Magnetic Resonance Imaging Contrast Research Articles

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.

Investigation of magnetic resonance contrast properties of PEG-coated gadolinium oxide nanoparticles in various biological environments

Abstract Magnetic nanoparticles (MNPs) are promising tools for biomedical applications, particularly in molecular imaging using magnetic resonance imaging (MRI). The unique magnetic properties of MNPs, combined with their similarity in size to biological objects, make them ideal candidates for in situ imaging probes. The present study explores the use of magnetic nanoparticles (MNPs) as contrast agents in magnetic resonance imaging (MRI) for improved diagnostic accuracy. Specifically, the study investigates the MR contrast properties of polyethylene glycol-coated gadolinium oxide nanoparticles (PEG@GONPs) in five different biological fluids. The nanoparticles were synthesized using the polyol route and their size, shape, and morphology were characterized using TEM, SEM, and FT-IR spectroscopy. The magnetic resonance (MR) relaxivity of PEG@GONPs was studied in different biologically relevant media, and results revealed highest relaxivity in plasma as compared to other media. In addition, comparative analysis of proton relaxivity of the synthesized nanoparticles was carried out with a well-known gadolinium-based contrast agent, Omniscan, in various medium. The present findings revealed that PEG@GONPs can serve as an effective contrast agent for MRI imaging in biological fluids such as plasma, which is crucial for preclinical diagnosis of specific diseases and lesions. The high relaxivity observed in plasma could be attributed to the interaction of the nanoparticles with plasma proteins, amplifying their magnetic properties which further improve their ability to produce contrast in MR images.

NIMG-23. A NOVEL APPROACH TO PERFUSION MRI STUDIES IN BRAIN TUMOR PATIENTS USING ENDOGENOUS DEOXYHEMOGLOBIN AS A CONTRAST AGENT: A PROOF-OF-CONCEPT STUDY

Abstract BACKGROUND Assessment of resting perfusion in brain tumors is clinically relevant and relies on dynamic susceptibility contrast magnetic resonance imaging using gadolinium contrast. Preliminary studies have introduced the use of controlled hemoglobin desaturation by means of a transient hypoxic stimulus during echo-planar imaging(EPI) as a surrogate for gadolinium for resting perfusion assessment in healthy subjects. In this proof of concept study, we investigated whether this approach is feasible in brain tumors and warrant further validation. METHODS A computer controlled gas blender was used to induce transient and standardized hypoxic stimulus in isocapnic conditions during EPI acquisition in a heterogenous cohort of tumor patients. The induced blood-oxygen-level-dependent(BOLD) signal changes determined by transit of a bolus of deoxygenated blood in the brain vasculature were used as a surrogate of gadolinium to calculate cerebral blood volume(CBV), cerebral blood flow(CBF) and mean transit time(MTT) using a global arterial input functions obtained through the BOLD signal measured over the middle cerebral artery as previously described by Poublanc et al. Perfusion parameters were calculated in the whole-brain voxel-by-voxel and in automatically segmented region of interest(ROI) using SPM, AFNI, Verbena softwares and MATLAB in-house written scripts. RESULTS Nine patients were included. MTT, rCBV, rCBF were calculated voxel-per-voxel. Obtained maps were overlayed on the co-registered T1 MRI scans and compared to T1CE and FLAIR to identify perfusion patterns in tumor ROIs (contrast enhancement, edema, necrosis). The deoxy-hemoglobin BOLD MRI perfusion were compared to clinical DSC-MRI when available and showed high qualitative agreement. CONCLUSION Transient and precise hemoglobin desaturation by controlled hypoxic gas modulation is safe and repeatable in brain tumor patients. The induced BOLD signal change allows measurement of resting perfusion, which qualitatively closely mimic gadolinium perfusion in different brain tumors. Deoxyhemoglobin-based perfusion warrant further quantitative validation against gadolinium in a larger cohort of heterogenous tumor patients.

A collagenase-decorated Cu-based nanotheranostics: remodeling extracellular matrix for optimizing cuproptosis and MRI in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC), characterized by a dense extracellular matrix (ECM), presents significant therapeutic challenges due to its poor prognosis and high resistance to chemotherapy. Current chemodrugs and diagnostic agents largely fail to cross the barrier posed by the ECM, which severely limits the PDAC theranostics. This study introduces a novel theranostic strategy using thioether-hybridized hollow mesoporous organosilica nanoparticles (dsMNs) for the co-delivery of copper (Cu) and disulfiram (DSF), aiming to induce cuproptosis in PDAC cells. Our approach leverages the ECM-degrading enzyme collagenase, integrated with dsMNs, to enhance drug penetration by reducing matrix stiffness. Furthermore, the innovative use of a pancreatic cancer cell membrane coating on the nanoparticles enhances tumor targeting and stability (dsMCu-D@M-Co). The multifunctional platform not only facilitates deep drug penetration and triggers cuproptosis effectively but also utilizes the inherent properties of Cu to serve as a T1-weighted magnetic resonance imaging (MRI) contrast agent. In vitro and in vivo assessments demonstrate significant tumor size reduction in PDAC-bearing mice, highlighting the dual functionality of our platform in improving therapeutic efficacy and diagnostic precision. This integrated strategy represents a significant advancement in the management of PDAC, offering a promising new direction for overcoming one of the most lethal cancers.Graphical

Development and validation of a controlled heating apparatus for long‐term MRI of 3D microfluidic tumor models

AbstractConventional testing of novel contrast agents for magnetic resonance imaging (MRI) involves cell and animal studies. However, 2D cultures lack dynamic flow and in vivo MRI is limited by regulatory approval of long‐term anesthesia use. Microfluidic tumor models (MTMs) offer a cost‐effective, reproducible, and high throughput platform for bridging cell and animal models. Yet, MRI of microfluidic devices is challenging, due to small fluid volumes generating low sensitivity. For the first time, an MRI of MTMs was performed at low field strength (1 T) using conventional imaging equipment without microcoils. To enable longitudinal MRI, we developed (1) CHAMP‐3 (controlled heating apparatus for microfluidics and portability) which heats MTMs during MRI scans and (2) an MRI‐compatible temperature monitoring system. CHAMP‐3 maintained chip surface temperature at ~37°C and the media inside at ~35.5°C. Enhanced T1‐weighted MRI contrast was achieved in 3D MTMs with free manganese (Mn2+) solutions and Mn2+ labeled tumor cells.

Can the second phase of contrast-enhanced MRA of the neck provide additional information in the acute stroke setting?

Double-concentration magnetic resonance imaging (MRI) contrast agents are frequently used in contrast-enhanced MR angiography (CE-MRA) of the head and neck. To avoid mistiming the peak concentration of intraluminal contrast (due to shorter duration of peak), a second acquisition is sometimes performed. To evaluate additional information from the second acquisition of CE-MRA and compare the collateral scoring to the hypoperfusion index obtained on MR perfusion, and to investigate presence of pseudo-occlusion using the second phase of CE-MRA. A retrospective study was conducted. CE-MRA of the brain/neck, dynamic susceptibility contrast (DSC) MR perfusion scan (in majority) and subsequent digital subtraction angiography (DSA) were evaluated in patients with previous acute internal carotid artery (ICA)/middle cerebral artery (MCA) occlusion. Evaluation of CE-MRA/MR perfusion and DSA was performed by three experienced neuroradiologists and one neurointerventionist, respectively. The site of ICA occlusion was seen to be distal to the site noted on early arterial phase (pseudo-occlusion of ICA) in 28.5% of patients. A significant negative correlation was seen between a higher HIR and collateral score. Evaluation of second phase CE-MRA can provide valuable information that may be otherwise lost if only the early arterial phase is evaluated.

Magnitude and timescales of Ca isotope variability in human urine: implications for bone mass balance monitoring.

Calcium (Ca) isotopes in blood/urine are emerging biomarkers of bone mineral balance (BMB) in the human body. While multiple studies have investigated Ca isotopes in patients suffering from diseases affecting BMB, comparatively little effort has been devoted to understanding the homeostasis of Ca isotopes in healthy individuals. Here, we report on a longitudinal study of the urine Ca isotope composition (δ44/42CaUrine) from 22 healthy participants (age 19 to 60) over timescales ranging from days to months. Data from a single participant collected over a 30-day period show that morning urine is an excellent proxy for 24 hr pooled urine fractions. Data from all participants reveal large inter-individual variability in δ44/42CaUrine (up to 2.2 ‰), which is partly due to anthropometric differences, as shown by a correlation between the participants' body mass index (BMI) and δ44/42CaUrine values. In contrast, intra-individual data reveal encouraging stability (within ∼ ±0.2-0.3 ‰) over timescales>160 days, indicating that self-referencing approaches for BMB monitoring hold greater promise than cross sectional ones. Our data confirm that intra-individual δ44/42CaUrine variations are mainly a function of Ca reabsorption in the kidney, but also reveal the impact of other (and at times equally important) drivers, such as diet, alcohol consumption, physical exercise, or fasting. We also find that a magnetic resonance imaging contrast agent (gadolinium) can lead to artifacts during Ca isotope analysis. Based on our results, a series of practical considerations for the use of Ca isotopes in urine as tracers of BMB is presented.

TME-Activated MnO2/Pt Nanoplatform of Hydroxyl Radical and Oxygen Generation to Synergistically Promote Radiotherapy and MR Imaging of Glioblastoma.

Radiotherapy (RT) is currently recognized as an important treatment for glioblastoma (GBM), however, it is associated with several challenges. One of these challenges is the radioresistance caused by hypoxia, whereas the other is the low conversion efficiency of the strongly oxidized hydroxyl radical (•OH), which is produced by the decomposition of water due to high-energy X-ray radiation. These factors significantly limit the clinical effectiveness of radiotherapy. To address these limitations, we developed a highly stable and efficient nanoplatform (MnO2/Pt@BSA). Compared to MnO2@BSA, this platform demonstrates high stability, a high yield of oxygen (O2), enhanced production of •OH, and reduced clearance of •OH. The system exhibited increased O2 production in vitro and significantly improved oxygen production efficiency within 100 s at the Pt loading of 38.7%. Furthermore, compared with MnO2, the expression rate of hypoxia-inducible factor (HIF-1α) in glioma cells treated with MnO2/Pt decreased by half. Additionally, the system promotes •OH generation and consumes glutathione (GSH), thereby inhibiting the clearance of •OH and enhancing its therapeutic effect. Moreover, the degradation of the nanoplatform produces Mn2+, which serves as a magnetic resonance imaging (MRI) contrast agent with a T1-weighted enhancement effect at the tumor site. The nanoplatform exhibited excellent biocompatibility and performed multiple functions related to radiotherapy, with simpler components. In U87 tumor bearing mice model, we utilized MnO2/Pt nanocatalysis to enhance the therapeutic effect of radiotherapy on GBM. This approach represents a novel and effective strategy for enhancing radiotherapy in gliomas, thereby advancing the field of catalytic radiotherapy and glioma treatment.

Targeted Magnetic Nanoparticles for Beta-Amyloid Detection

Background/Objectivities: The presence of beta-amyloid plaques is a part of the pathogenesis of Alzheimer’s disease, but there is currently no universally accepted method for magnetic resonance (MR) imaging of the disease. However, it is known that magnetic nanoparticles (MNPs) can improve the T2 contrast in MR images of various targets. Methods: We used cubic MNPs, which were produced by thermal decomposition and then it was covalently bonded to a modified fluorescently labeled tetrapeptide, HAEE-Cy5, for visualizing beta-amyloid plaques. The interaction of MNPs-HAEE-Cy5 and beta-amyloid was determinate by confocal microscopy using SH-SY5Y cell line. Results: MNPs exhibit relatively high relaxivity (approximately 200 mM−1s−1), which is crucial for enhancing target visibility in MR imaging. HAEE provides targeted delivery of MNPs by specifically interacting with beta-amyloid, while the fluorescent label Cy5 enables monitoring the efficacy of the interaction through confocal microscopy. Conclusions: The MNPs modified with HAEE-Cy5 demonstrated excellent binding to beta-amyloid plaques in vitro, as shown by experiments on the SH-SY5Y cell line. These results suggest that the proposed method has potential for use in future MR imaging studies of Alzheimer’s disease.

Changes in the relaxivity of water-organic solvent miscible systems: Hidden forces beyond metal ions.

The relaxivity of magnetic resonance imaging (MRI) contrast agents is primarily attributed to metal ions such as gadolinium (Gd) and iron. However, the impact of organic solutes on relaxivity, particularly through alterations in water molecule dynamics, has not been thoroughly investigated. This research was aimed to explore how organic solutes affect the relaxivities of water and Gd-based contrast agents (GBCAs), potentially revealing new aspects for the development of contrast agents. To investigate the effects of different proportions of water-soluble organic solvents mixed with pure water and GBCA on T1 and T2 relaxivities. Ethanol, dimethyl sulfoxide (DMSO), 1,4-dioxane, glycerin, ethylene glycol, diethylene glycol, polyethylene glycol (PEG) 200, and PEG 400 were mixed with ultrapure water in various ratios (100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80, 10:90, 0:100). GBCA was added to these mixtures at a concentration of 0.05 mmol/L. The mixtures underwent T1 and T2 mapping scans using a 3.0 Tesla MRI machine, and the relaxivities R1 (1/T1) and R2 (1/T2) were calculated and compared. The relaxivity R1 of ethanol, 1,4-dioxane, and DMSO mixtures with water or GBCA, as well as R2 of DMSO mixtures with GBCA, initially increased and then decreased. Conversely, R1 and R2 increased significantly with higher proportions of diethylene glycol, PEG 200, and glycerin in the mixtures with GBCA. The increase in relaxivity R1 was correlated with greater viscosity. When the proportion of DMSO and diethylene glycol exceeded 20%, minimal variability in R2 was observed as the water content decreased. Adding organic solvents to water and paramagnetic relaxation reagents could alter T1 and T2 relaxivities, suggesting potential new directions for modifying current contrast agents. Additionally, increasing the viscosity of the contrast agent was found to enhance the relaxivity.

Saturation transfer (CEST and MT) MRI for characterization of U-87 MG glioma in the rat.

The focus of this work was to identify the optimal magnetic resonance imaging (MRI) contrast between orthotopic U-87 MG tumours and normal appearing brain with the eventual goal of treatment response monitoring. U-87 MG human glioblastoma cells were injected into the brain of RNU nude rats (n= 9). The rats were imaged at 7T at three timepoints for all animals: 3-5, 7-9, and 11-13 days after implantation. Whole-brain T1-weighted (before and after gadolinium contrast agent injection), diffusion, and fluid-attenuated inversion recovery scans were performed. In addition, single-slice saturation-transfer-weighted chemical exchange saturation transfer (CEST), magnetization transfer (MT), and water saturation shift referencing (WASSR) contrast Z-spectra and T1 and T2 maps were also acquired. The MT and WASSR Z-spectra and T1 map were fitted to a two-pool quantitative MT model to estimate the T2 of the free and macromolecular-bound water molecules, the relative macromolecular pool size (M0, MT), and the magnetization exchange rate from the macromolecular pool to the free pool (RMT). The T1-corrected apparent exchange-dependent relaxation (AREX) metric to isolate the CEST contributions was also calculated. The lesion on M0, MT and AREX maps with a B1 of 2μT best matched the hyperintensity on the post-contrast T1-weighted image. There was also good separation in Z-spectra between the lesion and contralateral cortex in the 2-μT CEST and 3- and 5-μT MT Z-spectra at all time points. A pairwise Wilcoxon signed-rank tests with Holm-Bonferroni adjustment on MRI parameters was performed and the differences between enhancing lesion and contralateral cortex for the MT ratio with 2μT saturation at 3.6ppm frequency offset (corresponding to the amide chemical group) and M0, MT were both strongly significant (p< 0.001) at all time points. This work has identified that differences between enhancing lesion and contralateral cortex are strongest in MTR with B1=2μT at 3.6ppm and relative macromolecular pool size (M0, MT) images over entire period of 3-13 days after cancer cell implantation.

Relaxation-weighted MRI analysis of biofilm EPS: Differentiating biopolymers, cells, and water

Biofilms are a highly complex community of microorganisms embedded in a protective extracellular polymeric substance (EPS). Successful biofilm control requires a variety of approaches to better understand the structure-function relationship of the EPS matrix. Magnetic resonance imaging (MRI) is a versatile tool which can measure spatial structure, diffusion, and flow velocities in three dimensions and in situ. It is well-suited to characterize biofilms under natural conditions and at different length scales. MRI contrast is dictated by T1 and T2 relaxation times which vary spatially depending on the local chemical and physical environment of the sample. Previous studies have demonstrated that MRI can provide important insights into the internal structure of biofilms, but the contribution of major biofilm components—such as proteins, polysaccharides, and cells—to MRI contrast is not fully understood. This study explores how these components affect contrast in T1-and T2-weighted MRI by analyzing artificial biofilms with well-defined properties modeled after aerobic granular sludge (AGS), compact spherical biofilm aggregates used in wastewater treatment. MRI of these biofilm models showed that certain gel-forming polysaccharides are a major source of T2 contrast, while other polysaccharides show minimal contrast. Proteins were found to reduce T2 contrast slightly when combined with polysaccharides, while cells had a negligible impact on T2 but showed T1 contrast. Patterns observed in the model biofilms served as a reference for examining T2 and T1-weighted contrast in the void spaces of two distinct AGS granules, allowing for a qualitative evaluation of the EPS components which may be present. Further insights provided by MRI may help improve understanding of the biofilm matrix and guide how to better manage biofilms in wastewater, clinical, and industrial settings.

On the lifespan of Enchytraeus crypticus - impact of iron (nanomaterial and salt) on aging.

Iron oxide nanomaterials (Fe3O4 NMs) have important biomedical and environmental applications, e.g. drug delivery, chemotherapy, magnetic resonance imaging contrast agents, etc. However, the environmental risks of such Fe3O4 are not fully assessed, particularly for soil living invertebrates, which are among the ones in the first line of exposure. Research has showed that longer-term exposure time is required to assess hazards of NMs, not predicted when based on shorter time and are therefore recommended. Thus, in the present study the effects of Fe3O4 NMs and FeCl3 were assessed in the terrestrial environment, using the soil model species Enchytraeus crypticus (Oligochaeta), throughout its entire lifespan (202 days). Two animals' density were used: 1 (D1) and 40 (D40) animals per replicate, in LUFA 2.2 soil. The endpoints were survival and reproduction monitored over-time, up to 202 days. Results showed that density clearly affected the toxicity response, with higher toxicity and lower lifespan in D1 compared to D40. Overall, FeCl3 was more toxic than Fe3O4 NM in terms of reproduction, however, adult animals can be at higher (long-term) risk when exposed to Fe3O4 NM. Differences might be linked to slower Fe kinetics for the Fe3O4 NMs, i.e., slower Fe dissolution and release of ions.

Application of nanoliposome as contrast agents for magnetic resonance imaging technique

AbstractLiposomes, nano‐sized vesicles primarily comprising phospholipids and cholesterol, have emerged as pivotal tools in medical imaging, notably in magnetic resonance imaging (MRI), due to their biocompatibility and ability to encapsulate diverse molecules. Tailorable properties like size, surface charge, and encapsulation capacity make liposomes ideal for targeted delivery of imaging agents and drugs to specific tissues, improving pharmacokinetics. As MRI contrast agent (CA) carriers, liposomes encapsulate gadolinium, mitigating toxicity and boosting relaxivity and circulation times. Functionalization with targeting ligands and stimuli‐responsive designs enhances their controlled release and targeted delivery capabilities, crucial for cancer imaging and therapy. Benefits include reduced toxicity, prolonged circulation, targeted delivery, enhanced bioavailability, and potential for multimodal imaging. Challenges remain, such as stability, clearance, and manufacturing intricacies, requiring further research. Nonetheless, liposomal MRI CAs hold promise for enhancing diagnostic precision and therapeutic effectiveness in oncology and neurology, offering a robust pathway for future biomedical advancements. Addressing existing limitations could unlock their full potential in improving patient care and outcomes.

EDITORIAL: RETURNING THE CENTRAL LYMPHATIC SYSTEM TO THE CENTER OF LYMPHOLOGY

After the introduction of conventional oil contrast lymphography and the founding of the discipline of lymphology, great impetus was given to investigating central lymphatic system and its disorders along with lymphatic involvement and specifically lymphostasis in common diseases of major organs such as the liver (cirrhosis) and heart (heart failure). Gradually interest shifted to more peripheral disorders such as limb lymphedema and its treatment by physical and surgical measures. At the same time, basic lymphology turned to the study of isolated ex vivo and in vitro, including lymphatic endothelial models and more recently, molecular lymphology focusing on lymphatic growth and modulating factors, genes and proteins underlying primary lymphedema, and more potential biomarkers of lymphatic disease have gained prominence. However, it has been advances in lymphatic imaging, namely lymphoscintigraphy with SPECT-CT high resolution 3-D pictures and magnetic resonance imaging (contrast and non-contrast) of the peripheral and particularly central lymphatic system by more invasive means combined with endovascular interventional techniques to treat complex and life-threatening lymphatic disorders that has returned the central lymphatic system to the center of lymphology, where the journey began.

Role of Contrast Perfusion Weighted Magnetic Resonance Imaging in Grading of Brain Tumors with Histopathological Correlation

Background: Traditional MRI sequences provide precise anatomical information about brain tumors. But these sequences can’t quantitatively evaluate vascular physiology, or capture tumor biology at the molecular level; which is important for tumor grading, therapeutic assessment, and prognostication. Furthermore, non-enhancing parts of the tumor affected brain, which generally indicates peri-tumoral brain edema with infiltrative tumor cells, is not visible on conventional MRI sequences. Perfusion weighted Magnetic Resonance Imaging (PW-MRI) techniques such as Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) and Dynamic Susceptibility Contrast Magnetic Resonance Imaging (DSC-MRI) have shown promise as imaging biomarkers for glioma therapy, since these new sequences can also provide information about vascular hemodynamics. Our study was first prospective study from Himalayan belt of India, wherein we tried to assess the role of PW-MRI in the grading of brain tumors, with histopathological correlation. Aim and Objective: To compare tumor perfusion and histopathological tumor grading, in evaluation of brain tumor especially gliomas. Material and Method: 40 patients who were referred to Department of Radiodiagnosis for evaluation of brain tumor, and who gave informed consent, were included in this prospective study, done over a period of 18 months. All patients underwent MRI, followed by surgical resection. Observation and Result: In our study, diagnostic accuracy was 90% for mean rCBV (lesion) (cut off: 7 by ROC), mean rCBF (lesion) (cut off: 13.9 by ROC), and rCBF ratio (cut off: 2.9 by ROC); for differentiating benign versus malignant brain tumor. rCBF ratio was found to be best diagnostic parameter with sensitivity of 96%, specificity of 80%, positive predictive value of 89%, negative predictive value of 92%, diagnostic accuracy of 90%, area under ROC curve=0.909, and p value&lt;0.001. Conclusion: We come to conclusion that high grade brain tumor display higher CBF, than do low grade brain tumor. Three parameters showed good diagnostic accuracy, which includes rCBF ratio, mean rCBF (lesion), and mean rCBV (lesion). These parameters can be used to predict the grade of the brain tumor, with good diagnostic accuracy.

Progressive Unilateral Foot Drop in a Child due to Neuromuscular Choristoma.

An 8.5-year-old boy presented with a history of progressive unilateral foot drop. A contrast magnetic resonance imaging of the pelvic girdle and the lumbosacral plexus revealed a diffuse fusiform thickening of the right lumbosacral trunk and the sciatic nerve in the intrapelvic and gluteal regions, with findings characteristic of a choristoma. Clinical and radiologic features as well as complications of this unusual entity are described.