Imaging Contrast Effect Research Articles

Edge enhancement in three-dimensional vortex imaging based on FINCH by Bessel-like spiral phase modulation.

Edge enhancement, as an important part of image processing, has played an essential role in amplitude-contrast and phase-contrast object imaging. The edge enhancement of three-dimensional (3D) vortex imaging has been successfully implemented by Fresnel incoherent correlation holography (FINCH), but the background noise and image contrast effects are still not satisfactory. To solve these issues, the edge enhancement of FINCH by employing Bessel-like spiral phase modulation is proposed and demonstrated. Compared with the conventional spiral phase modulated FINCH, the proposed technique can achieve high-quality edge enhancement 3D vortex imaging with lower background noise, higher contrast and resolution. The significantly improved imaging quality is mainly attributed to the effective sidelobes' suppression in the generated optical vortices with the Bessel-like modulation technique. Experimental results of the small circular aperture, resolution target, and the Drosophila melanogaster verify its excellent imaging performance. Moreover, we also proposed a new method for selective edge enhancement of 3D vortex imaging by breaking the symmetry of the spiral phase in the algorithmic model of isotropic edge enhancement. The reconstructed images of the circular aperture show that the proposed method is able to enhance the edges of the given objects selectively in any desired direction.

Two-photon nanoprobes based on bioorganic nanoarchitectonics with a photo-oxidation enhanced emission mechanism

Two-photon absorption (TPA) fluorescence imaging holds great promise in diagnostics and biomedicine owing to its unparalleled spatiotemporal resolution. However, the adaptability and applicability of currently available TPA probes, which act as a critical element for determining the imaging contrast effect, is severely challenged by limited photo-luminescence in vivo. This is particularly a result of uncontrollable aggregation that causes fluorescence quenching, and inevitable photo-oxidation in harsh physiological milieu, which normally leads to bleaching of the dye. Herein, we describe the remarkably enhanced TPA fluorescence imaging capacity of self-assembling near-infrared (NIR) cyanine dye-based nanoprobes (NPs), which can be explained by a photo-oxidation enhanced emission mechanism. Singlet oxygen generated during photo-oxidation enables chromophore dimerization to form TPA intermediates responsible for enhanced TPA fluorescence emission. The resulting NPs possess uniform size distribution, excellent stability, more favorable TPA cross-section and anti-bleaching ability than a popular TPA probe rhodamine B (RhB). These properties of cyanine dye-based TPA NPs promote their applications in visualizing blood circulation and tumoral accumulation in real-time, even to cellular imaging in vivo. The photo-oxidation enhanced emission mechanism observed in these near-infrared cyanine dye-based nanoaggregates opens an avenue for design and development of more advanced TPA fluorescence probes.

Adjacency effect correction of the GF-1 image in coastal waters of Hangzhou Bay and Taihu Lake, China

For coastal waters, the radiation signals received by the sensor are affected by the high reflectance of the coastal land, inducing reduced image contrast and significant adjacency effect. Eliminate the atmospheric attenuation and adjacency effect, and obtain the accurate remote sensing reflectance above water surface is an important prerequisite for the quantitative water color remote sensing. Based on the in situ spectral data of the coastal Hangzhou Bay, China on July 23, 2017 and the Taihu Lake, China on April 29, 2016, as well as the synchronous Gaofen-1 wide field-of-view camera (GF-1/ WFV) images, the 6S model was used to eliminate the atmospheric attenuation, and a point spread kernel function was used to correct the adjacency effect. The experimental results show that the images after adjacency effect correction are clearer, with increased image contrast and more abundant information of the water body. Compared to the atmospheric correction results only after the 6S model, the average relative errors of three in situ synchronous samples in Hangzhou Bay after adjacency effect correction are reduced by 8.39%, 10.81% and 7.29%, and that in Taihu Lake after adjacency effect correction are reduced by 10.8%, 5.24% and 0.39%, respectively. The adjacency effect correction improves the radiation detection accuracy of the remote sensing reflectance above water surface and can be a reference for quantitative water color remote sensing in coastal waters.

Modification of PEG reduces the immunogenicity of biosynthetic gas vesicles.

Nanobubbles have received great attention in ultrasound molecular imaging due to their capability to pass through the vasculature and reach extravascular tissues. Recently, gas vesicles (GVs) from archaea have been reported as acoustic contrast agents, showing great potential for ultrasound molecular imaging. However, the immunogenicity and biosafety of GVs has not yet been investigated. In this study, we examined the immune responses and biosafety of biosynthetic GVs and polyethylene glycol (PEG)-modified GVs (PEG-GVs) in vivo and in vitro. Our findings suggest that the plain GVs showed significantly stronger immunogenic response than PEG-GVs. Less macrophage clearance rate of the RES and longer circulation time were also found for PEG-GVs, thereby producing the better contrast imaging effect in vivo. Thus, our study demonstrated the PEG modification of biosynthetic GVs from Halobacterium NRC-1 is helpful for the future application of GVs in molecular imaging and treatment.

The Influence of Echo Train Duration on Heavily T2-weighted-dimensional MR Cholangiopancreatography Using Turbo Spin-echo Technique: A Phantom Study

Magnetic resonance cholangiopancreatography (MRCP) is a valuable non-invasive technique that depicts bile or pancreatic juice as hyperintense in heavily T2-weighted images. Data acquisition in the three-dimensional multi-slice MRCP method is acquired with respiratory triggered. Echo train duration (ETD) is the data acquisition time every breath is in inverse proportion to total acquisition time, and has influence of image contrast and spatial resolution in turbo spin echo (TSE) imaging. Therefore, the effects of image contrast and spatial resolution of three-dimensional heavily T2-weighted variable refocusing flip angle TSE images on ETD in fundamental and clinical settings were measured using a phantom. No significant difference was detected with regard to image contrasts. Increasing ETD reduced spatial resolution, but no significant difference was detected regarding visual evaluation in the fundamental setting. On the other hand, in some of the clinical settings, increasing ETD with phase partial Fourier (PPF) reduced spatial resolution. The study result indicates that changing ETD fitting respiratory state of individual examinee without PPF is useful for optimized acquisition time without sacrificing image contrast and spatial resolution.

Biocompatible Mesoporous Silica-Polydopamine Nanocomplexes as MR/Fluorescence Imaging Agent for Light-Activated Photothermal-Photodynamic Cancer Therapy In Vivo.

Conventional cancer phototherapy with single modality suffers from low therapeutic efficacy and undesired posttreatment damage for adjacent normal tissues. Therefore, the lower NIR laser irradiation power is vital to the reduction or preclusion of risk of scalds and burns in normal tissues. Herein, we rationally proposed a novel multifunctional nanocomplex, which enabled good magnetic resonance (MR) imaging contrast effect and promising photothermal conversion efficacy. The prepared core/shell nanocomplexes [MSN-Ce6@PDA (Mn)] were composed of chlorin e6-embedded mesoporous silica/nanoparticle composites as the cores, and then polydopamine and manganese ions were conjugated on the cores to form protective shells. The MSN-Ce6@PDA (Mn) nanocomplexes revealed superior properties in colloidal stability, photothermal conversion, reaction oxygen species generation, magnetic resonance imaging, etc. Under the guidance of MR and fluorescence imaging, these MSN-Ce6@PDA (Mn) nanocomplexes were found to be primarily accumulated in the MDA-MB-231 tumor area. Furthermore, the combined photodynamic and photothermal therapy exhibited strong inhibition to the growth of MDA-MB-231 tumor in vitro and in vivo. Besides, the MSN-Ce6@PDA (Mn) nanocomplexes also exhibited excellent biocompatibility and low damage to the healthy animals. Hence, the results demonstrated that the prepared MSN-Ce6@PDA (Mn) nanocomplex would be a promising potential for multimodal imaging-guided phototherapy.

Steady-state visual evoked potential responses predict visual discomfort judgements.

It has been suggested that aesthetically pleasing stimuli are processed efficiently by the visual system, whereas uncomfortable stimuli are processed inefficiently. This study consists of a series of three experiments investigating this idea using a range of images of abstract artworks, photographs of natural scenes, and computer-generated stimuli previously shown to be uncomfortable. Subjective judgements and neural correlates were measured using electroencephalogram (EEG) (steady-state visual evoked potentials, SSVEPs). In addition, global image statistics (contrast, Fourier amplitude spectral slope and fractal dimension) were taken into account. When effects of physical image contrast were controlled, fractal dimension predicted discomfort judgements, suggesting the SSVEP response is more likely to be influenced by distribution of edges than the spectral slope. Importantly, when effects of physical contrast and fractal dimension were accounted for using linear mixed effects modelling, SSVEP responses predicted subjective judgements of images. Specifically, when stimuli were not matched for perceived contrast, there was a positive relationship between SSVEP responses and how pleasing a stimulus was judged to be, and conversely a negative relationship between discomfort and SSVEP response. This is significant as it shows that the neural responses in early visual areas contribute to the subjective (un)pleasantness of images, although the results of this study do not provide clear support for the theory of efficient coding as the cause of perceived pleasantness or discomfort of images, and so other explanations need to be considered.

Perfect social media image posts: symmetry and contrast influence consumer response

PurposeTwo studies investigate how different structural properties of images – symmetry (vertical and horizontal) and image contrast – affect social media marketing outcomes of consumer liking and engagement.Design/methodology/approachIn Study 1’s experiment, 361 participants responded to social media marketing images that varied in vertical or horizontal symmetry and level of image contrast. Study 2 analyzes field data on 610 Instagram posts.FindingsStudy 1 demonstrates that vertical or horizontal symmetry and high image contrast increase consumer liking of social media marketing images, and that processing fluency and aesthetic response mediate these relationships. Study 2 reveals that symmetry and high image contrast improve consumer engagement on social media (number of “likes” and comments).Research limitations/implicationsThese studies extend theory regarding processing fluency’s and aesthetic response’s roles in consumer outcomes within social media marketing. Image posts’ structural properties affect processing fluency and aesthetic response without altering brand information or advertising content.Practical implicationsBecause consumer liking of marketing communications (e.g. social media posts) predicts persuasion and sales, results should help marketers design more effective posts and achieve brand-building and behavioral objectives. Based on the results, marketers are urged to consider the processing fluency and aesthetic response associated with any image developed for social media marketing.Originality/valueAddressing the lack of empirical investigations in the existing literature, the reported studies demonstrate that effects of symmetry and image contrast in generating liking are driven by processing fluency and aesthetic response. Additionally, these studies establish novel effects of images’ structural properties on consumer engagement with brand-based social media marketing communications.

Enhancing magnetic resonance imaging of bio-based nano-contrast via anchoring manganese on rod-shaped cellulose nanocrystals

Manganese-based nano materials used to enhance nano-contrasts in magnetic resonance imaging have low toxicity but suffer from a weak contrast imaging effect due to their low longitudinal relaxivity (r1). Moreover, the nanoparticle contrasts of manganese salt probably release manganese ions into the patient body during and after imaging process, causing potential toxicity problems. Thus, we took advantage of rod-shaped cellulose nanocrystals (CNCs) functionalized by diethylenetriamine pentaacetic dianhydride (coded as DCNCs) to anchor Mn2+ and improve its r1 for biocompatibility, highly chemical activity, and high specific area. Theoretical analysis indicated that the r1 could increase with the anchoring rate of Mn2+ on rod-shaped particles, and the large number of hydroxyl groups on CNCs made them able to carry as much as 5.9 mmol·g−1 of Mn2+. Then, we found the r1 increased linearly as the anchoring degree increased, up to 57.71 mM−1·s−1. The obtained DCNCs anchoring Mn2+ (Mn2+@DCNCs) nano-contrast showed low toxicity on RAW 264.7 and HUVEC, where the viability of the two cells was higher than 80%. Therefore, such a high r1 Mn2+-based material presents great advantage of commercial manganese and gadolinium contrasts, making the Mn2+@DCNCs of potential on diagnosing tumors and drug release.

Functionalized g-C3N4 nanosheets for potential use in magnetic resonance imaging-guided sonodynamic and nitric oxide combination therapy

The oxygen consumption-induced hypoxia and the high concentration of glutathione in tumor microenvironment limit the treatment outcomes of sonodynamic therapy (SDT). SDT needs to be combined with other treatment modalities to achieve the desired therapeutic efficiency. In this study, an oxidized g-C3N4 (OCN) nanosheet-based theranostic nanoplatform is developed for sonodynamic and nitric oxide (NO) combination therapy of cancer. The OCN nanosheets are successively modified with amino-terminated 6-armed polyethylene glycol, chlorin e6, and Gd3+ ions, and then the as-prepared OCN-PEG-(Ce6-Gd3+) nanosheets are loaded with the NO donor N,N′-di-sec-butyl-N,N′-dinitroso-1,4-phenylenediamine (BNN6). Upon ultrasound (US) irradiation, the OCN-PEG-(Ce6-Gd3+)/BNN6 nanocomposite can induce the generation of reactive oxygen species (ROS) and simultaneously release NO molecules to effectively kill the cancer cells, thereby significantly suppressing the tumor growth. Moreover, a good in vivo T1-weighted magnetic resonance imaging (MRI) contrast effect is achieved after intravenous injection of OCN-PEG-(Ce6-Gd3+)/BNN6 due to remarkably enhanced contrast performance of the nanocomposite. Therefore, the OCN-PEG-(Ce6-Gd3+)/BNN6 formulation can serve as a promising theranostic agent for MRI-guided sonodynamic-NO combination therapy.

Sialic acid-engineered mesoporous polydopamine nanoparticles loaded with SPIO and Fe3+ as a novel theranostic agent for T1/T2 dual-mode MRI-guided combined chemo-photothermal treatment of hepatic cancer

Hepatic cancer is a serious disease with high morbidity and mortality. Theranostic agents with effective diagnostic and therapeutic capability are highly needed for the treatment of hepatic cancer. Herein, we aimed to develop a novel mesoporous polydopamine (MPDA)-based theranostic agent for T1/T2 dual magnetic resonance imaging (MRI)-guided cancer chemo-photothermal therapy. Superparamagnetic iron oxide (SPIO)-loaded MPDA NPs (MPDA@SPIO) was firstly prepared, followed by modifying with a targeted molecule of sialic acid (SA) and chelating with Fe3+ (SA-MPDA@SPIO/Fe3+ NPs). After that, doxorubicin (DOX)-loaded SA-MPDA@SPIO/Fe3+ NPs (SA-MPDA@SPIO/DOX/Fe3+) was prepared for tumor theranostics. The prepared SAPEG-MPDA@SPIO/Fe3+ NPs were water-dispersible and biocompatible as evidenced by MTT assay. In vitro photothermal and relaxivity property suggested that the novel theranostic agent possessed excellent photothermal conversion capability and photostability, with relaxivity of being r1 = 4.29 mM−1s−1 and r2 = 105.53 mM−1s−1, respectively. SAPEG-MPDA@SPIO/Fe3+ NPs could effectively encapsulate the DOX, showing dual pH- and thermal-triggered drug release behavior. In vitro and in vivo studies revealed that SA-MPDA@SPIO/DOX/Fe3+ NPs could effectively target to the hepatic tumor tissue, which was possibly due to the specific interaction between SA and the overexpressed E-selectin. This behavior also endowed SA-MPDA@SPIO/DOX/Fe3+ NPs with a more precise T1-T2 dual mode contrast imaging effect than the one without SA modification. In addition, SAPEG-MPDA@SPIO/DOX/Fe3+ NPs displayed a superior therapeutic effect, which was due to its active targeting ability and combined effects of chemotherapy and photothermal therapy. These results demonstrated that SAPEG-MPDA@SPIO/DOX/Fe3+ NPs is an effective targeted nanoplatform for tumor theranostics, having potential value in the effective treatment of hepatic cancer.

Model for selecting the Earth observation satellite systems by object recognition probability

Model for selecting the Earth observation satellite systems by object recognition probability

Biological Durability, Cytotoxicity and MRI Image Contrast Effects of Chitosan Modified Magnetic Nanoparticles.

In this manuscript, biological durability, cytotoxicity and MRI image contrast effect of chitosan modified magnetic nanoparticles were investigated. The result of durability study shows that the asprepared sample with average size of about 30 nm had a high stability under pH conditions in range of from 2 to 12 and at salt concentration in range of from 0 to 300 mM. The cytotoxicity testing indicates that the obtained Fe₃O₄@CS ferrofluid revealed a low cytotoxicity. After 48 h of test on the line of prostate tumor cells of Sarcoma 180, collected IC50 value was 178.5±22 (μg/ml), 7.5 to 27.9 times less cytotoxicity than that of reported ferromagnetic fluids. MRI data shows that the transverse relaxation rate (r2) of the ferrite nanoparticles was 130.32 (mM-1s-1), 2 and 1.44 times larger than that of the commercial products of Sinerem (AMI-227) and Ferumoxytol products, respectively. Invivo test in rabbit shows that the picture of body parts was clearly observed after the injection of the Fe₃O₄@CS ferrofluid. With these outstanding properties, this magnetic fluid based on the chitosan modified Fe₃O₄ nanoparticles had great potential for enhancing the image contrast in image diagnosis by MRI magnetic resonance imaging technique.

Targeted NIRF/MR dual-mode imaging of breast cancer brain metastasis using BRBP1-functionalized ultra-small iron oxide nanoparticles.

Tumor metastasis to brain is the main clinical manifestation of patients with advanced breast cancer, leading to poor survival prognosis. In order to detect the early incidence of brain metastasis, it is urgent to develop hypersensitive contrast agents for multimode imaging. In this study, PEG-phospholipids coated, a phage play derived peptide, BRBP1 peptide modified ultra-small iron oxide nanoparticles were prepared for targeted NIRF and MR imaging of breast cancer brain metastasis. The nanoparticles showed 10nm core-shell, high relaxivity values and photon emission efficiency in vitro. The nanoparticles offered a T2 contrast imaging effect and near-infrared fluorescent signal enhancement. Compared with control peptide modified nanoparticles, the MR/NIRF imaging signal of BRBP1-modified nanoparticles in tumor tissue was significantly enhanced, which should be induced by the targeting ability of BRBP1 peptide. These results indicated that BRBP1-SPIO@mPEG (DiR) nanoparticles could be applied as an effective targeted delivery system for diagnosis of breast cancer brain metastasis.

Inner structure- and surface-controlled hollow MnO nanocubes for high sensitive MR imaging contrast effect

Manganese oxide (MnO) nanocubes were fabricated and their surface were modified by ligand encapsulation or ligand exchange, to render them water-soluble. And then, MnO formed the hollow structure by etching using acidic solution (phthalate buffer, pH 4.0). Depending on the ligand of the MnO surface, it increases the interaction between MnO and water molecules. Also, the hollow structure of MnO, as well as the ligand, can greatly enhance the accessibility of water molecules to metal ions by surface area-to-volume ratio. These factors provide high R1 relaxation, leading to strong T1 MRI signal. We have confirmed T1-weighted MR contrast effect using 4-kinds of MnO nanocubes (MnOEn, MnOEnHo, MnOEx and MnOExHo). They showed enough a MR contrast effect and biocompatibility. Especially, among them, MnOExHo exhibited high T1 relaxivity (r1) (6.02 mM−1 s−1), even about 1.5 times higher sensitivity than commercial T1 MR contrast agents. In vitro/in vivo studies have shown that MnOExHo provides highly sensitive T1-weighted MR imaging, thereby improving diagnostic visibility at the disease site.

Genetic Encoding of Targeted Magnetic Resonance Imaging Contrast Agents for Tumor Imaging.

Tumor-selective contrast agents have the potential to aid in the diagnosis and treatment of cancer using noninvasive imaging modalities such as magnetic resonance imaging (MRI). Such contrast agents can consist of magnetic nanoparticles incorporating functionalities that respond to cues specific to tumor environments. Genetically engineering magnetotactic bacteria to display peptides has been investigated as a means to produce contrast agents that combine the robust image contrast effects of magnetosomes with the transgenic-targeting peptides displayed on their surface. This work reports the first use of magnetic nanoparticles that display genetically encoded pH low insertion peptide (pHLIP), a long peptide intended to enhance MRI contrast by targeting the extracellular acidity associated with the tumors. To demonstrate the modularity of this versatile platform to incorporate diverse targeting ligands by genetic engineering, we also incorporated the cyclic αv integrin-binding peptide iRGD into separate magnetosomes. Specifically, we investigate their potential for enhanced binding and tumor imaging both in vitro and in vivo. Our experiments indicate that these tailored magnetosomes retain their magnetic properties, making them well suited as T2 contrast agents, while exhibiting an increased binding compared to the binding in wild-type magnetosomes.

Photoacoustic Imaging Guided Photothermal and Chemodynamic Combined Therapy for Cancer Using "All in One" W18O49 Nanorod Agent.

Chemodynamic therapy based on Fenton or Fenton-like reactions is an emerging cancer therapy that has attracted considerable attention due to its high selectivity for tumors. However, the low catalytic efficiency of the Fenton or Fenton-like agent limits its therapeutic effect. Combination therapies based on chemodynamic therapy using "all-in-one" agents show great potential for cancer treatment. In this study, W18O49 nanorods with strong near-infrared absorption and excellent Fenton-like reaction performance were prepared, and their application in photoacoustic imaging-guided photothermal-chemodynamic combination cancer therapy was explored. First, hydrophobic W18O49 nanorods were synthesized via a one-step pyrolysis method. Hydrophilic W18O49 nanorods were then prepared via hydrophobic self-assembly between oleyl amine-coated W18O49 nanorods and an amphiphilic polymer. The W18O49 nanorods exhibited good photoacoustic, photothermal, and chemodynamic performance in vitro along with good photoacoustic imaging contrast and excellent therapeutic effect in photothermal-chemodynamic combination cancer therapy in vivo. This study provides a low-cost and easy-to-prepare agent for photothermal-chemodynamic combination therapy and promotes the application of photothermal-chemodynamic combination therapy in cancer treatment.

Novel contrast media based on the liquid metal gallium for in vivo digestive tract radiography: a feasibility study

The barium sulfate has been playing an important role as the contrast medium in gastrointestinal radiography and disease diagnosis. However, its application has been gradually reduced due to the limitation of its imaging effect and the progress of other imaging techniques. Here, the liquid metal gallium was proposed as an improved contrast agent, which was applied in the in vivo digestive tract radiography of the mice for the first time. Under the CT scanning, the gallium produced excellent contrast effect intuitively. According to the records of discharge time, the tissue sections of organs, the survival state and body weight, the liquid metal was proven to be capable and safe for gastrointestinal radiography. Further, the mixture of the gallium and the barium sulfate has been tested, which showed better performance in both contrast and detail. Therefore, with the characteristics of better imaging contrast effect and acceptable safety, the gallium and its mixture with the barium sulfate might be useful as potential candidates for digestive tract contrast agent in animal experiments, even possibly as alternative contrast agents for clinical use.

Magnetic targeting combined with active targeting of dual-ligand iron oxide nanoprobes to promote the penetration depth in tumors for effective magnetic resonance imaging and hyperthermia

The combination of multi-targeting magnetic nanoprobes and multi-targeting strategies has potential to facilitate magnetic resonance imaging (MRI) and magnetic induction hyperthermia of the tumor. Although the thermo-agents based on magnetic iron oxide nanoparticles (MION) have been successfully used in the form of intratumoral injection in clinical cure of glioblastoma, the tumor-targeted thermotherapy by intravenous administration remains challenging. Herein, we constructed a c(RGDyK)- and d-glucosamine-grafted bispecific molecular nanoprobe (Fe3O4@RGD@GLU) with a magnetic iron oxide core of size 22.17 nm and a biocompatible shell of DSPE-PEG2000, which can specially target the tumor vessel and cancer cells. The selection of c(RGDyK) could make the nanoprobe enter the neovascularization endotheliocyte through αvβ3-mediated endocytosis, which drastically reduced the dependence on the enhanced permeability and retention (EPR) effect in tumor. This dual-ligand nanoprobe exhibited strong magnetic properties and favorable biocompatibility. In vitro studies confirmed the anti-phagocytosis ability against macrophages and the specific targeting capability of Fe3O4@RGD@GLU. Then, the imaging effect and anti-tumor efficacy were compared using different targeting strategies with untargeted nanoprobes, dual-targeted nanoprobes, and magnetic targeting combined with dual-targeted nanoprobes. Moreover, the combination strategy of magnetic targeting and active targeting promoted the penetration depth of nanoprobes in addition to the increased accumulation in tumor tissue. Thus, the dual-targeted magnetic nanoprobe together with the combined targeting strategy could be a promising method in tumor imaging and hyperthermia through in vivo delivery of theranostic agents. Statement of SignificanceMagnetic induction hyperthermia based on iron oxide nanoparticles has been used in clinic for adjuvant treatment of recurrent glioblastoma. Nonetheless, this application is limited to intratumoral injection, and tumor-targeted hyperthermia by intravenous injection remains challenging. In this study, we developed a multi-targeted strategy by combining magnetic targeting with active targeting of dual-ligand magnetic nanoprobes. This combination mode acquired optimum contrast imaging effect through MRI and tumor-suppressive effect through hyperthermia under an alternating current magnetic field. The design of the nanoprobe was suitable for targeting most tumor lesions, which enabled it to be an effective theranostic agent with extensive uses. This study showed significant enhancement of the penetration depth and accumulation of nanoprobes in the tumor tissue for efficient imaging and hyperthermia.

Factors affecting the harmonization of disease-related metabolic brain pattern expression quantification in [18F]FDG-PET (PETMETPAT)

IntroductionThe implementation of spatial-covariance [18F]fluorodeoxyglucose positron emission tomography–based disease-related metabolic brain patterns as biomarkers has been hampered by intercenter imaging differences. Within the scope of the JPND-PETMETPAT working group, we illustrate the impact of these differences on Parkinson's disease–related pattern (PDRP) expression scores. MethodsFive healthy controls, 5 patients with idiopathic rapid eye movement sleep behavior disorder, and 5 patients with Parkinson's disease were scanned on one positron emission tomography/computed tomography system with multiple image reconstructions. In addition, one Hoffman 3D Brain Phantom was scanned on several positron emission tomography/computed tomography systems using various reconstructions. Effects of image contrast on PDRP scores were also examined. ResultsHuman and phantom raw PDRP scores were systematically influenced by scanner and reconstruction effects. PDRP scores correlated inversely to image contrast. A Gaussian spatial filter reduced contrast while decreasing intercenter score differences. DiscussionImage contrast should be considered in harmonization efforts. A Gaussian filter may reduce noise and intercenter effects without sacrificing sensitivity. Phantom measurements will be important for correcting PDRP score offsets.