Imaging Performance Research Articles

Exploring the value of multiparametric quantitative MRI in the assessment of pancreatic ductal adenocarcinoma fibrosis grading.

To analyze the performance of multiparametric magnetic resonance imaging (MRI) in quantification of pancreatic ductal adenocarcinoma (PDAC) fibrosis grading. This prospective study enrolled 79 patients with PDAC confirmed by pathology. Multiparametric MRI including native T1 mapping, intravoxel incoherent motion diffusion-weighted imaging (IVIM-DWI), diffusion kurtosis imaging diffusion-weighted imaging (DKI-DWI), and enhanced T1 mapping were performed before surgery. Masson staining was used to evaluate intratumoral fibrosis content and classified into low- and high-fibrosis groups. MRI parameters were compared between the two groups using multivariable logistic regression analysis. The correlations between fibrosis content and MRI parameters were evaluated using Pearson's correlation. D, f, mean diffusion (MD), and enhanced T1 mapping were lower in the high-fibrosis group than in the low-fibrosis group (p < 0.001, p < 0.001, p < 0.001, p = 0.026, respectively). Native T1 mapping and extracellular volume (ECV) were opposite (All p < 0.001). No significant differences in the rest. Multivariable logistic regression revealed that native T1 mapping, MD, and ECV were independent discriminators for PDAC fibrosis grading (p = 0.037, p = 0.031, p = 0.014, respectively); the area under the curve (AUC) of native T1 mapping, MD and ECV was 0.863, 0.798, and 0.929. Among them, ECV had an extremely strong positive correlation with intratumoral fibrosis content. Native T1 mapping and MD were correlated strongly with fibrosis content (positive and negative, respectively). ECV had the highest assessing performance for grading fibrosis in PDAC compared to other MRI parameters, and has the potential to be an imaging biomarker for predicting the fibrosis content of PDAC. Question The relationship between fibrosis grade of PDAC and quantitative MRI parameters based on T1 mapping and diffusion imaging has not been fully investigated. Findings ECV performed the best in distinguishing between fibrosis grade and increased as interstitial fibrosis increased; clinical indicators offered no added value. Clinical relevance Quantitative MRI parameters provide significant value in evaluating the fibrosis grade of PDAC, which bears significant implications for preoperative risk stratification and the selection of personalized treatment strategies for patients.

A device-dependent auto-segmentation method based on combined generalized and single-device datasets.

Although generalized-dataset-based auto-segmentation models that consider various computed tomography (CT) scanners have shown great clinical potential, their application to medical images from unseen scanners remains challenging because of device-dependent image features. This study aims to investigate the performance of a device-dependent auto-segmentation model based on a combined dataset of a generalized dataset and single CT scanner dataset. We constructed two training datasets for 21 chest and abdominal organs. The generalized dataset comprised 1203 publicly available multi-scanner data. The device-dependent dataset comprised 1253 data, including the 1203 multi-CT scanner data and 50 single CT scanner data. Using these datasets, the generalized-dataset-based model (GDSM) and the device-dependent-dataset-based model (DDSM) were trained. The models were trained using nnU-Net and tested on ten data samples from a single CT scanner. The evaluation metrics included the Dice similarity coefficient (DSC), the Hausdorff distance (HD), and the average symmetric surface distance (ASSD), which were used to assess the overall performance of the models. In addition, DSCdiff, HDratio, and ASSDratio, which are variations of the three existing metrics, were used to compare the performance of the models across different organs. For the average DSC, the GDSM and DDSM had values of 0.9251 and 0.9323, respectively. For the average HD, the GDSM and DDSM had values of 10.66 and 9.139mm, respectively; for the average ASSD, the GDSM and DDSM had values of 0.8318 and 0.6656mm, respectively. Compared with the GDSM, the DDSM showed consistent performance improvements of 0.78%, 14%, and 20% for the DSC, HD, and ASSD metrics, respectively. In addition, compared with the GDSM, the DDSM had better DSCdiff values in 14 of 21 tested organs, better HDratio values in 13 of 21 tested organs, and better ASSDratio values in 14 of 21 tested organs. The three averages of the variant metrics were all better for the DDSM than for the GDSM. The results suggest that combining the generalized dataset with a single scanner dataset resulted in an overall improvement in model performance for that device image.

Added diagnostic performance of diffusion-weighted imaging for differentiating malignant from benign gallbladder lesions: a systematic review with meta-analysis.

Gallbladder malignancies, especially gallbladder cancer, are aggressive lesions with a poor prognosis, and correct differentiation from benign lesions is crucial for improved outcomes. Recently, diffusion-weighted imaging (DWI) has demonstrated potential for this aim to evaluate suspicious lesions detected by initial imaging (e.g., ultrasound). The protocol of this review was pre-registered at ( https://osf.io/ury4k ) PubMed, Web of Science, Embase, and Cochrane Library were searched. The performance of both qualitative (i.e., visual) and quantitative (i.e., apparent diffusion coefficient (ADC)) DWIs was assessed for visualized suspicious lesions detected on preliminary imaging. The added value of combining DWI with conventional magnetic resonance imaging (MRI) for this purpose was also evaluated. After the screening, 27 studies were included. Qualitative analysis showed an area under curve (AUC) of 0.93 (95% confidence interval (CI) = 0.90 to 0.95), while AUC of quantitative analysis was 0.91 (95% CI = 0.89 to 0.94). Adding DWI to conventional MRI protocol added significant values of + 11.27% (95% CI = 0.78% to 21.76%) to sensitivity and + 9.64% (95% CI = 3.90% to 15.39%) to specificity for suspicious lesions on preliminary imaging. DWI offers an accurate, noninvasive method for differentiating benign gallbladder lesions from malignant ones after preliminary imaging. While adding the DWI protocol to conventional MRI imaging does not require technical resources, it significantly improves performance.

Functionalized Iron Oxide Nanoparticles for Both Dual-Modal Imaging and Erythropoiesis.

Cancer-related anemia (CRA), a complication of cancer, is considered the primary cause of high mortality for cancer patients. Safe and effective theranostics are desirable for realizing the high diagnostic accuracy of tumors and ameliorating CRA in the clinic. However, the available theranostics do not support dual-modal imaging and the amelioration of CRA at the same time. In this study, we synthesized functionalized iron oxide nanoparticles (Fe3O4 NPs) modified with protoporphyrin IX (PPIX) and folic acid (FA) by a one-step modification strategy (Fe3O4@NH-PPIX&FA NPs) or a step-by-step strategy (Fe3O4@NH-PPIX-FA NPs), aiming at both magnetic resonance imaging/fluorescence imaging (MRI/FI) and erythropoiesis. Fe3O4@NH-PPIX-FA NPs displayed better ability of MRI/FI than Fe3O4@NH-PPIX&FA NPs and had an efficient tumor targeting of 45 min after tail vein injection owing to the reduction of the steric effect and extension of FA groups. Fe3O4@NH-PPIX-FA NPs exhibited satisfactory erythropoiesis with up to 20% elevation of red blood cell (RBC) counts and hemoglobin concentrations in mice with CRA, which provided a safe alternative to RBC transfusions, especially for patients needing recurrent RBC transfusions. With excellent performance in both dual-modal imaging and erythropoiesis, Fe3O4@NH-PPIX-FA NPs could be a powerful tool for the theranostics of cancer patients with anemia.

Towards affordable biomedical imaging: Recent advances in low-cost, high-resolution optoacoustic microscopy.

This short review discusses the recent developments in low-cost, high-resolution optoacoustic microscopy systems, integrating laser diodes for signal excitation, which are 20-40 times cheaper than the typically employed Q-switched nanosecond laser sources. The development of laser diode-based microscopes can substantially improve not only cost efficiency, but also multispectral capabilities, robustness, portability and overall imaging performance of the optoacoustic technique. To this end, we demonstrate relevant implementations in both time and frequency domain, highlighting their representative applications in biomedical research such as microvasculature imaging, oxygen saturation assessments, hybrid and multiview microscopy of model organisms and tissues and Doppler flow speed measurements. Finally, we analyse the benefits and limitations of each approach, identifying the respective application contexts where they achieve optimum performance.

High-Performance Perovskite Flat Panel X-Ray Imagers via Blade Coating.

Perovskite X-ray detectors are recognized as the most promising candidates for low-dose detectors due to their superior performance. However, it is still full of challenging in the fabrication of flat-panel X-ray imagers (FPXIs), primarily due to the absence of large area thick films that exhibit high uniformity and long-term performance stability. A general synthesis route is urgently needed to grow large-scale halide perovskite thick films directly on a pixeled thin-film transistor (TFT) backplane with high uniformity, closing the gap between the great potential of perovskite X-ray detectors and their entry into the market. In this work, an advanced precursor paste suitable for blade coating is developed to enable high-throughput manufacturing of FPXIs. Highly uniform perovskite films with a thickness of 300-micrometers are directly deposited onto pixeled TFT substrates by the blade-coating method using the above paste, which governs a stable dark current and minimal noise of the X-ray detectors. As a result, (BA)2(MA)9Pb10I31 perovskite X-ray detectors achieved a high sensitivity of 15200 µC Gyair -1 cm-2 and a limit of detection (LoD) of 26.8 nGyair s-1. Moreover, FPXIs with a spatial resolution of 0.95 lp mm-1 (0.475 lp pixel-1) are obtained, which exhibits negligible signal crosstalk and excellent X-ray imaging performance.

Next step in Moore’s law: high NA EUV system overview and first imaging and overlay performance

Next step in Moore’s law: high NA EUV system overview and first imaging and overlay performance

The Effects of Manufacturing Errors on the Performance of Acoustic Metamaterial Lenses Operating in the MHz Regime

This article explores the use of acoustical metamaterials to design lenses in the megahertz frequency range of relevance to applications in nondestructive testing and medical imaging. In particular, the effect of manufacturing errors on their focusing performance is quantified. A rapid method for including manufacturing errors is described and this is used to perform Monte Carlo simulations of wave pressure fields from lenses with manufacturing errors. In this process, the required time delay distribution for a target focal length is calculated and the acoustical lenses with a chosen unit cell type are designed. Manufacturing errors of the unit cells are then added, considering their statistical properties and a large number of realizations. As an example, an acoustical lens with a focal length of 76 mm at a frequency of 1 MHz is designed using three different unit cell types: steel cross unit cell, resin circular void unit cell, and silicone–resin layered unit cell. Finally, the resulting acoustic pressure fields are computed using a Huygens’ principle model to assess the effects of manufacturing errors on lens performance, i.e., the focal length and the size of the focal spot. It is shown that the performance of lenses consisting of silicone–resin layered units is less affected by the manufacturing errors than for lenses constructed with the other unit cells. This study paves the way for selecting a suitable combination of metamaterial unit cell and manufacturing method to enable acceptable lens imaging performance.

The Analysis Study of Diagnostic Imaging Performance and Accuracy of Peripheral Artery Disease: A Comprehensive Systematic Review

Background: Imaging advancements in diagnosing peripheral artery disease (PAD) are crucial for improving patient outcomes. Digital subtraction angiography (DSA) is the gold standard, but non-invasive techniques like computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are preferred. Photon-counting computed tomography (PCCT) offers superior spatial resolution and reduced beam-hardening artifacts, enhancing the accuracy of detecting and quantifying stenotic disease. Methods: This systematic review adhered to the PRISMA 2020 guidelines, focusing exclusively on full-text articles published in English between 2013 and 2024. Editorials and review articles without a DOI were excluded to ensure high-quality sources. A literature search was conducted across reputable databases, including ScienceDirect, PubMed, and SagePub, to identify relevant studies. Result: This review included eight studies encompassing a total of over 1,000 patients. The methodological quality of the studies was moderate, with some risk of misclassification and verification bias. Each study was critically appraised, providing a comprehensive analysis of the diagnostic imaging performance and accuracy in the evaluation of peripheral artery disease. Conclusion: The study highlights the benefits of PCCT in diagnosing PAD, especially in patients with advanced disease, calcifications, or renal impairment. It offers superior spatial resolution, artifact reduction, and lower contrast media requirements, promising improved diagnostic accuracy.

Glass Silicone Oil Free Pre-filled Syringe as Primary Container in Autoinjector.

Pre-filled syringes (PFSs) have become popular as a convenient and cost-effective container closure system for delivering biotherapeutics. However, standard siliconized PFSs may compromise the stability of therapeutic proteins due to their exposure to the silicone oil-water interface. To address this concern, silicone oil-free (SOF) glass syringes coupled with silicone-oil free plunger stoppers have been developed. This study aims to compare the impact of silicone oil-free (SOF) and siliconized syringes as primary container on protein stability and device functionality of the combination products. The stability of proteins with different modalities was assessed in SOF and siliconized 1mL glass syringes for up to 6months at 5℃, 25℃, and 40℃ with levels of subvisible particles and soluble aggregate determined by micro-flow imaging (MFI) and ultra performance size-exclusion chromatography (UP-SEC). The functionality of SOF glass syringes, including break loose force, extrusion force and delivery time in autoinjectors, was evaluated at different time points during the stability study. Additionally, SOF glass syringes were filled with viscosity surrogate ranging from 1 to 90 cP to understand the impact of solution viscosity on break loose force, extrusion force, and autoinjector delivery time. SOF demonstrates compatibility with proteins and exhibited significantly low particle counts compared to siliconized PFS. SOF syringes show significantly higher break-loose and extrusion forces. However, unlike siliconized syringes where silicone oil migration increases extrusion force, no significant change in functionality was observed in SOF glass syringe during stability testing. Overall, SOF glass syringes showed great potential as an alternative package for biologics with comparable performance on functionality as siliconized PFS. The combination of SOF glass and its PTFE coated stopper presents a new primary container closure system with both adequate protein stability and desired functionality features.

Far‐Field Ultrasound Imaging with Subwavelength Resolution through Heterogeneous Medium Using Metagrating Illumination

AbstractUltrasound imaging technology is crucial for diagnostics in both biomedical and industrial fields. However, pushing the boundaries of resolution and overcoming difficulties presented by complex environments remain challenging. Traditionally, diffraction limits resolution due to the loss of valuable subwavelength information carried by evanescent waves. Scattering further complicates imaging through intricate materials or obstructions. Here, we presented an approach for achieving far‐field subwavelength resolution ultrasound imaging through heterogeneous mediums is presented. This method converts inaccessible evanescent wave into detectable propagating waves. These waves are then captured by a far‐field hydrophone and use in conjunction with the joint‐sparsity algorithm to reconstruct the object. These results demonstrate a remarkable resolution of 1/5λ, significantly surpassing the diffraction limit. This subwavelength imaging performance exhibits remarkable stability even in the presence of unwanted scatterers. The two‐dimensional imaging results and the influence of measurement parameters are further explored. These findings suggest that the combination of metagrating illumination and the joint‐sparsity algorithm offers a promising avenue for recovering subwavelength object information in the far‐field, eliminating the need for near‐field markers. This work paves the way for high‐fidelity subwavelength ultrasound imaging in heterogeneous environments, holding promising potential for advancements in biomedical imaging, nondestructive testing, and other related fields.

Radiomics based Machine Learning Models for Classification of Prostate Cancer Grade Groups from Multi Parametric MRI Images

Abstract Purpose: This study aimed to investigate the performance of multiparametric magnetic resonance imaging (mpMRI) radiomic feature-based machine learning (ML) models in classifying the Gleason grade group (GG) of prostate cancer. Methods: In this retrospective study, a total of 203 patients with histopathologically confirmed prostate cancer who underwent mpMRI before prostate biopsy were included. After manual segmentation, radiomic features (RFs) were extracted from T2-weighted, apparent diffusion coefficient, and high b-value diffusion-weighted magnetic resonance imaging (DWMRI). Patients were split into training sets and testing sets according to a ratio of 8:2. A pipeline considering combinations of two feature selection (FS) methods and six ML classifiers was developed and evaluated. The performance of models was assessed using the accuracy, sensitivity, precision, F1-measure, and the area under curve (AUC). Results: On high b-value DWMRI-derived features, a combination of FS method recursive feature elimination (RFE) and classifier random forest achieved the highest performance for classification of prostate cancer into five GGs, with 97.0% accuracy, 98.0% sensitivity, 98.0% precision, and 97.0% F1-measure. The method also achieved an average AUC for GG of 98%. Conclusion: Preoperative mpMRI radiomic analysis based on ML, as a noninvasive approach, showed good performance for classification of prostate cancer into five GGs. Advances in Knowledge: Herein, radiomic models based on preoperative mpMRI and ML were developed to classify prostate cancer into 5 GGs. Our study provides evidence that analysis of quantitative RFs extracted from high b-value DWMRI images based on a combination of FS method RFE and classifier random forest can be applied for multiclass grading of prostate cancer with an accuracy of 97.0%.

Detection of inflammation in abdominal aortic aneurysm with reduced field-of-view and low-b-value diffusion-weighted imaging.

To evaluate the performance of diffusion-weighted imaging (DWI) with an optimal b-value and field-of-view in identifying wall inflammation in abdominal aortic aneurysm (AAA) by comparing it to delayed enhancement T1-weighted imaging (DEI). Twenty-five males with AAA were prospectively enrolled and underwent fat-suppressed T1-weighted dark-blood imaging (T1WI), full field-of-view (f-FOV) and reduced field-of-view (r-FOV) DWI (b values = 0, 100, 400 and 800 s/mm2), and DEI. Corresponding images on f-FOV, r-FOV DWI and DEI at the same level were evaluated qualitatively and quantitatively using the paired t-test and Wilcoxon signed-rank test. The agreement in detecting wall inflammation between DWI and DEI sequences was analyzed using weighted kappa statistics. For both r-FOV and f-FOV DWI, the scores of delineation of aneurysm wall and lesion conspicuity, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were highest on DWI₁₀₀ (Ps < 0.05). The scores of delineation of aneurysm wall, geometric distortion, lesion conspicuity, and SNR, CNR were significantly higher on r-FOV DWI than those on f-FOV DWI (Ps < 0.05). r-FOV DWI₁₀₀ showed comparable performance to DEI in detecting wall inflammation (κ = 0.715), with superior blood suppression and higher SNR and CNR (Ps < 0.05). DWI with r-FOV and low b-value could be a promising alternative to DEI in identifying wall inflammation in AAA.

Impact of the fiber-optic faceplate on the imaging performance of a CMOS X-ray detector

Complementary metal-oxide-semiconductor (CMOS) active-pixel detectors are widely used in various imaging applications owing to their faster operation with lower noise and higher sensitivity than their conventional amorphous silicon-based counterparts. However, CMOS detectors are vulnerable to radiation damage owing to their crystalline structures. They also suffer from ghosting artifacts and gradual reduction of dynamic range along with their lifetime. Most CMOS detectors employ a fiber-optic faceplate (FOP) between the X-ray converter and CMOS active-pixel array to mitigate the radiation effect and increase longevity. In this study, we investigated the effect of an additional FOP layer on the imaging performance of a CMOS detector, including the modulation-transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). For X-ray energies ranging from 40 to 70 kV, we measured the large-area signal-transfer functions, MTFs, and NPSs and calculated the corresponding DQEs. The FOP degraded the MTF performance over the entire spatial frequency, but improved the NPS performance with increasing spatial frequency. Consequently, the FOP layer enhanced the DQE performance for the given energy ranges. The measured results are discussed in detail using a theoretical cascaded-systems model.

Comprehensive assessment of nonuniform image quality: Application to imaging near metal.

Comprehensive assessment of image quality requires accounting for spatial variations in (i) intensity artifact, (ii) geometric distortion, (iii) signal-to-noise ratio (SNR), and (iv) spatial resolution, among other factors. This work presents an ensemble of methods to meet this need, from phantom design to image analysis, and applies it to the scenario of imaging near metal. A modular phantom design employing a gyroid lattice is developed to enable the co-registered volumetric quantitation of image quality near a metallic hip implant. A method for measuring spatial resolution by means of local point spread function (PSF) estimation is presented and the relative fitness of gyroid and cubic lattices is examined. Intensity artifact, geometric distortion, and SNR maps are also computed. Results are demonstrated with 2D-FSE and MAVRIC-SL scan protocols on a 3T MRI scanner. The spatial resolution method demonstrates a worst-case error of 0.17 pixels for measuring in-plane blurring up to 3 pixels (full width at half maximum). The gyroid outperforms a cubic lattice design for the local PSF estimation task. The phantom supports four configurations toggling the presence/absence of both metal and structure with good spatial correspondence for co-registered analysis of the four quality factors. The marginal scan time to evaluate one scan protocol amounts to five repetitions. The phantom design can be fabricated in 2 days at negligible material cost. The phantom and associated analysis methods can elucidate complex image quality trade-offs involving intensity artifact, geometric distortion, SNR, and spatial resolution. The ensemble of methods is suitable for benchmarking imaging performance near metal.

Comparison of silent MRA and time-of-flight MRA in the depiction and grading of brain arteriovenous malformations.

Preliminary small-sample studies suggest that silent magnetic resonance angiography (MRA) has an advantage over time-of-flight MRA (TOF MRA) in the characterization of brain arteriovenous malformation (BAVM), but did not examine whether the imaging performance of silent MRA was affected by the intrinsic features of BAVM or common clinical factors. This study sought to compare silent MRA and TOF MRA in terms of the visualization and grading of BAVMs in various clinical settings. In total, 85 participants (50 males, 35 females; mean age: 33.5±15.2 years) with BAVM who underwent both silent MRA and TOF MRA using a 3 Tesla (3T) magnetic resonance imaging (MRI) system were consecutively recruited from the Capital Medical University Xuanwu Hospital between April 2020 and October 2022 to participate in this cross-sectional retrospective study. The patients were divided into subgroups according to new hemorrhage presentation, embolization, size, and nidus compactness. Image quality scoring on a 4-point scale, and the accuracy of characteristic visulization and Spetzler-Martin grading were compared between the two MRA techniques and each MRA subgroup using the rank-sum Wilcoxon test and Fisher's exact test with digital subtraction angiography (DSA) as the reference standard. A multivariable chi-square test was used to examine the interactions between the grouping factors. A P value <0.05 was considered statistically significant. The average image quality scores were significantly higher for silent MRA than those for TOF MRA overall (2.83±0.42 versus 2.46±0.66, P<0.001) and in each subgroup (P<0.05). For silent MRA, the average image quality score for BAVM in each subgroup did not differ significantly (P>0.05). For TOF MRA, the image quality scores for the new hemorrhage, small nidus, and diffuse nidus groups was significantly reduced (P=0.001, <0.001, and 0.037, respectively). The accuracy of silent MRA was significantly better than that of TOF MRA in terms of nidus size and Spetzler-Martin grading (P<0.001), but did not differ significantly in terms of deep venous drainage and associated aneurysm (P=0.402, 0.098, respectively). In relation to silent MRA, the image quality, detection of BAVM characteristics, and grading were similar across the new hemorrhage, embolization, size, and compactness subgroups (P=0.066-0.959). In relation to TOF MRA, the accuracy of nidus size grading was significantly lower in the medium-size subgroup than the small-size subgroup (P<0.001). Silent MRA performed well in imaging BAVM, and high performance in determining nidus size and Spetzler-Martin grading, but its ability to detect deep venous drainage was limited.

Ultrafast adaptive optics for imaging the living human eye

Adaptive optics (AO) is a powerful method for correcting dynamic aberrations in numerous applications. When applied to the eye, it enables cellular-resolution retinal imaging and enhanced visual performance and stimulation. Most ophthalmic AO systems correct dynamic aberrations up to 1−2 Hz, the commonly-known cutoff frequency for correcting ocular aberrations. However, this frequency may be grossly underestimated for more clinically relevant scenarios where the medical impact of AO will be greatest. Unfortunately, little is known about the aberration dynamics in these scenarios. A major bottleneck has been the lack of sufficiently fast AO systems to measure and correct them. We develop an ultrafast ophthalmic AO system that increases AO bandwidth by ~30× and improves aberration power rejection magnitude by 500×. We demonstrate that this much faster ophthalmic AO is possible without sacrificing other system performances. We find that the discontinuous-exposure AO-control scheme runs 32% slower yet achieves 53% larger AO bandwidth than the commonly used continuous-exposure scheme. Using the ultrafast system, we characterize ocular aberration dynamics in six clinically-relevant scenarios and find their power spectra to be 10−100× larger than normal. We show that ultrafast AO substantially improves aberration correction and retinal imaging performance in these scenarios compared with conventional AO.

Dendrimer‐Cu(II) Complexes Mediate Enzyme Delivery for Lactate Depletion‐Enhanced Combinational Treatment of Leukemia and Glioma

AbstractCancer cells engage in active aerobic glycolysis to meet their bioenergetic synthesis needs, which is known as the Warburg effect. Such a process leads to lactate accumulation in the tumor microenvironment (TME), further promoting cancer progression and inducing immunosuppression. Herein, functionalized dendrimer‐Cu(II) complexes (for short, D‐Cu(II)) as a nanocarrier, which enables a Fenton‐like reaction is developed to generate a large amount of hydroxyl radicals and shows a T1‐weighted magnetic resonance (MR) imaging performance. Importantly, the D‐Cu(II) allows efficient delivery of lactate oxidase (LOx) to cancer cells, directly downregulating the lactate levels. When combining with an immune activator of leukadherin‐1, the developed D‐Cu(II)/LOx complexes alleviate the symptoms of mouse leukemia. With a further coating of macrophage membranes, the generated D‐Cu(II)/LOx@M allows for effective blood‐brain barrier crossing to treat an orthotopic murine glioma model under the guidance of Cu(II)‐facilitated MR imaging. By integrating the LOx‐mediated lactate depletion with Cu(II)‐mediated chemodynamic therapy, the developed dendrimer nanomedicines improve the overall survival and antitumor immune responses of mice, and help to remodel the immunosuppressive TME in both cancer models, greatly sensitizing the treatment efficacy of immune activator. Such dendrimer technology may further be used for theranostics of other cancer types through lactate depletion‐enhanced combinational therapy.

Comparison of intravoxel incoherent motion and diffusion kurtosis imaging and 18- FDG PET/CT in response assessment in rectosigmoid carcinoma.

To evaluate the performance of intravoxel incoherent motion and diffusion kurtosis imaging (IVIM- DKI) in response assessment of rectosigmoid carcinoma to chemo-radiotherapy (CRT) and compare with 18-FDG PET/CT parameters. A total of 30 patients of recto-sigmoid cancer on CRT underwent baseline staging and follow-up with IVIM - DKI. Out of this cohort, 20 patients underwent 18-FDG PET/CT. IVIM- DKI MRI and PET/CT parameters were noted from both pre and post-chemoradiotherapy (done at 6 weeks after completion) scans. Quantitative IVIM-DKI parameters, viz. apparent (ADC) and molecular (D) diffusion coefficient, perfusion coefficient (f), and kurtosis (K) were measured from non-necrotic areas and semi-quantitative PET parameters including SUV max, SUV ratio, metabolic tumor volume (MTV), total lesion glycolysis (TLG) were also measured. All these parameters correlated with the patient's response keeping RECIST 1.1 criteria as reference standard. A statistically significant increase in D and ADC with a significant decline in K was noted after therapy in the entire cohort. These changes were observed in both responders as well as non-responders. No significant differences were observed in the percentage changes of these parameters post therapy amongst both groups. Among 20 patients with follow-up PET/CT imaging, a significant decline in all parameters of primary lesion was seen post-therapy. Responders (n = 12) showed a significant decline in MTV and TLG from baseline after therapy, whereas non-responders did not show any such decline. Change in TLG (ɗ TLG), followed by ɗ MTV had the strongest correlation with a positive response. A ɗ TLG value of ≥ 54.19 carried a 79% sensitivity and 83% specificity in differentiating responders from non responders. 18-FDG PET/CT is a more accurate single modality for assessing both response and tumor burden post therapy, while ADC and D from IVIM MRI are useful adjuncts to response assessment.

NIR Diradical-Featured Croconaine Nanoagent for Cancer Photoacoustic Imaging and Photothermal Therapy.

Radical-featured organic materials usually demonstrate significantly narrower bandgap than that of regular organic materials, which is beneficial for near-infrared (NIR) absorption and non-radiative decay process, making them good candidates for photothermal agents (PTAs) of photothermal therapy (PTT). However, most organic radicals are too short-lived to be separated and stable. Herein, a stable pyrylium-croconaine (CR) dye CR845 with high diradical character was synthesized and assembled into CR845 nanoparticles (NPs) to explore the photoacoustic imaging (PAI) and photothermal therapeutic performance under NIR irradiation in vitroand in vivo. CR845 exhibited a stable NIR absorption at 845 nm (ε= 3.37 × 105L mol-1cm-1) and a relatively high photothermal conversion efficiency (PCE) of 58.8%. When assembled into nanoparticles, CR845 NPs showed good photostability, good biocompatibility, favorable NIR photoacoustic potential, effective cancer cell killing and complete tumor elimination upon 850 nm laser irradiation. The work demonstrates a diradical-featured CR PTA with favorable PAI/PTT effects, which can help to provide new ideas for the development of NIR PTAs, and further promote the application of organic radical materials in the field of biomedicine.