Magnetic Resonance Imaging Contrast Research Articles

Deep Radiogenomics Sequencing for Breast Tumor Gene-Phenotype Decoding Using Dynamic Contrast Magnetic Resonance Imaging

Abstract Purpose We aim to perform radiogenomic profiling of breast cancer tumors using dynamic contrast magnetic resonance imaging (MRI) for the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) genes. Methods The dataset used in the current study consists of imaging data of 922 biopsy-confirmed invasive breast cancer patients with ER, PR, and HER2 gene mutation status. Breast MR images, including a T1-weighted pre-contrast sequence and three post-contrast sequences, were enrolled for analysis. All images were corrected using N4 bias correction algorithms. Based on all images and tumor masks, a bounding box of 128 × 128 × 68 was chosen to include all tumor regions. All networks were implemented in 3D fashion with input sizes of 128 × 128 × 68, and four images were input to each network for multi-channel analysis. Data were randomly split into train/validation (80%) and test set (20%) with stratification in class (patient-wise), and all metrics were reported in 20% of the untouched test dataset. Results For ER prediction, SEResNet50 achieved an AUC mean of 0.695 (CI95%: 0.610–0.775), a sensitivity of 0.564, and a specificity of 0.787. For PR prediction, ResNet34 achieved an AUC mean of 0.658 (95% CI: 0.573–0.741), a sensitivity of 0.593, and a specificity of 0.734. For HER2 prediction, SEResNext101 achieved an AUC mean of 0.698 (95% CI: 0.560–0.822), a sensitivity of 0.750, and a specificity of 0.625. Conclusion The current study demonstrated the feasibility of imaging gene-phenotype decoding in breast tumors using MR images and deep learning algorithms with moderate performance.

Innovative perspectives on metal free contrast agents for MRI: Enhancing imaging efficacy, and AI-driven future diagnostics.

The U.S. Food and Drug Administration (FDA) has issued a boxed warning and mandated additional safety measures for all gadolinium-based contrast agents (GBCAs) used in clinical magnetic resonance imaging (MRI) due to their prolonged retention in the body and associated adverse health effects. This review explores recent advancements in CAs for MRI, highlighting four innovative probes: ORCAs, CEST CAs, 19F CAs, and HP 13C MRI. ORCAs offer a metal-free alternative that enhances imaging through nitroxides. CEST MRI facilitates the direct detection of specific molecules via proton exchange, aiding in disease diagnosis and metabolic assessment. 19F MRI CAs identify subtle biological changes, enabling earlier detection and tailored treatment approaches. HP 13C MRI improves visualization of metabolic processes, demonstrating potential in cancer diagnosis and monitoring. Finally, this review concludes by addressing the challenges facing the field and outlining future research directions, with a particular focus on leveraging artificial intelligence to enhance diagnostic capabilities and optimize both the performance and safety profiles of these innovative CAs. STATEMENT OF SIGNIFICANCE: The review addresses the urgent need for safer MRI contrast agents in light of FDA warnings about GBCAs. It highlights the key factors influencing the stability and functionality of metal-free CAs and recent advancements in designing ORCAs, CEST CAs, 19F CAs, and HP 13C probes and functionalization that enhance MRI contrast. It also explores the potential of these agents for multimodal imaging and targeted diagnostics while outlining future research directions and the integration of artificial intelligence to optimize their clinical application and safety. This contribution is pivotal for driving innovation in MRI technology and improving patient outcomes in disease detection and monitoring.

2D manganese-doped calcium carbonate nanosheets as activable MRI/US imaging Guided enhanced calcium influx for Boosted regulatory cell death

Calcium ion (Ca2+) overload therapy has emerged as a promising approach for regulating mitochondrial functions and inducing immunogenic cell death. However, the limited intramitochondrial Ca2+ levels and immunosuppressive microenvironment significantly hamper its therapeutic efficacy. Herein, we present polyethylene glycol (PEG)-modified 2D manganese-doped calcium carbonate nanosheets (MnCaCP NSs) to improve Ca2+ overload efficacy through increasing the intramitochondrial Ca2+ levels and triggering obvious immunogenic response. The high surface area of MnCaCP NSs facilitates the rapid release of Ca2+ in the mildly acidic tumor microenvironment and quickly elevates intramitochondrial Ca2+ levels in tumor cells. The accompanying released Mn2+ and CO2 disrupted the calcium buffer system of tumor cells by interfering with the oxidative stress and mitochondrial dysfunction, significantly elevating Ca2+ levels and enhancing Ca2+ overload efficacy. We discovered that the increased Ca2+ levels and released Mn2+ activated regulated cell death (RCD) and stimulated the cGAS-STING pathway, transforming tumor tissue from immunosuppressive to immunostimulatory and inhibiting metastasis. Additionally, the tumor micronenvironment-responsive release of Mn2+ and CO2 enables MnCaCP NSs to act as activable magnetic resonance imaging (MRI) and ultrasound (US) contrast agents, allowing for real-time monitoring of therapeutic efficacy. This versatile intelligent nanomedicine integrates controllability, specificity and safety, positioning it as a promising candidate for precision cancer therapy.

Magnetic nanoparticle-mediated non-invasive imaging and eradication of lymph nodes.

Regional lymph node (LN) dissection is often used for the treatment of deep LNs in tumour surgery; however, the method is prone to incomplete LN dissection, trauma, complications, and other side effects. LN tracers make it easier to visualise and remove LNs. However, the current common LN tracers only have a single function or have radiation hazards related to their use. Therefore, the use of multi-functional LN tracers to improve the efficiency of deep LN eradication and reduce trauma and complications is currently a major challenge to be addressed. This study aimed to develop a multi-functional citrate-coated magnetite nanoparticle (CMNP) that could specifically drain to and accumulate in LNs. The CMNPs can be used as photoacoustic imaging contrast agents and magnetic resonance imaging contrast agents to image LNs. When an alternating magnetic field is applied, the CMNP can generate heat and raise the temperature of LNs, which is sufficient to coagulate and necrotise the LNs, thereby achieving LN inactivation. Eradication of LNs by magnetic hyperthermia is not limited by depth, and only LNs are specifically heated. Moreover, the method is less invasive and accurate for deep LNs.

Research progress of nitroxide radical-based MRI contrast agents: from structure design to application.

Magnetic resonance imaging (MRI) remains a cornerstone of diagnostic imaging, offering unparalleled insights into anatomical structures and pathological conditions. Gadolinium-based contrast agents have long been the standard in MRI enhancement, yet concerns over nephrogenic systemic fibrosis have spurred interest in metal-free alternatives. Nitroxide radical-based MRI contrast agents (NO-CAs) have emerged as promising candidates, leveraging their biocompatibility and imaging capabilities. This review summaries the latest advancements in NO-CAs, focusing on synthesis methodologies, influencing effects of structures of NO-CAs on relaxation efficiency and their applications across various clinical contexts. Comprehensive discussions encompass small molecular, polymeric, and nano-sized NO-CAs, detailing their unique properties and potential clinical utilities. Despite challenges, NO-CAs represent a dynamic area of research poised to revolutionize MRI diagnostics. This review serves as a critical resource for researchers and practitioners seeking to navigate the evolving landscape of MRI contrast agents.

Magnetic chromatography improves colloidal and MRI attributes of magnetoliposomes enabling evaluation of the impact of size on bio-distribution in an in vivo model of pancreatic cancer.

Magnetic chromatography was exploited to fractionate suspensions of magnetoliposomes (SML: lumen-free lipid-encapsulated clusters of multiple magnetic iron-oxide nanoparticles) improving their colloidal properties and relaxivity (magnetic resonance image contrast capability). Fractionation (i) removed sub-populations that do not contribute to the MRI response, and thus (ii) enabled evaluation of the size-dependence of relaxivity for the MRI-active part, which was surprisingly weak in the 55-90 nm range. MC was therefore implemented for processing multiple PEGylated SML types having average sizes ranging from 85 to 105 nm, which were then shown to have strongly size-dependent uptake in an in vivo pancreatic cancer model. Hence for applications in cancer diagnosis, selection of SML of suitable size for the biological target is more important than size-dependence of relaxivity.

Biotin Conjugated Fe(III)-Triscatecholate Complex as Tumour Targeting T1 MRI Contrast Agent via Second Sphere Water Relaxation.

The biotin-conjugated Fe(III) catecholate complex [Fe(BioL)3]3-, Fe(BioL)3 (BioLH2 = N-(3,4-dihydroxyphenethyl)-5-((3aS,4S,6aR)-2-oxohexahydro-1H-thieno[3,4-d]imidazol-4-yl)pentanamide) is reported as targeted magnetic resonance imaging (MRI) contrast agents (CAs) to increase the payload for early-stage imaging of tumours. The high spin state and octahedral coordination of the Fe(III) complex are confirmed by EPR spectra and DFT optimized structure, respectively. The formation constant (-log K) of Fe(BioL)3 is determined as 45, which is higher than the known, more stable complex [Fe(EDTA)]. The complex Fe(BioL)3 exhibited r1 relaxivity of 3.09 ± 0.10 and 1.95 ± 0.09 mM-1 s-1 at 25 °C and 37 °C, respectively, at 1.41T and pH 7.35 via second-sphere water interactions as due to the absence of inner water coordination. The interaction of Fe(BioL)3 with bovine serum albumin (BSA) and human serum albumin (HSA) displayed enhanced relaxivity of 5.16 ± 0.15 and 10.0 ± 0.19 mM-1s-1, respectively, at 25 °C and pH 7.3 possibly via lengthening of rotational correlational time. The complex Fe(BioL)3 uptake studies with the avidin, a biotin-binding protein pocket, showed 46 and 37% enhancements of r1 and r2 relaxivities. Complex Fe(BioL)3 showed 80% cell viability of the human gastric adenocarcinoma (AGS) cells, and 89% of iron has been uptaken into cells.

Delayed Magnetic Resonance Imaging of Alzheimer's Disease by Using Poly(2-(methacryloyloxy)ethyl phosphorylcholine)-Functionalized Nanoprobes.

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases, commonly affecting the aged, with pathophysiological changes presenting 15 to 20 years before clinical symptoms. Early diagnosis and intervention are crucial in effectively slowing the progression of AD. In the current study, poly(2-(methacryloyloxy)ethyl phosphorylcholine) (PMPC)-functionalized NaGdF4 nanoparticles (NaGdF4-PMPC) were developed as magnetic resonance imaging (MRI) contrast agents for targeting alpha 7 nicotinic acetylcholine receptors (α7 nAChRs) in AD mice. NaGdF4-PMPC showed excellent biocompatibility, targeting ability, and MRI performance, with the longitudinal molar relaxivity (r1) and transverse molar relaxivity (r2) being 1.21-fold and 1.33-fold higher than those of the clinical contrast agent Gd-DTPA, respectively, resulting in higher-sensitive MR angiography. After intravenous injection, 3D dynamic contrast-enhanced (DCE) MR images with high-resolution vasculature of the mouse brain were obtained. In addition, by using NaGdF4-PMPC, susceptibility-weighted imaging (SWI) signals in AD mouse brains were greatly retained compared to those in healthy mice for 24 h, emphasizing the excellent targeting ability of NaGdF4-PMPC. Furthermore, the CD31, α7 nAChRs, and Thioflavin S staining were also utilized to investigate the relationship among vascular inflammation, α7 nAChRs, and amyloid-β (Aβ) deposition in AD mice. This work highlights a promising targeted imaging strategy for the timely diagnosis of AD.

Synthesis and Relaxivity study of amino acid-branched radical dendrimers as MRI contrast agents for potential brain tumor imaging.

This study introduces a series of water-soluble radical dendrimers (G0 to G5) as promising magnetic resonance imaging (MRI) contrast agents that could potentially address clinical safety concerns associated with current gadolinium-based contrast agents. By using a simplified synthetic approach based on a cyclotriphosphazene core and lysine-derived branching units, we successfully developed a G5 dendrimer containing up to 192 units of 2,2,6,6-Tetramethylpiperidinyloxy (TEMPO) radical. This synthesis offers advantages including ease of preparation, purification, and tunable water solubility through the incorporation of glutamic acid anion residues. Comprehensive characterization using 1H NMR, FT-IR, and SEC-HPLC confirmed the dendrimers' structures and purity. Electron paramagnetic resonance (EPR) spectroscopy revealed that TEMPO groups in higher generation dendrimers exhibited decreased mobility and stronger spin exchange in their local environments. In vitro MRI showed that relaxivity (r1) increased with higher dendrimer generations, with G5 exhibiting an exceptionally high r1 of over 24 mM-1s-1. Molecular dynamics simulations provided crucial insights into structure-property relationships, revealing the importance of water accessibility to TEMPO groups for enhancing relaxivity. Vero cell viability assay demonstrated G3 and G3.5 have good biocompatibility. In vivo MRI experiments in mice demonstrated that G3.5 was excreted through the kidneys and selectively accumulated in glioblastoma tumors. STATEMENT OF SIGNIFICANCE: This study explores a class of MRI contrast agents based on organic radical dendrimers as a potential alternative to gadolinium-based agents. We present a simplified synthesis method for water-soluble dendrimers containing up to 192 TEMPO radical units-the highest number achieved to date for this class of compounds-resulting in record-high relaxivity values. Our approach offers easier preparation, purification, and tunable water solubility, representing an improvement over existing methods. Through combined experimental and computational studies, we provide insights into the structure-property relationships governing relaxivity. In vivo experiments demonstrate the dendrimers' potential for glioblastoma imaging, with predominantly renal excretion. This work represents a step towards developing metal-free MRI contrast agents with promising relaxivity and biocompatibility, potentially opening new avenues for diagnostic imaging research.

AI-Based Evaluation of Prostate MR Imaging at a Modern Low-field 0.55 T Scanner Compared to 3 T in a Screening Cohort

PurposeTo evaluate the effect of lower field strength on quantitative apparent-diffusion-coefficient (ADC) values, contrast of the T2-weighted MR images and the performance of an AI-based segmentation. Materials and Methods25 screening clients (61.6 ± 7.5 years) from a study on a 3T scanner were included and underwent a second examination on a 0.55T scanner. Axial T2 weighted and diffusion-weighted images (DWI) sequences were acquired. An AI-based segmentation was performed. Based on this, the segmentation, volumetry, ADC values and the ratio of central gland (CG) and peripheral zone (PZ) in T2 weighting were compared by using correlations coefficient (Pearson), Bland–Altman plots and a non-inferior test with a paired t-test and a margin of ±20% (lower and upper boundary). ResultsVolumetric assessment (peripheral zone//central gland) showed no significant (p=0.13//0.38) difference between 3T (mean volume: 14.81 (12.53 – 17.09) // 23.07 (15.06 – 31.08) ml) and 0.55T (mean volume of 14.29 (12.03 – 16.54; p = 0.13) // 22.77 (14.41 – 31.12) ml). The deviation of the 0.55 T ADC values from the 3 T values was -10.14% (-16.09% - -4.18%) for the PZ and -4.68% (-10.12% - 0.76%) for the CG. Therefore, all confidence intervals remained within a margin of +/- 20% and thus demonstrated significant non-inferiority. ConclusionBiparametric prostate imaging is feasible at 0.55 T: ADC values vary within a common inter-scanner range compared to a 3T and no difference can be observed regarding contrast ratio between peripheral zone and central gland in T2 weighted images, volumetry and AI-based segmentation compared to 3T.

FA-PEG Modified ZIF(Mn) Nanoparticles Loaded with Baicalin for Imaging-Guided Treatment of Melanoma in Mice.

Melanoma is an aggressive skin tumor with limited therapeutic options due to rapid proliferation, early metastasis, and poor prognosis. Baicalin (BA), a natural flavonoid, shows promise in inducing ferroptosis and apoptosis but faces challenges of poor solubility and bioavailability. To address these issues, we developed a multifunctional drug delivery system: manganese-doped ZIF-8 nanoparticles (ZIF(Mn)) loaded with BA and modified with folic acid (FA) and polyethylene glycol (PEG). FA targets melanoma cells by exploiting folate receptor overexpression, while PEG enhances biocompatibility and systemic circulation. Manganese enables magnetic resonance (MR) imaging for real-time, non-invasive therapy monitoring. BA-loaded ZIF(Mn)/FA-PEG nanoparticles were synthesized via a one-pot method, enabling drug encapsulation, Mn²+ incorporation, and surface modification. The nanoparticles were comprehensively characterized (particle size, Zeta potential, FTIR, and XRD). Cytotoxicity and cellular uptake were evaluated in B16-F10 melanoma cells, and in vivo experiments in C57BL/6J mice investigated MR imaging capability, antitumor efficacy, and biosafety. BA@ZIF(Mn)/FA-PEG nanoparticles demonstrated excellent stability, a BA loading capacity of 33.50 ± 0.04%, and pH-responsive release, with accelerated drug release under acidic tumor conditions. Mn²+ provided strong T1-weighted MR imaging contrast. Cellular and animal studies showed enhanced uptake, reduced premature drug release, and improved compatibility. Mechanistically, the nanoparticles induced significant ferroptosis and apoptosis in melanoma cells, leading to potent antitumor effects. The BA@ZIF(Mn)/FA-PEG nanoplatform effectively integrates targeted delivery, imaging guidance, and dual ferroptosis-apoptosis induction, offering a promising strategy for improving melanoma treatment outcomes.

Blood-brain barrier breakdown in brain ischemia: Insights from MRI perfusion imaging.

Brain ischemia is a major cause of neurological dysfunction and mortality worldwide. It occurs not only acutely, such as in acute ischemic stroke (AIS), but also in chronic conditions like cerebral small vessel disease (cSVD). Any other conditions resulting in brain hypoperfusion can also lead to ischemia. Ischemic events can cause blood-brain barrier (BBB) disruption and, ultimately, white matter alterations, contributing to neurological deficits and long-term functional impairments. Hence, understanding the mechanisms of BBB breakdown and white matter injury across various ischemic conditions is critical for developing effective interventions and improving patient outcomes. This review discusses the proposed mechanisms of ischemia-related BBB breakdown. Moreover, magnetic resonance imaging (MRI) based perfusion-weighted imaging (PWI) techniques sensitive to BBB permeability changes are described, including dynamic contrast-enhanced (DCE-MRI) and dynamic susceptibility contrast MRI (DSC-MRI), two perfusion-weighted imaging (PWI). These PWI techniques provide valuable insights that improve our understanding of the complex early pathophysiology of brain ischemia, which can lead to better assessment and management. Finally, in this review, we explore the implications of the mentioned neuroimaging findings, which emphasize the potential of neuroimaging biomarkers to guide personalized treatment and inform novel neuroprotective strategies. This review highlights the importance of investigating BBB changes in brain ischemia and the critical role of advanced neuroimaging in improving patient care and advancing stroke research.

A multifunctional nanoplatform capable of dual action on tumor PD-L1 for enhanced cancer theranostics

Due to the large amount of PD-L1 on the surface of tumor cells, antibody drugs can only block a small part of PD-L1, limiting the effectiveness of immunotherapy. Here, a MnS nanocluster grafted with dimeric PD-L1 affibody (ZPD-L1) was developed to double act on PD-L1 of tumor cells. ZPD-L1 can specifically target PD-L1 on the surface of tumor cells, and block the interaction between PD-1 and PD-L1 to a certain extent. In acidic tumor microenvironment, MnS nanoclusters can release Mn2+ and H2S. The released Mn2+ can induce reactive oxygen species (ROS) generation through Fenton-like reaction, and serve as magnetic resonance imaging (MRI) contrast agent for effective therapeutic monitoring. H2S can down-regulate PD-L1 expression of tumor cells by amplifying ROS production to inhibit ATP level. Based on ZPD-L1-mediated PD-1/PD-L1 blocking and ROS-induced downregulation of PD-L1 expression, MnS nanoclusters can achieve dual action on tumor PD-L1, amplify immunogenic cell death, maximize the activation of anti-tumor immune response and inhibit tumor growth.

A Bioinspired Cu2+-Responsive Magnetic Resonance Imaging Contrast Agent with Unprecedented Turn-On Response and Selectivity.

Imaging extracellular Cu2+ in vivo is of paramount interest due to its biological importance in both physiological and pathological states. Magnetic resonance imaging (MRI) is a powerful technique to do so. However, the development of efficient MRI contrast agents selective for Cu2+, particularly versus the more abundant Zn2+ ions, is highly challenging. We present here an innovative Cu2+-responsive MRI contrast agent that contains a bioinspired Cu2+ binding site. This sensor shows a remarkable increase in relaxivity of nearly 400% in the presence of Cu2+, which could be rationalized in terms of an increase in the hydration number of the Ln3+ ion, as demonstrated by spectroscopic and relaxometric studies and supported by density functional theory calculations. Importantly, the system also shows an unprecedented selectivity for Cu2+, in particular over Zn2+. Phantom MRI images were recorded at 9.4 T to highlight the potential of such probes, which lies directly in their bioinspired design.

Utilization of nanomaterials in MRI contrast agents and their role in therapy guided by imaging.

Magnetic Resonance Imaging (MRI) is a globally acknowledged diagnostic procedure particularly recognized for its superior soft tissue contrast, high-resolution imaging, and non-ionizing radiation properties, making it an indispensable tool in the medical field. However, to optimize MRI's sensitivity and specificity towards certain diseases, use of contrast agents becomes necessary. Recent developments focus on nanomaterial-based MRI contrast agents to improve diagnostic accuracy and image quality. This review highlights advancements in such agents, including metal oxide nanoparticles, carbon-based materials, gold nanoparticles, and quantum dots. It discusses their roles in MRI-guided therapies like targeted drug delivery, hyperthermia, radiation therapy, photodynamic therapy, immunity-boosting therapy, and gene therapy. Insights into the future potential of MRI contrast agents in imaging medicine are also provided.

Artificially Engineered Nanoprobes for Ultrasensitive Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) is a noninvasive and radiation-free technique used for soft tissue. However, there are some limitations of the MRI modality, such as low sensitivity and poor image resolution. Artificially engineered magnetic nanoprobes have been extensively explored as a versatile platform for ultrasensitive MRI contrast agents due to their unique physiochemical characteristics and tunable magnetic properties. In this review, the emphasis is on recent progress in MRI nanoprobes with different structures and elements, including gadolinium-, iron-, manganese-based and metal-free nanoprobes. The key influencing factors and advanced engineering strategies for modulating the relaxation ratio of MRI nanoprobes are systematically condensed. Furthermore, the widespread and noninvasive visualization applications of MRI nanoprobes for real time monitoring of major organs and accurate disease diagnosing, such as cerebrovascular, ischemia, Alzheimer's disease, liver fibrosis, whole-body tumors, inflammation, as well as multi-mode imaging applications are summarized. Finally, the challenges and prospects for the future development of MRI nanoprobes are discussed, and promising strategies are specifically emphasized for improving biocompatibility, precisely engineering of optimal size, AI-driven prediction and design, and multifunctional self-assembly to enhance diagnostics. This review will provide new inspiration for artificial engineering and nanotechnology-based molecular probes for medical diagnosis and therapy with ultrasensitive MRI.

Single-point mutated lanmodulin as a high-performance MRI contrast agent for vascular and kidney imaging

Magnetic resonance imaging contrast agents can enhance diagnostic precision but often face limitations such as short imaging windows, low tissue specificity, suboptimal contrast enhancement, or potential toxicity, which affect resolution and long-term monitoring. Here, we present a protein contrast agent based on lanmodulin, engineered with a single-point mutation at position 108 from N to D to yield maximum gadolinium binding sites. After loading with Gd3+ ions, the resulting protein complex, LanND-Gd, exhibits efficient renal clearance, high relaxivity, and prolonged renal retention compared to commercial agents. LanND-Gd enables high-performance visualization of whole-body structures and brain vasculature in male mice at a resolution finer than one hundred micrometers. In male ischemia mouse models, LanND-Gd also improves kidney dysfunction monitoring while minimizing risks of neural toxicity or immunogenic reactions. This protein-based contrast agent offers superior image quality, improved biocompatibility, and extended imaging timeframes, promising significant advancements in magnetic resonance-based diagnostics and patient outcomes.

Biomass-Derived Organonanomaterials as Contrast Agents for Efficient Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) is a popular imaging tool that is valuable for the early detection and monitoring of malignancies because it does not involve radiation and is noninvasive. Metal-based contrast agents (CAs) are commonly used in clinical settings despite concerns about the toxicity of free metals. Therefore, finding alternative nontoxic imaging probes is vital. In this work, we have synthesized and effectively utilized sustainable biomass lignin-based all-organic nanoconjugates linked with nitroxide radicals as MRI CAs. Lignin grafted with poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl) (LPGT) exhibits a longitudinal relaxivity of 0.54 mM-1 s-1. LPGT shows exceptional characteristics, including resistance to reduction and nontoxicity toward living organisms. LPGT displays enhanced MRI contrast in the BALB/c mouse model for a duration exceeding 4.35 h. Our primary goal is to design MRI agents that are exceptionally effective sustainable biomass-derived materials and do not require the use of metals. Nicely, LPGT offers adequate contrast enhancement at 5-fold lower (0.020 mmol/kg) than the standard dose (0.1 mmol/kg), easing worries about toxic metal buildup. Consequently, LPGT shows promise as a feasible CA for metal-free MRI.

Abstract 4137891: Treated HIV infection is not associated with carotid vascular inflammation or plaque progression as assessed by dynamic contrast magnetic resonance imaging

Background: Inflammation and immune dysregulation are thought to drive residual cardiovascular disease risk among persons living with HIV (PLWH) despite effective viral suppression with antiretroviral therapy (ART). Question: We investigated differences in carotid vascular inflammation and atherosclerosis in a longitudinal cohort of virally suppressed PLWH (n = 50; on stable ART with CD4 >250 cells/mm 3 , viral load <200 copies/mL for >6 months) and HIV-uninfected controls (n = 51) matched for age, sex, hypertension, diabetes, smoking, hyperlipidemia, and family history of premature coronary artery disease. Methods&Results: Participants were > 40 years old at enrollment, 8% female, and had a high prevalence of cardiovascular risk factors ( Table 1 ). Measures of carotid inflammation and capillary permeability ( K trans ), neovascularization ( V p ), and wall thickness were assessed at baseline, 1 year, and change over 1 year by dynamic contrast-enhanced magnetic resonance imaging. Both PLWH and controls demonstrated a reduction in systolic and diastolic blood pressures and total cholesterol over 1 year; however, the difference was not significant by HIV status. PLWH had a significant reduction in triglycerides compared with controls (-48.8 mg/dL vs 12.8 mg/dL; p = 0.026). HIV was not associated with baseline, follow-up, or change in markers of systemic inflammation assessed by plasma cytokines (C-reactive protein, interleukin-6, interleukin-1ß), nor vascular inflammation or plaque as assessed by K trans , V p , carotid wall thickness, or percent wall volume ( Tables 2 & 3 ). Conclusions: In contrast to other studies of chronically treated and virally suppressed PLWH, HIV infection was not associated with carotid inflammation or plaque.

Improving arterial stiffness prediction with machine learning utilizing hemodynamics and biomechanical features derived from phase contrast magnetic resonance imaging.

Arterial stiffness has emerged as a prominent marker of risk for cardiovascular diseases. Few studies are interested in predicting symptomatic or asymptomatic arterial stiffness from hemodynamics and biomechanics parameters. Machine learning models can be used as an intelligent tool for arterial stiffness detection based on hemodynamic and biomechanical parameters. Indeed, in the case of arterial stiffness hemodynamics and biomechanics parameters present significant change, such as an increase in age, local wave velocity, arterial elastance, Young's modulus, reflected wave amplitude, decrease in arterial compliance, reflected wave arrival time, and reflection coefficient. This study aims to assess the impact of artificial intelligence using machine-learning algorithms for the detection of arterial stiffness. The ability of various machine-learning approaches can be investigated to predict wall stiffness in the carotid artery and to evaluate the risk of cardiovascular events. A mathematical model developed in previous work was used to determine hemodynamic and biomechanical parameters. Accuracy, sensitivity, and specificity are calculated to evaluate the performance of the proposed models. All used classifiers demonstrated high performance in predicting arterial stiffness, notably with the Support Vector Machine, Artificial Neural Network, and Decision Tree classifiers achieving exceptional accuracies of 100%. In this study, the potential of machine learning based on hemodynamic parameters for the prediction of symptomatic and asymptomatic arterial stiffness was demonstrated.