Split Glomerular Filtration Rate Research Articles

Noninvasive assessment of single kidney glomerular filtration rate using multiple diffusion weighted imaging models.

This study aimed to assess single kidney glomerular filtration rate (GFR) using various diffusion weighted imaging (DWI) models. We reviewed adult patients with kidney diseases who underwent magnetic resonance imaging (MRI) examination from February 2021 to December 2023. DWI with 13 b-values was performed using 3.0-T scanners. Diffusion parameters were calculated with multi-slice ROIs positioned in renal parenchyma using four DWI models, including monoexponential model (MEM), diffusion kurtosis imaging (DKI), stretched exponential model (SEM), and intravoxel incoherent motion (IVIM). The split GFRs were measured by 99mTc-DTPA scintigraphy using Gates' method. Four different regression algorithms including the linear regression, regression tree, Gaussian regression and support vector machine (SVM) regression were employed to predict the GFR value based on different diffusion parameters. The leave-one-out cross validation was used to evaluate prediction ability of different models, and the performance of each model was quantified using the root mean square error (RMSE) and correlation coefficient. Fifteen (male/female, 10/5; age, 41.60±10.83 years) patients were included in this study. Among the four DWI models, the IVIM parameters with SVM regression model achieved the best performance with 0.184 RMSE and 0.789 correlation coefficient ( ). The parameters combining the four DWI models with SVM regression algorithm achieved the best performance in this study, with 0.171 RMSE and 0.815 correlation coefficient ( ). The DWI characteristics are able to serve as imaging biomarkers for assessing the function of single kidney. The integration of DWI into clinical practice could contribute to the advancement of non-invasive diagnostic methodologies.

Deep learning-based measurement of split glomerular filtration rate with 99mTc-diethylenetriamine pentaacetic acid renal scan

PurposeTo develop a deep learning (DL) model for generating automated regions of interest (ROIs) on 99mTc-diethylenetriamine pentaacetic acid (DTPA) renal scans for glomerular filtration rate (GFR) measurement.MethodsManually-drawn ROIs retrieved from a Picture Archiving and Communications System were used as ground-truth (GT) labels. A two-dimensional U-Net convolutional neural network architecture with multichannel input was trained to generate DL ROIs. The agreement between GFR values from GT and DL ROIs was evaluated using Lin’s concordance correlation coefficient (CCC) and slope coefficients for linear regression analyses. Bias and 95% limits of agreement (LOA) were assessed using Bland-Altman plots.ResultsA total of 24,364 scans (12,822 patients) were included. Excellent concordance between GT and DL GFR was found for left (CCC 0.982, 95% confidence interval [CI] 0.981–0.982; slope 1.004, 95% CI 1.003–1.004), right (CCC 0.969, 95% CI 0.968–0.969; slope 0.954, 95% CI 0.953–0.955) and both kidneys (CCC 0.978, 95% CI 0.978–0.979; slope 0.979, 95% CI 0.978–0.979). Bland-Altman analysis revealed minimal bias between GT and DL GFR, with mean differences of − 0.2 (95% LOA − 4.4–4.0), 1.4 (95% LOA − 3.5–6.3) and 1.2 (95% LOA − 6.5–8.8) mL/min/1.73 m² for left, right and both kidneys, respectively. Notably, 19,960 scans (81.9%) showed an absolute difference in GFR of less than 5 mL/min/1.73 m².ConclusionOur DL model exhibited excellent performance in the generation of ROIs on 99mTc-DTPA renal scans. This automated approach could potentially reduce manual effort and enhance the precision of GFR measurement in clinical practice.

Influence of a simple cyst on kidney function.

The aim of the study was to estimate the influence of a simple kidney cyst on kidney function and to determine indications for surgical treatment. In this prospective cohort study, we analyze data on 109 patients who sought counseling with a simple kidney cyst. Patients with solitary cyst of the right or left kidney, grade I-IIF according to the Bosniak classification, were included. Split glomerular filtration rate (sGFR) was calculated. The maximum size of the cyst, single kidney volumes (SKV) and the volume of the lost (atrophied) parenchyma were estimated with computed tomography (CT) scan of the urinary tract with contrast. The average difference between the sGFR of a healthy and affected kidney cyst was 11 [8.70; 13.44] ml/min, which is a statistically significant value (p = 0.001). Correlation analysis revealed a statistically significant relationship between the proportion of lost parenchyma and the maximum cyst size: p = 0.37 with 95% CI [0.20; 0.52] (p = 0). A multivariate logistic regression model showed that a statistically significant factor influencing the likelihood of a significant decrease in sGFR is the percentage of lost kidney parenchyma (OR = 1.13; p = 0). The growth of kidney cyst causes atrophy of the renal parenchyma and a decrease in the sGFR of the affected kidney. An increase in the volume of the atrophied parenchyma leads to a decrease in the sGFR of the affected kidney.

Predicting estimated glomerular filtration rate after partial and radical nephrectomy based on split renal function measured by radionuclide: a large-scale retrospective study

PurposeThe purpose of this study was to develop predictive models for postoperative estimated glomerular filtration rate (eGFR) based on the split glomerular filtration rate measured by radionuclide (rGFR), as choosing radical nephrectomy (RN) or partial nephrectomy (PN) for complex renal masses requires accurate prediction of postoperative eGFR.MethodsPatients who underwent RN or PN for a single renal mass at Xijing Hospital between 2008 and 2022 were retrospectively included. Preoperative split rGFR was evaluated using technetium-99 m-diethylenetriaminepentaacetic acid (Tc-99 m DTPA) renal dynamic imaging, and the postoperative short-term (< 7 days) and long-term (3 months to 5 years) eGFRs were assessed. Linear mixed-effect models were used to predict eGFRs, with marginal R2 reflecting predictive ability.ResultsAfter excluding patients with missing follow-up eGFRs, the data of 2251 (RN: 1286, PN: 965) and 2447 (RN: 1417, PN: 1030) patients were respectively included in the long-term and short-term models. Two models were established to predict long-term eGFRs after RN (marginal R2 = 0.554) and PN (marginal R2 = 0.630), respectively. Two other models were established to predict short-term eGFRs after RN (marginal R2 = 0.692) and PN (marginal R2 = 0.656), respectively. In terms of long-term eGFRs, laparoscopic and robotic surgery were superior to open surgery in both PN and RN.ConclusionsWe developed novel tools for predicting short-term and long-term eGFRs after RN and PN based on split rGFR that can help in preoperative decision-making.

Assessment of the kidney functional state prior and after partial nephrectomy for a unilateral tumor using mathematical processing of computed tomography data with contrast enhancement

Background. According to the contemporary data available contrast-enhanced computed tomography can be used to assess total and split kidney function. The Urology Clinic of the I.M. Sechenov First Moscow State Medical University, Ministry of Health of Russia (Sechenov University) utilizes mathematical processing of computed tomography data for the assessment of split kidney function.Aim. To evaluate the effect of main renal artery clamping (warm ischemia time) during partial nephrectomy for a unilateral tumor on the kidney function.Materials and methods. 33 patients of both sexes who underwent partial nephrectomy for unilateral kidney tumor were enrolled in the study. Prior to and 3–6 months after the surgery, 3D glomerular filtration rate (GFR), 3D perfusion, 3D volume of the renal parenchyma were evaluated by mathematical processing of computed tomography data with contrast enhancement. As well as that the dynamics of the total GFR (CKD-EPI equation) and total volume of the kidneys were assessed.Results. No significant changes were registered for both general functional renal parameters (creatinine level, total GFR, total volume of functioning renal parenchyma) and split 3D GFR. There were significant differences in 3D perfusion and kidney parenchyma volume prior and after partial nephrectomy.Conclusion. The results of the research highlight good reserve capacity the kidneys after partial nephrectomy with main renal artery clamping. The evidence that the non-operated kidney takes over the function of the resected kidney is based on the fact that there is an increase in its perfusion and volume of the kidney in the postoperative period. This state can also be regarded as a redistribution of functional loads between the kidneys, which is an adaptive mechanism in the postoperative period.

Percutaneous nephrolithotomy and laparoscopic surgery efficacy and renal function outcomes for large and complex renal calculi

Abstract Background There is limited published evidence regarding the incidence of intraoperative and postoperative events and the effect of percutaneous nephrolithotomy (PCNL) in supine and prone positions and laparoscopic pyelolithotomy on kidney function in patients with large and complex calculi. Materials and methods We evaluated the surgical outcomes of 97 patients with large and complex kidney stones. The patients were divided into 3 groups: those who underwent PCNL in the prone position, PCNL in the supine position, and pyelolithotomy by laparoscopy and retroperitoneoscopy. General surgical outcomes, size of residual stones, stone-free rate, glomerular filtration rate (GFR), and split GFR obtained from Tc-99m renal dynamic scintigrams were analyzed. Results Percutaneous nephrolithotomy in the prone position was correlated with improved function of the affected kidney. In the supine PCNL group, none of the analyzed indicators demonstrated a significant difference. Dynamic nephroscintigrams revealed negative changes in terms of accumulation and secretion of the affected kidney. A slight decrease in creatinine clearance was noted. However, positive dynamics in split GFR and secretory index were seen in this group. The laparoscopic group showed positive results in all analyzed parameters. However, full assessment of the function of the affected kidney in this group was limited due to restricted use of laparoscopic pyelolithotomy for complex stones. Conclusions Percutaneous nephrolithotomy in the prone position resulted in the most favorable renal functional outcomes for patients with high-grade renal calculi, whereas a laparoscopic approach may be preferred for patients with stones of lower grades. The most significant factors that adversely affected renal function were intraoperative bleeding volume, kidney stone size and density, and body mass index.

Use of CT-based renal volumetry for the measurement of split renal function: a split glomerular filtration rate prediction model based on unilateral renal volume parameters

To develop a split glomerular filtration rate (sGFR) prediction model based on unilateral renal volume parameters using three-dimensional (3D) computed tomography (CT) volumetry. Clinical data (age, sex, height, weight, serum creatinine level [sCr], and sGFR measured by 99mTc-diethylene triamine pentaacetic acid nuclear renal scintigraphy with the double plasma sample method) of 67 healthy renal donors and 111 patients with hydronephrosis admitted from April 2016 to September 2021 were analysed. The split renal parenchymal volume (sRPV) and split renal calyces and pelvis volume (sRCPV) of 67 unilateral donor left kidneys and 111 hydronephrotic kidneys were measured. Statistical analysis of these parameters was performed to develop and validate the sGFR prediction model. sRPV (p<0.001), sRCPV (p=0.012), age (p=0.015), serum creatinine level (p=0.004), and weight (p=0.006) were significantly associated with the measured sGFR and were included in the sGFR prediction formula, which was constructed as: 68.710+0.093×sRPV-0.041×sRCPV-0.228×W-0.219×A-14.432×sCr (r2=0.416; where A is age, W is weight). The paired difference of internal validation between the measured sGFR (42.34±13.71 ml/min/1.73 m2) and the sGFR estimated by the prediction model (41.46±8.99 ml/min/1.73 m2) was 0.879±11.475 ml/min/1.73 m2 (p=0.492) with a 95% confidence interval of the mean difference of ±2.54 ml/min/1.73 m2. The proposed model based on sRPV and sRCPV parameters could be used for estimating split renal function of healthy renal donors and patients with hydronephrosis to some extent. Further studies are required to evaluate and rectify the model.

Assessment of angiotensin-converting enzyme inhibitor/angiotensin receptor blocker on the split renal function in the patients with primary hypertension.

Bilateral kidney damage in hypertensive patients is not parallel. Angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (ACEI/ARB), as a commonly used antihypertensive drug, could protect kidney function and delay its deterioration. Most studies focused on overall renal function, but the researches on split renal function (SRF) are rare. We investigated the effects of ACEI/ARB on the SRF in patients with primary hypertension.Patients with primary hypertension (n = 429; male: 213; female: 216) admitted to our department between January 2014 and December 2016 were included in this study. The glomerular filtration rate (GFR) of split and total renal function were determined using diethylenetriaminepentaacetic acid tagged with 99mTc renal dynamic imaging method. For the same patient, the side with high GFR was considered as higher GFR kidney, whereas that with a low GFR was considered as lower GFR kidney. The split function score (Q value) was utilized to evaluate the differences of bilateral renal function. The patients were divided into 3 groups based on the Q values (Group 1, Q value <5%; Group 2, Q value of 5%–10%; Group 3, Q value ≥10%). All the patients received antihypertensive therapy based on ACEI/ARB. The renal dynamic imaging was performed in the 1-year follow-up to investigate the changes of the SRF.Compared with the baseline level, significant decline was noticed in the serum creatinine (Scr) in Group 2 and Group 3 (P < .05). The cystatin C in Group 3 showed significant decline (P < .05). Compared with the baseline, there was significant decline in the Q value in Group 2, whereas the GFR of lower GFR kidney showed significant increase (P < .05). No statistical differences were noticed in the Q value and split GFR in Group 1 and Group 3 (P > .05).In primary hypertension patients, ACEI/ARB therapy could improve the SRF of lower GFR kidney in the presence of certain differences between the SRF. As a result, the SRF difference was reduced. In case of Q value in a range of 5% to 10%, ACEI/ARB could improve the renal function effectively. It may be significant for the design of antihypertensive drugs.

A Novel Method for Accurate Quantification of Split Glomerular Filtration Rate Using Combination of Tc-99m-DTPA Renal Dynamic Imaging and Its Plasma Clearance.

Purpose To precisely quantify split glomerular filtration rate by Tc-99m-DTPA renal dynamic imaging and plasma clearance in order to increase its consistency among doctors. Methods Tc-99m-DTPA renal dynamic imaging was performed according to the conventional radionuclide renal dynamic imaging by five double-blinded doctors independently and automatically calculated split GFR, namely, gGFR. Moreover, the conventional radionuclide renal dynamic imaging was assessed to only outline the kidney, blank background, and automatically calculated split GFR, gGFR′. The total GFR value of patients, tGFR, was obtained by the double-plasma method. According to the formula, Precise GFR (pGFR) = gGFR′/(gGFR′ + gGFR′) × tGFR. The precise GFR value of the divided kidney, pGFR, was calculated. The Kendall's W test was used to compare the consistency of gGFR and pGFR drawn by five physicians. Results According to Kendall's W consistency test, Kendall's coefficient of concordance was 0.834, p = 0.0001 using conventional method. The same five doctors used blank background again and the same standard Gates method to draw the kidneys, which automatically calculated gGFR′. Using input formula, the pGFR was calculated and Kendall's W consistency test (Kendall′s coefficient of concordance = 0.956, p = 0.0001). Conclusion The combination of Tc-99m-DTPA renal dynamic imaging combined with the double-plasma method could achieve accurate split GFR, and because of the omission of influence factors, the consistency of pGFR obtained by different doctors using this method was significantly higher than that of conventional Tc-99m-DTPA renal dynamic imaging.

Quantitative evaluation of chronically obstructed kidneys from noncontrast computed tomography based on deep learning

ObjectiveTo quantitatively report renal parenchymal volume (RPV), renal sinus volume (RSV), and renal parenchymal density (RPD) for chronically obstructed kidneys from noncontrast computed tomography (NCCT). MethodsThis retrospective study was approved by the institutional review board of our hospital with a waiver of informed consent. We retrospectively collected 304 consecutive NCCT scans of urinary obstruction and constructed two datasets: one with 167 patient scans for parenchyma and sinus segmentation (segmentation dataset) and the other containing 137 scans from different patients diagnosed with chronic urinary obstruction (CUO dataset) and paired with split glomerular filtration rate (sGFR). A cascaded three-dimensional (3D) U-Net model was developed and validated for parenchyma and sinus segmentation. The RPV, RSV, and RPD of the CUO dataset were calculated by the model with manual editing. A multivariate analysis was performed to show the association between all parameters and the sGFR. ResultsIn the test dataset, the Dice values for parenchyma and sinus segmentation were 0.95 ± 0.04 and 0.90 ± 0.05, respectively. Compared with those of nonobstructed kidneys, the RSV and RPD of obstructed kidneys increased, but RPV and sGFR decreased (P < .001). For chronically obstructed kidneys, age (r = −0.292, P < .001), RPV (r = 0.849, P < .001), RSV (r = -0.331, P < .001), and RPD (r = −0.296, P < .001) were significantly correlated with sGFR. The fitted regression model was sGFR = 10.873−0.111 Age + 0.211 RPV - 0.022 RSV (r2 = 0.712). ConclusionsNCCT combined with deep learning has the potential to be a single radiological procedure for morphological and functional evaluation of chronically obstructed kidneys.

Influence of Early Bladder Imaging in Experimental Rabbits on the Quantitative Determination of Glomerular Filtration Rate by the Gates Method.

Objective To investigate the influence of early bladder imaging (EBI) in experimental rabbits on the quantitative calculation of glomerular filtration rate (GFR) by the Gates method. Methods We retrospectively analyzed the data of dynamic renal scintigraphy (DRS) in experimental rabbits. We calculated renal uptake during minutes 1-2 and 2-3 by correcting bladder radioactivity and computed the split GFR by renal uptake. Then, the EBI and GFR between 1-2 min and 2-3 min were compared, respectively. Results The EBI proportion (57.3%) at 2-3 min of DRS was higher than that (8.5%) at 1-2 min (P < 0.05). The correlations between the 1-2 min and 2-3 min uptake rates of unobstructed kidneys after correction (r = 0.952‐0.979) were higher than those before correction (r = 0.859‐0.936). However, the correlation between the two in obstructed kidneys was not improved (rbefore = 0.967 versus rafter = 0.968). For unobstructed kidneys, the difference in GFR based on 2-3 min uptake between before and after correction was significant (P < 0.05), but not in obstructed kidneys (P > 0.05). For GFR based on 1-2 min uptake, the difference between before and after correction was not significant in obstructed or unobstructed kidneys (P > 0.05). Before correction, the GFR of unobstructed kidneys of 10.5% of the rabbits in the protein load test was lower than that in the baseline status, but not so after correction. Conclusion The 2-3 min EBI on DRS has a significant influence on the GFR calculated by the Gates method in experimental rabbits. Controlling water intake or calculating the GFR by 1-2 min renal uptake helps to avoid the influence of EBI on GFR.

Early Renal Function Alterations in Renal Branches vs. Renal Fenestrations – A Dynamic Scintigraphy Based Prospective Study

The objective of this prospective single centre study was to assess whether branches and fenestrations have different outcomes on renal function in the early phase. From March 2018 to June 2019, 67 patients who underwent elective fenestrated and branched endovascular aneurysm repair (F/BEVAR) procedures were enrolled in this study. The patients were divided into two groups according to the renal bridging component configuration (fenestration vs. branch). All of them underwent dynamic renal scintigraphy with 99mTc diethylenetriaminepentaacetic acid (DTPA), two weeks pre-operatively, and three months and one year post-operatively. The primary end points were peri-procedural technical success, 30 day major adverse events, differences in glomerular filtration rate (GFR) between the branch and fenestration configurations, and variations between the pre-operative and the post-operative dynamic renal scintigraphy. Overall, 135 kidneys were analysed: 63 in the 32 patients treated with fenestrations, and 72 in the 35 patients treated with branches; the mean GFR on baseline scintigraphy was 58.4±30.9mL/min in the fenestration group, and 65.1±29.2mL/min in the branch group. Only kidneys associated with a patent fenestration/branch were included in the split GFR final analysis. The mean total GFR at three month scintigraphy decreased by 6.0±2.9mL/min in the fenestration group and by 23.4±6.4mL/min in the branch group. The split GFR decreased by 3.5±0.6mL/min in the fenestration group, and by 15.4±5.4mL/min in the branch group. The GFR decrease remained stable at one year. In this study, the use of branches for renal arteries during F/BEVAR resulted in a greater decrease in the GFR than in those patients who were treated with fenestrations alone. The scintigraphic alterations were evident at an early phase.

Feasibility of gamma camera-based GFR measurement using renal depth evaluated by lateral scan of 99mTc-DTPA renography.

Gamma camera-based measurement of glomerular filtration rate (GFR) with 99mTc-diethylenetriaminepentaacetic acid (DTPA) is an established non-invasive measurement of split renal function; however, it is not as accurate as the plasma sample method. Therefore, study into improving the accuracy of such method is clinically relevant. The aim of this study was to elucidate the feasibility of gamma camera-based GFR measurement using renal depth evaluated by lateral scan of 99mTc-DTPA renography and comparing the results with those of GFR using renal depth measured by CT, and three representative formulas. The study population comprised 38 patients (median, 69years; male 28, female 10; median estimated GFR, 67.4ml/min) with renourinary disorders. Scintigraphy was performed after intravenous injection of 370MBq 99mTc-DTPA by dynamic data acquisition for 20min, followed by a bilateral static scan of the abdomen for 3min. All patients underwent computed tomography (CT) within 2months from renography. GFR was calculated by renography using renal depth determined in five ways; lateral scan of 99mTc-DTPA, CT, and three formulas previously created with using weight, height and age. GFRs were compared with estimated GFR (eGFR). The depth of both kidneys measured as described above was compared and evaluated the laterality of the renal depth. The median values of GFR calculated with renal depth determined by 99mTc-DTPA renography, CT, and the three formulas were 87.3, 83.9, 67.8, 68.3, and 71.5ml/min, respectively. All of them correlated significantly with eGFR (r = 0.734, r = 0.687, r = 0.728, r = 0.726, and r = 0.686, respectively), however, no significant difference was observed among five correlation coefficients. Bland-Altman plot revealed that eGFR had error and fixed bias when compared with GFRs calculated using renal depth determined by renography, CT, and Taylor's formula. The depth of both kidneys measured by 99mTc-DTPA renography was equivalent to that measured by CT, however, those measured by the three formulas were significantly smaller than that measured by 99mTc-DTPA renography. The depth of the right kidney was larger than that of the left kidney using all three formulas in all patients. However, CT detected only 66% of patients to have a deeper right kidney than left kidney. Lateral scanning is a feasible procedure to measure renal depth for accurate and reasonable split GFR measurements using 99mTc-DTPA renography.

Результаты анализа структурно-функционального состояния почек методом математической обработки данных МСКТ с контрастированием у пациентов с мочекаменной болезнью

and Objectives: to date there have been several hypotheses on the causes of kidney stone formation. Compromised intrarenal blood flow might play one of major roles in stone formation. Advances in software and 3D technologies have unveiled the nature of contrast medium flow in the intrarenal structures. Mathematical analysis and 3D rendering of computed tomography (CT) scans was utilized for inrarenal contrast medium flow assessment in patients with stone kidney disease. This study aimed at assessing split glomerular filtration rate (sGFR) in patients at the initial stage of stone kidney disease (SKD). sGFR was measured by means of mathematical analysis of 3D rendering abdominal contrast enhanced CT scans. As well as that, possible correlations between irregular inrarenal contrast medium flow and causes of stone formation were considered. 23 patients of both sexes with stone kidney disease (SKD) were recruited. They underwent US/Dopler investigation of the kidneys and the bladder, plain X-ray, histopathological evaluation of the tissues (those patients who were operated on), spectroscopic analysis of the stone(s). Mathematical analysis of 3D rendering of CT scans was utilized for sGFR assessment (sGFR reference value: 0,55% of contrast medium per second). Inclusion criteria are as follows: 1) newly diagnosed SKD; 2) stone size less than 1,5-2,0 cm 3) stones that do not block urine flow 4) non-operated young patients; 5) patients free of comorbidities. Inclusion criteria were set to mitigate the effects of other factors that might influence on intrarenal blood flow and conduct the study per se. Mathematical analysis of 3D rendering of CT scans allowed to elucidate changes in sGFR in 22 (95,6%) patients out of 23. HypErfiltration (hyperF) was detected in 10 (43,5%) patients, hypOfiltration (hypoF) was detected in 11(47,8%) patients. sGFR values were statistically significantly different in these groups both on the left (p=0,000142) and on the right (p=0,00068). No significant gender differences were observed (hypoF group aged 25-67 years with the mean age of 43,5 years; hyperF group aged 17-57 years with the mean age of 39 years (p=0,563). Ultrasound Doppler renal resistive index in renal arteries was within the normal range in both groups with no statistically significant difference between the groups. However, 1 patient demonstrated no sGFR changes. Another patient had hyporfiltration on the left (0,48%) and hyperfiltration on the right (0,62%) Conclusions: sGFR alterations (hypo- or hyperfiltration) were detected in the majority of the patients with SKD (95,6%). This in turn might be suggestive of compromised intrarenal blood flow. Further studies are needed to elucidate the optimal management of these patients.

Evaluation of Quantitative and Qualitative Renal Outcome Following Nephron Sparing Surgery.

Purpose:Preservation of renal function after nephron-sparing surgery (NSS) is multifactorial and the impact of individual factors on it is still a debate. This prospective study investigates the impact of factors responsible for quantitative and functional outcome after NSS.Patients and Methods:Fifty-two patients of localized renal mass (≤7 cm) were included in the study. A contrast-enhanced computed tomography abdomen was performed for characterization of tumor. Glomerular filtration rate (GFR) was calculated using Tc99m-diethylenetriamine pentaacetic acid (DTPA) scan and Cockcroft-Gault (CG) formula. All relevant intra- and peri-operative events were noted. Follow-up work up performed at 3 months.Results:Overall, the mean ischemia time was 30.6 min, with 7.7% decrease in renal volume in the operated moiety. In follow-up, the total and ipsilateral GFR decreased. Change in renal parenchymal volume, total GFR by CG and DTPA, split GFR of tumor-bearing moiety was significant in follow-up. Size, stage, polar location of tumor, duration of surgery, type of ischemia, preoperative chronic kidney disease, and need of blood transfusion did not affect change in renal volume and function in the follow-up period.Conclusion:Renal parenchymal loss and duration of ischemia have impact on the follow-up renal function.

Peritumoral Artery Scoring System: a Novel Scoring System to Predict Renal Function Outcome after Laparoscopic Partial Nephrectomy

The present study aimed to assess the impact of peritumoral artery characteristics on renal function outcome prediction using a novel Peritumoral Artery Scoring System based on computed tomography arteriography. Peritumoral artery characteristics and renal function were evaluated in 220 patients who underwent laparoscopic partial nephrectomy and then validate in 51 patients with split and total glomerular filtration rate (GFR). In particular, peritumoral artery classification and diameter were measured to assign arteries into low, moderate, and high Peritumoral Artery Scoring System risk categories. Univariable and multivariable logistic regression analyses were then used to determine risk factors for major renal functional decline. The Peritumoral Artery Scoring System and four other nephrometry systems were compared using receiver operating characteristic curve analysis. The Peritumoral Artery Scoring System was significantly superior to the other systems for predicting postoperative renal function decline (p < 0.001). In receiver operating characteristic analysis, our category system was a superior independent predictor of estimated glomerular filtration rate (eGFR) decline (area-under-the-curve = 0.865, p < 0.001) and total GFR decline (area-under-the-curve = 0.796, p < 0.001), and split GFR decline (area-under-the-curve = 0.841, p < 0.001). Peritumoral artery characteristics were independent predictors of renal function outcome after laparoscopic partial nephrectomy.

Use of computed tomography assessed kidney length to predict split renal GFR in living kidney donors.

Screening of living kidney donors may require scintigraphy to split glomerular filtration rate (GFR). To determine the usefulness of computed tomography (CT) to split GFR, we compared scintigraphy-split GFR to CT-split GFR. We evaluated CT-split GFR as a screening test to detect scintigraphy-split GFR lower than 40mL/min/1.73m2/kidney. This was a monocentric retrospective study on 346 potential living donors who had GFR measurement, renal scintigraphy, and CT. We predicted GFR for each kidney by splitting GFR using the following formula: Volume-split GFR for a given kidney = measured GFR*[volume of this kidney/(volume of this kidney + volume of the opposite kidney)]. The same formula was used for length-split GFR. We compared length- and volume-split GFR to scintigraphy-split GFR at donation and with a 4-year follow-up. A better correlation was observed between length-split GFR and scintigraphy-split GFR (r = 0.92) than between volume-split GFR and scintigraphy-split GFR (r = 0.89). A length-split GFR threshold of 45mL/min/1.73m2/kidney had a sensitivity of 100% and a specificity of 75% to detect scintigraphy-split GFR less than 40mL/min/1.73m2/kidney. Both techniques with their respective thresholds detected living donors with similar eGFR evolution during follow-up. Length-split GFR can be used to detect patients requiring scintigraphy. • Excellent correlation between kidney length and scintigraphy predicted GFR • Kidney length screening detects all donors with GFR lower than 40mL/min/1.73m 2 • Kidney length screening can replace scintigraphy screening.

Variations in renal morphometry: A hospital-based Indian study.

Introduction:The currently available standard renal nomograms for comparison of renal dimensions in India are based on the measurements made in the Western population. The objectives of our study were to identify variations in renal morphometric parameters in subjects with no known renal disease in a hospital-based Indian population and to find out any correlation between renal volumes with split renal functions and body mass index (BMI).Materials and Methods:One hundred and fifty-one subjects undergoing contrast-enhanced computerized tomography (CT) scan for various purposes, including donor nephrectomy, from June 2012 to August 2014 were included in the study. The renal and ureteral dimensions were assessed from the contrast-enhanced CT scan images of these patients.Results:The mean length, width, thickness and volume of the left kidney were 11.02 ± 1.13 cm, 5.21 ± 0.75 cm, 4.65 ± 0.84 cm and 138.22 ± 29.81 mL, respectively, and those for the right kidney were 10.86 ± 1.12 cm, 5.13 ± 0.77 cm, 4.73 ± 0.95 cm and 137.54 ± 34.48 mL, respectively. The mean length of the left ureter was 23.51 ± 1.48 cm and that of the right ureter was 23.24 ± 1.93 cm. The mean volume of the kidneys in males and females was also different. The volume of the kidney did not statically correlate with the split glomerular filtration rate ((P = 0.12) and BMI (P = 0.52)).Conclusions:Our study revealed that there exist differences in various morphometric parameters of the kidney and ureter in different subsets of the Indian population attending our hospital as compared with the standard values quoted in the world literature.

CT-based renal volume measurements: correlation with renal function in patients with renal tumours

To evaluate the correlations between renal cortical volume (RCV), renal parenchymal volume (RPV), and renal function in patients with renal tumours before and after laparoscopic partial nephrectomy (LPN). Thirty-five patients with a single unilateral renal tumour who had undergone contrast-enhanced computed tomography (CT) and renal nuclear scintigraphy before and after LPN were retrospectively studied. RCV and RPV were calculated as renal volume, excluding tumours or cysts, using a semi-automatic segmentation program. The correlations between RCV, RPV, and glomerular filtration rate (GFR) were undertaken preoperatively and postoperatively using the Pearson correlation coefficient. Preoperatively, the correlations between RCV and GFR, and RPV and GFR for the operated kidneys was r=0.502 (p=0.002) and 0.527 (p=0.001), respectively, whereas the correlations for the contralateral side were r=0.384 (p=0.023) and r=0.412 (p=0.014). The mean RCV and RPV of the operated kidneys decreased by 27.4% and 24.8%. The mean split GFR of the operated kidneys decreased by 36.4%. Postoperatively, residual RCV (r=0.619, p<0.001) and RPV (r=0.593, p<0.001) correlated moderately with the GFR of the operated kidneys. Renal volume, both RCV and RPV, had a moderate relationship with renal function before and after operation. CT-based renal volume measurements could serve as a simple and effective method for estimation of postoperative renal function.

Tc-99m Hydroxymethylene Diphosphonate (HMDP) Renal Uptake as a Surrogate Marker of Postoperative Impairment of the Glomerular Filtration Rate in Renal Tumor Patients Following Nephron-Sparing Surgery

We investigated Tc-99m hydroxymethylene diphosphonate (HMDP) scintigraphy findings in renal tumor patients from the perspective of postoperative renal dysfunction following nephron-sparing surgery (NSS). Forty-three renal tumor patients (M:F = 28:15, age 53.9 ± 12.5years) who had undergone Tc-99m HMDP scintigraphy after NSS were enrolled. The patients were divided into HMDP(+) or HMDP(-) groups by visual assessment, and the asymmetric index (ASI) was calculated using a region-of-interest analysis. In 16 patients, the total and split glomerular filtration rate (GFR) was assessed using Tc-99m diethylenetriaminepentaacetic acid (DTPA) scintigraphy at baseline and at 3 and 6 months post-NSS. High Tc-99m HMDP uptake was observed in the operated kidneys, but this did not persist later than 7days post-NSS. Split GFR of the operated kidneys at baseline (58.5 ± 9.3ml/min) was significantly reduced at 6months post-NSS (40.1 ± 5.9ml/min, p < 0.001) in only those who showed intense uptake of Tc-99m HMDP. Declines in both total GFR (p = 0.010 and p = 0.002 for 3 and 6months, respectively) and split GFR of the operated kidneys (p < 0.001 and p < 0.001 for 3 and 6months, respectively) were clearly evidenced at 3 and 6months post-NSS only in patients with high Tc-99m HMDP in the operated kidneys. The ASI was negatively correlated with %change in the split GFR of these operated kidneys at 6months post-NSS (rho =-0.578, p = 0.0304). Tc-99m HMDP uptake within 1week following NSS is a surrogate marker of GFR impairment over 6months post-NSS.