biomarkers Indicating Metastasis.

Melanoma is the most aggressive type of skin cancer, leading to metabolic rewiring and enhancement of metastatic transformation. Efforts to improve its early and accurate diagnosis are largely based on preclinical models and especially cell lines. Hence, we herein present a combinational Nuclear Magnetic Resonance (NMR)- and Ultra High Performance Liquid Chromatography-High-Resolution Tandem Mass Spectrometry (UHPLC-HRMS/MS)-mediated untargeted metabolomic profiling of melanoma cells, to landscape metabolic alterations likely controlling metastasis. The cell lines WM115 and WM2664, which belong to the same patient, were examined, with WM115 being derived from a primary, pre-metastatic, tumor and WM2664 clonally expanded from lymph-node metastases. Metabolite samples were analyzed using NMR and UHPLC-HRMS. Multivariate statistical analysis of high resolution NMR and MS (positive and negative ionization) results was performed by Principal Component Analysis (PCA), Partial Least Squares-Discriminant Analysis (PLS-DA) and Orthogonal Partial Least Squares-Discriminant Analysis (OPLS-DA), while metastasis-related biomarkers were determined on the basis of VIP lists, S-plots and Student’s t-tests. Receiver Operating Characteristic (ROC) curves of NMR and MS data revealed significantly differentiated metabolite profiles for each cell line, with WM115 being mainly characterized by upregulated levels of phosphocholine, choline, guanosine and inosine. Interestingly, WM2664 showed notably increased contents of hypoxanthine, myo-inositol, glutamic acid, organic acids, purines, pyrimidines, AMP, ADP, ATP and UDP(s), thus indicating the critical roles of purine, pyrimidine and amino acid metabolism during human melanoma metastasis.

Accuracy of combined quantitative diffusion-weighted MRI and routine contrast-enhanced MRI in discrimination of benign and malignant salivary gland tumors.

Preoperative imaging of salivary gland tumors is important for predicting and differentiating benign from malignant tumors, and for aiding management planning. We aimed to investigate the accuracy of combined quantitative diffusion-weighted magnetic resonance imaging (MRI) and routine contrast-enhanced MRI in the evaluation of salivary gland tumors and the differentiation of benign from malignant tumors. This study included 51 patients with a total of 16 benign and 35 malignant lesions that were detected by histopathological analysis. There was a statistically significant difference between the apparent diffusion coefficient values (ADC) of malignant and benign lesions (0.69 ± 0.22 × 10-3 mm2/s and 1.39 ± 0.52 × 10-3 mm2/s respectively). The optimal cut-off ADC value was 1.08 with 75% specificity and 97% sensitivity. The routine contrast-enhanced MRI had predicted benign and malignant tumors with 65% sensitivity and 44% specificity. The sensitivity and specificity were greatly increased when quantitative diffusion-weighted MRI was combined with routine contrast-enhanced MRI: 100%, and 88% respectively. A receiver operating curve was generated. The area under curve was 0.88 (p < 0.001, 95% CI: 0.76-0.99). Combined quantitative diffusion-weighted MRI with ADC measurements and routine contrast-enhanced magnetic resonance imaging are helpful tools for the evaluation of salivary gland tumors and help differentiate benign from malignant lesions.