Dual T2 Research Articles

A Novel Permeability Prediction Model for Deep Coal via NMR and Fractal Theory

A quantitative description of the permeability of deep coal is of great significance for improving coalbed methane recovery and preventing gas disasters. The Schlumberger–Doll research (SDR) model is often used to predict rock permeability, but it has inherent defects in characterizing the pore structure of deep coal. In this study, a permeability model with fractal characteristics (FCP model) is established for deep coal based on nuclear magnetic resonance (NMR). The constants in the SDR model are theoretically explained by the relevant parameters in the FCP model. Centrifugation and NMR experiments were performed to determine the optimal centrifugal force and dual T2 cutoff values. The results show that the coal samples are mainly composed of micrometer and nanometer pores. The adsorption pores account for the largest proportion, followed by the percolation pores and migration pores. In addition, the prediction accuracy of the FCP model is significantly higher than that of the other three models, which provides a fast and effective method for the evaluation of deep coal permeability.

LI-RADS Category on MRI Is Associated With Recurrence of Intrahepatic Cholangiocarcinoma After Surgery: A Multicenter Study.

The Liver Imaging Reporting and Data System (LI-RADS) is a comprehensive system for standardizing the terminology and interpretation of liver imaging. The association between the LI-RADS category and tumor recurrence in patients with intrahepatic cholangiocarcinomas (iCCAs) has not yet been evaluated in a multicenter study. To retrospectively investigate the preoperative clinical and imaging features associated with recurrence-free survival (RFS) after curative resection of iCCAs and to identify the role of the LI-RADS category in at-risk patients. Retrospective, multicenter. A total of 113 patients (mean age: 61.1 years; 74 men, 39 women) who underwent preoperative contrast-enhanced MRI and curative surgical resection for a single treatment-naive iCCA between 2008 and 2021. A 3 T dual gradient-echo T1 WI with in- and opposed-phase, turbo spin-echo T2 WI, diffusion-weighted echo-planar images, and three-dimensional gradient-echo T1 WI before and after administration of contrast agent. MR imaging features were evaluated and assigned for each lesion using LI-RADS version 2018. RFS was calculated from the date of surgery to tumor recurrence or the last imaging date without evidence of recurrence. Factors affecting RFS were evaluated using clinical and imaging features. Cox proportional hazards model, Kaplan-Meier method, and log-rank test. A P-value of <0.05 was considered statistically significant. A total of 93 (82.3%) were categorized as LR-M and 20 (17.7%) were categorized as LR-4 or 5. In the multivariable analysis, LR-M category (hazard ratio [HR], 8.035; 95% confidence interval [CI], 1.096-58.931) and a tumor size >3cm on MRI (HR, 2.690; 95% CI, 1.319-5.487) were independent factors for poor RFS. The 5-year RFS rate was significantly higher in patients with iCCA categorized as LR-4 or 5 than in those categorized as LR-M (94.4% vs. 51.9%, respectively). Patients with iCCA categorized as LR-4 or 5 may have a better RFS than those categorized as LR-M. 3 TECHNICAL EFFICACY: Stage 2.

A multifractal-based method for determination NMR dual T2 cutoffs in coals

An accurate classification of pore fluid typing in coals is critical for understanding and assessing fluid flow characteristics during coalbed methane production, but the widely used nuclear magnetic resonance (NMR) single T2 cutoff (T2C) model remains some apparent defects. In this study, we proposed a novel NMR dual T2 cutoffs model for fluid typing classification based on the multifractal theory. Firstly, the NMR and high-speed centrifugal combined measurements were performed for twenty-one coals with strikingly different ranks. Secondly, the multifractal analysis theory was introduced to investigate multifractal characteristics of the fully water-saturated NMR spectra. Thirdly, the correlations between dual T2 cutoffs and multifractal parameters were systematically analyzed. Fourthly, a multifractal-based model was established to evaluate the NMR dual T2 cutoffs values in coals. Results show that the pore fluid typing was re-divided into: absolute irreducible- (T2 < T2C1), absolute movable-(T2 > T2C2), and partial movable-fluid (T2C1 < T2 < T2C2) based on dual T2 cutoffs. The values of T2C1 and T2C2 were in the range of 0.049–0.455 ms and 36.12–102.34 ms, respectively. Multifractal numerical simulations indicate the coals have typical multifractal characteristics. The minimum multifractal dimension (Dmin), singularity strength subtraction (αmax-αmin), and singularity strength proportion (αmax/αmin) were linearly correlated with dual T2 cutoffs, that can be further used for model-building. The dual T2 cutoffs calculated from the proposed multifractal-based model qualitatively agree with those obtained from complicated laboratory experiments, indicating the accuracy of the established multifractal-based model in this study – from the validations of six non-modeling coals. It can be concluded that the proposed multifractal-based model is accurate and convenient, also be scalable in the applications of other rocks such as shales.

Characteristics and Early Recurrence of Hepatocellular Carcinomas Categorized as LR-M: Comparison with Those Categorized as LR-4 or 5.

According to the Liver Imaging Reporting and Data System (LI-RADS), the LI-RADS category M (LR-M), which are probably or definitely malignant but are not specific for hepatocellular carcinomas (HCCs), does not exclude HCCs. A gap in knowledge remains, including their characteristics and recurrence of HCCs categorized as LR-M. To compare the characteristics of HCCs categorized as LR-M with HCCs categorized as LR-4 or LR-5 (LR-4/5) using the LI-RADS version 2018 and evaluate the relationship of these categories with the risk of early recurrence after curative resections of single HCCs. Retrospective. Two hundred and eighty-one patients (mean age, 57 years; 191 men and 90 women) who underwent curative resections for single HCCs and preoperative contrast-enhanced MRI between 2015 and 2017. 3T Dual gradient-echo T1 WI with in- and opposed-phase, turbo spin-echo T2 WI, diffusion-weighted echo-planar images, and three-dimensional gradient-echo T1 WI before and after administration of contrast agent. MRI features according to the LI-RADS version 2018 were evaluated and LI-RADS category were assigned for each observation. Clinical, imaging, and histopathological features were compared based on LI-RADS categorization. Early recurrence rates (<2 years) and associated factors were also evaluated. Fisher's exact test, two-sample t test after satisfying assumption of normality through Shapiro-Wilk test, Fleiss κ coefficient, Cox proportional hazards regression analysis, Kaplan-Meier method, and log-rank test. Forty-one HCCs (14.6%) were categorized as LR-M and 240 HCCs (85.4%) were categorized as LR-4/5. LR-M HCCs showed poorer differentiation than LR-4/5 HCCs. In the multivariate analysis, the LR-M category was an independent predictor for early recurrence (hazard ratio, 1.904; 95% confidence interval, 1.024-3.542; P < 0.05). Early recurrence rates were significantly higher in patients with LR-M HCCs than in patients with LR-4/5 HCCs (32.0% vs. 18.4%, respectively, P < 0 05). Compared to LR-4/5 HCCs, LR-M HCCs were associated with poorer tumor differentiation and higher early recurrence rates after curative resections of single HCCs. 3 Technical Efficacy Stage: 2.

Fe/Mn multilayer nanowires as dual mode T1 -T2 magnetic resonance imaging contrast agents.

To overcome the negative contrast limitations, and to improve the sensitivity of the magnetic resonance signals, the mesoporous silica coated Fe/Mn multilayered nanowires (NWs) were used as a T1 -T2 dual-mode contrast agents (CAs). The single component Fe and Mn NWs, and Fe/Mn multilayer NWs were synthesized by electrodeposition in the homemade anodic aluminum oxide (AAO) templates with the aperture of about 30 nm. The structural characterization and morphology of single component and multisegmented NWs was done by X-ray diffraction and transmission electron microscopy. The elemental composition of Fe/Mn multilayerd NWs was confirmed by energy-dispersive X-ray and energy-dispersive spectrometer. Vibrating sample magnetometer was used to test the magnetic properties, and 1.5 T magnetic resonance imaging (MRI) scanner was used to measure the relaxation efficiency. Importantly, the MRI study indicated that the Fe/Mn multilayer NWs showed a significant T1 -T2 imaging effect, and have longitudinal relaxivity (r1 ) value, that is, 1.25 ± 0.0329 × 10-4 μM-1 s-1 and transverse relaxivity (r2 ), that is, 5.13 ± 0.123 × 10-4 μM-1 s-1 , which was two times of r1 value (0.654 ± 0.00899 × 10-4 μM-1 s-1 ) of Mn NWs, and r2 value (2.96 ± 0.0415 × 10-4 μM-1 s-1 ) of Fe NWs. Hence, Fe/Mn multilayer NWs have potential to be used as T1 -T2 dual-mode CAs.

A novel pore size classification method of coals: Investigation based on NMR relaxation

Nuclear magnetic resonance (NMR) severs as a nondestructive and relative new technique that has been widely used in characterizing reservoir fluids and pore size distribution (PSD) of coals. Conventionally, pore fluids in coals are classified into movable fluid and irreducible fluid based on a single NMR T2 cutoff value (T2C). However, the single NMR T2 cutoffs model has some apparent defects in pore fluid/size classification, and few researches have reported the limitation of the single T2 cutoffs model. In contrast, the dual T2 cutoffs model may provide an accurate quantified model to classify different pore fluid types in coals. In this study, fifteen coal samples with different ranks were conducted in systematic NMR and centrifugal experiments to investigate the characteristics of pore fluid typing and PSD. Results show that when tried applying the single NMR T2 cutoffs model to classify the pore fluid typing, there are still some movable fluids when T2 < T2C. At the same time, when T2 > T2C, there is remaining some irreducible fluid in pores after high pressure centrifugal experiments. These results indicated the limited application of single NMR T2 cutoffs model in pore fluid classification. By introducing a novel pore fluid classification method (i.e. the dual T2 cutoffs model), a typical T2 spectrum under fully-saturated condition, the absolute irreducible fluid T2 cutoffs (T2C1) and absolute movable fluid T2 cutoff (T2C2) can re-divide the pore fluid typing of coal into three types: absolute irreducible fluid (T2 < T2C1), partial movable fluid (T2C1 < T2 < T2C2), and absolute movable fluid (T2 > T2C2). The results show that the T2C1 is in the range of 0.10–0.32 ms, while the T2C2 has a wider range from 36.12 ms to 89.07 ms. Finally, a conceptional model were proposed to clarify a full-scale PSD classification that includes the absolute irreducible fluid pores, partial movable fluid pores and absolute movable fluid pores. The model established in this study, can also be applicable for other rock types (e.g., sandstones, carbonates and shales).

Glutathione‐Depleting Nanoenzyme and Glucose Oxidase Combination for Hypoxia Modulation and Radiotherapy Enhancement

Nanoenzymes perceive the properties of enzyme-like catalytic activity, thereby offering significant cancer therapy potential. In this study, Fe3 O4 @MnO2 , a magnetic field (MF) targeting nanoenzyme with a core-shell structure, is synthesized and applied to radiation enhancement with using glucose oxidase (GOX) for combination therapy. The glucose is oxidized by the GOX to produce excess H2 O2 in an acidic extracellular microenvironment, following which the MnO2 shell reacts with H2 O2 to generate O2 and overcome hypoxia. Concurrently, intracellular glutathione (GSH)-which limits the effects of radiotherapy (RT)-can be oxidized by the MnO2 shell while the latter is reduced to Mn2+ for T1 -weighed MRI. The core Fe3 O4 , with its good magnetic targeting ability, can be utilized for T2 -weighed MRI. In summary, the work demonstrates that Fe3 O4 @MnO2 , as a dual T1 - and T2 -weighed MRI contrast agent with strong biocompatibility, exhibits striking potential for radiation enhancement under magnetic targeting.

Current use of the automatic retinal oximetry. Review.

To inform about possible use of the automatic retinal oximetry for the retinal oxygen saturation measurement in the eye and systemic diseases. We performed aliterature review dealing with issues of retinal oxygen saturation monitoring by dual non-invasive retinal oximetry Oxymap T1 (Oxymap ehf. Reykjavík, Iceland). We have found two main strains writing our paper on retinal oxygen saturation eye diseases. The first section concerns diseases created by having hypoxia as its main pathological factor - for example diabetes mellitus and retinal vein occlusion. The second group deals with atrophy as the main pathological mechanism which is typical for decreasing retinal oxygen consumption - for example glaucoma or retinitis pigmentosa (the second one named is not included in our work). Oximetry in systemic diseases creates arelatively new chapter of this branch with avery big potential of interdisciplinary cooperation for the future. It is possible the cooperation will not only include diabetologists but also neurologists (for example, in diseases like sclerosis multiplex or Devics, Alzheimersand Parkinsonsdisease) and haematologists (retinal oxygen saturation changes in patients with different rheological attributes of blood). Retinal oxygen saturation measuring by automatic retinal oximetry is arelatively new method with scientifically confirmed high reproducibility of results. Currently it is the only experimental method with vast potentials not only in the realm of the possibility of observing eye diseases (diabetic retinopathy, retinal vein occlusion or glaucoma) but also in developing interdisciplinary cooperation with diabetologists, neurologists and haematologists.

Deep-Learning-Based Neural Tissue Segmentation of MRI in Multiple Sclerosis: Effect of Training Set Size.

The dependence of deep-learning (DL)-based segmentation accuracy of brain MRI on the training size is not known. To determine the required training size for a desired accuracy in brain MRI segmentation in multiple sclerosis (MS) using DL. Retrospective analysis of MRI data acquired as part of a multicenter clinical trial. In all, 1008 patients with clinically definite MS. MRIs were acquired at 1.5T and 3T scanners manufactured by GE, Philips, and Siemens with dual turbo spin echo, FLAIR, and T1 -weighted turbo spin echo sequences. Segmentation results using an automated analysis pipeline and validated by two neuroimaging experts served as the ground truth. A DL model, based on a fully convolutional neural network, was trained separately using 16 different training sizes. The segmentation accuracy as a function of the training size was determined. These data were fitted to the learning curve for estimating the required training size for desired accuracy. The performance of the network was evaluated by calculating the Dice similarity coefficient (DSC), and lesion true-positive and false-positive rates. The DSC for lesions showed much stronger dependency on the sample size than gray matter (GM), white matter (WM), and cerebrospinal fluid (CSF). When the training size was increased from 10 to 800 the DSC values varied from 0.00 to 0.86 ± 0.016 for T2 lesions, 0.87 ± 009 to 0.94 ± 0.004 for GM, 0.86 ± 0.08 to 0.94 ± 0.005 for WM, and 0.91 ± 0.009 to 0.96 ± 0.003 for CSF. Excellent segmentation was achieved with a training size as small as 10 image volumes for GM, WM, and CSF. In contrast, a training size of at least 50 image volumes was necessary for adequate lesion segmentation. 1 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2020;51:1487-1496.

Multifunctional MIL-S─CUR@FC nanoparticles: a targeted theranostic agent for magnetic resonance imaging and tumor targeted delivery of curcumin

Introduction: Noninvasive magnetic resonance imaging (MRI) and targeted drug delivery systems, usually referred to as theranostic agents, are being developed to enable detection, site-specific treatment, and long-term monitoring. Materials and Methods: To elucidate the effects of coating on cellular uptake and biodistribution of nanoparticles (NPs), negatively charged Fe-MIL-88B-NH2 (MIL-S) was developed and loaded by curcumin (CUR). After that, chitosan (CS) was conjugated to folic acid (FA). Then MIL-S─CUR was coated by CS targeted by FA (FC) and partially negatively charged MIL-S─CUR@FC was developed. Results: MIL-S and MIL-S─CUR@FC owned Zeta potentials of -23 and -2 mV, respectively. MTT assay showed MIL-S─CUR@FC could have maximum cell toxicity on cancer cells due to partially negative charge and active targeting. In vivo magnetic resonance imaging (MRI) images suggested that liver uptake was very high for negatively charged MIL-S. The high T2 contrast effect of MIL-S in liver is likely due to active phagocytosis by macrophages (Kupffer cells) in the liver. In contrast, liver uptake was very low, but tumor uptake was very high for MIL-S─CUR@FC showing high dual contrast (T1/T2). The pH-responsive behavior of MIL- S─CUR@FC in tumor tissue made it dual T1 /T2 contrast agent by decomposition of NPs. Conclusion: It could be concluded that coating, active targeting, and reducing the surface charge of MIL-S─CUR@FC reduced the undesirable clearance by the reticuloendothelial system (RES) such as liver. On the other hand, the anti-cancer drug delivery improved more efficiently to the tumor sites and maximized therapeutic efficacy and predictable in vivo properties. Here described a pH sensitive MRI NPs, may serve as a useful theranostic agent for cancer diagnosis and treatment.

Dual T1/ T2 Nanoscale Coordination Polymers as Novel Contrast Agents for MRI: A Preclinical Study for Brain Tumor.

In the last years, extensive attention has been paid on designing and developing functional imaging contrast agents for providing accurate noninvasive evaluation of pathology in vivo. However, the issue of false-positives or ambiguous imaging and the lack of a robust strategy for simultaneous dual-mode imaging remain to be fully addressed. One effective strategy for improving it is to rationally design magnetic resonance imaging (MRI) contrast agents (CAs) with intrinsic T1/ T2 dual-mode imaging features. In this work, the development and characterization of one-pot synthesized nanostructured coordination polymers (NCPs) which exhibit dual mode T1/ T2 MRI contrast behavior is described. The resulting material comprises the combination of different paramagnetic ions (Fe3+, Gd3+, Mn2+) with selected organic ligands able to induce the polymerization process and nanostructure stabilization. Among them, the Fe-based NCPs showed the best features in terms of colloidal stability, low toxicity, and dual T1/ T2 MRI contrast performance overcoming the main drawbacks of reported CAs. The dual-mode CA capability was evaluated by different means: in vitro phantoms, ex vivo and in vivo MRI, using a preclinical model of murine glioblastoma. Interestingly, the in vivo MRI of Fe-NCPs show T1 and T2 high contrast potential, allowing simultaneous recording of positive and negative contrast images in a very short period of time while being safer for the mouse. Moreover, the biodistribution assays reveals the persistence of the nanoparticles in the tumor and subsequent gradual clearance denoting their biodegradability. After a comparative study with commercial CAs, the results suggest these nanoplatforms as promising candidates for the development of dual-mode MRI CAs with clear advantages.

Gd doped hollow nanoscale coordination polymers as multimodal imaging agents and a potential drug delivery carriers

Gd doped hollow nanoscale coordination polymers with multimodal imaging capabilities were synthesized by solvothermal method and further coated by silica layer. The in vitro tests demonstrated uncoated and silica-coated nanoprobes exhibit longitudinal relaxivities (r1) of 7.38 and 13.57 (mmol/L)−1·s−1, and transverse relaxivities (r2) of 180.6 and 304.8 (mmol/L)−1·s−1, showing fairly good dual T1&T2 contrast effects, and it also emits excellent multicolor fluorescence under laser beams of various wavelengths. With the combination of magnetic resonance imaging (MRI) (both T1 and T2) and fluorescence optical imaging (FOI), the nanoprobes could correlate preoperative diagnosis with intraoperative pathology. Furthermore, it also exhibits high drug loading capacity of 1166 mg/g and encapsulation efficiency of 83.29%, which makes it a potential platform as drug carriers. The MTT assay demonstrates the moderate toxicity of the NPs, and after the silica coating process, not only the MRI contrast effects but also the biocompatibility have been enhanced. The versatility of the highly integrated systems can make up for the limitations of each imaging modality and exhibit great potentials for cancer theranostics.

Paramagnetic Surface Active Ionic Liquids: Interaction with DNA and MRI Application

Paramagnetic surface active ionic liquids (PMSAILs) have been synthesized wherein long alkyl chain bearing imidazoilium, pyridinium or isoquinolinium are cationic and bromotrichloroferrate (III) is paramagnetic counterion constituents. PMSAILs have been investigated for their aggregation properties using surface tension, conductivity, and dynamic light scattering (DLS). Interaction of PMSAILs with DNA in aqueous solutions has been examined through CD, fluorescence, ITC, DLS, zeta potential, and agarose gel electrophoresis. DNA compaction has been observed upon interaction with PMSAILs in dilute solutions. PMSAIL with isoquinolinium cation was found more efficient towards the DNA compaction. Decompaction of DNA could be achieved simply with the addition of NaCl. Further, the application of PMSAILS as MRI contrast materials has been explored. All the investigated PMSAILS exhibited excellent dual mode T1 & T2 contrast property in low concentration regime. To improve the real-time practical importance, MRI results have been compared with clinically available Gd-BOPTA based MRI contrast agent.

T1- and T2-weighted Magnetic Resonance Dual Contrast by Single Core Truncated Cubic Iron Oxide Nanoparticles with Abrupt Cellular Internalization and Immune Evasion.

Conventional T1- or T2-weighted single mode contrast-enhanced magnetic resonance imaging (MRI) may produce false results. Thereby, there is a need to develop dual contrast agents, T1- and T2-weighted, for more accurate MRI imaging. The dual contrast agents should possess high magnetic resonance (MR) relaxivities, targeted tumor linking, and minimum recognition by the immune system. We have developed nitrodopamine-PEG grafted single core truncated cubic iron oxide nanoparticles (ND-PEG-tNCIOs) capable of producing marked dual contrasts in MRI with enhanced longitudinal and transverse relaxivities of 32 ± 1.29 and 791 ± 38.39 mM–1 s–1, respectively. Furthermore, the ND-PEG-tNCIOs show excellent colloidal stability in physiological buffers and higher cellular internalization in cancerous cells than in phagocytic cells, indicating the immune evasive capability of the nanoparticles. These findings indicate that tNCIOs are strong candidates for dual contrast MRI imaging, which is vital for noninvasive real-time detection of nascent cancer cells in vivo and for monitoring stem cells transplants.

Shale pore size classification: An NMR fluid typing method

Abstract Shale reservoir is characterized by complex pore networks, within which there are various pore fluids including unrecoverable fluid, capillary bound fluid and movable fluid. Although considerable literature has investigated the pore structure of gas shale using different laboratory testing techniques, few papers have provided a quantified model to distinguish different types of fluids (corresponding to different pore types) in shale. In this study, seven shale core plugs from the Sichuan Basin were measured in a series of NMR experiments under full brine-saturated, centrifugal and heat-treated conditions to analyze the pore structure information and pore fluid transport during the processes of centrifuging and heating. For a typical T2 spectrum of 100% brine-saturated shale, the movable fluid T2 cutoff (T2C1) and unrecoverable fluid cutoff (T2C2) were derived from NMR centrifugal and heat-treated experiments to distinguish the unrecoverable fluid (T2 T2C1). Our results show that for the investigated shales, the T2C2 ranges from 0.09 ms to 0.36 ms, and T2C1 has a wide range from 0.45 ms to 2.98 ms. The surface relaxivities range from 0.00426 μm/ms to 0.02822 μm/ms, and the shales having high silicate mineral contents commonly have low surface relaxivities. A conceptional model based on the dual T2 cutoff method was constructed to illustrate the full-scale pore size distribution: unrecoverable fluid pores, capillary bound fluid pores and movable fluid pores. This study provides a new method of pore fluid typing and full-scale pore size distribution classification for shales.

Dual T1 and T2 weighted magnetic resonance imaging based on Gd3+ loaded bioinspired melanin dots

In this report, a novel T1/T2 dual modal nanoprobe based on highly efficient and bioinspired melanin dots (M-dots) with directly loading gadolinium (Gd-M-dots) for magnetic resonance imaging (MRI) is described. In vitro and in vivo investigations have revealed that Gd-M-dots showed nontoxicity and good biocompatibilitity. Gd-M-dots relaxivity values on 3 T were determined to be r1 = 23.4 and r2 = 123.3 mM−1 s−1, which were much higher than both Gd-DTPA (r1 = 5.1, r2 = 6.2 mM−1 s−1) and Fe-M-dots (r1 = 1.2, r2 = 2.1 mM−1 s−1). For in vivo MRI, after injection of Gd-M-dots, simultaneous T1 and T2 contrast enhancement have been observed in the MRI of mice abdomen and mice bearing U87MG tumors. Furthermore, all the veins showed high signal intensity on T1-weighted MRI and remained for 2 h. Overall, in vitro and in vivo studies indicate that Gd-M-dot with high r1 relaxivity and r2 relaxivity has high potential to be a promising nanoprobe for MR venography and molecular imaging.

Novel bionanotechnological solutions based on metal oxide and metal to preserve and assess organs for transplantation

Our research has focused on nanomaterials for the diagnosis and treatment of cardiovascular disease (CVD) such as thrombosis. These materials can be adapted for preserving and assessing organs for transplantation. Magnetic resonance imaging (MRI) has been used as a powerful and indispensable tool in medical research and clinical diagnosis. We have developed both targeted negative contrast agents and targeted dual positive/negative contrast agents for molecular imaging of thrombosis. The simultaneous use of positive and negative MRI imaging that employs the same contrast agents will significantly improve detection accuracy. Using the dual contrast agent, both T1- and T2-weighted MRI of thrombosis can be simultaneously recorded which enables self-confirmation of images and leads to a greater diagnostic accuracy1 . To prepare these targeted agents, we employed a single-chain antibody that targets activated platelets, a major player in thrombus formation. Our contrast agents can be adapted for assessing organs during and after transplantation. It has been reported that platelets are activated early during reperfusion after an ischaemia/reperfusion injury (IRI). Therefore, by targeting activated platelets and platelet accumulation, it is possible to noninvasively detect and assess IRI early, maximizing medical interventions. We have also developed smart MRI nanosensors based on iron oxide and gadolinium that can not only detect, but also sense and report the stage or progression of CVD such as thrombosis. The early detection and accurate characterization of life-threatening diseases such as CVD are critical to the design of treatment. Knowing whether a thrombus in a blood vessel is new/fresh or old/constituted is very important for physicians to decide on a treatment protocol. These nanosensors can be adapted, modified and applied for detecting and grading other diseases such as cancer, and also for sensitive detection of inflammatory reactions during organ preservation, perfusion and transplantation processes. It can be a useful technique to potentially allow other researchers to access information previously difficult to obtain. It can also be a new tool for clinicians to assess organs before and after transplantation, maximizing opportunities for medical intervention. Since our nanosensors are iron oxide and gadolinium based materials, they can also be used for preservation of organs/tissues. Recently researchers have reported a way to safely thaw frozen tissues with the aid of iron oxide nanoparticles2 . By suffusing the nanosensors over organs/tissues before freezing, they may help in the thawing process and may directly provide information on inflammatory reactions within the organs/tissues after thawing and reperfusion

Gadolinium-labelled iron/iron oxide core/shell nanoparticles as T 1-T 2 contrast agent for magnetic resonance imaging.

Magnetic resonance imaging (MRI) is indispensable and powerful in modern clinical diagnosis and has some advantages such as non-invasiveness and high penetration depth. Furthermore, dual T1–T2 MR imaging has attracted crucial interest as it can decrease the risk of pseudo-positive signals in diagnosing lesions. And it's worth nothing that the dual-mode MR imaging displays a vital platform to provide relatively comprehensive diagnosis information and receive accurate results. Herein, we report a dual T1–T2 MR imaging contrast agent (CA) grounded on the iron/iron oxide core/shell nanomaterials conjugated with gadolinium chelate. The Gd-labeled Fe@Fe3O4 NPs reveal the feasibility to utilize them to serve as a dual T1–T2 MR imaging CA, and the relaxivity results in a 0.5 T MR system showed a longitudinal relaxivity value (r1) and transverse relaxivity value (r2) of 7.2 mM−1 s−1 and 109.4 mM−1 s−1, respectively. The MTT results demonstrate the Gd-labeled Fe@Fe3O4 NPs have no obvious cytotoxicity and a good compatibility. The in vitro and in vivo MRI generated a brighter effect and darkening in T1-weighted MR imaging and T2-weighted images, respectively. The results clearly indicate that Gd-labeled Fe@Fe3O4 NPs have potential as a magnetic resonance imaging contrast reagent.

Application of Dye‐coated Ultrasmall Gadolinium Oxide Nanoparticles for Biomedical Dual Imaging

Nanoparticles are very important in biomedical imaging because their imaging properties are superior to those of small molecules. They can be further functionalized for multimodal imaging through surface modification. In this study, we synthesized dye‐coated ultrasmall gadolinium oxide nanoparticles [dye = fluorescein and fluorescein isothiocyanate (FITC)] in one‐pot and investigated their dual imaging properties. The dye‐coated gadolinium oxide nanoparticles exhibited excellent relaxometric properties suitable for T1 magnetic resonance imaging (MRI): r1 = 9.8 s−1mM−1 (r2/r1 = 2.6) for fluorescein‐coated nanoparticles (davg = 1.6 ± 0.1 nm) and r1 = 12.3 s−1mM−1 (r2/r1 = 2.3) for FITC‐coated nanoparticles (davg = 1.4 ± 0.1 nm), and strong photoluminescence (PL) in the green region (around 514 nm) suitable for fluorescent imaging (FI). The dye‐coated nanoparticles exhibited strong fluorescence in cellular confocal images and high contrast in T1 MR images in mice, suggesting that they are potential dual T1 MRI‐FI agents.

Gadolinium hybrid iron oxide nanocomposites for dual T1- and T2-weighted MR imaging of cell labeling.

Tracking of cells in biological systems is critically important for monitoring disease treatment, such as in stem cell therapy. This report prepared new types of biocompatible gadolinium hybrid iron oxide (GdIO) nanocomposites, which demonstrated high sensitivity for dual T1- and T2-weighted magnetic resonance imaging (MRI). The GdIO nanocomposites could efficiently label mesenchymal stem cells (MSCs) by incubation for 24 h at a safe dose, as they did not affect the cell viability, proliferation or differentiation capacity. There was high contrast enhancement in the GdIO-labeled stem cells for dual T1- and T2-weighted MR imaging. In addition, the GdIO nanocomposites were injected into adult mouse lateral ventricles, where cells could be labeled to monitor their biological behaviors by MRI. These GdIO nanocomposites with dual-imaging functions are a good platform for cell labeling and other diagnostic applications.