Renal Volume Research Articles

Drug Interaction of SGLT2Is and ARNI on Acute Kidney Injury: A Real-world Pharmacovigilance Analysis Through the FAERS

Sodium–glucose cotransporter 2 inhibitors (SGLT2Is) and angiotensin receptor–neprilysin inhibitor (ARNI) may cause potential renal damage, the combined impact of SGLT2Is and ARNI on acute kidney injury (AKI) remains unclear. This pharmacovigilance study conducted a disproportionality analysis using reports from the FAERS database. The reporting odds ratio (ROR) was used as an estimate for detecting AKI signal. A total of 659,573 reports on at least one glucose-lowering drug and/or ARNI were obtained. Of the 413 reports on co-therapy of SGLT2Is and ARNI, 99 (24.0%) reports mentioned AKI. Overall, the AKI reporting rate significantly increased in co-therapy (adjusted ROR, 95%CI:8.04, 6.20–10.42, P<0.001), with a stronger AKI signal in co-therapy of canagliflozin and ARNI (16.82, 3.75–75.57, P<0.001). Specifically, no increased AKI signal was detected in HF cases receiving co-therapy after adjustment for sex and age (HF:1.27, 0.89–1.80, P=0.189; HF plus diabetes:2.08, 0.99–4.40, P=0.055; or HF plus hypertension:1.69, 0.53–5.35, P=0.376), whereas enhanced AKI signals were detected in cases with diabetes (20.57, 11.93–35.46, P<0.001), hypertension (4.30, 1.98–9.37, P<0.001), or diabetes plus hypertension (5.44, 1.92–15.43, P=0.001). This study reveals that superimposed renal impairment results from co-therapy with SGLT2Is and ARNI. It is necessary to be vigilant that the elderly, patients with diabetes, hypertension or CKD are more susceptible to AKI, especially if they likewise receive diuretics. When co-therapy is unavoidable, early monitoring of renal function, blood volume and blood pressure is excessively crucial. However, it is relatively safe in HF patients.

Utilizing computed tomography-based renal parenchymal volumes to calculate split renal function in patients with ureteral stricture disease.

Evaluation of split renal function (SRF) is critical for guiding surgical treatment decisions for patients with ureteral stricture disease (USD). We aimed to determine whether computed tomography (CT)-based renal parenchymal volumes may be used to predict SRF in patients with USD. We retrospectively reviewed all patients undergoing surgical management for USD at a single institution from October 2021 to January 2024. Patients who had preoperative nuclear medicine scan (NMS) and CT scan with intravenous contrast that were obtained within six weeks of each other were included. Interval between NMS and CT could be longer if the affected renal unit was drained with ureteral stent and/or percutaneous nephrostomy. Volume measurements were obtained using the 3D Region of Interest (ROI) Tool on Visage®7 Enterprise Imaging Platform (Visage Inc., San Diego, USA) by two investigators that were blinded to NMS derived SRF. Intraclass correlation coefficient (ICC) was used to assess consistency between investigators. Predictive accuracy was assessed using Pearson correlation coefficient (r) and linear regression. 40 of 160 patients met inclusion criteria. There was excellent reliability in calculating renal parenchymal volume between raters (ICC = 0.990). There was a strong linear correlation between estimated CT SRF and NMS SRF (r = 0.912, p < 0.00001). A linear regression model found RObservedSRF = -0.013 + 1.015(REstimatedSRF), with r2 = 0.832. CT-derived parenchymal volume analysis may be used to estimate SRF in patients with USD. This may obviate the need to obtain preoperative renal scans for SRF measurement in selected patients when assessing surgical management options.

Quantifying preserved renal volume and function in patients undergoing standard partial nephrectomy vs. tumor enucleation for localized renal tumors

IntroductionRenal parenchymal volume loss from standard partial nephrectomy (SPN) is a significant prognosticator for postoperative renal function. Tumor enucleation (TE) minimizes parenchymal loss compared to SPN. Little is known regarding discrete changes in renal function associated with volume loss. We sought to quantify the differences between SPN and TE in preserving parenchymal volume and estimated glomerular filtration rate (eGFR). MethodsWe identified 420 patients who underwent robotic partial nephrectomy (SPN or TE) at our tertiary care center from 2009 to 2022. Parenchymal volumes were calculated using TeraRecon 3D reconstruction software from axial imaging performed preoperatively and within 6 months postoperatively. Renal volume preserved and renal function were evaluated with multivariable linear and logistic regression models. ResultsAt 1 year, eGFR was 7% lower in patients undergoing SPN compared to TE (P < 0.01). Across both SPN and TE, only volume of preserved parenchyma was predictive of eGFR and chronic kidney disease (CKD) progression (both P < 0.01). TE preserved more healthy parenchymal volume compared to SPN (median percentage 97.6% vs 89.2%; P < 0.001). Each 1% of volumetric loss corresponded to a 0.35% decrease in eGFR at 1 year postoperatively (P < 0.01). ConclusionsVolume of preserved renal parenchyma was the strongest factor associated with preserved eGFR and reduced odds of CKD progression. TE preserved more parenchyma than SPN, which translated to higher eGFR preservation at 1 year postoperatively.

Comprehensive evaluation of fetal renal ultrasound parameters for fetal growth restriction

ObjectiveThis study aims to investigate variances in renal ultrasound parameters between fetuses experiencing fetal growth restriction (FGR) and those with normal intrauterine development, with the intent to offer actionable insights for clinical management. MethodForty-five pregnant women diagnosed with FGR between 28 and 36 weeks of gestation, who underwent examination at Wenzhou People's Hospital from September 2021 to June 2023, constituted the FGR group. Concurrently, 65 pregnant women with normal intrauterine development at matching gestational weeks formed the control group. Renal ultrasound parameters, encompassing renal artery peak systolic velocity (PSV), end diastolic velocity (EDV), time averaged maximum velocity (TAMX), resistive indices (S/D, PI, RI), ratios of renal volume to gestational age (RV/WEEK) and estimated fetal weight (RV/EFW), vascular indices (VI, FI, VFI), were compared between the two groups. All parameters represented the mean values of bilateral kidneys. ResultIn the FGR group, fetal renal artery PSV (37.71 ± 9.93 cm/s), EDV (6.19 ± 1.50 cm/s), TAMX (15.10 ± 3.83 cm/s), RV/WEEK (0.45 ± 0.12), RV/EFW (7.53 ± 3.24), VI (22.19 ± 15.00), and VFI (5.53 ± 3.63) were significantly lower compared to the control group (PSV: 47.11 ± 11.24 cm/s, EDV: 7.13 ± 2.00 cm/s, TAMX: 17.85 ± 3.85 cm/s, RV/WEEK: 0.66 ± 0.19, RV/EFW:9.20 ± 3.17, VI: 28.67 ± 14.72, VFI: 7.40 ± 3.68). Conversely, fetal renal artery resistive indices (S/D: 9.09 ± 2.58, PI: 2.71 ± 0.56, RI: 0.92 ± 0.04) in the FGR group were notably higher than those in the control group (S/D: 6.22 ± 1.93, PI: 2.20 ± 0.73, RI: 0.87 ± 0.04), with statistical significance (P < 0.05). No significant difference was found in renal FI between the FGR group (26.78 ± 6.59) and the control group (26.89 ± 5.82) (P > 0.05). Receiver operating characteristic (ROC) curve analysis revealed higher diagnostic efficacy for RV/WEEK and RI among individual indicators, while combined parameter application yielded the highest diagnostic efficiency. ConclusionUtilizing a comprehensive evaluation of fetal kidney ultrasound parameters with multiple indices facilitates early screening and diagnosis of FGR fetuses, thereby aiding clinical decision-making and enhancing newborn birth outcomes.

Kidney effects of triple CFTR modulator therapy in people with cystic fibrosis.

Elexacaftor/tezacaftor/ivacaftor (ETI) is a new cystic fibrosis transmembrane conductance regulator (CFTR) modulator that has transformed the respiratory prognosis of people with cystic fibrosis (pwCF). However, its impact on other organs such as the kidneys, where CFTR is expressed, remains unclear. Since pwCF are risk of both kidney disease and urolithiasis, we aimed to study the potential effects of ETI on renal function, volume status, and risk factors for urolithiasis. This prospective, observational, single-center, before-after cohort study, involved adult pwCF eligible for ETI. The changes in plasma and urinary profiles were assessed by comparing renal function (using 2021 CKD-EPIcreatinine and 2021 CKD-EPIcreatinine-cystatin C formulas), volume status (using aldosterone/renin ratio and blood pressure), and risk factors for urolithiasis, at the time of ETI introduction (M0) and 7 months after (M7). Nineteen pwCF were included. No significant change in renal function was observed between M0 and M7 (2021 CKD-EPIcreatinine: 105.5ml/min/1.73 m² at M0 vs. 103.3ml/min/1.73 m² at M7; P=.17). There was a significant reduction in aldosterone level (370.3pmol/l at M0 vs. 232.4pmol/l at M7; P=.02) and aldosterone/renin ratio (33.6 at M0 vs. 21.8 at M7; P=.03). Among the risk factors for urolithiasis, a significant reduction in magnesuria level was found (4.6mmol/d at M0 vs. 3.8mmol/d at M7; P=.01). These findings suggest that ETI seem to have no short-term impact on the renal function of adult pwCF and appears to correct secondary hyperaldosteronism due to excessive sweat losses. Further investigations are needed to determine the potential impact of decreased magnesuria observed under ETI therapy on the risk of urolithiasis.

Renal function-adjusted contrast medium volume is a major risk factor in the occurrence of acute kidney injury after endovascular aneurysm repair: Erratum.

Renal function-adjusted contrast medium volume is a major risk factor in the occurrence of acute kidney injury after endovascular aneurysm repair: Erratum.

AI-based segmentation of renal enhanced CT images for quantitative evaluate of chronic kidney disease

To quantitatively evaluate chronic kidney disease (CKD), a deep convolutional neural network-based segmentation model was applied to renal enhanced computed tomography (CT) images. A retrospective analysis was conducted on a cohort of 100 individuals diagnosed with CKD and 90 individuals with healthy kidneys, who underwent contrast-enhanced CT scans of the kidneys or abdomen. Demographic and clinical data were collected from all participants. The study consisted of two distinct stages: firstly, the development and validation of a three-dimensional (3D) nnU-Net model for segmenting the arterial phase of renal enhanced CT scans; secondly, the utilization of the 3D nnU-Net model for quantitative evaluation of CKD. The 3D nnU-Net model achieved a mean Dice Similarity Coefficient (DSC) of 93.53% for renal parenchyma and 81.48% for renal cortex. Statistically significant differences were observed among different stages of renal function for renal parenchyma volume (VRP), renal cortex volume (VRC), renal medulla volume (VRM), the CT values of renal parenchyma (HuRP), the CT values of renal cortex (HuRC), and the CT values of renal medulla (HuRM) (F = 93.476, 144.918, 9.637, 170.533, 216.616, and 94.283; p < 0.001). Pearson correlation analysis revealed significant positive associations between glomerular filtration rate (eGFR) and VRP, VRC, VRM, HuRP, HuRC, and HuRM (r = 0.749, 0.818, 0.321, 0.819, 0.820, and 0.747, respectively, all p < 0.001). Similarly, a negative correlation was observed between serum creatinine (Scr) levels and VRP, VRC, VRM, HuRP, HuRC, and HuRM (r = − 0.759, − 0.777, − 0.420, − 0.762, − 0.771, and − 0.726, respectively, all p < 0.001). For predicting CKD in males, VRP had an area under the curve (AUC) of 0.726, p < 0.001; VRC, AUC 0.765, p < 0.001; VRM, AUC 0.578, p = 0.018; HuRP, AUC 0.912, p < 0.001; HuRC, AUC 0.952, p < 0.001; and HuRM, AUC 0.772, p < 0.001 in males. In females, VRP had an AUC of 0.813, p < 0.001; VRC, AUC 0.851, p < 0.001; VRM, AUC 0.623, p = 0.060; HuRP, AUC 0.904, p < 0.001; HuRC, AUC 0.934, p < 0.001; and HuRM, AUC 0.840, p < 0.001. The optimal cutoff values for predicting CKD in HuRP are 99.9 Hu for males and 98.4 Hu for females, while in HuRC are 120.1 Hu for males and 111.8 Hu for females. The kidney was effectively segmented by our AI-based 3D nnU-Net model for enhanced renal CT images. In terms of mild kidney injury, the CT values exhibited higher sensitivity compared to kidney volume. The correlation analysis revealed a stronger association between VRC, HuRP, and HuRC with renal function, while the association between VRP and HuRM was weaker, and the association between VRM was the weakest. Particularly, HuRP and HuRC demonstrated significant potential in predicting renal function. For diagnosing CKD, it is recommended to set the threshold values as follows: HuRP < 99.9 Hu and HuRC < 120.1 Hu in males, and HuRP < 98.4 Hu and HuRC < 111.8 Hu in females.

Shear-wave elastography in renal stiffness in children with hematuria and/or proteinuria.

We sought to evaluate renal stiffness in children with hematuria and/or proteinuria using shear wave elastography (SWE) and to investigate the clinical value of renal stiffness in children with hematuria and/or proteinuria. According to the results of urinary occult blood and urinary protein tests, 349 pediatric patients were categorized into one of four groups: pure hematuria (HU), pure proteinuria (PU), concomitant hematuria and proteinuria (HUPU), or control (non-HUPU). Patient demographic data, laboratory test results, and renal ultrasound data were collected. There were significant differences in cortical/medullary elasticity among the four groups (the most sensitive cutoff value between HU and PU was 1.72) (P < 0.05). We found that hematuria and proteinuria interacted with renal cortical elasticity (P < 0.05) but that hematuria and proteinuria did not interact with renal medullary elasticity or cortical/medullary elasticity (P > 0.05). Renal elasticity values correlated with sex, age, body surface area, body mass index, qualitative urinary protein, urine N-acetyl-β-D-glucosaminidase, 24-hour urinary protein quantity, renal volume, and renal cortical thickness (P < 0.05). SWE can be used to detect changes in renal stiffness in children with hematuria and/or proteinuria. SWE is beneficial for the early detection of glomerular disease in children with abnormal urine test results. This study evaluated the utility of shear wave elastography for the assessment of renal elasticity in pediatric patients presenting with hematuria and/or proteinuria. Children with pure proteinuria had significantly higher renal cortical/medullary elasticity values than those with pure hematuria. An interaction effect between hematuria and proteinuria on renal cortical stiffness was observed. Shear wave elastography can be used as a tool to assess early renal injury in children with urinalysis abnormalities.

Correlation of Ablation Volume with Renal Function Loss after Cryoablation in Solitary Functioning Kidneys

PurposeTo determine the degree of renal function deterioration after renal cryoablation in patients with a solitary functioning kidney on the basis of ablation volume. Materials and MethodsOver a 15-year period, 81 percutaneous cryoablations were performed in solitary functioning kidneys. After exclusion of patients with baseline end-stage renal disease (ESRD) and insufficient follow-up, analysis was performed on 65 procedures in 52 patients (40 men; mean age, 63.5 years). The postcryoablation renal function was based on the lowest serum creatinine within 6 months after procedure. Renal function change was defined as percentage glomerular filtration rate (GFR) change. Volumetric analysis was performed on the target lesion, renal parenchyma, and ablation zone. ResultsThe median tumor diameter was 2.0 cm (range, 0.8–4.7 cm). The median baseline GFR decreased from 56.4 mL/min/1.73 m2 (range, 17.5–89.7 mL/min/1.73 m2) to 46.9 mL/min/1.73 m2 (range, 16.5–89.7 mL/min/1.73 m2) at median of 95 days (P < .001), equating to a −7.9% median renal function change (range, −45.0% to +30.7%). All patients had Stage 2 or worse chronic kidney disease, and baseline function did not correlate with renal function change. The median volume of ablated parenchyma was 19.7 mL (range, 2.4–87.3 mL), equating to 8.1% (range, 0.7%–37.2%) of total parenchyma. The volume of parenchymal volume ablated correlated significantly with renal function loss, whereas age, hypertension, and diabetes mellitus did not. No patient developed ESRD within 1 year after cryoablation. ConclusionsCryoablation in solitary functioning kidneys resulted in a modest reduction in renal function, even in patients with chronic kidney disease and ablations of up to 20% of renal parenchymal volume.

Can CT or MRI volumetry substitute scintigraphy in living kidney donor evaluation? A systematic review

BackgroundCurrent potential living kidney donor’s assessment includes functional and anatomical evaluation. Scintigraphy is recommended in some cases and some centers include this test in the donor’s protocol. Recent studies advocate for the avoidance of this test as CT or MRI volumetry showed to accurately assess donor’s renal function.ObjectiveTo summarize scientific evidence on image tests for pre-donation and/or post-nephrectomy renal function evaluation.Evidence acquisitionThis review followed the guidelines set by the European Association of Urology and adhered to PRISMA 2020 recommendations. The protocol was registered in PROSPERO on 10th December 2022 (ID: CRD42022379273).Evidence synthesisTwenty-one studies met the inclusion criteria after thorough screening and eligibility assessment. According to QUADAS-2, patient selection and flow/timing domains showed a predominant low risk of bias.The correlation between split renal function (SRF) using CT and scintigraphy varied from weak (r = 0.21) to remarkably strong (r = 0.949). Bland–Altman agreement demonstrated moderate to excellent results, with mean differences ranging from -0.06% to 1.76%. The correlation between split renal volume (CT) and estimated glomerular filtration rate (eGFR) at 6 months or 1 year after nephrectomy showed a moderate correlation, with coefficients ranging from 0.708 to 0.83.The correlation between SRF (MRI) and renal scintigraphy reported a moderate correlation, with correlation coefficients of 0.58 and 0.84. MRI and scintigraphy displayed a good agreement, with a 66% agreement observed and mean differences of ± 0.3%.ConclusionsDespite study heterogeneity, MRI or CT-based renal volumetry appears promising compared to scintigraphy, with favorable correlations and agreement.

Kidney volume-to-birth weight ratio as an estimate of nephron endowment in extremely low birth weight preterm infants

In humans, nephrogenesis is completed by 32–36 weeks gestation, with a highly variable total number of nephrons, ranging from 200,000 to over 2 million. Premature birth disrupts the development and maturation of the kidneys, leading to a reduction in the final number of nephrons. Due to significant genetic variability in the number of nephrons among individuals, it is crucial to identify premature infants with fewer nephrons at birth as early as possible. These infants are more susceptible to developing renal failure with advancing age compared to those with a higher nephron endowment. Bedside ultrasound, an effective and non-invasive tool, is practical for identifying newborns with a lower nephron count. However, renal volume alone cannot reliably indicate the number of nephrons due to substantial variability at birth, influenced by gestational age when nephron maturation is incomplete. This variability in kidney volumes persists as newborns grow. In this observational study we hypothesize that the relationship between renal volume and birth weight may serve as an indicator of nephron endowment in premature infants with birth weight less than 1000 g. This finding could represent the basis for defining appropriate surveillance protocols and developing targeted therapeutic approaches.

Renal fat deposition measured on dixon-based MRI is significantly associated with early kidney damage in obesity.

To investigate the renal fat deposition on Dixon-based magnetic resonance imaging (MRI) and to explore the predictive value of renal fat biomarkers of magnetic resonance (MR-RFBs) for early kidney damage in obesity. This prospective study included 56 obese volunteers and 47 non-obese healthy volunteers. All volunteers underwent renal magnetic resonance examinations. The differences in MR-RFBs [including renal proton density fat fraction (PDFF), renal sinus fat volume (RSFV), and perirenal fat thickness (PRFT)] measured on Dixon-based MRI between the obese and non-obese volunteers were analyzed using a general linear model, taking sex, age, diabetes, and hypertension as covariates. The relationship between estimated glomerular filtration rate (eGFR) and demographic, laboratory, and imaging parameters in obese volunteers was examined by correlation analysis. Obese volunteers had higher MR-RFBs than non-obese volunteers after controlling for confounders (all p < 0.001). Renal PDFF (r = -0.383; p = 0.004), RSFV (r = -0.368; p = 0.005), and PRFT (r = -0.451; p < 0.001) were significantly negatively correlated with eGFR in obesity. After adjusting for age, sex, body mass index, diabetes, hypertension, visceral adipose tissue, subcutaneous adipose tissue, renal PDFF, and RSFV, PRFT remained independently negatively associated with eGFR (β = -0.587; p = 0.003). All MR-RFBs are negatively correlated with eGFR in obesity. The MR-RFBs, especially PRFT, may have predictive value for early kidney damage in obesity.

#745 Age and gender specific reference values for renal volume and association with risk factors for chronic kidney disease in a general population

Abstract Background and Aims Renal volume (RV) is associated with renal function and with a variety of cardiovascular risk factors (CVRF). We analyzed RV by magnetic resonance imaging (MRI) in a large population-based study (Study of Health in Pomerania; SHIP-TREND) and tested the influence of age, sex, smoking status, BSA, systolic and diastolic blood pressure, type 2 diabetes, HDL-C, LDL-C, estimated glomerular filtration rate (eGFR) and uric acid on RV. Method 1,815 participants without kidney disease (930 women) aged 21-81 years were included in our study. Right and left RV with and without body surface area (BSA) indexation were compared among three age groups (22-39 years, 40-59 years, 60-81 years) by median and interquartile range and tested separately in women and men. Results eGFR, uric acid, right and left RV were higher in men compared to women (all p &amp;lt; 0.001). Left kidney were larger than right kidneys (both sexes). With age, RV showed a continuously decreasing trend in women and an upside down U-shape relation in men. In multivariable linear regression models, current smoking (β = 14.96, 95% CI 12.12; 17.79), BSA (β = 97.66, 95% CI 90.4; 104.93), diastolic blood pressure (β = 0.17, 95% CI 0.01; 0.32), and eGFR (β = 0.57, 95% CI 0.50; 0.65) were positively associated with both left and right renal volume whereas uric acid (β = −0.03, 95% CI −0.05; −0.01) showed an inverse association with RV. Interestingly, the same eGFR correlated with higher RV in men compared to women. Conclusion Reference values for RV are different for age-groups and sex. For any given age, female kidneys are smaller than male kidneys. RV associates positively with eGFR, but for any chosen eGFR, renal volume in females is lower compared to males. RV decreases with age, but in men, RV first increases in the age group 40-59 years before finally decreasing with a faster decline after 60 years. This may reflect hyperfiltration and glomerular hypertrophy associated with the presence of CVRF.

#337 Renal 3D photoacoustic imaging and contrast-enhanced ultrasound to assess oxygenation and perfusion and to predict fibrosis after ischemia-reperfusion

Abstract Background and Aims Renal 3D photo-acoustic imaging (3D-PAI) and contrast-enhanced ultrasound (CEUS) are promising tools in mice models to assess repeatedly and non-invasively renal ischemia-reperfusion (RIR) consequences and damages, or their improvement by nephroprotective strategies like mild therapeutic hypothermia (mTH), at the early phase of reperfusion as well as in the chronic late phase. Method C57Bl6 mice underwent 15 minutes of unilateral renal vascular clamping, with body temperature at 37°C (RIR-37°C, n=7) or mTH at 34°C (RIR-34°C, n=7), or a sham procedure (Sham, n=5). Renal volume and oxygen saturation (sO2-3D; corresponding to the percentage of oxyhemoglobin over the total hemoglobin content) were measured with 3D-PAI (3D reconstruction of the whole kidney through multi-plane acquisition with an automatized mobile support), and renal perfusion parameters (rBV, mTT, rBF) with CEUS (“destruction-replenishment” model of intravenous microbubbles), performed with VEVO3100 echograph (Fujifilm Visualsonic) 1 week before RIR (basal), 20 minutes after reperfusion, and 1 month after. Renal fibrosis was quantified at 1 month with Masson's trichrome coloration on histological samples. Data were compared with Mann-Whitney test or Wilcoxon test (paired data) as appropriate. Correlation was tested by Spearman test. All animal procedures were approved by the Ethics Committee. Results Sham showed no significant changes during follow-up. RIR-37°C led to renal hypotrophy (volume on 3D-PAI) and fibrosis at 1 month, compared to RIR-34°C (median volume 76 IQR [71-119] vs 143 IQR[108-180] mm3; p=0.03), and those parameters were correlated (R=−0.49; p=0.03). In RIR-37°C, sO2-3D tended to lower at 20 minutes compared to basal values (median sO2-3D 37 IQR [37-44] vs 49 IQR [36-57]%; p=0.08), but not in RIR-34°C (p &amp;gt; 0.99), and these early variations of sO2-3D were correlated with fibrosis at 1 month (R=−0.48; p=0.04). Renal perfusion was altered in RIR-37°C at 20 minutes compared to basal values (median rBV 73 IQR [46-105] vs 100 IQR [89-126] a.u.; p=0.047), and remained altered at 1 month (median rBV 71 IQR [57-83] a.u.; p=0.03), but not in RIR-34°C (p=0.47 at both 20 minutes and 1 month). Renal perfusion early alterations at 20 minutes were correlated with late alterations at 1 month (R=0.63; p=0.005), and tended to correlate with fibrosis (R=−0.41; p=0.08). Conclusion Renal 3D-PAI (on the whole 3D-reconstructed kidney) and CEUS can detect early alterations of renal perfusion and oxygen saturation after RIR, and predict chronic disturbances of perfusion and the onset of fibrosis, as well as the protection conferred by mTH. 3D-PAI can also be used to evaluate non-invasively renal volume as a surrogate of renal fibrosis after RIR.

#2115 Phase-contrast magnetic resonance imaging (PC-MRI) for quantification of volumetric flow in renal transplant arteries: an observational cohort study

Abstract Background and Aims Impaired renal transplant blood flow, a manifestation of severe transplant renal artery stenosis (TRAS), can negatively impact transplant function and survival. Phase-contrast magnetic resonance imaging (PC-MRI) is a non-invasive method of quantifying blood flow volume. Recent work has demonstrated the utility of this technique in measuring native renal blood flow, whilst validating the use of flow measurements taken on the aorta above and below the origin of the renal arteries to calculate flow in the renal arteries [1]. As part of a quality improvement study incorporating PC-MRI into renal transplant assessment, this study set out to (a) establish the normal range for transplant renal blood flow volume and (b) assess whether PC-MRI improved screening for TRAS. Method Between January 2019 and February 2021, PC-MRI sequences were included in the protocols for all magnetic resonance angiograms (MRA) performed as part of clinically-indicated renal transplant assessment. As part of the MRA study, using a coronal localizer MR image, planes were prescribed on the external iliac artery (EIA) both proximal and distal to the transplant artery anastomosis site in a perpendicular orientation (Fig. 1A). Using CV142 software [2], arterial cross-sections were highlighted manually at the pre-determined planes (Fig. 1B) to generate flow curves that coincided with the cardiac cycle (Fig. 1C). Studies were excluded if: the EIA flow waveform was incongruous with the cardiac cycle, contemporaneous heart rate data was not recorded, or the calculated flow volume was a negative value. Results During the study period 392 transplant MRAs were performed, of which 218 were included in this analysis. Potential TRAS was identified in 49 (22.5%) studies, with 19 (8.7%) having this diagnosis confirmed by intra-arterial digital subtraction angiography (IADSA). In the 169 (77.5%) studies without evidence of TRAS, the mean flow in the proximal EIA was 0.90 L/min (95% CI 0.85-0.94 L/min) and in the distal EIA 0.47 L/min (95% CI 0.44-0.50 L/min). The difference between the two measurement points, that is the flow in the transplant renal artery, was 0.42 L/min (95% CI 0.39-0.45 L/min) (Fig. 2A). In the 19 studies with TRAS confirmed by IADSA, mean flow at the time of the initial MRA was 0.34 L/min (95% CI 0.25-0.43 L/min); there was no difference when compared with the group without evidence of TRAS on MRA (p = 0.09) (Fig. 2B). Of the patients who had potential TRAS identified on MRA, 30 patients proceeded to IADSA; there was no difference in PC-MRI flow volume in the 11 who had a diagnosis of TRAS refuted on IADSA and the 19 who had diagnosis of TRAS confirmed (p = 0.97). ROC curve analysis of PC-MRI arterial flow measurement as a diagnostic test for TRAS, whereby the positive group of 19 had IADSA confirmed TRAS, the negative group of 176 had either normal MRA artery appearances or normal IADSA, and the disease prevalence is 13.7% [3], shows AUC 0.62 (95% CI 0.55-0.69) P = 0.09, sensitivity 57.9 specificity 67.1 (Fig. 2C). Conclusion This is the largest study to incorporate functional PC-MRI sequences into MRA protocols for the assessment of people with any form of kidney disease. The results suggest that the blood flow volume in healthy transplant renal arteries lies between 0.39–0.45 L/min. In comparative analysis between patients with healthy transplant arteries and those with IADSA-confirmed TRAS, there was no difference in arterial flow volume, though the study was limited by the small population in the group with IADSA-confirmed TRAS. PC-MRI does not appear to improve the screening accuracy of MRA in identifying TRAS. However, there may be a future role for PC-MRI as part of multi-parametric MR protocols for comprehensive assessment of patients with kidney transplants.

Prediction models for postoperative renal function after living donor nephrectomy: a systematic review.

Living-donor nephrectomy (LDN) is the most valuable source of organs for kidney transplantation worldwide. The current preoperative evaluation of a potential living donor candidate does not take into account formal estimation of postoperative renal function decline after surgery using validated prediction models. The aim of this study was to summarize the available models to predict the mid- to long-term renal function following LDN, aiming to support both clinicians and patients during the decision-making process. A systematic review of the English-language literature was conducted following the principles highlighted by the European Association of Urology (EAU) guidelines and following the PRISMA 2020 recommendations. The protocol was registered in PROSPERO on December 10, 2022 (registration ID: CRD42022380198). In the qualitative analysis we selected the models including only preoperative variables. After screening and eligibility assessment, six models from six studies met the inclusion criteria. All of them relied on retrospective patient cohorts. According to PROBAST, all studies were evaluated as high risk of bias. The models included different combinations of variables (ranging between two to four), including donor-/kidney-related factors, and preoperative laboratory tests. Donor age was the variable more often included in the models (83%), followed by history of hypertension (17%), Body Mass Index (33%), renal volume adjusted by body weight (33%) and body surface area (33%). There was significant heterogeneity in the model building strategy, the main outcome measures and the model's performance metrics. Three models were externally validated. Few models using preoperative variables have been developed and externally validated to predict renal function after LDN. As such, the evidence is premature to recommend their use in routine clinical practice. Future research should be focused on the development and validation of user-friendly, robust prediction models, relying on granular large multicenter datasets, to support clinicians and patients during the decision-making process.

Late Changes in Renal Volume and Function after Proton Beam Therapy in Pediatric and Adult Patients: Children Show Significant Renal Atrophy but Deterioration of Renal Function Is Minimal in the Long-Term in Both Groups.

To compare late renal effects in pediatric and adult patients with malignancies after PBT involving part of the kidney. A retrospective study was conducted to assess changes in renal volume and function in 24 patients, including 12 children (1-14 years old) and 12 adults (51-80 years old). Kidney volumes were measured from CT or MRI images during follow-up. Dose-volume histograms were calculated using a treatment planning system. In children, the median volume changes for the irradiated and control kidneys were -5.58 (-94.95 to +4.79) and +14.92 (-19.45 to +53.89) mL, respectively, with a relative volume change of -28.38 (-119.45 to -3.87) mL for the irradiated kidneys. For adults, these volume changes were -22.43 (-68.7 to -3.48) and -21.56 (-57.26 to -0.16) mL, respectively, with a relative volume change of -5.83 (-28.85 to +30.92) mL. Control kidneys in children exhibited a marked increase in size, while those in adults showed slight volumetric loss. The percentage of irradiated volume receiving 10 Gy (RBE) (V10) and 20 Gy (RBE) (V20) were significantly negatively associated with the relative volume change per year, especially in children. The CKD stage based on eGFR for all patients ranged from 1 to 3 and no cases with severe renal dysfunction were found before or after PBT. Late effects on the kidneys after PBT vary among age groups. Children are more susceptible than adults to significant renal atrophy after PBT. V10 and V20 might serve as predictors of the degree of renal atrophy after PBT, especially in children. PBT has a minimal impact on deterioration of renal function in both children and adults.

Comparative sonographic assessment of renal volume and arterial Doppler velocimetric indices among women with pregnancy-induced hypertension and normotensive controls in Northern Nigeria

Introduction: Pregnancy-induced hypertension is a global public health problem, worsening maternal morbidity and mortality. Renal complications have additional devastating consequences on maternal morbidity. Renal Doppler ultrasound is a valuable tool in the management of pregnancy-induced hypertension. It helps in the assessment of renal hemodynamics with the potential to monitor renal function and predict complications. We aimed to determine the relationship between the renal volume and arterial Doppler velocimetric indices in pregnancy-induced hypertension and matched normotensive controls. Methods: Following the documentation of demographic and basic obstetric characteristics of 150 women with pregnancy-induced hypertension and an equal number of their matched controls, a 3.5-MHz convex transducer was used to measure the maternal renal volumes and renal arterial Doppler velocimetric indices (peak systolic velocity, end diastolic velocity, resistive index, pulsatility index, and systolic–diastolic radio). Student’s t-test and linear regression were used to determine the differences and relationships between the quantitative variables among women with pregnancy-induced hypertension and their controls. The association chi-square test was used to determine the association between the qualitative and categorical variables. A p-value of less than 0.05 was considered significant. Results: The mean renal volume of pregnancy-induced hypertension patients is higher bilaterally when compared to normotensive women. The mean peak systolic velocity and resistive index in pregnancy-induced hypertension patients were significantly higher compared to normotensives (59.13 ± 13.5 vs 54.19 ± 9.8 cm/s; p &lt; 0.001) and (0.74 ± 0.2 vs 0.68 ± 0.3). Conclusion: The maternal renal volume and peak systolic velocity of the renal arteries are significantly higher in women with pregnancy-induced hypertension compared to normotensives.

Non-contrast preoperative MRI for determining renal perfusion and visualizing renal arteries in potential living kidney donors at 1.5 Tesla.

The aim of this work was to create and evaluate a preoperative non-contrast-enhanced (CE) magnetic resonance imaging (MRI)/angiography (MRA) protocol to assess renal function and visualize renal arteries and any abnormalities in potential living kidney donors. In total, 28 subjects were examined using scintigraphy to determine renal function. In addition, 3D-pseudocontinuous arterial spin labeling (pCASL), a 2D-non-CE electrocardiogram-triggered radial quiescent interval slice-selective (QISS-MRA), and 4D-CE time-resolved angiography with interleaved stochastic trajectories (CE-MRA) were performed to assess renal perfusion, visualize renal arteries and detect any abnormalities. Two glomerular filtration rates [described by Gates (GFRG) and according to the Chronic Kidney Disease Epidemiology Collaboration formula (GFRCKD-EPI)]. The renal volumes were determined using both MRA techniques. The mean value of regional renal blood flow (rRBF) on the right side was significantly higher than that on the left. The agreements between QISS-MRA and CE-MRA concerning the assessment of absence or presence of an aberrant artery and renal arterial stenosis were perfect. The mean renal volumes measured in the right kidney with QISS-MRA were lower than the corresponding values of CE-MRA. In contrast, the mean renal volumes measured in the left kidney with both MRA techniques were similar. The correlation between the GFRG and rRBF was compared in the same manner as that between GFRCKD-EPI and rRBF. The combination of pCASL and QISS-MRA constitute a reliable preoperative protocol with a total measurement time of <10min without the potential side effects of gadolinium-based contrast agents or radiation exposure.

Dependence of Renal Uptake on Kidney Function in [68Ga]Ga-PSMA-11 PET/CT Imaging.

(1) Background: PSMA ligand PET/CT is increasingly important for diagnostics of prostate cancer and other tumor diseases. In particular, the radiopharmaceutical [68Ga]Ga-PSMA-11 is widely used. Besides its tumor-specific binding, the uptake within the kidneys is dominant and seems to visualize the renal cortex specifically. Kidney diseases may alter the uptake of radiopharmaceuticals. Therefore, the correlation between renal uptake in PET/CT imaging and renal function should be investigated. (2) Methods: A group of 103 male patients were retrospectively evaluated for eGFR according to the CKD-EPI equation, tracer uptake intensity (SUVmax, SUVpeak, SUVmean), the molecular volume of the renal cortex, morphological kidney size, and total renal uptake. Manual and three different computer-assisted contouring methods (thresholds at 50% of SUVmax, 30% of SUVmax, and absolute SUV of 20) were used for measurements. Correlations between parameters were calculated using linear regression models. (3) Results: Renal SUVmax, SUVpeak, and SUVmean do not correlate with eGFR for manual or computer-assisted measurements. In contrast, molecular cortex volume shows a moderate correlation with eGFR (R2 = 0.231, p < 0.001), superior to morphological kidney size. A contouring threshold of 30% of SUVmax outperformed the other settings for renal cortex volume and total renal uptake. (4) Conclusions: Renal uptake of [68Ga]Ga-PSMA-11 cannot predict eGFR, but the functional renal cortex can be quantified by PET/CT imaging.