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Iodinated contrast material (ICM) is a critical component for many radiologic examinations and procedures. However, ICM has often been withheld in the past out of concern for its potential nephrotoxicity and increased risk of morbidity and mortality, often at the expense of diagnostic accuracy and timely diagnosis. Evidence from controlled studies now suggest that most cases of acute kidney injury (AKI) caused by ICM were instead due to contrast-independent causes of AKI or normal variation in renal function. This study will discuss current knowledge of contrast-induced AKI, including the incidence, sequelae, risk factors, and prevention strategies of this potential complication., Competing Interests: Disclosure J.S. McDonald and R.J. McDonald report investigator-initiated research grants with GE Healthcare, United Kingdom. J.S. McDonald and R.J. McDonald serve as consultants and scientific advisors for GE Healthcare regarding preclinical and clinical studies., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Hemodynamic monitoring is crucial for the comprehensive management of children with sepsis, particularly those involving the kidneys. Sepsis-associated acute kidney injury (S-AKI) is closely linked to poor outcomes. Recently, ultrasonography modalities have been widely accepted as a non-invasive, rapid, and reliable tool for assessing volume status. We conducted research to determine intravascular volume based on ultrasound examination in S-AKI patients., Methods: A prospective cohort study was conducted between December 2023 and March 2024 in the Pediatric Intensive Care Unit (PICU) at Hasan Sadikin General Hospital. We divided the patients into two groups: those with sepsis without AKI and those with S-AKI. The intravascular volume was measured by the IVC/Ao (inferior vena cava/abdominal aorta) ratio using two-dimensional ultrasonography and USCOM before and 24 h after fluid treatment. The results were analyzed using SPSS 25, with a significance level of p < 0.05., Results: A total of 36 pediatric patients (aged 1 month-18 years) with sepsis were included. The IVC/Ao ratio before and after the fluid intervention demonstrated significant differences between the two groups (p < 0.001). USCOM Cardiac Index (CI) before and after the intervention also showed significant differences between the two groups (p < 0.001). Patients with S-AKI exhibited a poor hemodynamic response in the IVC/Ao ratio two-dimensional ultrasonography and USCOM examination., Conclusions: IVC/Ao ratio measurement is as accurate as USCOM and can be used as a simple and cost-effective alternative for hemodynamic monitoring., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

A major challenge in prevention and early treatment of organ fibrosis is the lack of valuable tools to assess the evolving profibrotic maladaptive repair after injury in vivo in a non-invasive way. Here, using acute kidney injury (AKI) as an example, we tested the utility of fibroblast activation protein (FAP) imaging for dynamic assessment of maladaptive repair after injury. The temporospatial pattern of kidney FAP expression after injury was first characterized. Single-cell RNA sequencing and immunostaining analysis of patient biopsies were combined to show that FAP was specifically upregulated in kidney fibroblasts after AKI and was associated with fibroblast activation and chronic kidney disease (CKD) progression. This was corroborated in AKI mouse models, where a sustained and exaggerated kidney FAP upregulation was coupled to persistent fibroblast activation and a fibrotic outcome, linking kidney FAP level to post-insult maladaptive repair. Furthermore, using positron emission tomography (PET)/CT scanning with FAP-inhibitor tracers ([ 18 F]FAPI-42, [ 18 F]FAPT) targeting FAP, we demonstrated the feasibility of non-invasively tracking of maladaptive repair evolution toward kidney fibrosis. Importantly, a sustained increase in kidney [ 18 F]FAPT (less hepatobiliary metabolized than [ 18 F]FAPI-42) uptake reflected persistent kidney upregulation of FAP and characterized maladaptive repair after AKI. Kidney [ 18 F]FAPT uptake at hour 2-day 7 correlated with kidney fibrosis 14 days after AKI. Similar changes in [ 18 F]FAPI-42 PET/CT imaging were observed in patients with AKI and CKD progression. Thus, persistent kidney FAP upregulation after AKI was associated with maladaptive repair and a fibrotic outcome. Hence, FAP-specific PET/CT imaging enables dynamic visualization of maladaptive repair after AKI and prediction of kidney fibrosis within a clinically actionable window., (Copyright © 2024 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.)

Optical imaging is a powerful tool for early disease detection and effective treatment planning, but its accuracy is often compromised by the uptake of imaging materials by the mononuclear phagocyte system (MPS). Herein, we leverage multivalent host-guest interactions between cyanine dyes and β-cyclodextrin polymers to develop supramolecular probes with enhanced stability, optical, and transport profiles for accurate in vivo imaging. These multivalent interactions not only ensure the stability of the probes but also enhance fluorescence efficiency by minimizing nonradiative decay. Our self-assembly approach effectively modulates probe size and surface properties, enabling evasion of MPS clearance and promoting prolonged bloodstream circulation, thereby improving the signal-to-background ratio for imaging. The effectiveness of our design is demonstrated by substantial advancements in the early diagnosis of acute kidney injury and by providing high-contrast imaging and precise surgical navigation across various tumor models. Our strategy not only advances optical imaging materials toward clinical translation but also establishes a versatile platform applicable to multiple imaging modalities.

Purpose of Review: Acute kidney injury (AKI) is common in critical illness and associated with adverse outcomes. Imaging, specifically ultrasound, is increasingly finding a role in AKI diagnostics. This includes the assessment of arterial and venous blood flow, tissue perfusion and the condition of the renal parenchyma. This review provides an update on ultrasound techniques and their application to AKI in critical care., Recent Findings: Advances have been made in arterial and venous Doppler, contrast enhanced ultrasound (CEUS) and shear wave elastography (SWE). Doppler and CEUS techniques offer benefit in terms of AKI diagnosis and in identifying patients at risk. In addition, through the demonstration of altered flow or impaired perfusion, these techniques provide information on the pathophysiology of AKI, offering potential for targeted intervention. Renal SWE, an emerging technique, assesses tissue stiffness potentially allowing exploration of the role of venous congestion in the pathogenesis of AKI., Summary: Ultrasound continues to demonstrate great promise in the diagnosis and management of AKI, offering a noninvasive means to diagnose perfusion deficits and assess response to treatments. Further research, with standardization of techniques, may allow multifaceted renal ultrasound assessment in the critically ill for more accurate diagnosis and tailored intervention in AKI., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: To gauge the utility of multiparametric MRI in characterizing pathologic changes after iodinated contrast-induced acute kidney injury (CI-AKI) in rats., Methods: We randomly grouped 24 rats injected with 8 g iodine/kg of body weight (n = 6 each) and 6 rats injected with saline as controls. All rats underwent T1, T2 mapping and diffusion kurtosis imaging (DKI) after contrast injection at 0 (control), 1, 3, 7, 13 days. T1, T2, and mean kurtosis (MK) values were performed in renal outer/inner stripes of outer medulla (OSOM and ISOM) and cortex (CO), and their diagnosis performance for CI-AKI also been evaluated. Serum creatinine (SCr), insulin-like growth factor-binding protein 7 (IGFBP7), tissue inhibitor metalloproteinase 2 (TIMP-2), aquaporin-1 (AQP1), α-smooth muscle actin (α-SMA), and histologic indices were examined., Results: Compared with controls, urinary concentrations of both TIMP-2 and IGFBP7 were obviously elevated from Day 1 to Day 13 (all p < 0.05). T2 values were significantly higher than control group for Days 1 and 3, and T1 and MK increased were more remarkable at all time points (Days 1-13) in CI-AKI (all p < 0.05) than control group. Changes in T1 and MK strongly correlated with renal injury scores of all anatomical compartments and with expression levels of AQP1 and moderately correlated with α-SMA. Changes in T2 values correlating moderately with renal scores of CO, ISOM and OSOM and AQP1. The MK obtained the highest area under the receiver operating characteristic (ROC) curve of 0.846 with a sensitivity of 70.8 % and specificity of 88.9 %., Conclusions: Combined use of multiparametric MRI could be a valid noninvasive method for comprehensive monitoring of CI-AKI. Among these parameters, MK may achieve the best diagnostic performance for CI-AKI., Competing Interests: Declaration of competing interest The authors report there are no competing interests to declare., (Copyright © 2024. Published by Elsevier Inc.)

Purpose: To investigate the renal pathophysiological processes and protective effect of quercetin on contrast-induced acute kidney injury (CI-AKI) in mice with type 1 diabetic mellitus(DM) using diffusion tensor imaging(DTI). Methods: Mice with DM were divided into two groups. In the diabetic + contrast medium(DCA) group, the changes of the mice kidneys were monitored at 1, 24, 48, and 72 h after the injection of iodixanol(4gI/kg). The mice in the diabetic + contrast medium + quercetin(DCA + QE) group were orally given different concentrations of quercetin for seven days before injection of iodixanol. In vitro experiments, renal tubular epithelial (HK-2) cells exposed to high glucose conditions were treated with various quercetin concentrations before treatment with iodixanol(250 mgI/mL). Results: DTI-derived mean diffusivity(MD) and fractional anisotropy(FA) values can be used to evaluate CI-AKI effectively. Quercetin significantly increased the expression of Sirt 1 and reduced oxidative stress by increasing Nrf 2/HO-1/SOD1. The antiapoptotic effect of quercetin on CI-AKI was revealed by decreasing proteins level and by reducing the number of apoptosis-positive cells. In addition, flow cytometry indicated quercetin-mediated inhibition of M1 macrophage polarization in the CI-AKI. Conclusions: DTI will be an effective noninvasive tool in diagnosing CI-AKI. Quercetin attenuates CI-AKI on the basis of DM through anti-oxidative stress, apoptosis, and inflammation.

Background: This study aimed to discuss the diagnostic value of multi-parameter ultrasound evaluation in sepsis complicated with acute kidney injury (AKI)., Methods: Patients were divided into an AKI group ( n  = 50) and a non-injury group ( n  = 50) based on the presence of AKI. The clinical characteristics were collected, and renal function parameters between the two groups were compared, including 24-h urine volume, serum creatinine, urea, serum cystatin C (CysC), renal parenchymal thickness (RPT), renal artery resistance index (RI), and multi-parameter ultrasound scoring (MPUS). Additionally, logistic regression analysis was conducted to determine the influencing factors of sepsis complicated with AKI. The prediction value was evaluated using a receiver operating characteristic (ROC) curve., Results: In the AKI group, creatinine, CysC, urea, MPUS score, RPT, and RI values were significantly higher, while the 24-h urine volume was lower than those in the non-injury group ( p  < 0.01). Moreover, multivariate logistic analysis indicated that high CysC and RI values were independent risk factors, whereas high 24-h urine volume and low MPUS were independent protective factors for sepsis-induced AKI. The ROC curve demonstrated that RI (AUC = 0.906) was more effective than 24-h urine volume (AUC = 0.797), CysC (AUC = 0.730), and MPUS (AUC = 0.794) in identifying sepsis-induced AKI., Conclusion: High RI values increase the risk of sepsis-induced AKI, whereas low MPUS may reduce it. RI showed high diagnosis values for sepsis complicated with AKI.

Color pulsed-wave Doppler ultrasound (CPWD-US) emerges as a pivotal tool in intensive care units (ICUs) for diagnosing acute kidney injury (AKI) swiftly and non-invasively. Its bedside accessibility allows for rapid assessments, making it a primary imaging modality for AKI characterization. Furthermore, CPWD-US serves as a guiding instrument for key diagnostic-interventional procedures such as renal needle biopsy and percutaneous nephrostomy, while also facilitating therapy response monitoring and AKI progression tracking. This review shifts focus towards the integration of renal ultrasound into ICU workflows, offering contemporary insights into its utilization through a diagnostic standard-oriented approach. By presenting a flow chart, this review aims to provide practical guidance on the appropriate use of point-of-care ultrasound in critical care scenarios, enhancing diagnostic precision, patient management and safety, albeit amidst a backdrop of limited evidence regarding long-term outcomes., (© The Author(s) 2024. Published by Oxford University Press on behalf of the ERA.)

Kidney diseases pose a global healthcare burden, with millions requiring renal replacement therapy. Ischemia/reperfusion injury (IRI) is a common pathology of acute kidney injury, causing hypoxia and subsequent inflammation-induced kidney damage. Accurate detection of acute kidney injury due to IRI is crucial for timely intervention. We used longitudinal, multi-parametric magnetic resonance imaging (MRI) employing arterial spin labelling (ASL), diffusion weighted imaging (DWI), and dynamic contrast enhanced (DCE)-MRI to assess IRI induced changes in both the injured and healthy contralateral kidney, in a unilateral IRI mouse model (n = 9). Multi-parametric MRI demonstrated significant differences in kidney volume (p = 0.001), blood flow (p = 0.002), filtration coefficient (p = 0.038), glomerular filtration rate (p = 0.005) and apparent diffusion coefficient (p = 0.048) between the injured kidney and contralateral kidney on day 1 post-IRI surgery. Identification of the injured kidney using principal component analysis including most of the imaging parameters demonstrated an area under the curve (AUC) of 0.97. These results point to the utility of multi-parametric MRI in early detection of IRI-induced kidney damage suggesting that the combination of various MRI parameters may be suitable for monitoring the extent of injury in this model., (© 2024. The Author(s).)

Objectives: Prior studies have examined the association between timing of cardiac surgery after coronary angiography with risk of acute kidney injury, but this remains controversial. The purpose of this study was to investigate the association between interval from coronary angiography to urgent coronary artery bypass grafting with acute kidney injury, and to examine this possible effect in patients with preexisting kidney disease., Methods: Patients from a single institution undergoing urgent, isolated coronary artery bypass grafting within 7 days of coronary angiography were included. Patients were subdivided by chronic kidney disease stage and angiography-to-surgery interval. Locally estimated scatterplot smoothing was used to evaluate the functional relationship of the probability of acute kidney injury and time interval. Adjusted odds ratios were calculated for each time interval group compared against the Day 0 to 1 interval group, controlling for multiple covariates. Analyses were repeated for each chronic kidney disease subgroup., Results: A total of 2249 patients were included in this study. There were 271 (12.0%) patients with postoperative acute kidney injury. Plots demonstrated a decreasing risk of kidney injury from Day 0 to 1 to Day 3 following coronary angiography. Adjusted odds ratios also showed a significant decrease in risk of kidney injury on Day 3 compared with Day 0 to 1. Analyses repeated for each chronic kidney disease stage showed similar trends., Conclusions: For patients undergoing urgent coronary artery bypass grafting, there is a decreased risk of kidney injury in those having surgery on day 3 after coronary angiography compared with those having surgery on Day 0 to 1, regardless of preexisting kidney disease., (Copyright © 2023 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

The aim of the present study was to define the risk factors associated with contrast-induced acute kidney injury (CI-AKI) in patients who underwent coronary artery angiography (CAG). In this retrospective cohort study, patients who underwent CAG between March 2014 and January 2022 were evaluated. A total of 2923 eligible patients were included in the study. Univariate and multivariate logistic regression analysis was used to identify the predictive factors. CI-AKI developed in 77 (2.6%) of 2923 patients. In multivariate analysis, diabetes mellitus (DM), chronic kidney disease (CKD), and estimated glomerular filtration rate (eGFR) were found to be independent factors associated with CI-AKI. In the subgroup analysis of patients with eGFR ≥60 mL/min/1.73 m 2 , eGFR remained a predictor of CI-AKI (Odds ratio (OR): .89, 95% CI: .84-.93; that is, a lower eGFR remains a risk factor for CI-AKI). In the receiving operating characteristic (ROC) analysis of patients with eGFR ≥60 mL/min/1.73 m 2 , the area under the curve of the eGFR was .826. Using the ROC curve based on Youden's index, the eGFR cut-off was found to be 70 mL/min/1.73 m 2 for patients with eGFR ≥60 mL/min/1.73 m 2 . eGFR is also an important risk factor in patients with eGFR 60-70 mL/min/1.73 m 2 ., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Competing Interests: Conflict of Interest Statement The authors reported no conflicts of interest. The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

Objectives: This study aimed to identify the incidence and risk factors for contrast-associated acute kidney injury nephropathy (CA-AKI) in patients undergoing contrast-enhanced computed tomography (CCT) in the emergency department., Materials and Methods: In this retrospective single-center study, patients aged 18 and older who visited the emergency department and underwent CCT between January and February 2022 were included. The Mehran score, calculated from patient data, was used to assess risk. CA-AKI development was determined by measuring serum creatinine (SCr) levels 48-72 h post-contrast administration., Results: The study included 532 patients, with a mean age of 57 ± 19 years; 53.2% were male. CA-AKI developed in 16% of cases, 5.82% required hemodialysis, and 7.9% died. The Mehran score was the only significant predictor of CA-AKI development. Patients with a Mehran score of 16 or higher had a 161-fold increased risk of developing CA-AKI compared to those with a score of 5 or lower. The model achieved a 91.3% correct classification rate. Logistic regression analysis showed that CA-AKI significantly increased mortality risk by 15.7 times., Conclusion: The Mehran score, originally developed for predicting CA-AKI risk post-coronary intervention, is also effective for predicting CA-AKI risk after CCT. While CA-AKI is a significant factor affecting mortality, it is not the sole cause of death (Nagelkerke R2 value 0.310).

Objective: This study aimed to evaluate the diagnostic efficacy and safety of low-contrast-dose, dual-source dual-energy CT before transcatheter aortic valve replacement (TAVR) in patients with compromised renal function., Materials and Methods: A total of 54 consecutive patients (female:male, 26:38; 81.9 ± 7.3 years) with reduced renal function underwent pre-TAVR dual-energy CT with a 30-mL contrast agent between June 2022 and March 2023. Monochromatic (40- and 50-keV) and conventional (120-kVp) images were reconstructed and analyzed. The subjective quality score, vascular attenuation, contrast-to-noise ratio (CNR), and signal-to-noise ratio (SNR) were compared among the imaging techniques using the Friedman test and post-hoc analysis. Interobserver reliability for aortic annular measurement was assessed using the intraclass correlation coefficient (ICC) and Bland-Altman analysis. The procedural outcomes and incidence of post-contrast acute kidney injury (AKI) were assessed., Results: Monochromatic images achieved diagnostic quality in all patients. The 50-keV images achieved superior vascular attenuation and CNR ( P < 0.001 in all) while maintaining a similar SNR compared to conventional CT. For aortic annular measurement, the 50-keV images showed higher interobserver reliability compared to conventional CT: ICC, 0.98 vs. 0.90 for area and 0.97 vs. 0.95 for perimeter; 95% limits of agreement width, 0.63 cm² vs. 0.92 cm² for area and 5.78 mm vs. 8.50 mm for perimeter. The size of the implanted device matched CT-measured values in all patients, achieving a procedural success rate of 92.6%. No patient experienced a serum creatinine increase of ≥ 1.5 times baseline in the 48-72 hours following CT. However, one patient had a procedural delay due to gradual renal function deterioration., Conclusion: Low-contrast-dose imaging with 50-keV reconstruction enables precise pre-TAVR evaluation with improved image quality and minimal risk of post-contrast AKI. This approach may be an effective and safe option for pre-TAVR evaluation in patients with compromised renal function., Competing Interests: Kyunghwa Han, who holds the respective position of Statistical Consultant of the Korean Journal of Radiology, was not involved in the editorial evaluation or decision to publish this article. The remaining author has declared no conflicts of interest., (Copyright © 2024 The Korean Society of Radiology.)

Background: Early diagnosis of postoperative acute kidney injury (AKI) is crucial. This study investigated the changes and early diagnostic value of Doppler ultrasound parameters in patients with AKI after laparoscopic radical prostatectomy (LRP)., Methods: This study retrospectively analysed the clinical data of 198 patients with LRP undergoing Doppler ultrasound from May 2020 to May 2022. The incidence of AKI after LRP was measured based on diagnostic criteria of AKI developed by Kidney Disease: Improving Global Outcomes. The patients were divided into AKI group (n = 12) and non-AKI group (n = 186) in accordance with the presence or absence of AKI. This study compared changes in Doppler ultrasound parameters between two groups, and evaluated the clinical efficacy of single and combined diagnosis of ultrasound parameters using receiver operating characteristic (ROC) curve and area under the curve (AUC)., Results: Twelve patients experienced postoperative AKI, with an incidence rate of 6.06%. No significant difference was found in baseline data, serum creatinine (Scr), urinary output and blood potassium levels of both groups ( p > 0.05). The urinary output 1 day after surgery was significantly lower than that before surgery ( p < 0.05). The AKI group demonstrated higher pulsatility index (PI) and resistive index (RI) of the renal interlobar artery than the non-AKI group ( p < 0.05), with no significant difference in peak systolic velocity (PSV) in both groups ( p > 0.05). No significant difference was observed in the Doppler ultrasound parameters of renal segmental artery and main renal artery ( p > 0.05). The AUCs in the PI of the renal interlobar artery, the RI of the renal interlobar artery, and the combined diagnosis were 0.720, 0.704 and 0.724, respectively. ROC curve showed that the above two Doppler ultrasound parameters had good diagnostic efficacy for AKI after LRP ( p < 0.05)., Conclusions: The PI and RI of renal interlobar artery in the AKI group after LRP were significantly different from those in the non-AKI group. These two Doppler ultrasound parameters had good diagnostic efficacy in the early identification of AKI after LRP. Thus, they could provide reference and guidance for clinical practice., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s).)

The risk of acute renal failure (ARF) following iodinated contrast media injection has long been overestimated because of the previous use of more toxic ICPs and uncontrolled studies. Nowadays, this concept is being questioned. Patients with severe renal failure and/or ARF are the only group still considered at risk. In these patients, it is necessary to discuss an alternative without an iodinated contrast agent. Contrast-enhanced ultrasound, MRI, spectral CT or PET-CT scan can be used instead of contrast-enhanced CT. Preventive measures should be applied when appropriate substitute to CT is not available or not diagnosed (minimum necessary dose of ICP, interruption of some treatments and prior hydration). These recommendations formalized by the European Society of Urogenital Radiology (ESUR) in 2018 address most situations faced by clinicians. In complex situations, an opinion from a nephrologist remains necessary after asking the radiologist about the availability of acceptable substitutes., (Copyright © 2022 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

Background: Ischemia reperfusion injury (IRI)-induced acute kidney injury (AKI) may occur after renal ischemic injury. There is a lack of an accurate and comprehensive detection technique for IRI-AKI., Purpose: To longitudinally evaluate IRI-AKI in rats by renal structure, function, and metabolites using multi-parametric MRI (mpMRI)., Study Type: Prospective., Animal Model: Forty-eight rats undergoing IRI-AKI., Field Strength/sequence: 7-T, T 1 mapping, and arterial spin labeling (ASL): echo planar imaging (EPI) sequence; blood oxygen level-dependent (BOLD): gradient recalled echo (GRE) sequence; T 2 mapping, quantitative magnetization transfer (qMT), and chemical exchange saturation transfer (CEST): rapid acquisition with relaxation enhancement (RARE) sequence., Assessment: The mpMRI for IRI-AKI was conducted at 0 (control), 1, 3, 7, 14, and 28 days, all included eight rats. The longitudinal mpMRI signal of manually outlined cortex, outer stripe of the outer medulla (OSOM), inner stripe of the outer medulla, and medulla plus pelvis were calculated and compared, their diagnosis performance for IRI-AKI also been evaluated., Statistical Tests: Pearson correlations analysis for correlation between mpMRI signal and renal injury, unpaired t-tests for comparing the signal changes, and receiver operating characteristics (ROC) analysis was used to identify most sensitive indicator of mpMRI. A P-value <0.05 was considered statistically significant., Results: Compared with control kidneys, the T 1 and T 2 values of the cortex and medulla in IRI kidneys increased and reached their highest values on day 14, and the kidneys also showed the most severe edema and segments blurred. The RBF in the cortex and OSOM showed a significant decline after day 3. The BOLD signal in the OSOM largest increased on day 28. The cortical PSR and the amine-CEST both decreased with IRI-AKI progression, and amine-CEST achieved the highest AUC for the diagnosis (0.899)., Data Conclusion: Multi-parametric MRI may show comprehensive variations in IRI-AKI, and amine-CEST may exhibit the highest accuracy for diagnosis of IRI-AKI., Level of Evidence: 1 TECHNICAL EFFICACY: Stage 2., (© 2023 International Society for Magnetic Resonance in Medicine.)

Iodinated contrast material (ICM) has revolutionized the field of diagnostic radiology through improvements in diagnostic performance and the expansion of clinical indications for radiographic and CT examinations. Historically, nephrotoxicity was a feared complication of ICM use, thought to be associated with a significant risk of morbidity and mortality. Such fears often precluded the use of ICM in imaging evaluations, commonly at the expense of diagnostic performance and timely diagnosis. Over the past 20 years, the nephrotoxic risk of ICM has become a topic of debate, as more recent evidence from higher-quality studies now suggests that many cases of what was considered contrast-induced acute kidney injury (CI-AKI) likely were cases of mistaken causal attribution; most of these cases represented either acute kidney injury (AKI) caused by any of myriad other known factors that can adversely affect renal function and were coincidentally present at the time of contrast media exposure (termed "contrast-associated AKI" [CA-AKI]) or a manifestation of the normal variation in renal function that increases with worsening renal function. This Special Series Review discusses the current state of knowledge regarding CI-AKI and CA-AKI, including the incidence, risk factors, outcomes, and prophylactic strategies in the identification and management of these clinical conditions.

Background: Acute kidney injury (AKI) is a common condition in critically ill children and is associated with increased morbidity and mortality. This study aimed to assess the performance of point-of-care ultrasonography to predict AKI in children undergoing cardiac surgery., Methods: In this prospective study, consecutive children underwent kidney Doppler ultrasound examination within 24 h following cardiac surgery, and an experienced operator obtained both renal resistive index (RRI) and renal pulsatility index (RPI). AKI was defined by the Kidney Disease Improving Global Outcome (KDIGO) criteria. The primary outcome was the diagnosis of severe AKI (KDIGO stage 2 or 3) on day 3., Results: A total of 58 patients were included. Median age and weight were 12.9 months (IQR 6.0-37.9) and 7.36 kg (IQR 5.19-11.40), respectively. On day 3, 13 patients were classified as having AKI, of which 11 were severe. RRI could effectively predict AKI (area under the ROC curve [AUC] 0.83, 95% CI 0.71-0.92; p < 0.001) as well as RPI (AUC 0.81, 95% CI 0.69-0.90; p < 0.001). The optimal cutoff value for RRI was 0.85 (sensitivity, 73%; specificity, 83%; positive predictive value [PPV], 50%; and negative predictive value [NPV], 93%), while for RPI was 1.95 (sensitivity, 73%; specificity, 78%; PPV, 44%; and NPV, 92%). Similar results were found in the analysis for prediction on day 5. Significant correlations were found between Doppler-based variables and estimated GFR and furosemide dose on day 3., Conclusions: Kidney Doppler ultrasound may be a promising tool for predicting AKI in children undergoing cardiac surgery., (© 2024. The Author(s), under exclusive licence to International Pediatric Nephrology Association.)

Background: Kidney echogenicity is typically determined subjectively but may have a quantifiable relationship to kidney function. Similarly, kidney length has been shown to correlate with kidney function. This study sought to quantify echogenicity using readily available software. Secondarily, we aimed to evaluate the correlation between quantified echogenicity and kidney length to the estimated glomerular filtration rate (eGFR) in children with acute kidney injury (AKI) and chronic kidney disease (CKD)., Methods: In a single-center retrospective observational study, echogenicity index (EI) was determined using a ratio of right kidney to liver mean pixel density. The kidney length ratio (KLR) was determined by the actual to predicted lengths of both kidneys. Both variables were correlated to eGFR using correlation analyses and predictive capacity was determined with receiver operating characteristic curve (ROC) analysis., Results: Of 94 subjects, 46% (43/94) had AKI, 28% (26/95) had CKD and 26% (25/95) were controls. The higher the EI the lower the eGFR (r = - 0.46, p < 0.0001). EI between 1.0 and 1.1 predicted an eGFR < 90 ml/min/1.73m 2 with an AUC of 0.71-0.78 while an EI between 1.1 and 1.2 predicted an eGFR < 60 ml/min/1.73m 2 with AUC of 0.75-0.80. Overall, the larger the KLR the lower the eGFR (r = - 0.25, p 0.018)., Conclusion: We have developed an accessible methodology to quantify kidney echogenicity. Overall, there was an inverse correlation between EI and eGFR in pediatric CKD and AKI. However, these correlations did not persist within subgroups which could be due to small sample size and heterogeneity of etiologies. Overall, KLR had a weaker correlation to eGFR, compared to EI. Despite these correlations, both EI and KLR had "fair" to "good" performance as a biomarker for an eGFR < 60 ml/min/1.73m 2 ., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Acute kidney injury (AKI) has become an increasing concern for patients due to the widespread clinical use of nephrotoxic drugs. Currently, the early diagnosis of AKI is still challenging and the available therapeutic drugs cannot meet the clinical demand. Herein, this work has investigated the key redox couple involved in AKI and develops a tailored photoacoustic (PA) imaging probe (AB-DiOH) which can reversibly respond to hypochlorite (ClO-)/glutathione (GSH) with high specificity and sensitivity. This probe enables the real-time monitoring of AKI by noninvasive PA imaging, with better detection sensitivity than the blood test. Furthermore, this probe is utilized for screening nephroprotective drugs among natural products. For the first time, astragalin is discovered to be a potential new drug for the treatment of AKI. After oral administration, astragalin can be efficiently absorbed by the animal body, alleviate kidney injury, and meanwhile induce no damage to other normal tissues. The treatment mechanism of astragalin has also been revealed to be the simultaneous inhibition of oxidative stress, ferroptosis, and cuproposis. The developed PA imaging probe and the discovered drug candidate provide a promising new tool and strategy for the early diagnosis and effective treatment of AKI., (© 2024 Wiley‐VCH GmbH.)

Understanding the pharmacokinetic profiles of nanomaterials in living organisms is essential for their application in disease treatment. Bipyramidal DNA frameworks (BDFs) are a type of DNA nanomaterial that have shown prospects in the fields of molecular imaging and therapy. To serve as a reference for disease-related studies involving the BDF, we constructed a 68 Ga-BDF and employed positron emission tomography (PET) imaging to establish its pharmacokinetic model in healthy mice. Our investigation revealed that the BDF was primarily eliminated from the body via the urinary system. Ureteral obstruction could significantly alter the metabolism of the urinary system. By utilizing the established pharmacokinetic model, we sensitively observed distinct imaging indicators in unilateral ureteral obstruction and acute kidney injury (a complication of ureteral obstruction) mouse models. Furthermore, we observed that the BDF showed therapeutic effects in an AKI model. We believe that the established pharmacokinetic model and unique renal excretion characteristics of the BDF will provide researchers with more information for studying kidney diseases.

Background: Acute kidney injury (AKI) is common in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Early detection of AKI is likely to speed diagnosis and implementation of measures to preserve renal function. To evaluate if renal Doppler resistive index (RI) would predict AKI in patients with NSTEMI on presentation in the emergency department., Methods: Patients with NSTEMI at the emergency department were included. The renal Doppler RI was measured. Baseline demographic data and clinical characteristics of patients at admittance were recorded. Based on discharge diagnosis, the patients were divided into AKI group and no-AKI group. Multiple logistic regression analysis was performed to determine predictor variables significantly associated with AKI., Results: A total of 293 patients were included in the analysis; 44 (15.0%) developed AKI without need for dialysis. There were statistical differences in the age, incidence of diabetes mellitus and cerebrovascular disease, beta-receptor blockers, serum creatinine and renal index between the two groups. Using multivariate logistic regression analysis, age [OR 1.87; 95% confidence interval (CI) 1.595-2.585; p = 0.027], diabetes mellitus (OR 2.007, 95% CI: 1.489-2.793; p = 0.014), serum creatinine (OR 1.817, 95% CI: 1.568-2.319; p = 0.013), and RI (OR 2.168, 95% CI: 1.994-4.019; p = 0.003) predicted AKI in patients with NSTEMI. According to receiver operating characteristic (ROC) analysis, RI showed a significantly increased area under the curve (AUC) compared to serum creatitine (AUC: 0.891 vs 0.679; p < 0.001)., Conclusions: Renal Doppler RI may be a useful predictor of AKI in patients with NSTEMI in the emergency department., Competing Interests: Declaration of Competing Interest The author has no financial or other conflicts of interest to disclose., (Copyright © 2023 Southern Society for Clinical Investigation. Published by Elsevier Inc. All rights reserved.)

Background: Contrast-associated acute kidney injury (CA-AKI) is a prevalent complication following coronary angiography (CAG). However, there is ongoing controversy surrounding its precise definition. Although previous studies have demonstrated the successful application of appropriate definitions in managing high-risk CA-AKI patients, there remains limited research on the association between different definitions and prognosis specifically in patients with chronic kidney disease (CKD)., Methods: A total of 4197 CKD patients undergoing coronary angiography (CAG) were included in this study. Two definitions of contrast-associated acute kidney injury (CA-AKI) were used: CA-AKI A , which was defined as an increase of ≥0.5 mg/dL or >25% in serum creatinine (SCr) from baseline within 72 hours after CAG, and CA-AKI B , which was defined as an increase of ≥0.3 mg/dL or >50% in SCr from baseline within 48 hours after CAG. Cox regression analysis was employed to assess the association between these two definitions and long-term mortality. Additionally, population attributable risks (PARs) were calculated to evaluate the impact of CA-AKI definitions on long-term prognosis., Results: During the median follow-up period of 4.70 (2.50-7.78) years, the overall long-term mortality was 23.6%, and the long-term mortality in patients with CA-AKI according to both CA-AKI A and CA-AKI B criteria were 33.5% and 33.8%, respectively. We found that CA-AKI A (HR: 1.45, 95% CI: 1.23-1.70, p<0.001) and CA-AKI B (HR: 1.44, 95% CI: 1.23-1.69, p<0.001) were associated with long-term mortality. The PARs were the highest for CA-AKI A (5.87%), followed by CA-AKI B (5.70%)., Conclusion: Contrast-associated acute kidney injury (CA-AKI) is a frequently observed complication in CKD patients undergoing coronary angiography (CAG), and both definitions of CA-AKI are significantly correlated with a poor long-term prognosis. Consequently, in the clinical management of CKD patients, it is crucial to prioritize CA-AKI, irrespective of the specific CA-AKI definition used., Competing Interests: The authors declare that they have no competing interests in this work., (© 2024 Feng et al.)

Contrast-enhanced magnetic resonance imaging (CE-MRI) of acute kidney injury (AKI) is severely hindered by the poor targeting capacity and potential toxicity of current contrast agents. Herein, we propose one-step fabrication of a bovine serum albumin@polydopamine@Fe (BSA@PDA@Fe, BPFe) nanoprobe with self-purification capacity for targeted CE-MRI of AKI. BSA endows the BPFe nanoprobe with renal tubule-targeting ability, and PDA is capable of completely inhibiting the intrinsic metal-induced reactive oxygen species (ROS), which are always involved in Fe/Mn-based agents. The as-prepared nanoprobe owns a tiny size of 2.7 nm, excellent solubility, good T 1 MRI ability, superior biocompatibility, and powerful antioxidant capacity. In vivo CE-MRI shows that the BPFe nanoprobe can accumulate in the renal cortex due to the reabsorption effect toward the serum albumin. In the AKI model, impaired renal reabsorption function can be effortlessly detected via the diminishment of renal cortical signal enhancement. More importantly, the administration of the BPFe nanoprobe would not aggravate renal damage of AKI due to the outstanding self-purification capacity. Besides, the BPFe nanoprobe is employed for CE-MR angiography to visualize fine vessel structures. This work provides an MRI contrast agent with good biosafety and targeting ability for CE-MRI of kidney diseases.

Aims: Acute kidney injury (AKI) has been associated with a variety of neurological problems, while the neurobiological mechanism remains unclear. In the present study, we utilized resting-state functional magnetic resonance imaging (rs-fMRI) to detect brain injury at an early stage and investigated the impact of microglia on the neuropathological mechanism of AKI., Methods: Rs-fMRI data were collected from AKI rats and the control group with a 9.4-Tesla scanner at 24, 48, and 72 h post administration of contrast medium or saline. The amplitude of low-frequency fluctuations (ALFF) was then compared across the groups at each time course. Additionally, flow cytometry and SMART-seq2 were employed to evaluate microglia. Furthermore, pathological staining and Western blot were used to analyze the samples., Results: MRI results revealed that AKI led to a decreased ALFF in the hippocampus, particularly in the 48 h and 72 h groups. Additionally, western blot suggested that AKI-induced the neuronal apoptosis at 48 h and 72 h. Flow cytometry and confocal microscopy images demonstrated that AKI activated the aggregation of microglia into neurons at 24 h, with a strong upregulation of M1 polarization at 48 h and peaking at 72 h, accompanying with the release of proinflammatory cytokines. The ALFF value was strongly correlated with the proportion of microglia (|r| > 0.80, p < 0.001)., Conclusions: Our study demonstrated that microglia aggregation and inflammatory factor upregulation are significant mechanisms of AKI-induced neuronal apoptosis. We used fMRI to detect the alterations in hippocampal function, which may provide a noninvasive method for the early detection of brain injury after AKI., (© 2023 The Authors. CNS Neuroscience & Therapeutics Published by John Wiley & Sons Ltd.)

Traditional markers, such as serum creatinine and blood urea nitrogen, frequently show delayed elevations following acute kidney injury (AKI), limiting their utility for prompt detection and timely intervention in AKI management. Shear wave elastography (SWE) exhibits potential for AKI diagnosis by measuring tissue stiffness. Our study aimed to evaluate the diagnostic performance of SWE in detecting AKI by measuring the stiffness of kidney tissue. Between July 2022 and December 2022, a total of 103 consecutive participants who met the eligibility criteria were prospectively enrolled, underwent SWE measurements, and were classified into AKI or non-AKI groups based on the 2012 Kidney Disease: Improving Global Outcomes (KDIGO) criteria. A receiver operating characteristic (ROC) curve was drawn to examine the feasibility of differentiating between AKI and non-AKI patients and assessing diagnostic performance. The effects of tissue anisotropy on SWE measurements were also examined. Our results revealed that patients in the AKI group exhibited significantly increased stiffness values in specific kidney regions compared with those in the non-AKI group. For the diagnosis of AKI, the optimal cut-off values were identified as 9.9 kPa, 2.9 kPa, and 4.4 kPa for the upper pole medulla, middle cortex, and middle medulla, respectively, in the longitudinal plane. Correspondingly, the areas under the ROC curves for these regions were 0.737 (95% confidence interval [CI]: 0.637, 0.822), 0.736 (95% CI: 0.637, 0.821), and 0.784 (95% CI: 0.688, 0.861). Additionally, we observed a significant variability in stiffness values due to tissue anisotropy, specifically in the segments of the upper pole cortex, and medulla across both longitudinal and transverse planes. SWE serves as a noninvasive approach for the quantification of tissue stiffness and shows promise as an adjunctive tool for the assessment of AKI., Competing Interests: The authors declare that there are no competing interests associated with this manuscript., (Copyright: © 2024 Qiang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Renal perfusion status remains poorly studied at the bedside during sepsis associated acute kidney injury (AKI). The aim of the study is to examine renal cortical and medullary perfusion using renal contrast enhanced ultrasound (CEUS) in septic patients., Methods: In this single-center, prospective longitudinal study, septic patients were enrolled. Renal ultrasonography was performed within 24 hours of ICU admission (D1), then repeated at D3, D5 and D7. Each measurement consisted of three destruction replenishment sequences that were recorded for delayed analysis with dedicated software (Vuebox). Renal cortex and medulla perfusion were quantified by measuring time to peak (TTP). Receiver operating characteristic (ROC) analysis was used to evaluate 28-day renal prognosis., Results: The study included 149 septic patients, including 70 non-AKI patients and 79 AKI patients. Both renal cortical and medullary TTP was longer in the AKI group than in the non-AKI group. The difference of TTP between renal cortex and medulla in AKI group was higher than that in the non-AKI group (p = 0.000). Medullary TTP on day 3 had the best performance in predicting the prognosis of 28-day renal function (AUC 0.673, 95% confidence interval 0.528-0.818, p = 0.024), and its cut-off value was 45 s with a sensitivity 52.2% and a specificity of 82.1%. Cortical TTP on day 3 also had the performance in predicting the prognosis of 28-day renal function (AUC 0.657, 95% confidence interval 0.514-0.800, p = 0.039), and its cut-off value was 33 s with a sensitivity 78.3% and a specificity of 55.0%., Conclusion: Renal medullary perfusion alterations differ from those in cortex, with the medulla is worse. Simultaneous and dynamic assessment of cortical and medullary microcirculatory flow alterations necessary. TTP on day 3, especially medullary TTP, seems to be a relatively stable and useful indicator, which correlates with 28-day renal function prognosis in septic patients. Early correction of renal cortical and medullary perfusion alterations reduces the incidence of adverse renal events.

To combat the irreversible decline in renal function associated with kidney disease, it is essential to establish non-invasive biomarkers for assessing renal microcirculation. However, the limited resolution and/or vascular sensitivity of existing diagnostic imaging techniques hinders the visualization of complex cortical vessels. Here, a 3D renal ultrafast Doppler (UFD) imaging system that uses a high ultrasound frequency (18 MHz) and ultrahigh frame rate (1 KHz per slice) to scan the entire volume of a rat's kidney in vivo is demonstrated. The system, which can visualize the full 3D renal vascular branching pyramid at a resolution of 167 µm without any contrast agent, is used to chronically and noninvasively monitor kidneys with acute kidney injury (AKI, 3 days) and diabetic kidney disease (DKD, 8 weeks). Multiparametric UFD analyses (e.g., vessel volume occupancy (VVO), fractional moving blood volume (FMBV), vessel number density (VND), and vessel tortuosity (VT)) describe rapid vascular rarefaction from AKI and long-term vascular degeneration from DKD, while the renal pathogeneses are validated by in vitro blood serum testing and stained histopathology. This work demonstrates the potential of 3D renal UFD to offer valuable insights into assessing kidney perfusion levels for future research in diabetes and kidney transplantation., (© 2023 The Authors. Advanced Science published by Wiley-VCH GmbH.)

Background: Preventing sepsis-associated acute kidney injury (S-AKI) can be challenging because it develops rapidly and is often asymptomatic. Probability assessment of disease progression for therapeutic follow-up and outcome are important to intervene and prevent further damage., Purpose: To establish a noninvasive multiparametric MRI (mpMRI) tool, including T 1 , T 2 , and perfusion mapping, for probability assessment of the outcome of S-AKI., Study Type: Preclinical randomized prospective study., Animal Model: One hundred and forty adult female SD rats (65 control and 75 sepsis)., Field Strength/sequence: 9.4T; T 1 and perfusion map (FAIR-EPI) and T 2 map (multiecho RARE)., Assessment: Experiment 1: To identify renal injury in relation to sepsis severity, serum creatinine levels were determined (31 control and 35 sepsis). Experiment 2: Animals underwent mpMRI (T 1 , T 2 , perfusion) 18 hours postsepsis. A subgroup of animals was immediately sacrificed for histology examination (nine control and seven sepsis). Result of mpMRI in follow-up subgroup (25 control and 33 sepsis) was used to predict survival outcomes at 96 hours., Statistical Tests: Mann-Whitney U test, Spearman/Pearson correlation (r), P < 0.05 was considered statistically significant., Results: Severely ill septic animals exhibited significantly increased serum creatinine levels compared to controls (70 ± 30 vs. 34 ± 9 μmol/L, P < 0.0001). Cortical perfusion (480 ± 80 vs. 330 ± 140 mL/100 g tissue/min, P < 0.005), and cortical and medullary T 2 relaxation time constants were significantly reduced compared to controls (41 ± 4 vs. 37 ± 5 msec in cortex, P < 0.05, 52 ± 7 vs. 45 ± 6 msec in medulla, P < 0.05). The combination of cortical T 2 relaxation time constants and perfusion results at 18 hours could predict survival outcomes at 96 hours with high sensitivity (80%) and specificity (73%) (area under curve of ROC = 0.8, J max  = 0.52)., Data Conclusion: This preclinical study suggests combined T 2 relaxation time and perfusion mapping as first line diagnostic tool for treatment planning., Level of Evidence: 2 TECHNICAL EFFICACY STAGE: 2., (© 2023 The Authors. Journal of Magnetic Resonance Imaging published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)

Aims of our study were to evaluate the feasibility and diagnostic value of two-dimensional shear wave elastography in dogs with acute kidney injury, chronic kidney disease, and acute on chronic kidney disease, its correlation with renal functional (creatinine, urea), and prognostic parameters (serum calcium-phosphorus product, urinary output), and with contrast-enhanced ultrasound (qualitative and quantitative evaluation). The study was prospective. A group of healthy (Group A) and a group of nephropathic dogs (Group B) were included. Shear wave elastography was performed on the left kidney of the subjects of both groups; contrast-enhanced ultrasound was performed only in dogs with acute kidney injury and acute on chronic kidney disease. Sixty-four dogs were included (Group A, n=24; Group B, n=40). The renal stiffness values were significantly higher in Group B than Group A; optimal cut-off stiffness values for detection of renal pathology were: ≥1.51 m/sec (area under the curve, 0.84; 95% confidence interval 0.74-0.94) and ≥6.75 kPa (area under the curve, 0.84; 95% confidence interval 0.73-0.94). For contrast-enhanced ultrasound, a significant positive correlation was found between renal stiffness, area under the curve, and wash-out area under the curve values of cortex quantitative analysis. No correlations were found between renal stiffness and renal functional and prognostic parameters. Shear wave elastography showed diagnostic utility to detect renal abnormalities in dogs with acute kidney injury, chronic kidney disease and acute on chronic kidney disease, however, it could not differentiate between these different nephropathies.

Objectives: To evaluate the feasibility of multimodal diffusion-weighted imaging (DWI) for detecting the occurrence and severity of acute kidney injury (AKI) caused by severe acute pancreatitis (SAP) in rats., Methods: SAP was induced in thirty rats by the retrograde injection of 5.0% sodium taurocholate through the biliopancreatic duct. Six rats underwent MRI of the kidneys 24 h before and 2, 4, 6, and 8 h after this AKI model was generated. Conventional and functional MRI sequences were used, including intravoxel incoherent motion imaging (IVIM), diffusion tensor imaging (DTI), and diffusion kurtosis imaging (DTI). The main DWI parameters and histological results were analyzed., Results: The fast apparent diffusion coefficient (ADC) of the renal cortex was significantly reduced at 2 h, as was the fractional anisotropy (FA) value of the renal cortex on DTI. The mean kurtosis (MK) values for the renal cortex and medulla gradually increased after model generation. The renal histopathological score was negatively correlated with the medullary slow ADC, fast ADC, and perfusion scores for both the renal cortex and medulla, as were the ADC and FA values of the renal medulla in DTI, whereas the MK values of the cortex and medulla were positively correlated (r = 0.733, 0.812). Thus, the cortical fast ADC, medullary MK, FA DTI , and slow ADC were optimal parameters for diagnosing AKI. Of these parameters, cortical fast ADC had the highest diagnostic efficacy (AUC = 0.950)., Conclusions: The fast ADC of the renal cortex is the core indicator of early AKI, and the medullary MK value might serve as a sensitive biomarker for grading renal injury in SAP rats., Clinical Relevance Statement: The multimodal parameters of renal IVIM, DTI, and DKI are potential beneficial for the early diagnosis and severity grading of renal injury in SAP patients., Key Points: • The multimodal parameters of renal DWI, including IVIM, DTI, and DKI, may be valuable for the noninvasive detection of early AKI and the severity grading of renal injury in SAP rats. • Cortical fast ADC, medullary MK, FA, and slow ADC are optimal parameters for early diagnosis of AKI, and cortical fast ADC has the highest diagnostic efficacy. • Medullary fast ADC, MK, and FA as well as cortical MK are useful for predicting the severity grade of AKI, and the renal medullary MK value exhibits the strongest correlation with pathological scores., (© 2023. The Author(s), under exclusive licence to European Society of Radiology.)

Acute kidney injury (AKI) is a common medical condition with high morbidity and mortality. Although urinalysis provides a noninvasive and convenient diagnostic method for AKI at the molecular level, the low sensitivity of current chemical probes used in urinalysis hinders the time diagnosis of AKI. Herein, we achieved the sensitive and early diagnosis of AKI by the development of a chemiluminescent probe CL-Pa suitable for detection of urinary Vanin-1. Vanin-1 is considered as an early and sensitive biomarker for AKI, while few chemical probes have been applied to for its efficient detection. By virtue of the low autofluorescence interference during urine imaging in the chemiluminescence model, CL-Pa could realize the monitoring of the up-regulated urinary Vanin-1 with a high signal-to-noise ratio (∼588). Importantly, under the help of CL-Pa , the up-regulation of urinary Vanin-1 of cisplatin-induced AKI mice at 12 h post cisplatin injection was detected, which was much earlier than clinical biomarkers (sCr and BUN) and change of kidney histology (48 h post cisplatin injection). Furthermore, using this probe, the fluctuation of urinary Vanin-1 of mice with different degrees of AKI was monitored. This study demonstrated the ability of CL-Pa in sensitively detecting drug-induced AKI through urinalysis and suggested the great potential of CL-Pa for early diagnosis of AKI and evaluate the efficiency of anti-AKI drugs clinically.

Background: Acute kidney injury is common in severe malaria and is independently associated with mortality. The pathogenesis of acute kidney injury (AKI) in severe malaria remains incompletely understood. Ultrasound-based tools such as point-of-care ultrasound (POCUS), ultrasound cardiac output monitors (USCOMs) and renal arterial resistive index (RRI) can be used to detect hemodynamic and renal blood flow abnormalities contributing to AKI in malaria., Methods: We conducted a prospective study of Malawian children with cerebral malaria to determine the feasibility of using POCUS and USCOM to characterize hemodynamic contributors to severe AKI (Kidney Disease: Improving Global Outcomes stage 2 or 3). The primary outcome was feasibility (completion rate of study procedures). We also assessed for differences in POCUS and hemodynamic variables for patients with or without severe AKI., Results: We enrolled 27 patients who had admission cardiac and renal ultrasounds and USCOM. Completion rates were high for cardiac (96%), renal (100%) and USCOM studies (96%). Severe AKI occurred in 13 of 27 patients (48%). No patients had ventricular dysfunction. Only 1 patient in the severe AKI group was determined to be hypovolemic ( P = 0.64). No significant differences in USCOM, RRI or venous congestion parameters were detected among patients with and without severe AKI. Mortality was 11% (3/27) with the 3 deaths occurring in the severe AKI group ( P = 0.056)., Conclusions: Ultrasound-based cardiac, hemodynamic and renal blood flow measurements appear to be feasible in pediatric patients with cerebral malaria. We were unable to detect hemodynamic or renal blood flow abnormalities contributing to severe AKI in cerebral malaria. Larger studies are needed to corroborate these findings., Competing Interests: M.L.R. conducted the study as a fellow for the Global Health Pediatric Critical Fellowship at the University of Maryland, School of Medicine (5U01AI126610-06). The other authors have no conflicts of interest to disclose., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

BACKGROUND. Patients with cancer undergo frequent CT examinations with iodinated contrast media and may be uniquely predisposed to contrast-associated acute kidney injury (CA-AKI). OBJECTIVE. The purpose of this study was to develop and validate a model for predicting the risk of CA-AKI after contrast-enhanced CT in patients with cancer. METHODS. This retrospective study included 25,184 adult patients (12,153 men, 13,031 women; mean age, 62.3 ± 13.7 [SD] years) with cancer who underwent 46,593 contrast-enhanced CT examinations between January 1, 2016, and June 20, 2020, at one of three academic medical centers. Information was recorded regarding demographics, malignancy type, medication use, baseline laboratory values, and comorbid conditions. CA-AKI was defined as a 0.3-mg/dL or greater increase in serum creatinine level from baseline within 48 hours after CT or a 1.5-fold or greater increase in the peak measurement within 14 days after CT. Multivariable models accounting for correlated data were used to identify risk factors for CA-AKI. A risk score for predicting CA-AKI was generated in a development set ( n = 30,926) and tested in a validation set ( n = 15,667). RESULTS. CA-AKI occurred after 5.8% (2682/46,593) of CT examinations. The final multivariable model for predicting CA-AKI included hematologic malignancy, diuretic use, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use, chronic kidney disease (CKD) stage 3a, CKD stage 3b, CKD stage 4 or 5, serum albumin level less than 3.0 g/dL, platelet count less than 150 × 10 3 /μL, 1+ or greater proteinuria on baseline urinalysis, diabetes mellitus, heart failure, and contrast medium volume 100 mL or greater. A risk score (range, 0-53 points) was generated with these variables. The most points (13) were for CKD stage 4 or 5 and for albumin level less than 3 g/dL. The frequency of CA-AKI progressively increased in higher risk categories. For example, in the validation set, CA-AKI occurred after 2.2% of CT examinations in the lowest risk category (score ≤ 4) and after 32.7% of CT examinations in the highest risk category (score ≥ 30). The Hosmer-Lemeshow test result indicated that the risk score was a good fit ( p = .40). CONCLUSION. A risk model in which readily available clinical data are used to predict the likelihood of CA-AKI after contrast-enhanced CT in patients with cancer was developed and validated. CLINICAL IMPACT. The model may help facilitate appropriate implementation of preventive measures in the care of patients at high risk of CA-AKI.

Objective: The aim was to quantify macroscopic renal blood flow and renal cortical microcirculation in patients with septic acute kidney injury (AKI) using ultrasound and contrast-enhanced ultrasound., Methods: In this case-control study, patients in the intensive care unit diagnosed with septic AKI were divided into stages 1-3 based on the 2012 KDIGO (Kidney Disease: Improving Global Outcomes) AKI diagnostic criteria. The patients were categorized into mild (stage 1) and severe (stages 2 and 3) groups, while septic patients without AKI served as the control group. Ultrasound parameters such as macrovascular renal blood flow and time-averaged velocity, as well as cardiac function parameters such as cardiac output and cardiac index, were measured. The time-intensity curve in the microcirculation was analyzed through contrast-enhanced ultrasound imaging software to calculate imaging parameters such as peak time, rise time, fall half-time and mean transit time of the interlobar arteries in the renal cortex., Results: In terms of macrocirculation, renal blood flow and time-averaged velocity decreased gradually with the progression of septic acute renal injury (p = 0.004, p < 0.001). There was no difference in cardiac output and cardiac index values among the three groups (p = 0.17 and p = 0.12). In terms of microcirculation, ultrasonic Doppler parameters of the renal cortical interlobular artery, such as peak intensity, risk index and ratio of peak systolic velocity to end-diastolic velocity, gradually increased (all p values <0.05). The temporal contrast-enhanced ultrasound parameters-time to peak, rise time, fall half-time and mean transit time-were prolonged in AKI groups when compared with the control group (p < 0.001, p = 0.003, p = 0.004 and p = 0.009, respectively)., Conclusion: In patients with septic AKI, the renal blood flow and time average velocity of macrocirculation in the kidneys are reduced, while the time parameters of microcirculation such as time to peak, rise time, fall half-time and mean transit time are prolonged, especially in patients with severe AKI. These changes are not related to changes in cardiac output or cardiac index., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: The aim of the work described here was to provide an evidence-based evaluation of contrast-enhanced ultrasonography (CEUS) in acute kidney injury (AKI) and assess variations in renal microperfusion with CEUS quantitative parameters in patients at a high risk of developing AKI., Methods: A meta-analysis and systematic review were conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the Embase, MEDLINE, Web of Science and the Cochrane Library databases were used to search the relevant articles systematically (2000-2022). Studies using CEUS to assess renal cortical microcirculation in AKI were included., Results: Six prospective studies (374 patients) were included. The overall quality of included studies was moderate to high. CEUS measures, maximum intensity (standard mean difference [SMD]: -1.37, 95% confidence interval [CI]: -1.64 to -1.09) and wash-in rate (SMD: -0.77, 95% CI: -1.09 to -0.45) were lower in the AKI+ group than in the AKI- group, and mean transit time (SMD: 0.76, 95% CI: 0.11-1.40) and time to peak (SMD: 1.63, 95% CI: 0.99-2.27) were higher in the AKI+ group. Moreover, maximum intensity and wash-in rate values changed before creatinine changed in the AKI+ group., Conclusion: Patients with AKI had reduced microcirculatory perfusion, prolonged perfusion time and a reduced rising slope in the renal cortex, which occurred before serum creatinine changes. And they could be measured using CEUS, indicating that CEUS could help in the diagnosis of AKI., Competing Interests: Conflict of interest The authors declare no competing interests., (Copyright © 2023 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.)

With the widespread use of drugs, drug-induced acute kidney injury (AKI) has become an increasingly serious health concern worldwide. Currently, early diagnosis of drug-induced AKI remains challenging because of the lack of effective biomarkers and noninvasive imaging tools. SO 2 plays important physiological roles in living systems and is an important antioxidant for maintaining redox homeostasis. However, the relationship between SO 2 (in water as SO 3 2- /HSO 3 - ) and drug-induced AKI remains largely unknown. Herein, we report the highly sensitive near-infrared fluorescence probe DSMN , which for the first time reveals the relationship between SO 2 and drug-induced AKI. The probe responds to SO 3 2- /HSO 3 - selectively and rapidly (within seconds) and shows a significant turn-on fluorescence at 710 nm with a large Stokes shift (125 nm). With these properties, the probe was successfully applied to detect SO 2 in living cells and mice. Importantly, the probe can selectively target the kidneys, allowing for the detection of changes in the SO 2 concentration in the kidneys. Based on this, DSMN was successfully used to detect cisplatin-induced AKI and revealed an increase in the SO 2 levels. The results indicate that SO 2 is a new biomarker for AKI and that DSMN is a powerful tool for studying and diagnosing drug-induced AKI.