Evaluation of renal tubular function by multiparametric functional MRI in early diabetes

Purpose To evaluate the tubular function in an alloxan-induced type 1 diabetes mellitus (DM) rabbit model measured by renal oxygenation (R2*), oxygen extraction fraction (OEF), and renal blood flow (RBF) using blood oxygenation level dependent, asymmetric spin echo, and arterial spin labeling MRI. Methods Twenty-six rabbits were randomized into the 3-day DM group (n = 13) and the 7-day DM group (n = 13). We performed pairs of multiparametric MRIs (before and after furosemide injection) at baseline and 3/7 days post-DM, and scored pathological kidney injury. We performed statistical analyses using non-parametric, chi-square, and Spearman correlation tests. Results At baseline, medullary R2* significantly decreased by 24.97% and 16.74% in the outer and inner stripes of the outer medulla (OS and IS, p = 0.006 and 0.003, respectively) after furosemide administration. While the corresponding OEF decreased by 15.91% for OS and 16.67% for IS (both p = 0.003), and no significant change in medullary RBF was observed (p > 0.05). In the 3-day DM group, the decrease of medullary R2* and OEF post-furosemide became unremarkable, suggesting tubular dysfunction. We noticed similar changes in the 7-day DM group. Correlation analysis showed pathological tubular injury score significantly correlated with medullary ∆R2* (post-furosemide - pre-furosemide difference, r = 0.82 for OS and 0.82 for IS) and ∆OEF (r = 0.82 for OS and 0.82 for IS) (p < 0.001, respectively). Conclusion: The combination of medullary OEF and R2* in response to furosemide could detect renal tubular dysfunction in early DM.

Coronary microvascular dysfunction: prevalence and aetiology in patients with suspected myocardial ischaemia

AIM

To evaluate the prevalence, aetiology, and corresponding morbidity of coronary microvascular dysfunction (CMD) in patients with suspected myocardial ischaemia.

MATERIALS AND METHODS

The present study included 115 patients with suspected myocardial ischaemia who underwent stress perfusion cardiac magnetic resonance imaging. CMD was assessed visually based on the myocardial perfusion results. The CMR-derived myocardial perfusion reserve index (MPRI) and left ventricular (LV) strain parameters obtained using the post-processing software CVI42 were employed to evaluate LV myocardial perfusion and deformation. LV strain parameters included global longitudinal, circumferential, and radial strain (GLS, GCS, and GRS), global systolic/diastolic longitudinal, circumferential, and radial strain rates (SLSR, SCSR, SRSR, DLSR, DCSR, and DRSR).

RESULTS

Of the 115 patients, 12 patients were excluded and 103 patients were finally included in the study. CMD was observed in 79 % (81 patients, aged 53 ± 12 years) of patients. Regarding aetiology, 91 (88 %) patients had non-obstructive coronary artery disease (CAD), eight (8 %) had obstructive CAD, and four (4 %) had hypertrophic cardiomyopathy (HCM). The incidence of CMD was highest (100 %) in patients with HCM, followed by those with non-obstructive CAD (up to 79 %). There were no statistical differences between CMD and non-CMD groups in GCS, GRS, GLS, SRSR, SCSR, SLSR, DCSR, DRSR and DLSR.

CONCLUSION

The incidence of CMD was higher in patients with signs and symptoms of ischaemia. CMD occurred with non-obstructive CAD, obstructive CAD, and HCM, with the highest prevalence of CMD in HCM.

[Effects of macrophage glycolytic reprogramming on tuberculosis granuloma formation]

The formation of granulomatous lesions is a typical pathological feature of tuberculosis, and infection with Mycobacterium tuberculosis is the main cause. Although the mechanism underlying granuloma formation remains unclear, increasing evidence suggests that immune metabolism plays an important role. In this review, we summarized the latest advances in macrophage glycolytic reprogramming in tuberculosis granuloma formation to discover new methods for early diagnosis and provided new ideas for tuberculosis therapeutics based on the regulation of immune metabolism.

Fabrication of THz corrugated wakefield structure and its high power test

We present overall process for developing terahertz (THz) corrugated structure and its beam-based measurement results. 0.2-THz corrugated structures were fabricated by die stamping method as the first step demonstration towards GW THz radiation source and GV/m THz wakefield accelerator. 150-[Formula: see text]m thick disks were produced from an OFHC (C10100) foil by stamping. Two types of disks were stacked alternately to form 46 mm structure with [Formula: see text] 170 corrugations. Custom assembly was designed to provide diffusion bonding with a high precision alignment of disks. The compliance of the fabricated structure have been verified through beam-based wakefield measurement at Argonne Wakefield Accelerator Facility. Both measured longitudinal and transverse wakefield showed good agreement with simulated wakefields. Measured peak gradients, 9.4 MV/m/nC for a long single bunch and 35.4 MV/m/nC for a four bunch trains, showed good agreement with the simulation.

Predictive Value of 18 F-FDG PET/MRI for Pleural Invasion in Solid and Subsolid Lung Adenocarcinomas Smaller Than 3 cm

BACKGROUND

Positron emission tomography (PET)/MRI combines the characteristics of metabolism imaging and high soft tissue resolution, and could provide high diagnostic efficacy for assessment of pleural invasion (PI) of lung cancer.

PURPOSE

To investigate the application of ¹⁸ F-fluorodeoxyglucose (FDG) PET/MRI for predicting PI of lung cancer with the maximum diameter ≤3 cm.

STUDY TYPE

Prospective.

POPULATION

A total of 44 patients with non-small cell lung cancer (NSCLC), age from 39 to 79 years old, including 19 (56.82%) females.

FIELD STRENGTH/SEQUENCE

A 3-T, hybrid PET/MRI including axial fast spin echo respiratory-triggered T2 fat-suppressed imaging (T2FS) and echo planar imaging diffusion-weighted imaging (DWI).

ASSESSMENT

The maximum standardized uptake value (SUVmax) of all lesions was measured on PET images. Localized effusion outside the contact between the nodules and the pleura on T2FS and signal at the contact between the nodules and the pleura on DWI were evaluated by experienced physicians through visual assessment of the MRI sequences.

STATISTICAL TESTS

Three models (models 1-3) were developed, incorporating CT, CT and PET, PET and MRI features, and Lasso regression was used in feature selection. The receiver operating characteristic (ROC) curve for PI diagnosis was visualized for each model, and the area under the curve (AUC) was calculated. The DeLong test was used to compare the different AUCs. A P value < 0.05 was considered statistically significant.

RESULTS

The AUC of models 1-3 was 0.762, 0.829, and 0.915, respectively. The DeLong test showed a statistically significant difference between the AUCs of model 1 vs. model 3, while the differences between the AUCs of model 1 vs. model 2 (P = 0.253) and model 2 vs. model 3 (P = 0.075) were not statistically significant.

DATA CONCLUSION

¹⁸ F-FDG PET/MRI might show high predictive value for lung adenocarcinoma smaller than 3 cm with PI.

EVIDENCE LEVEL

1 TECHNICAL EFFICACY: Stage 2.

[Progress in clinical diagnosis and treatment of multiple primary lung cancer]

With the application of high-resolution chest imaging system and lung cancer screening program, patients with multiple primary lung cancer (MPLC) are becoming a growing population in clinical practice. However, the diagnostic criteria of MPLC and its differentiation from intrapulmonary metastasis of lung cancer (IM) are still controversial, especially in cases with similar histology. On the basis of reviewing the existing literature, this paper discusses the changes of the diagnostic criteria of MPLC and the differential diagnosis methods of imaging, histology and molecular genetics of MPLC and IM, and briefly introduces the application of multidisciplinary diagnosis, algorithm, predictive model and artificial intelligence in the differential diagnosis of MPLC. In addition, we also discuss the latest progress in the treatment of MPLC. Radical surgery is the main method for the treatment of MPLC. Stereotactic body radiation therapy (SBRT) is safe and feasible for inoperable MPLC patients, and targeted therapy and immunotherapy can also be used in MPLC after appropriate patient selection.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Value of 18F-FDG PET/MRI in the Preoperative Assessment of Resectable Esophageal Squamous Cell Carcinoma: A Comparison With 18F-FDG PET/CT, MRI, and Contrast-Enhanced CT

Objectives

To investigate the value of ¹⁸F-FDG PET/MRI in the preoperative assessment of esophageal squamous cell carcinoma (ESCC) and compare it with ¹⁸F-FDG PET/CT, MRI, and CECT.

Methods

Thirty-five patients with resectable ESCC were prospectively enrolled and underwent PET/MRI, PET/CT, and CECT before surgery. The primary tumor and regional lymph nodes were assessed by PET/MRI, PET/CT, MRI, and CECT, respectively, and the diagnostic efficiencies were determined with postoperative pathology as a reference standard. The predictive role of imaging and clinical parameters on pathological staging was analyzed.

Results

For primary tumor staging, the accuracy of PET/MRI, MRI, and CECT was 85.7%, 77.1%, and 51.4%, respectively. For lymph node assessment, the accuracy of PET/MRI, PET/CT, MRI, and CECT was 96.2%, 92.0%, 86.8%, and 86.3%, respectively, and the AUCs were 0.883, 0.745, 0.697, and 0.580, respectively. PET/MRI diagnosed 13, 7, and 6 more stations of lymph node metastases than CECT, MRI, and PET/CT, respectively. There was a significant difference in SUV_max, TLG, and tumor wall thickness between T1-2 and T3 tumors (p = 0.004, 0.024, and < 0.001, respectively). Multivariate analysis showed that thicker tumor wall thickness was a predictor of a higher T stage (p = 0.040, OR = 1.6).

Conclusions

¹⁸F-FDG PET/MRI has advantages over ¹⁸F-FDG PET/CT, MRI, and CECT in the preoperative assessment of primary tumors and regional lymph nodes of ESCC. ¹⁸F-FDG PET/MRI may be a potential supplement or alternative imaging method for preoperative staging of ESCC.

Content-Noise Complementary Learning for Medical Image Denoising

Medical imaging denoising faces great challenges, yet is in great demand. With its distinctive characteristics, medical imaging denoising in the image domain requires innovative deep learning strategies. In this study, we propose a simple yet effective strategy, the content-noise complementary learning (CNCL) strategy, in which two deep learning predictors are used to learn the respective content and noise of the image dataset complementarily. A medical image denoising pipeline based on the CNCL strategy is presented, and is implemented as a generative adversarial network, where various representative networks (including U-Net, DnCNN, and SRDenseNet) are investigated as the predictors. The performance of these implemented models has been validated on medical imaging datasets including CT, MR, and PET. The results show that this strategy outperforms state-of-the-art denoising algorithms in terms of visual quality and quantitative metrics, and the strategy demonstrates a robust generalization capability. These findings validate that this simple yet effective strategy demonstrates promising potential for medical image denoising tasks, which could exert a clinical impact in the future. Code is available at: https://github.com/gengmufeng/CNCL-denoising.

Dynamic R2' Imaging can Be a Biomarker for Diagnosing and Staging Early Acute Kidney Injury in Animals

Background: Early diagnosis of acute kidney injury (AKI) is essential in clinical settings. None of the current biomarkers are widely applied. The combination of pulse-shifting multi-echo asymmetric spin-echo sequence (psMASE) and a modified hemodynamic response imaging (HRI) technique is promising. The purpose of this study was to evaluate the feasibility of psMASE combined with HRI in detecting early ischemic AKI in animal models of different severities.

Methods: Twenty rabbits were divided into four groups (mild, moderate, and severe AKI and control groups). Transarterial embolization with different doses of microspheres was performed to establish AKI animal models of different severities. The 3T psMASE and HRI scans of kidneys were conducted. The R2^*, R2, and R2' during room air and gas stimulation were acquired and the difference of R2' (dR2') was evaluated in different AKI groups.

Results: The values were not different in R2^* and R2 during room air and in R2^* and R2, and R2' during gas stimulation. The value of R2' was significantly different during room air (P = 0.014), but the difference was only found between control and moderate/severe AKI groups (P = 0.032 and 0.022). The values of dR2' were different among groups (P < 0.0001) and differences between every two groups except comparison of moderate and severe AKI groups were significant (P < 0.01).

Conclusion: The dR2' imaging acquired by a combination of renal psMASE and HRI technique can serve as a potential quantitative biomarker for early detection and staging of AKI.

Evolution of the grass leaf by primordium extension and petiole-lamina remodeling

[Figure: see text].

Catalytic core-shell nanoparticles with self-supplied calcium and H2O2 to enable combinational tumor inhibition

Nanoparticles, presenting catalytic activity to induce intracellular oxidative species, have been extensively explored for tumor treatment, but suffer daunting challenges in the limited intracellular H₂O₂ and thus suppressed therapeutic efficacy. Here in this study, a type of composite nanoparticles, consisting CaO₂ core and Co-ferrocene shell, is designed and synthesized for combinational tumor treatment. The findings indicate that CaO₂ core can be hydrolyzed to produce large amounts of H₂O₂ and calcium ions at the acidic tumor sites. Meanwhile, Co-ferrocene shell acts as an excellent Fenton catalyst, inducing considerable ROS generation following its reaction with H₂O₂. Excessive cellular oxidative stress triggers agitated calcium accumulation in addition to the calcium ions released from the particles. The combined effect of intracellular ROS and calcium overload causes significant tumor inhibition both in vitro and in vivo.

Cu-Ferrocene-Functionalized CaO2 Nanoparticles to Enable Tumor-Specific Synergistic Therapy with GSH Depletion and Calcium Overload

The conversion of endogenous H2 O2 into toxic hydroxyl radical (• OH) via catalytic nanoparticles is explored for tumor therapy and received considerable success. The intrinsic characteristics of microenvironment in tumor cells, such as limited H2 O2 and overexpressed glutathione (GSH), hinder the intracellular • OH accumulation and thus weaken therapeutic efficacy considerably. In this study, fine CaO2 nanoparticles with Cu-ferrocene molecules at the surface (CaO2 /Cu-ferrocene) are successfully designed and synthesized. Under an acidic condition, the particles release Ca2+ ions and H2 O2 in a rapid fashion, while they can remain stable in neutral. In addition, agitated production of • OH occurs following the Fenton reaction of H2 O2 and ferrocene molecules, and GSH is consumed by Cu2+ ions to avoid the potential • OH consumption. More interestingly, in addition to the exogenous Ca2+ released by the particles, the enhanced • OH production facilitates intracellular calcium accumulation by regulating Ca2+ channels and pumps of tumor cells. It turns out that promoted • OH induction and intracellular calcium overload enable significant in vitro and in vivo antitumor phenomena.

Cell-Free DNA Tissue Damage Mapping in Transplant Patients Infected with COVID-19

Purpose

Patients with COVID-19 show variable clinical course; transplant patients often show worse outcomes. The effect of COVID-19 on the allograft and the sources of tissue injury that contribute to such poor outcomes are poorly defined. This study leverages cell-free DNA (cfDNA) to measure allograft injury as donor-derived cfDNA (ddcfDNA) and injury from different tissue types using tissue-specific DNA methylomic signatures.

Methods

14 consecutive COVID-19 transplant patients (8 Kidney, 3 Lung, 1 Heart, 1 Liver, and one multi-organ transplant patients) and 30 healthy controls were included. Plasma nuclear cfDNA (ncfDNA) and mitochondrial cfDNA (mtcfDNA) level were measured via digital droplet PCR, and ddcfDNA using AlloSure (CareDx). cfDNA whole-genome bisulfite sequencing was performed to identify cfDNA tissues of origin leveraging tissue specific DNA methylomes and deconvolution algorithm.

Results

75% of the COVID-19 transplant patients showed high ddcfDNA level compared to published quiescent values, including all lung, 50% of the kidney, liver and multi-organ transplant patients (8.5, 4.4, 30 and 16-X fold change, respectively). Total ncfDNA and mtcfDNA were 15X and 310X higher in COVID-19 transplant patients compared to controls, respectively; < 0.0001.The predominant tissues contributing to cfDNA were hematopoietic cells (80%) (Figure). More importantly, COVID-19 transplant patients showed 10 to 100 fold higher tissue specific cfDNA derived from monocyte, neutrophil, erythroblast, vascular endothelium, adipocyte, hepatocyte, kidney, heart and lung compared to controls. Analysis comparing cfDNA in transplant and non-transplant COVID-19 patients is on-going.

Conclusion

The allograft undergoes significant injury following COVID-19. Further, cfDNA from multiple tissue types is significantly higher in COVID-19 transplant patients. Future studies in a larger cohorts of transplant and non-transplant patients are needed to elucidate why transplant patients show worse COVID-19 outcomes.

[Establishment of animal model of bacterial microleakage at implant-abutment interface]

Objective: To study the bacterial microleakage at the interface between dental implant and abutment in rats. Methods: Under aseptic conditions, suspension of 0.25 μl of Porphyromonas gingivalis (Pg) (10(9) CFU/ml) was added into the customized implant. After the abutment was connected, the suspension was cultured in an Ep (eppendorf) tube containing 1 ml brain heart infusion (BHI) culture medium. After 7 days and 14 days, the liquid in the Ep tube was taken and inoculated, and the growth of bacteria was observed. Six male SD rats with 12 implants were divided into experimental group (4 implants), negative control group (4 implants) and blank control group (4 implants). All 6 rats had two implants implanted in their bilateral upper jaws. During the second operation, suspension of 0.25 μl Pg (10(9) CFU/ml) was added to the inner part of the implant of the experimental group, culture solution of 0.25 μl was added to the control group and nothing was added to the blank control group. The amount of Pg and total bacteria in each group were evaluated by quantitative real-time PCR (qPCR). The inflammatory cell infiltrate in the peri-implant mucosa was evaluated histomorphometrically. Results: The in vitro model directly verified the presence of bacterial microleakage at implant-abutment interface (IAI), and the animal model confirmed the existence of microleakage through the infiltrate of inflammatory cells near the micro-gap in the experimental group indirectly. In vitro experiments found that Pg had penetrated from the implant within a week by observation and culture. In animal study, the presence of 10(2)-10(4) Pg was detected in the experimental group and it was not detected in the negative control group and the blank control group. At the same time, under the light microscope, in the experimental group, there were inflammatory cells aggregation in the connective tissue around the micro-gap and the density of inflammatory cells gradually decreased from the micro-gap to coronal and the apical of the connective tissue, while there were only scattered inflammatory cells in the connective tissue around the blank control group and the negative control group. In the experimental group, inflammatory cells density in area of 0.25-0.50 mm, 0-0.25 mm coronal to the micro-gap and 0-0.25 mm, 0.25-0.50 mm apical to the mico-gap was respectively, 976 (655), 1 673 (1 245), 2 267 (819) and 895 (162) cells/mm(2),which was significantly more than the blank control group in the corresponding position [respectively 201 (180), 321 (351), 309 (236) and 218 (272) cells/mm(2)] (P<0.05). Conclusions: Pg in the dental implants of rats can be found in the microleakage through implant-abutment interface, and cause the soft tissue inflammation around the implant, and the inflammation has certain distribution characteristics.

Feasibility of MRI based oxygenation imaging for the assessment of acute limb ischemia

Background

Acute limb ischemia (ALI) can lead to death and amputation. Evaluating the severity of ischemia is important but difficult, through current methods of examination. The purpose of this research was to demonstrate the feasibility of magnetic resonance imaging (MRI) susceptibility-based imaging techniques for use in assessing muscle oxygenation alterations in ALI.

Methods

ALI animal models were established in 11 rabbits. Their left iliac arteries were embolized by microspheres. MRI scans were conducted 24 hours before (Pre) and 1 hour (Post 1) and 3 hours (Post 2) after the procedure. A susceptibility model was used to calculate skeletal muscle oxygenation extraction fraction (SMOEF) and relaxation rate (R2’). T2 weighted (T2w) imaging and diffusion-weighted (DW) imaging were performed.

Results

The average calf muscle SMOEF in the embolized hindlimbs increased from 0.43±0.02 (Pre) to 0.48±0.02 (Post 1) and 0.50±0.02 (Post 2), both P<0.05. The R2’ value increased from 13.01±2.31 s⁻¹ (Pre) to 16.78±2.28 s⁻¹ (Post 1) and 17.90±3.29 s⁻¹ (Post 2), both P<0.05. No significant changes of SMOEF and R2’ were found after embolization in the contralateral hindlimbs. Apparent diffusion coefficient (ADC) values derived from DW imaging remained unchanged at different stages compared to before the procedures (all P>0.05). No abnormal signals were observed in the anatomical T2w images at Post 1 and Post 2.

Conclusions

This study demonstrates the feasibility of using SMOEF for the assessment of oxygenation alterations in ALI models. SMOEF is more sensitive than T2w and DW imaging in detecting acute muscle ischemia at an early stage.

A feasibility study of using noninvasive renal oxygenation imaging for the early assessment of ischemic acute kidney injury in an embolization model

PURPOSE

To investigate the feasibility of using MRI based oxygenation imaging for early assessment of ischemic acute kidney injury (AKI) in an embolization model.

METHODS

Ischemic AKI model was induced in 40 rabbits by injection of microspheres into the right renal arteries. Animals were grouped according to the dose of microspheres: Severe AKI group, 2.0 mg (N = 10); Moderate AKI group, 1.0 mg (N = 10); Mild AKI group, 0.5 mg (N = 10); Control group, saline without microspheres (N = 10). A serial MRI examination was performed at intervals of 1 h, 1 day, 1 week and 4 weeks to evaluate the deterioration of renal function. A multi-echo ASE sequence was implemented for renal oxygenation measurement 1 h after surgery. Pathological examinations were performed 4 weeks after the surgery.

RESULTS

In renal cortex, renal oxygen extraction fraction (OEF) raised significantly after embolization procedures in all experimental groups (severe AKI: 0.39 ± 0.05, P < 0.05; moderate AKI: 0.36 ± 0.03, P < 0.05; mild AKI: 0.34 ± 0.02, P < 0.05) compared to the control group (0.29 ± 0.02). In outer medulla, significant difference was observed between control group (0.29 ± 0.03) and severe AKI group (0.35 ± 0.03, P < 0.05), and between control group and moderate AKI group (0.34 ± 0.04, P < 0.05). Corresponding lesions were found in pathological examinations 4 weeks after the procedure.

CONCLUSION

This study demonstrates the feasibility of using oxygenation imaging to assess the embolization induced ischemic AKI at an early stage.

[Risk factors of postoperative complications after laparoscopic surgery for pheochromocytoma]

Objective: To investigate the effects of intraoperative hemodynamic instability on postoperative complications of laparoscopic surgery for pheochromocytoma. Methods: It was a retrospective cohort study. According to inclusion/exclusion criteria, adult patients underwent laparoscopic surgery for pheochromocytoma from January 2005 to December 2017 in Peking University First Hospital were enrolled in this study. Eligible patients were divided into two groups by evidence of postoperative complications to find out the effects of intraoperative hemodynamic instability and its' effects on other prognostic indices. The normally distributed continuous variables were compared between two groups by Student's t test, Mann-Whitney U test were used for the comparison for non-normally distributed continuous variables and χ(2) test for categorical variables. Results: A total of 198 patients were finally enrolled in this study, including 87 males and 111 females with an average age of (47±15) years. Postoperative complications occurred in 17 patients with an incidence of 8.6%, and intraoperative hemodynamic instability occurred in 45 patients (22.7%). It was found that history of stroke[odds ratio (OR)=13.387, 95% confidence interval (CI): 2.284-78.460, P=0.004], intraoperative hemodynamic instability (OR=3.351, 95%CI: 1.119-10.039, P=0.031) and intraoperative positive fluid balance (for each additional 100 ml) (OR=1.087, 95%CI: 1.031-1.146, P=0.002)were the independent risk factors of postoperative complications of laparoscopic surgery for pheochromocytoma. Furthermore, more postoperative complications, higher rate of admitting to ICU and longer hospital stay was found in patients with hemodynamic instability. Conclusion: Intraoperative hemodynamic instability is an independent risk factor for postoperative complications of laparoscopic surgery in patients with pheochromocytoma, and it associates with more postoperative complications and higher rate of admitting to ICU.

Comparison of blood oxygen level-dependent imaging and diffusion-weighted imaging in early diagnosis of acute kidney injury in animal models

BACKGROUND

Early diagnosis of acute kidney injury (AKI) has clinical importance. Current methods are neither adequately sensitive nor specific. Blood oxygen level-dependent (BOLD) imaging and diffusion-weighted imaging (DWI) may help to assess AKI in the early phase.

PURPOSE

To investigate the feasibility of BOLD imaging and DWI in the assessment of AKI and compare the sensitivities of both techniques in early detection of renal damage.

STUDY TYPE

Prospective animal study.

ANIMAL MODEL

Thirty New Zealand white rabbits.

FIELD STRENGTH/SEQUENCE

3 T clinical MRI/BOLD and DWI.

ASSESSMENT

Thirty rabbits were divided into three groups (severe AKI group, mild AKI group, and control group). Transarterial renal embolization with different doses of microspheres was performed to create severe and mild AKI disease models. All the MRI scans of kidneys were conducted within 2 hours after the embolization procedure. Histological examinations with hematoxylin and eosin staining were performed to validate renal damage.

STATISTICAL TESTS

Analysis of variance (ANOVA) for comparisons between groups, and paired t-test for tests within the same group. P < 0.05 was considered statistically significant.

RESULTS

Both R2* and apparent diffusion coefficient (ADC) showed significant differences between the severe AKI group (56.34 ± 3.45 s-1 for R2*, 1.14 ± 0.23 mm² /s for ADC) and the control group (28.24 ± 2.26 s-1 for R2*, 1.94 ± 0.33 mm² /s for ADC, both P < 0.01). However, the ADC values did not show significant differences (P = 0.41) between mild AKI group (1.88 ± 0.31 mm² /s for ADC) and the control group (1.94 ± 0.33 mm² /s for ADC), while R2* was still useful in differentiating the two groups (52.32 ± 4.1 s-1 vs. 28.24 ± 2.26 s-1 for R2*, P < 0.01). The histopathologic results were found to be correlated with MRI findings.

DATA CONCLUSION

BOLD contrast and DW images are both effective in detecting AKI noninvasively, but BOLD imaging is more sensitive in early detection of mild ischemia than DWI.

LEVEL OF EVIDENCE

1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2019;50:719-724.

Early assessment of acute kidney injury using targeted field of view diffusion-weighted imaging: An in vivo study

Acute kidney injury (AKI) is a common complication in various clinical settings. In recent years, AKI diagnostics have been investigated intensively showing the emerging need for early characterization of this disease. To verify whether targeted field-of-view diffusion-weighted imaging (tFOV-DWI) is feasible to significantly improve the performance of traditional full field-of-view diffusion-weighted imaging (fFOV-DWI) in the early assessment of AKI. 14 rabbits with unilateral AKI were induced by injection of microspheres under the guidance of digital subtraction angiography (DSA). All rabbits underwent tFOV-DWI and fFOV-DWI immediately after the surgery. Artifacts, distortion and lesion identification were graded by two experienced radiologists, and the signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were measured. Apparent diffusion coefficient (ADC) maps were then derived. Blood samples were collected pre- and post-surgery and serum creatinine weres measured. Renal specimen and biopsy were performed as the reference standard. Student t-test was used to ascertain statistical significance between the above parameters for tFOV-DWI and fFOV-DWI. The interobserver agreement and ADC measurements agreement were assessed. A higher percentage of renal lesions (17 out of 19) were detected in tFOV-DWI compared with fFOV-DWI (14 out of 19). Significant differences were observed in ADC value for both techniques between the lesion regions and normal tissues (p < 0.001). Histological findings were inversely correlated with ADC values of tFOV-DWI (r = -0.97, P < 0.001 for cortex; r = -0.98, P < 0.001 for medulla) and fFOV-DWI sequences (r = -0.95, P < 0.001 for cortex; r = -0.98, P < 0.001 for medulla). Those tFOV-DW images rated by the radiologists exhibit superior performance in terms of all assessed measures (P < 0.05), and interobserver agreement was excellent (ICC, 0.78 to 0.92). Besides, the ADC values derived from tFOV-DWI had a satisfactory agreement with those estimated by fFOV-DWI. The animal study demonstrates that the tFOV-DWI strategy provided visually better image quality and lesion depiction than conventional fFOV-DWI for early assessment of AKI.