A simple method to estimate renal volume from computed tomography

Repetitive endoscopic drainage as initial intervention is safe and effective for early treatment of pancreatic necrotic collections

BACKGROUND

While endoscopic step-up approach with delayed drainage (more than 28 days from diagnosis) was shown to produce the best outcomes in the treatment of pancreatic walled-off necrosis (WON), we assessed our single centre experience of early versus delayed endoscopic drainage of pancreatic necrotic collections.

METHODS

Patients who underwent endoscopic drainage of pancreatic necrotic collections between 2011 and 2022 under Monash Health were identified. They were excluded if below 18 years old or their follow up data were missing. The included patients' medical records, pathology results, and imaging findings were retrospectively reviewed.

RESULTS

A total of 60 patients were included. 31.58% required percutaneous drainage and 15% received either endoscopic or surgical necrosectomy. The disease related mortality was 8.47% and the average length of stay (LOS) was 70.92 days. No significant difference was shown in disease-related mortality (10.5% vs. 7.5%, P = 0.697) or LOS (75.35 vs. 68.7, P = 0.644) between early and delayed drainage cohorts, but patients who received early drainage have higher qSOFA score on the day of drainage (2 vs. 0, P = 0.004).

DISCUSSION

Repetitive endoscopic drainage with selective percutaneous drainage is effective in the management of pancreatic necrotic collections. Early drainage should be considered in patients who developed severe sepsis.

Development and Validation of a 3D Resnet Model for Prediction of Lymph Node Metastasis in Head and Neck Cancer Patients

The accurate diagnosis and staging of lymph node metastasis (LNM) are crucial for determining the optimal treatment strategy for head and neck cancer patients. We aimed to develop a 3D Resnet model and investigate its prediction value in detecting LNM. This study enrolled 156 head and neck cancer patients and analyzed 342 lymph nodes segmented from surgical pathologic reports. The patients' clinical and pathological data related to the primary tumor site and clinical and pathology T and N stages were collected. To predict LNM, we developed a dual-pathway 3D Resnet model incorporating two Resnet models with different depths to extract features from the input data. To assess the model's performance, we compared its predictions with those of radiologists in a test dataset comprising 38 patients. The study found that the dimensions and volume of LNM + were significantly larger than those of LNM-. Specifically, the Y and Z dimensions showed the highest sensitivity of 84.6% and specificity of 72.2%, respectively, in predicting LNM + . The analysis of various variations of the proposed 3D Resnet model demonstrated that Dual-3D-Resnet models with a depth of 34 achieved the highest AUC values of 0.9294. In the validation test of 38 patients and 86 lymph nodes dataset, the 3D Resnet model outperformed both physical examination and radiologists in terms of sensitivity (80.8% compared to 50.0% and 91.7%, respectively), specificity(90.0% compared to 88.5% and 65.4%, respectively), and positive predictive value (77.8% compared to 66.7% and 55.0%, respectively) in detecting individual LNM + . These results suggest that the 3D Resnet model can be valuable for accurately identifying LNM + in head and neck cancer patients. A prospective trial is needed to evaluate further the role of the 3D Resnet model in determining LNM + in head and neck cancer patients and its impact on treatment strategies and patient outcomes.

Real-time estimation of nephron activity with a linear measurement system (RENAL-MS) predicts postoperative estimated glomerular filtration rate

OBJECTIVE

To determine whether a simple point-of-care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function.

PATIENTS AND METHODS

We performed a retrospective review of patients who underwent abdominal cross-sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real-time estimation of nephron activity with a linear measurement system (RENAL-MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni- and multivariate linear and logistic regression.

RESULTS

A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61-80) years. The median (IQR) pre- and postoperative eGFR was 74 (IQR 58-90) and 46 (35-62) mL/min/1.73 m2 , respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL-MS or NMRS methods were used, with correlation using RENAL-MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL-MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] CONCLUSION: A point-of-care tool to estimate renal parenchymal volume (RENAL-MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting.

Non-contrast low-dose CT can be used for volumetry of ADPKD

BACKGROUND

Kidney volume provides important information for the diagnosis and prognosis of autosomal dominant polycystic kidney disease (ADPKD), as well as for the evaluation of the effects of drugs such as tolvaptan. Non-contrast computed tomography (CT) is commonly used for volumetry, and this study examined the correspondence and correlation of kidney volume measured by standard-dose or low-dose CT.

METHODS

Axial standard-dose and low-dose CT images with 1-mm slices were obtained from 24 ADPKD patients. The kidney was segmented in the Synapse 3D software and the kidney volume was calculated using stereology. The kidney volume was compared between the two sets of images using R2, Bland-Altman plots, coefficient of variation, and intra-class correlation coefficients (ICCs).

RESULTS

The mean age of the 24 patients was 48.4 ± 10.9 years, and 45.8% were men (n = 11). The mean total kidney volume on standard-dose CT was 1501 ± 838.2 mL. The R2 of volume between standard-dose and low-dose CT was 0.995. In the Bland-Altman plot, except for one case with a large kidney volume, the two measurements were consistent, and the coefficient of variation and ICC were also good (0.02, 0.998). The CT radiation dose (dose-length product) was 229 ± 68 mGy·cm for standard-dose CT and 50 ± 19 mGy·cm for low-dose CT. A comparable volume was obtained with 20% of the radiation dose of standard-dose CT.

CONCLUSIONS

Standard-dose and low-dose CT showed comparable kidney volume in ADPKD. Therefore, low-dose CT can substitute for ADPKD volumetry while minimizing radiation exposure.

Left Renal Vein Division during Open Surgical Repair for Abdominal Aortic Aneurysm May Cause Long-Term Kidney Remodeling

BACKGROUND

Left renal vein division (LRVD) is a maneuver performed during open surgical repair for abdominal aortic aneurysms. Even so, the long-term effects of LRVD on renal remodeling are unknown. Therefore, we hypothesized that interrupting the venous return of the left renal vein might cause renal congestion and fibrotic remodeling of the left kidney.

METHODS

We used a murine left renal vein ligation model with 8-week-old to 12-week-old wild-type male mice. Bilateral kidneys and blood samples were harvested postoperatively on days 1, 3, 7, and 14. We assessed the renal function and the pathohistological changes in the left kidneys. In addition, we retrospectively analyzed 174 patients with open surgical repairs between 2006 and 2015 to assess the influence of LRVD on clinical data.

RESULTS

Temporary renal decline with left kidney swelling occurred in a murine left renal vein ligation model. In the pathohistological assessment of the left kidney, macrophage accumulation, necrotic atrophy, and renal fibrosis were observed. In addition, Myofibroblast-like macrophage, which is involved in renal fibrosis, was observed in the left kidney. We also noted that LRVD was associated with temporary renal decline and left kidney swelling. LRVD did not, however, impair renal function in long-term observation. Additionally, the relative cortical thickness of the left kidney in the LRVD group was significantly lower than that of the right kidney. These findings indicated that LRVD was associated with left kidney remodeling.

CONCLUSIONS

Venous return interruption of the left renal vein is associated with left kidney remodeling. Furthermore, interruption in the venous return of the left renal vein does not correlate with chronic renal failure. Therefore, we suggest careful follow-up of renal function after LRVD.

Studying the effect of donor kidney volume ratios to recipients' body surface area, body mass index, and total body weight on post-transplant graft function

OBJECTIVES

The goal of this study was to retrospectively investigate the relationship between renal transplanted volume indexes (Total kidney volume (TKV)/Body surface area (BSA), Renal parenchymal volume (RPV)/BSA, Renal cortical volume (RCV)/BSA, RPV/Body mass index (BMI), RCV/BMI, RPV/Weight, RCV/Weight), and short- and long-term function of the graft.

METHODS

One-hundred and twelve live donor-recipient pairs from 2017 to 2018, whose donors underwent preoperative renal computed tomography angiography and recipients survived during 12 months of follow-up, were included in this study.

RESULTS

The crude and adjusted linear regressions for the effect of volume measurements by voxel and ellipsoid methods on the estimated glomerular filtration rate (eGFR) at different post-transplantation times demonstrated that the RPV/weight ratio had the most substantial crude effect on the eGFR 12 months and 4 years after renal transplant. Receiver operating characteristic (ROC) curves for six different renal volume ratios demonstrated no significant difference between these ratios in terms of discriminative ability (p value < 0.05). A strong direct correlation between TKV calculated by the ellipsoid formula with RPV and RCV measured using OsiriX software was noted. Analysis of ROC curves for renal volume indices has demonstrated fair to good discriminative ability of our cut-off points to estimate 4-year post-transplantation eGFR > 60 mL/min.

CONCLUSION

Renal transplant recipients' volume indices, such as RPV/weight, had strong correlations with eGFR at different points in time, and renal transplant recipients with the volume ratios higher than our cut-off points had a good chance of having a 4-year post-transplantation eGFR higher than 60 mL/min.

Age and sex related variations of adult human ocular volumes in the Sri Lankan population: an evaluation using magnetic resonance imaging

INTRODUCTION

Variations in the human ocular volumes are related to ocular pathologies including congenital glaucoma, microphthalmus, buphthalmus, and macrophthalmus. As the currently published reference ocular volumes are prone to physiological and racial variations, population specific values may provide more precision in ophthalmological interventions. This study was conducted to assess the age and sex dependent differences in ocular volumes in Sri Lankan individuals using magnetic resonance imaging (MRI).

METHODS

The study was undertaken using the brain MRI scans from 200 patients which were reported as normal. Study sample consisted of patients between 18 years and 90 years of age with 91 male subjects and 109 female subjects. Two independent observers measured ocular volumes using a software-based method and an MRI planimetry based method. Age and sex of the study participants were recorded for the further analysis.

RESULTS

Statistically significant differences in both ocular volumes were found between males and females (p < 0.05) when using both volume analysis methods. The mean ± SD ocular volumes obtained as right software based volume, right MRI planimetry volume, left software based volume and left MRI planimetry volume were 6.8 ± 0.6, 6.0 ± 0.6, 6.6 ± 0.7 and 5.9 ± 0.6 cm³ in females and 6.9 ± 0.8, 6.3 ± 0.7, 6.9 ± 0.8 and 6.2 ± 0.7 cm³ in males. While software-based measurements show a significant linear correlation with age in both eyeball volumes, MRI planimetry measurement showed a significant linear correlation with age only in the left eyeball (p < 0.05). Weak negative correlations were found with age in right ocular volume in both MRI planimetry based (r = -0.121) and software based (r = -0.168) measurements and in left ocular volume in MRI planimetry based (r = -0.151) and software based (r = -0.179) measurements. Furthermore, ocular volumes obtained from the software-based method were significantly greater than the MRI planimetry based ocular volumes (p < 0.05) in both eyes, despite having a strong positive correlation.

CONCLUSION

The mean ocular volumes obtained from this study revealed a significant variation between the right and left eyes as well as a sexual dimorphism. Moreover, since the two measurement methods show a significant difference, the choice of measurement method should depend on the required accuracy of the eye volume decided with respect to the clinical implication.

IMPLICATIONS FOR PRACTICE

Since there are no reference values for Sri Lankan adult ocular volumes, this study may serve that purpose in the current population, while supporting ophthalmologists and radiologists to quantitatively evaluate ocular pathologies and to follow precise interventions.

Chronic Kidney Disease and Its Clinical Correlates in a Rural Community in Southwestern Nigeria

Chronic kidney disease (CKD) is a burgeoning problem globally, and more than a billion adults were affected as of 2016, with 1.2 million people dying from renal failure in 2017. To arrest the seemingly relentless progression of CKD to renal failure, there is a need to detect CKD early in the community. A community-based study was carried out to look at the prevalence and risk factors of CKD. Anthropometric and other clinical variables were measured. Blood samples were taken for determining creatinine, uric acid, urea, and lipids. CKD was defined as an estimated glomerular filtration rate of ≤60 mL/min/1.73 m2. Electrocardiograms and renal ultrasound scans were performed. In total, 201 people were recruited. Those with CKD had a male:female ratio of 1:3.9 and were older. The prevalence of autosomal-dominant polycystic kidney disease and CKD was 531.9 persons/100,000 population and 46.3%, respectively. Systolic blood pressure, pulse pressure, total cholesterol, triglycerides, high-density lipoprotein (HDL), uric acid, QTc interval, and electrocardiographic left ventricular hypertrophy were higher in those with CKD. Age, female sex, and HDL were independently associated with CKD. There was a steep rise in CKD at the community level. Increased awareness of CKD and prompt interventions are therefore imperative.

Long-term Benefits of Treatment with Tolvaptan in Patients with Autosomal Dominant Polycystic Kidney Disease

BACKGROUND

Tolvaptan is the first effective drug treatment for autosomal dominant polycystic kidney disease (ADPKD) patients, but few long-term observations of the effects of tolvaptan have been reported.

METHODS

In this single center, retrospective cohort study, we investigated nine patients who participated in a phase 3 trial of tolvaptan for ADPKD patients at our hospital between 2008 and 2014. Six of the patients discontinued tolvaptan at the end of the clinical trial and were defined as the discontinuation group, and three continued to take it; these were defined as the continuation group. The observation period was 3 years before and after the end of the tolvaptan trial, and we compared the following data in each group: serum creatinine, estimated glomerular filtration rate (eGFR), total kidney volume, serum sodium concentration, and urine specific gravity.

RESULTS

eGFR was significantly improved after the end of the trial in the continuation group (P = 0.0446), but there was no significant change in the regression line before and after the end of the trial in the discontinuation group. The increases in mean total kidney volume rates over the 3 years before and after the trial were 0.01 %/year vs. 0.067 %/year in the discontinuation group (P = 0.0247). On the other hand, serum sodium concentration and urine specific gravity showed no change during the observation period.

CONCLUSION

This study suggested that long-term administration of tolvaptan may improve renal function and inhibit total kidney volume growth.

Cinacalcet may suppress kidney enlargement in hemodialysis patients with autosomal dominant polycystic kidney disease

A massively enlarged kidney can impact quality of life of autosomal dominant polycystic kidney disease (ADPKD) patients. A recent in vitro study demonstrated that an allosteric modulator of the calcium sensing receptor decreases adenosine-3′,5′-cyclic monophosphate, an important factor for kidney enlargement in ADPKD. Therefore, the present study was performed to determine whether cinacalcet, a calcium sensing receptor agonist, suppresses kidney enlargement in hemodialysis patients with ADPKD. Alteration of total kidney volume together with clinical parameters was retrospectively examined in 12 hemodialysis patients with ADPKD treated at a single institution in Japan. In the non-cinacalcet group with longer hemodialysis duration (n = 5), total kidney volume had an annual increase of 4.19 ± 1.71% during an overall period of 877 ± 494 days. In contrast, the annual rate of increase in total kidney volume in the cinacalcet group (n = 7) was significantly suppressed after cinacalcet treatment, from 3.26 ± 2.87% during a period of 734 ± 352 days before the start of cinacalcet to − 4.71 ± 6.42% during 918 ± 524 days after initiation of treatment (p = 0.047). The present findings showed that cinacalcet could be a novel therapeutic tool for suppression of kidney enlargement in hemodialysis patients with ADPKD.

Initial radiological findings associated with active bleeding control necessity and long term functional outcomes after isolated high grade blunt renal trauma

INTRODUCTION

To assess the predictors for conservative management failure and long term outcomes after isolated blunt high grade renal trauma (HGRT).

METHODS

 A retrospective analysis of patients with isolated blunt HGRT (renal trauma grade ≥ IV) was conducted. Patients' demographics, clinical presentation, laboratory and radiological investigations, and different lines of treatment were retrieved. The primary outcome was to assess the predictors of conservative treatment failure (need for active bleeding control e.g.: transarterial angioembolization (TAE) and/or surgical exploration). The secondary outcome was to assess the renal parenchymal volume (RPV) changes post HGRT in correlation with the different lines of management using CT-measured RPV. The difference in RPV ≥ 5% at follow up was considered significant.

RESULTS

The study included 63 patients, mean (SD) age was 35.1 (16.6) years. Conservative management was successful in 39 patients (62%), while the need for active bleeding control was required in 16 and 8 patients who underwent TAE and surgical exploration, respectively. Increased hematoma rim distance (HRD), laceration numbers > 3, parenchymal devascularization ≥ 25%, and presence of vascular contrast extravasation (VCE) were predictors for conservative treatment failure (P= 0.006, 0.02, 0.045 and 0.002, respectively). After a mean of 19 months follow up, patients were subclassified into 2 groups: patients with preserved RPV (28 patients) and patients with decreased RPV (29 patients). Renal parenchymal devascularization ≥ 25% was found a predictor for ipsilateral RPV decrease (P = 0.02).

CONCLUSION

Increased HRD, laceration numbers > 3, parenchymal devascularization ≥ 25%, and presence of VCE are findings that reflect the necessity for active bleeding interventions after isolated blunt HGRT. Parenchymal devascularization ≥ 25% is an independent factor for RPV deterioration. Neither the grade of renal trauma nor the type of treatment is a predictor for such deterioration.

Correlation of Kidney Size on Computed Tomography with GFR, Creatinine and HbA1C for an Accurate Diagnosis of Patients with Diabetes and/or Chronic Kidney Disease

Diabetes is considered one of the major causes of chronic kidney disease (CKD), affecting renal blood vessels and nerves. Diagnosis of CKD by traditional biochemical serum and blood analyses is insufficient and insensitive, thus requiring the development of a more robust technique. This novel study aims to propose a new method for the accurate diagnosis of CKD, quantification of kidney damage, and its prognosis by physicians by measuring the kidney volume on computed tomography (CT). In total, 251 patients were enrolled in this retrospective study. They were divided into four groups: control, patients having diabetes, patients having CKD, and patients having both diabetes and CKD. Results showed that kidney volume correlated negatively with both GFR and HbA1C on CT images, in addition to decreasing faster in males than females. Moreover, HbA1C was shown to correlate positively with creatinine and negatively with GFR. Finally, GFR was more robust than creatinine when correlated with age. The association between kidney volume with GFR and HbA1c can be used to accurately anticipate kidney volume in established CKD on CT scan, especially in resource-poor settings. Furthermore, HbA1C can serve as a powerful biomarker for studying renal function in diabetic CKD patients as it correlates with creatinine and GFR.

Outcomes of Artificial Intelligence Volumetric Assessment of Kidneys and Renal Tumors for Preoperative Assessment of Nephron Sparing Interventions

Background Renal cell carcinoma is the most common kidney cancer and the 13th most common cause of cancer death worldwide. Partial nephrectomy and percutaneous ablation, increasingly utilized to treat small renal masses and preserve renal parenchyma, require precise preoperative imaging interpretation. We sought to develop and evaluate a convolutional neural network (CNN), a type of deep learning artificial intelligence, to act as a surgical planning aid by determining renal tumor and kidney volumes via segmentation on single-phase computed tomography (CT). Materials and Methods After institutional review board approval, the CT images of 319 patients were retrospectively analyzed. Two distinct CNNs were developed for (1) bounding cube localization of the right and left hemi-abdomen and (2) segmentation of the renal parenchyma and tumor within each bounding cube. Training was performed on a randomly selected cohort of 269 patients. CNN performance was evaluated on a separate cohort of 50 patients using Sorensen-Dice coefficients (which measures the spatial overlap between the manually segmented and neural network derived segmentations) and Pearson correlation coefficients. Experiments were run on a GPU-optimized workstation with a single NVIDIA GeForce GTX Titan X (12GB, Maxwell architecture). Results Median Dice coefficients for kidney and tumor segmentation were 0.970 and 0.816, respectively; Pearson correlation coefficients between CNN-generated and human-annotated estimates for kidney and tumor volume were 0.998 and 0.993 (p < 0.001), respectively. End-to-end trained CNNs were able to perform renal parenchyma and tumor segmentation on a new test case in an average of 5.6 seconds. Conclusions Initial experience with automated deep learning artificial intelligence demonstrates that it is capable of rapidly and accurately segmenting kidneys and renal tumors on single-phase contrast-enhanced CT scans and calculating tumor and renal volumes.

Determination of split renal function in voluntary renal donors by multidetector computed tomography and nuclear renography: How well do they correlate?

Background

The use of computed tomography (CT) for estimation of split renal function (SRF) has been reported previously. However, most of these studies have small samples, and many do not account for the renal attenuation at CT.

Objective

The aim of this study was to compare multidetector computed tomography (MDCT) volumetry-attenuation-based SRF with that obtained via Tc99m-diethylenetriaminepentaacetic acid (DTPA) renal scintigraphy in voluntary renal donors.

Methods

Between January 2017 and January 2020, 526 voluntary renal donors were enrolled prospectively. All donors underwent contrast CT and DTPA scan before surgery. The semiautomatic region of interest (ROI) tool was applied slice by slice on axial CT images acquired in the arterial phase. The renal contour was drawn semiautomatically with mouse clicks around the renal parenchyma, and the renal volume was ascertained. Using renal volume and attenuation, SRF was determined and compared with results obtained at DTPA imaging.

Results

The mean age was 44.91 ± 10.97 years (mean ± s.d.). There was no significant difference in SRF based on DTPA and MDCT volumetry for the left kidney (49.18% ± 3.40% vs. 49.15% ± 3.38%, p = 0.540) and for the right kidney (50.82% ± 3.40% vs. 50.86% ± 3.39%, p = 0.358). A very good correlation was observed between the two methods for the left kidney (r = 0.953, p = 0.000) and the right kidney (r = 0.955, p = 0.000). On simple linear regression analysis, 90.8% of DTPA SRF values for the left kidney and 91.3% of DTPA SRF values for the right kidney could be predicted correctly using the corresponding MDCT SRF values.

Conclusion

MDCT volumetry-attenuation-derived estimation of SRF for living renal donors could be an alternative to renal scintigraphy-based SRF estimation.

Rapid Segmentation of Renal Tumours to Calculate Volume Using 3D Interpolation

Small renal masses are commonly diagnosed with modern medical imaging. Renal tumour volume has been explored as a prognostic tool to help decide when intervention is needed and appears to provide additional prognostic information for smaller tumours compared with tumour diameter. However, the current method of calculating tumour volume in clinical practice uses the ellipsoid equation (π/6 × length × width × height) which is an oversimplified approach. Some research groups trace the contour of the tumour in every image slice which is impractical for clinical use. In this study, we demonstrate a method of using 3D segmentation software and the 3D interpolation method to rapidly calculate renal tumour volume in under a minute. Using this method in 27 patients that underwent radical or partial nephrectomy, we found a 10.07% mean absolute difference compared with the traditional ellipsoid method. Our segmentation volume was closer to the calculated histopathological tumour volume than the traditional method (p = 0.03) with higher Lin's concordance correlation coefficient (0.79 vs 0.72). 3D segmentation has many uses related to 3D printing and modelling and is becoming increasingly common. Calculation of tumour volume is one additional benefit it provides. Further studies on the association between segmented tumour volume and prognosis are needed.

Computer vision applied to dual-energy computed tomography images for precise calcinosis cutis quantification in patients with systemic sclerosis

Background

Although treatments have been proposed for calcinosis cutis (CC) in patients with systemic sclerosis (SSc), a standardized and validated method for CC burden quantification is necessary to enable valid clinical trials. We tested the hypothesis that computer vision applied to dual-energy computed tomography (DECT) finger images is a useful approach for precise and accurate CC quantification in SSc patients.

Methods

De-identified 2-dimensional (2D) DECT images from SSc patients with clinically evident lesser finger CC lesions were obtained. An expert musculoskeletal radiologist confirmed accurate manual segmentation (subtraction) of the phalanges for each image as a gold standard, and a U-Net Convolutional Neural Network (CNN) computer vision model for segmentation of healthy phalanges was developed and tested. A validation study was performed in an independent dataset whereby two independent radiologists manually measured the longest length and perpendicular short axis of each lesion and then calculated an estimated area by assuming the lesion was elliptical using the formula long axis/2 × short axis/2 × π, and a computer scientist used a region growing technique to calculate the area of CC lesions. Spearman’s correlation coefficient, Lin’s concordance correlation coefficient with 95% confidence intervals (CI), and a Bland-Altman plot (Stata V 15.1, College Station, TX) were used to test for equivalence between the radiologists’ and the CNN algorithm-generated area estimates.

Results

Forty de-identified 2D DECT images from SSc patients with clinically evident finger CC lesions were obtained and divided into training (N = 30 with image rotation × 3 to expand the set to N = 120) and test sets (N = 10). In the training set, five hundred epochs (iterations) were required to train the CNN algorithm to segment phalanges from adjacent CC, and accurate segmentation was evaluated using the ten held-out images. To test model performance, CC lesional area estimates calculated by two independent radiologists and a computer scientist were compared (radiologist 1 vs. radiologist 2 and radiologist 1 vs. computer vision approach) using an independent test dataset comprised of 31 images (8 index finger and 23 other fingers). For the two radiologists’, and the radiologist vs. computer vision measurements, Spearman’s rho was 0.91 and 0.94, respectively, both p < 0.0001; Lin’s concordance correlation coefficient was 0.91 (95% CI 0.85–0.98, p < 0.001) and 0.95 (95% CI 0.91–0.99, p < 0.001); and Bland-Altman plots demonstrated a mean difference between radiologist vs. radiologist, and radiologist vs. computer vision area estimates of − 0.5 mm² (95% limits of agreement − 10.0–9.0 mm²) and 1.7 mm² (95% limits of agreement − 6.0–9.5 mm², respectively.

Conclusions

We demonstrate that CNN quantification has a high degree of correlation with expert radiologist measurement of finger CC area measurements. Future work will include segmentation of 3-dimensional (3D) images for volumetric and density quantification, as well as validation in larger, independent cohorts.

Resection of adult polycystic kidney with retroperitoneal laparoscopic technique assisted by arterial embolization

Background

Traditional surgical methods have high complication rate and large injury in the resection of adult polycystic kidney. We investigated the effect of retroperitoneal laparoscopic resection of adult polycystic kidney assisted by arterial embolization.

Methods

The data of adult polycystic kidney patients who underwent laparoscopic surgery assisted by arterial embolization from November 2015 to November 2018 in our hospital were retrospectively analyzed, and the data of patients who underwent open surgery during the same period were collected. The basic data, surgical conditions, postoperative recover situation, and complications of the two groups were compared.

Results

There was no significant difference in the basic situation between the laparoscopic operation group and open operation (control) group. The bleeding volume, hospitalization time, and the length of incision in the laparoscopic operation group were significantly better than those in the open operation (control) group, but the operation time was significantly longer than that in the open operation group. There was no significant difference in drainage tube extraction time, bed rest time and blood transfusion rate between the two groups. There was no significant difference in the complication rate between the two groups.

Conclusions

Arterial interventional embolization-assisted retroperitoneal laparoscopy is an effective method for the resection of polycystic kidney.

Impact of volume calculation formulae on volume estimation accuracy of different shaped objects: an in vitro ultrasound and CT study

BACKGROUND

In image-assisted volume estimation, the volume of the object is calculated with a formula, using linear measurements of the objects. Since the volume estimation accuracy is thought to be influenced by the shape of the object, the volume estimation error would be related to the calculation formula used.

PURPOSE

To evaluate the volume estimation accuracy of selected volume calculation formulae, for different shaped objects.

MATERIAL AND METHODS

Globular (n = 5), elongated (n = 5), and near-spherical shaped plastic objects (n = 5), filled with water were subjected to ultrasound (US) and computed tomography (CT) in February 2018, to obtain the length, width, depth, and estimated volumes (EV). The volume was calculated manually using prolate, ellipsoid, and Lambert formulae. The actual volume (AV), EV, and calculated volumes were compared.

RESULTS

The AV was in the range of 10-445 mL. The reliability of measurements was high as assessed by the intra-class variability (Cronbach's alpha = 0.992). The EV has shown a high correlation to AV (US: ρ = 0.914, P < 0.001; CT: ρ = 0.943, P < 0.001; ellipsoid: ρ = 0.876, P < 0.001; prolate: ρ = 0.891, P < 0.001; Lambert: ρ = 0.876, P < 0.001). Regardless of the shape, the highest and lowest estimation accuracies were reported for prolate (bias = -0.7) and Lambert formulae (bias = +23.3), respectively. By any method, the globular objects were estimated with the highest accuracy: (US [bias = -0.31]; CT [bias = -0.14]; ellipsoid [bias = -1.5]; prolate [bias = -0.7]; Lambert [bias = 32.9]); and elongated objects were estimated with the lowest accuracy: (US [bias = -17.5]; CT [bias = -32.6]; ellipsoid [bias = -18.4]; prolate [bias = -0.3]; Lambert [bias = 11.4]).

CONCLUSION

The shape of the object and the calculation formula used has an impact on the volume estimation accuracy.

Estimation of Renal Function Using Unenhanced Computed Tomography in Upper Urinary Tract Stones Patients

Objectives: The aim of this study was to determine whether unenhanced computed tomography (CT) imaging can estimate differential renal function (DRF) in patients with chronic unilateral obstructive upper urinary tract stones.

Materials and Methods: This was a single-center retrospective study of 76 patients. All the patients underwent unenhanced CT and nuclear renography (RG) at an interval of 4 to 6 weeks due to chronic unilateral obstructive urinary stones. Renal CT measurements (RCMs), including residual parenchymal volume (RPV) and volumetric CT texture analysis parameters, were obtained through a semiautomatic method. Percent RCMs were calculated and compared with renal function determined by RG.

Results: The strongest Pearson coefficient between percent RCM and DRF was reflected by RPV (r = 0.957, P < 0.001). Combinations of RPV and other parameters did not significantly improve the correlation compared with RPV alone (r = 0.957 vs. r = 0.957, 0.957, 0.887, 0.815, and 0.956 for combination with Hounsfield unit, parenchymal voxel, skewness, kurtosis, and entropy, respectively; all P < 0.001). Percent RPV was subsequently introduced into linear regression, and the equation y = −2.66 + 1.07^* × (P < 0.001) was derived to calculate predicted DRF. No statistically difference was found between predicted DRF using the equation and observed DRF according to RG (P = 0.959).

Conclusion: Unenhanced CT imaging can estimate DRF in patients with chronic unilateral obstructive upper urinary tract stones, and RG might not be necessary as a conventional method in clinical.

Supranormal differential renal function in adults with ureteropelvic junction obstruction: Does it really exist?

Introduction

Some patients with ureteropelvic junction obstruction (UPJO) have supranormal differential renal function (snDRF). We aimed to study the outcomes of pyeloplasty in adult patients with UPJO and either snDRF or normal differential renal function (nDRF) and to identify preoperative factors responsible for the snDRF phenomenon.

Materials and Methods

We retrospectively retrieved data for all patients who underwent pyeloplasty and had snDRF (differential renal function [DRF] ≥55%) and nDRF (DRF between 45 and 55%) preoperatively. Preoperative radiological data using computed tomography or magnetic resonance imaging were correlated with the presence of snDRF phenomenon. In addition, scintigraphic findings pre- and post-operatively were also assessed to evaluate the functional outcomes.

Results

Of a total of 856 patients, 31 had snDRF (group 1) and 42 had nDRF (group 2). After a mean of 37 months' follow-up in Group 1, 22 patients developed DRF reduction with non-obstructive pattern. Mean DRF % decreased from 59 ± 2.8 to 48 ± 13 (P < 0.0001). However, in Group 2, five patients had DRF decrease. Four patients developed snDRF phenomenon postoperatively. Increased renal pelvis volume ≥50 mm³ and increased anteroposterior pelvic diameter (APD) ≥37 mm were found to predict snDRF phenomenon. The same findings, in addition to preoperative snDRF, correlated with postoperative DRF decrease.

Conclusion

SnDRF function could be expected in patients with increased renal pelvis volume and APD. The absolute value or changes in DRF are not reliable to judge treatment failure.

Living kidney donor assessment: Kidney length vs differential function

BACKGROUND

The key question in living kidney donor assessment is how best to determine the contribution of each kidney to overall renal function and guide selection of which kidney to donate, ensuring safety of procedure and good outcome for both recipient and donor. It is thought that a length difference > 2 cm may indicate significant difference in function and therefore need for measurement of differential function.

AIM

To determine the effect of using kidney length to decide which kidney to donate in a retrospective cohort of potential donors.

METHODS

All 333 potential living kidney donors between January 2009 and August 2018 who completed assessment were retrospectively evaluated. Donor assessment was performed as per United Kingdom guidelines. Data included age, sex, kidney length (cranio-caudal) obtained by computed tomography/ultrasono-graphy,51-chromium ethylenediamine tetraacetatic acid measured glomerular filtration rate, mercapto acetyl tri glycine split function and vascular anatomy. There were 48 exclusions due to inadequate data or incomplete investigations. Statistical analysis was performed using Excel pivot tables and GraphPad Prism. Correlation between kidney length and differential function was determined with Pearson's correlation coefficient.

RESULTS

Of 285 potential donors included in the study, there were 144 males (mean age 49.9 ± 14.75) and 141 females (mean age 51.2 ± 11.23). Overall, the Pearson's correlation between differences in length and divided function of kidney pairs was 0.1630, P = 0.0058. Of 73 with significant difference (> 10%) in divided function, 18 (24.7%) had no difference in kidney length; 54 (74%) had a difference of < 2 cm and only one of > 2 cm. Using a length difference of > 1 cm would only predict significant difference in divided function in 8/34 (23.5%) of cases. Using a difference of > 2 cm as cut off for performing split function would lead to false reassurance in 72 patients (6 had > 20% difference in divided function whereas 66 had 10%-20% difference).

CONCLUSION

Length difference between kidney pairs alone is not sufficient to replace measurement of divided function. This issue requires a randomised controlled trial to resolve it.

Correlation between computed tomography volumetry and nuclear medicine split renal function in live kidney donation: a single-centre experience

BACKGROUND

Potential live renal donors undergo both renal computed tomography angiogram (CTA) and nuclear imaging dimercaptosuccinic acid (DMSA) scans. Each kidney's renal function and vascular anatomy influences the choice of donor side. Although DMSA measures differential blood flow, it is a surrogate for renal function and nephron mass. Computed tomography techniques can provide volumetry information. The aim of this study was to determine the relationship between measured split renal volumes on computed tomography versus renal volumes derived from DMSA split function in live donors.

METHODS

Prospective data of live kidney donors assessed at a single Australian centre from 2014 to 2017 were reviewed. All patients had pre-operative CTA and DMSA imaging. Renal volume was determined via semi-automated software calculation from CTA three-dimensional image reconstructions by one investigator. Measured split renal volume was compared against calculated renal volume using measured DMSA split function (percentage split function multiplied by total renal volume).

RESULTS

Fifty-three patients were included in the study. Split renal volumes on three-dimensional CTA images correlate to calculated split volumes determined from DMSA (Pearson coefficient 0.95 for right renal volume, 0.95 for left). The decision of which kidney to remove can be achieved with CTA only. Omitting a DMSA scan would reduce the radiation load by 0.70 mSv (35 chest X-rays) and potential cost saving of AU$1062.00 per donor.

CONCLUSION

CTA technology allows accurate assessment of renal volumes that correlate well with DMSA split function. Avoiding a DMSA scan results in cost and radiation reduction in the assessment of a live kidney donor.

CT volumetric measurements correlate with split renal function in renal trauma

PURPOSE

To evaluate whether volumetric measurements of segmental vascular injuries (SVIs) based on computed tomography (CT) imaging obtained during an initial trauma survey correlate with future nuclear medicine (NM) split renal function.

METHODS

A retrospective review was performed of renal trauma patients treated at a level 1 trauma center between 2008 and 2015. Patients with unilateral SVIs on initial CT imaging with follow-up NM renal scans were evaluated. CT-based split renal function was calculated by assessing the ratio of ipsilateral uninjured kidney volume to bilateral total uninjured kidney volume by two separate radiologists.

RESULTS

Eight patients with unilateral SVIs on initial CT trauma evaluation underwent follow-up NM renal scans at a mean of 4 months (range 2-6) after injury. Mean NM split renal function of the injured kidney was 43% (range 22-57). Based on the CT volumetric measurements of the affected kidney, mean percent injured was 23% (range 7-62) with a calculated mean split renal function of 44% (range 23-60). Calculated mean CT split function correlated with NM split function (R = 0.89). Intraclass correlation measuring inter-rater reliability for CT volumetric measurements was 0.94 (95% confidence interval 0.72-0.99).

CONCLUSION

Volumetric measurements based on CT imaging obtained during the initial trauma evaluation correlated with future NM split renal function after SVIs with high inter-rater reliability. This method utilizes pre-existing imaging and avoids additional radiation exposure, work burden, and financial cost from a NM scan. Further evaluation is required to assess feasibility with more complex injuries.

Does the renal parenchymal thickness affect the efficacy of the retrograde intrarenal surgery? A prospective cohort study

Retrograde intrarenal surgery (RIRS) is one of the minimally invasive main treatment modalities in renal stone disease. There are many factors which affect stone-free rate (SFR). Our study was based on the hypothesis that higher renal parenchymal thickness (RPT) which may include higher average number of nephrons provides better diuresis. We investigated the efficacy of RPT on success of RIRS. This study is a single-centered prospective surgical cohort study. A total of 383 patients were analyzed. Regularly followed 304 patients with unilateral kidney stone at single pole or renal pelvis and who underwent single-session RIRS were included in the final analysis, and the patients' preoperative and postoperative 1st and 3rd months' data were evaluated. RPT was measured on the non-contrast computed tomography (CT) images. ROC analysis was performed to estimate the cutoff value of RPT for SFR. Univariate and multivariate logistic regression analyses were used to model the relationship between RPT and SFR after RIRS. ROC analysis revealed the best cutoff value of the RPT for predicting residual stone as 19 mm for both the 1st and 3rd month visits with Youden indexes of 0.397 and 0.406, respectively. To the best of our knowledge, this is the first study which evaluated the effect of RPT on the efficacy of RIRS. RPT measurement is a cost-effective method that can be easily performed on routinely applied non-contrast CT and may have predictive value for the surgical success in patients with nephrolithiasis.

Assessment of 2D ultrasound fluid volume estimation accuracy in different shaped objects: an in vitro study

Background

Volume estimation of organs using two-dimensional (2D) ultrasonography is frequently warranted. Considering the influence of estimated volume on patient management, maintenance of its high accuracy is empirical. However, data are scarce regarding the accuracy of estimated volume of non-globular shaped objects of different volumes.

Purpose

To evaluate the volume estimation accuracy of different shaped and sized objects using high-end 2D ultrasound scanners.

Material and Methods

Globular (n=5); non-globular elongated (n=5), and non-globular near-spherical shaped (n=4) hollow plastic objects were scanned to estimate the volumes; actual volumes were compared with estimated volumes. T-test and one-way ANOVA were used to compare means; P<0.05 was considered significant.

Results

The actual volumes of the objects were in the range of 10–445 mL; estimated volumes ranged from 6.4–425 mL ( P=0.067). The estimated volume was lower than the actual volume; such volume underestimation was marked for non-globular elongated objects. Regardless of the scanner, the highest volume estimation error was for non-globular elongated objects (<40%) followed by non-globular near-spherical shaped objects (<23.88%); the lowest was for globular objects (<3.6%). Irrespective of the shape or the volume of the object, volume estimation difference among the scanners was not significant: globular (F=0.430, P=0.66); non-globular elongated (F=3.69, P=0.064); and non-globular near-spherical (F=4.00, P=0.06). A good inter-rater agreement (R=0.99, P<0.001) and a good correlation between actual versus estimated volumes (R=0.98, P<0.001) were noted.

Conclusion

The 2D ultrasonography can be recommended for volume estimation purposes of different shaped and different sized objects, regardless the type of the high-end scanner used.

Spontaneous renal hemorrhage: critical analysis of different lines of management in non-traumatic patients: a single tertiary center experience

PURPOSE

To assess clinical presentation and outcomes of different treatment strategies in cases of spontaneous renal hemorrhage (SRH).

METHODS

A retrospective analysis of patients with SRH between 2000 and 2018 was performed. Patients' demographics, clinical presentation, laboratory and radiological investigations, and different lines of treatment were retrieved. The primary outcome was to assess the predictors of the success of conservative treatment. The secondary outcome was to assess the long-term renal function outcome comparing serum creatinine, e GFF, and CT-assessed renal volume at last follow-up with baseline values.

RESULTS

The study included 42 (23 males and 19 women) patients with mean ± SD age was 48.1 ± 17.8 years. Conservative management was successful in 19 (46%) patients. Trans-arterial embolization (TAE) was performed in 13 patients (30%) to control active bleeding. Ten patients (25%) required surgical exploration and nephrectomy. Lower serum creatinine (P = 0.003), higher prothrombin concentration (P = 0.04), lower hematoma size (P = 0.02), and non-AML lesions (P = 0.03) were independent predictors of conservative management success. Unlike the TAE-treated group, serum creatinine increased significantly (P = 0.04) with a significant decrease in e-GFR (P = 0.02) and renal volume (P < 0.001) of affected kidneys at last follow-up after conservative treatment.

CONCLUSION

Although SRH is a life-threatening condition, conservative treatment is successful in a certain subset of patients. However, it is associated with significant deterioration of the affected kidney function as well as renal volume.

Can Split Renal Volume Assessment by Computed Tomography Replace Nuclear Split Renal Function in Living Kidney Donor Evaluations? A Systematic Review and Meta-Analysis

Background:

As part of their living kidney donor assessment, all living donor candidates complete a computed tomography (CT) angiogram, but some also receive a nuclear renogram for split renal function (SRF%).

Objective:

We considered whether split renal volume (SRV%) assessed by CT can predict SRF%.

Design:

Systematic review and meta-analysis.

Setting:

Living donor candidates undergoing evaluation as potential living kidney donors.

Patients:

Living donor candidates who received both a nuclear renogram for split function and CT for SRV as part of their living donor work-up.

Measurements:

Split renal volume from CT scans and SRF from nuclear renography.

Methods:

We performed a systematic review and meta-analysis of the literature, abstracting data and digitizing plots where possible. We searched Medline, EMBASE, and the Cochrane Library. We added data from donor candidates assessed in London, Ontario from 2013 to 2016. We used fixed and random-effects models to pool Fisher’s z-transformed Pearson’s correlation coefficient (r). We conducted random-effects meta-regression on digitized and aggregate data. Studies were restricted to living kidney donors or living donor candidates.

Results:

After pooling 19 studies (n = 1479), we obtained a pooled correlation of r = 0.74 (95% confidence interval [CI] = 0.61-0.82). By linear regression using individual-level data, we observed a 0.76% (95% CI = 0.71-0.81) increase in SRF% for every 1% increase in SRV%. Split renal volume had a specificity of 88% for discriminating SRF at a threshold that could influence the decision of which kidney is to be removed (between-kidney difference ≥10%). Predonation SRV and SRF both moderately predicted kidney function 6 to 12 months after donation: r = 0.75 for SRV and r = 0.73 for SRF; Δr = 0.05 (–0.02, 0.13).

Limitations:

Most studies were retrospective and measured SRV and SRF only on selected living donor candidates. Efficiency gains in removing the SRF from the evaluation will depend on the transplant program.

Conclusion:

Split renal volume has the potential to replace SRF for some candidates. However, it is uncertain whether it can do so reliably and routinely across different transplant centers. The impact on clinical decision-making needs to be assessed in well-designed prospective studies.

Trial registration:

The digitized data are registered with Mendeley Data (doi10.17632/dyn2bfgxxj.2).

Renal volume matters: Assessing the association between excisional volume loss and renal function after partial nephrectomy

BACKGROUND/OBJECTIVES

To investigate the oncological and functional outcomes after partial nephrectomy for clinical stage T1 (cT1) renal cell carcinoma (RCC), and assess the association between excisional volume loss (EVL) and postoperative renal function.

METHODS

We retrospectively reviewed 150 patients with cT1 RCC undergoing partial nephrectomy from 2002 to 2016. End-point evaluation was assessed by recurrence free survival (RFS), overall survival (OS), stage III and stage IV chronic kidney disease (CKD). Regression models were used to determine the risk factors of CKD after surgery. The relationship between EVL and renal function decline was evaluated using Spearman correlation method.

RESULTS

Ninety patients with clinical stage T1a (cT1a) tumors and 60 patients with clinical stage T1b (cT1b) tumors were included. There were no differences in RFS, OS, and risk of stage III and stage IV CKD between the two groups. In Cox regression models, multivariate analysis showed that preoperative estimated glomerular filtration rate (eGFR) was an independent risk factor for developing stage III (hazard ratio 0.937, P < 0.001) and stage IV CKD (hazard ratio 0.929, P = 0.027). EVL was significantly associated with postoperative eGFR decrease. (Correlation Coefficient = 0.325, P = 0.003).

CONCLUSIONS

Patients with cT1a and cT1b RCC have comparable oncological and functional outcome after partial nephrectomy, and preoperative eGFR is an independent factor to predict developing CKD. EVL has influence on the postoperative renal function decline.

The Accuracy of Renal Function Measurements in Obstructive Hydronephrosis Using Dynamic Contrast-Enhanced MR Renography

OBJECTIVE. The objective of our study was to assess the accuracy of glomerular filtration rate (GFR) evaluation in patients with obstructive hydronephrosis using dynamic contrast-enhanced MR renography (DCE-MRR). MATERIALS AND METHODS. A group of 28 adult volunteers were enrolled in this study: 13 without hydronephrosis, eight with low-grade hydronephrosis, and seven with high-grade hydronephrosis. The GFR obtained from DCE-MRR (GFR_MRR) and the GFR obtained from renal scintigraphy (GFR_RS) were compared with the reference GFR (GFR_Ref) acquired using the two plasma sample method. The correlation and agreement between GFR_MRR and GFR_Ref, GFR_RS and GFR_Ref, and single-kidney GFR_MRR (skGFR_MRR) and single-kidney GFR_RS (skGFR_RS) were assessed. The interrater reliability of DCE-MRR and the interrater reliability of renal scintigraphy (RS) were measured. RESULTS. Both GFR_MRR and GFR_RS correlated well with GFR_Ref. In patients with hydronephrosis, DCE-MRR and RS overestimated GFR by 12.8 ± 13.9 mL/min (mean ± SD) and 11.5 ± 12.3 mL/min, respectively. The skGFR_RS was higher than skGFR_MRR by 5.7 ± 3.8 mL/min in high-grade hydronephrotic kidneys (p = 0.004). Good interrater reliability was observed for skGFR_MRR (intraclass correlation coefficient [ICC] = 0.82-0.92) and skGFR_RS (ICC = 0.79-0.90) for both nonhydronephrotic kidneys and hydronephrotic kidneys. The overall mean SDs of repeated measurements from three investigators were 4.0 and 3.8 mL/min for skGFR_MRR and skGFR_RS, respectively. CONCLUSION. Both DCE-MRR and RS tend to overestimate GFR in patients with hydronephrosis. RS-derived skGFR is slightly higher than that of DCE-MRR in kidneys with high-grade hydronephrosis. DCE-MRR is comparable to RS and may serve as an alternative noninvasive method for GFR measurement.

PKD1 Duplicated regions limit clinical Utility of Whole Exome Sequencing for Genetic Diagnosis of Autosomal Dominant Polycystic Kidney Disease

Autosomal dominant polycystic kidney disease (ADPKD) is an inherited monogenic renal disease characterised by the accumulation of clusters of fluid-filled cysts in the kidneys and is caused by mutations in PKD1 or PKD2 genes. ADPKD genetic diagnosis is complicated by PKD1 pseudogenes located proximal to the original gene with a high degree of homology. The next generation sequencing (NGS) technology including whole exome sequencing (WES) and whole genome sequencing (WGS), is becoming more affordable and its use in the detection of ADPKD mutations for diagnostic and research purposes more widespread. However, how well does NGS technology compare with the Gold standard (Sanger sequencing) in the detection of ADPKD mutations? Is a question that remains to be answered. We have evaluated the efficacy of WES, WGS and targeted enrichment methodologies in detecting ADPKD mutations in the PKD1 and PKD2 genes in patients who were clinically evaluated by ultrasonography and renal function tests. Our results showed that WES detected PKD1 mutations in ADPKD patients with 50% sensitivity, as the reading depth and sequencing quality were low in the duplicated regions of PKD1 (exons 1–32) compared with those of WGS and target enrichment arrays. Our investigation highlights major limitations of WES in ADPKD genetic diagnosis. Enhancing reading depth, quality and sensitivity of WES in the PKD1 duplicated regions (exons 1–32) is crucial for its potential diagnostic or research applications.

Hepatocyte Growth Factor-Secreting Mesothelial Cell Sheets Suppress Progressive Fibrosis in a Rat Model of CKD

BACKGROUND

Although hepatocyte growth factor (HGF) has antifibrotic effects and is involved in angiogenesis and vasodilation, systemic administration of HGF to prevent kidney fibrosis is not a feasible strategy for suppressing interstitial fibrosis in patients with CKD.

METHODS

We investigated a novel therapy involving HGF transgenic cell sheets grown in culture from human mesothelial cells and administered to rats with unilateral ureteral obstruction (UUO). We compared progression of fibrosis in rats with UUO that received one of five interventions: HGF-transgenic mesothelial cell sheets transplanted to the kidney surface, HGF-transgenic mesothelial cell sheets transplanted to thigh, mesotherial cell sheets transplanted to kidney, no sheets, or HGF injections.

RESULTS

HGF transgenic cell sheets transplanted to the kidney strongly suppressed the induction of myofibroblasts and collagen in the kidney for 28 days; other interventions did not. Additionally, the HGF-secreting cell sheets ameliorated loss of peritubular capillaries and maintained renal blood flow.

CONCLUSIONS

These findings suggest that cell sheet therapy is a novel and promising strategy for inhibiting progressive fibrosis in CKD.

The correlation between affected renal function and affected renal residual volume: A retrospective outcome of laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking-up for localized renal tumors

Laparoscopic nephron-sparing partial nephrectomy with segmental renal artery blocking (SRPN) has been widely used in the treatment of localized renal tumors. However, the impact of ischemia-reperfusion injury (IRI) during SRPN remains controversial. This study aims to evaluate the correlation between affected renal function and affected renal volume after SRPN for localized renal tumor treatment, explore the effect of IRI on renal function after SRPN.A total of 39 patients who underwent SRPN for localized renal tumor from June 2009 to April 2012 were reviewed. These patients were followed-up for 5 years. The preoperative affected renal glomerular filtration rate (aGFRpre), postoperative affected renal glomerular filtration rate (aGFRpost), preoperative affected renal volume (aVolpre), and postoperative affected renal volume (aVolpost) were collected during the follow-up period. The correlation between aGFRpost/aGFRpre and aVolpost/aVolpre was compared.A total of 33 patients were successfully followed up. After 3, 6, 12, 24, and 60 months, aGFRpost was 34.6 ± 4.6, 34.7 ± 4.8, 34.9 ± 4.4, 35.1 ± 4.4, and 35.2 ± 4.2 mL/min. The correlation coefficients between aGFRpost/aGFRpre and aVolpost/aVolpre were 0.659 (P = .000), 0.667 (P = .000), 0.663 (P = .000), 0.629 (P = .000), and 0.604 (P = .000), respectively. The limitation of this study was the small cohort size.For the localized renal tumor, aGFRpost was associated with aVolpost, but was not associated with intraoperative factors, such as the time of clamping of the affected segmental renal artery. As a part of nephrons, the resected tumor tissue caused the lack of inherent nephrons, resulting in the loss of renal function. More nephrons should be maintained before resecting the tumor completely during SRPN.Trial registration: ChiCTR-RRC-17011418.

Clinical outcomes associated with anti-coagulant therapy in patients with renal infarction

BACKGROUND

Patients with renal infarction are vulnerable to thromboembolic complications with poor outcomes. There is limited report concerning the effect of anti-coagulant therapy in this population.

AIM

To assess the impact of anti-coagulant therapy on outcomes in patients with renal infarction.

DESIGN

A retrospective cohort study of 101 renal infarction patients was conducted.

METHODS

The association between anti-coagulant therapy, all-cause mortality, thromboembolic complications and renal outcome was evaluated. Demographic data and comorbidities were collected for analysis. Anti-coagulant therapy was treated as a time-dependent variable. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using multi-variate Cox proportional hazards models.

RESULTS

Fifty-seven (56.4%) patients with renal infarction received anti-coagulant therapy during the study period. The all-cause mortality rate was 7.56 per 100 patient-years. Age (HR 1.05, 95% CI 1.02-1.08) was a risk factor for all-cause mortality and anti-coagulant therapy was associated with a 92% improved survival (HR 0.08, 95% CI 0.02-0.34). Twelve (11.9%) thromboembolic events occurred following renal infarction. Current smoking (HR 10.37, 95% CI 1.60-67.43) had an adverse effect and anti-coagulant therapy (HR 0.14, 95% CI 0.03-0.73) had a significant protective impact on thromboembolic complications. There was no significant association between anti-coagulant therapy and long-term renal outcome in renal infarction patients including the monthly change in the estimated glomerular filtration rate (eGFR), the incidence of eGFR reduction of more than 50% and end-stage renal disease.

CONCLUSION

Anti-coagulant therapy in patients with renal infarction was associated with better survival and reduced thromboembolic complications.

Comparative biodistribution analysis across four different 89Zr-monoclonal antibody tracers-The first step towards an imaging warehouse

Rationale: Knowledge on monoclonal antibody biodistribution in healthy tissues in humans can support clinical drug development. Molecular imaging with positron emission tomography (PET) can yield information in this setting. However, recent imaging studies have analyzed the behavior of single antibodies only, neglecting comparison across different antibodies. Methods: We compared the distribution of four ⁸⁹Zr-labeled antibodies in healthy tissue in a retrospective analysis based on the recently published harmonization protocol for ⁸⁹Zr-tracers and our delineation protocol. Results: The biodistribution patterns of ⁸⁹Zr-lumretuzumab, ⁸⁹Zr-MMOT0530A, ⁸⁹Zr-bevacizumab and ⁸⁹Zr-trastuzumab on day 4 after tracer injection were largely similar. The highest tracer concentration was seen in healthy liver, spleen, kidney and intestines. About one-third of the injected tracer dose was found in the circulation, up to 15% in the liver and only 4% in the spleen and kidney. Lower tracer concentration was seen in bone marrow, lung, compact bone, muscle, fat and the brain. Despite low tracer accumulation per gram of tissue, large-volume tissues, especially fat, can influence overall distribution: On average, 5-7% of the injected tracer dose accumulated in fat, with a peak of 19% in a patient with morbid obesity. Conclusion: The similar biodistribution of the four antibodies is probably based on their similar molecular structure, binding characteristics and similar metabolic pathways. These data provide a basis for a prospectively growing, online accessible warehouse of molecular imaging data, which enables researchers to increase and exchange knowledge on whole body drug distribution and potentially supports drug development decisions.

Using kidney size for early detection of contrast-induced nephropathy in the emergency department setting

AIM

We aimed to examine the relationship between kidney size and contrast-induced nephropathy (CIN) in patients who underwent contrast-enhanced computed tomography (CT) in the emergency department.

METHODS

This single-center retrospective observational study was undertaken to evaluate risk factors for CIN at Okayama Saiseikai General Hospital (Okayama, Japan) from January 2014 through to December 2016. Contrast-induced nephropathy was defined as an absolute increase in serum creatinine level of ≥0.5 mg/dL or ≥25% over the baseline value within 72 h after contrast-enhanced CT. Independent risk factors for CIN were determined by multiple logistic regression analysis. The thickness of the kidney was evaluated as a predictor of CIN using the area under the receiver operating characteristic curve. We also analyzed CIN as an outcome using the Kaplan-Meier method.

RESULTS

The incidence of CIN was 26/262 (9.9%). In the multivariate analysis, CIN was associated with renal thickness (odds ratio = 0.65; 95% confidence interval, 0.53-0.81). No patient underwent renal replacement therapy.

CONCLUSION

Renal thickness could be used as a reliable, simple, and easily obtainable marker for identifying CIN in patients undergoing contrast-enhanced CT in the emergency department.

Predictors and outcomes of laparoscopic nephrectomy in autosomal dominant polycystic kidney disease

Purpose

Autosomal dominant polycystic kidney disease (ADPKD) is the most common hereditary kidney disease, and 20% of patients eventually require nephrectomies due to compressive symptoms or renal-related complications. Traditionally, nephrectomies were performed via the open approach in view of space constraints. We evaluate our institution's outcomes for laparoscopic nephrectomy (LN) for ADPKD.

Materials and Methods

We retrospectively reviewed 33 patients with ADPKD who underwent nephrectomies from November 2005 to December 2016 at a tertiary institution. Preoperative kidney volume was calculated via the ellipsoid method by using computed tomography scan.

Results

The median age was 51.0 years (interquartile range [IQR], 44.5–56.0 years). Sixteen patients (48.5%) underwent open nephrectomy (ON), 15 patients (45.5%) had LNs, and 2 patients (6.1%) had laparoscopic converted to ON due to dense adhesions. Thirteen patients had bilateral while 18 patients had unilateral nephrectomies. Median kidney volume in the open group was 1,042 cm³ (IQR, 753–2,365 cm³) versus 899 cm³ (IQR, 482–1,914 cm³) in the laparoscopy group and did not differ significantly. The operative time was comparable between both groups. Patients who underwent LN had lesser blood loss (350 mL vs. 650 mL; 95% confidence interval [CI], 1.822–3.533; p=0.016) and shorter length of hospital stay (4.0 days vs. 6.5 days; 95% CI, 1.445–5.755; p=0.001) compared to patients who underwent ON. Both groups had similar low morbidity rate and no mortality.

Conclusions

LN for ADPKD is a safe and effective alternative to ON independent of kidney size with comparable outcomes and benefits of minimally invasive surgery.

Renal cortical volume: High correlation with pre- and post-operative renal function in living kidney donors

BACKGROUND

CT volumetry has previously been proposed as an alternative to scintigraphy for the evaluation of pre-donation split renal function and the prediction of post-donation renal function in living kidney donors. The aim of our study was to retrospectively assess the relevance of three CT volumetry techniques for estimating pre-donation kidney function and predicting the risk for chronic kidney disease (CKD) at 1-year post-nephrectomy in a French cohort of living donors using isotopic measures of kidney function.

METHODS

Kidney volume was quantified pre-donation for 105 donors using three methods total parenchymal three-dimensional renal volume (3DRV), total parenchymal renal volume contouring (RVCt), and renal cortical volume (RCoV). Subjects also had a 51Cr-EDTA scintigraphy to measure glomerular filtration rate (mGFR) pre-donation and 1-year after donation. For each volume, we tested for association with mGFR using univariate regression models, and computed receiver operating characteristics analyses to assess their predictive potential of post-donation CKD.

RESULTS

Our population was composed of healthy subjects, who were predominantly female (69%) with a median age at donation of 51yo. Median mGFR was 102 mL/min/1.73 m² at pre-donation and 66 mL/min/1.73 m² 1-year after nephrectomy. The pre-donation median volume of the preserved kidney was 156 cm³, 163 cm³ and 99 cm³ for the 3DRV, RVCt and RCoV methods respectively, with a high correlation observed between each technique (R > 0.84). For all methods, total kidney volume was significantly associated with pre-donation mGFR (P < 0.001). Preserved kidney volume was also strongly correlated with post-donation mGFR (P < 0.0001), with the strongest correlation observed for RCoV (R = 0.60 vs. R = 0.39 and R = 0.51 for 3DRV and RVCt, respectively). Finally, the RCoV method yielded the best predictive value of 1-year post-donation CKD (AUC = 0.80 vs. AUC = 0.76 and 0.70 for RVCt and 3DRV, respectively).

CONCLUSIONS

In our cohort of healthy donors with measured kidney function, cortical volumetry (RCoV) appears as the best volumetric technique to use as a surrogate to scintigraphy for estimating pre-donation split renal function and predicting post-donation renal outcomes.

A useful method for assessing differences of compensatory hypertrophy in the contralateral kidney before and after radical nephrectomy in patients with renal cell carcinoma: ellipsoid formula on computed tomography

OBJECTIVE

To investigate the usefulness of the ellipsoid formula for assessing compensatory hypertrophy of the contralateral kidney on pre-operative and post-operative CT in renal cell carcinoma (RCC) patients.

METHODS

We retrospectively identified 389 patients who had radical nephrectomy for RCC between 2011  and 2015. Contrast-enhanced CT was performed within 3 months pre-operative and at 1 year post-operative. The kidney volumes were calculated from CT using the ellipsoid formula. We subdivided patients into three groups based on tumour size (I: ≤4 cm, II: 4-7 cm, III: >7 cm). Volumetric renal parameters were compared and multivariate analyses were performed to determine predictors associated with pre-operative  and post-operative compensatory hypertrophy.

RESULTS

Kidney volume calculation using the ellipsoid  method took a median of 51 s. Group III had a significantly larger median pre-operative contralateral renal volume than Groups I and II (I:  140.4, II: 141.6, III: 166.7 ml, p < 0.05). However, the median ratio of post-operative contralateral renal volume change was significantly higher in Groups I and II than Group III (I: 0.36, II: 0.23, III: 0.12, p < 0.001). On multivariate analysis, tumour size revealed the strongest positive association with pre-operative contralateral kidney volume (partial regression coefficient: β = 30.8, >7 cm) and ratio of post-operative contralateral kidney volume change (β  = 0.214, I vs III; β = 0.168, II vs III).

CONCLUSION

Kidney volume calculation for assessing pre- and post-operative compensatory hypertrophy of the contralateral kidney in RCC patients can be easily and rapidly performed from CT images using the ellipsoid formula. Advances in knowledge: The ellipsoid formula allows reliable method for assessing pre-operative and post-operative compensatory hypertrophy of the contralateral kidney in RCC.

Clinical utility of FDG PET/CT in acute complicated pyelonephritis-results from an observational study

BACKGROUND

Acute complicated pyelonephritis (ACP) is an upper urinary tract infection associated with coexisting urinary tract abnormalities or medical conditions that could predispose to serious outcomes or treatment failures. Although CT and magnetic resonance imaging (MRI) are frequently used in patients with ACP, the clinical value of ¹⁸F-fluorodeoxyglucose positron emission tomography and computed tomography (FDG PET/CT) has not been systematically investigated. This single-center retrospective study was designed to evaluate the potential usefulness of FDG PET/CT in patients with ACP.

METHODS

Thirty-one adult patients with ACP who underwent FDG PET/CT were examined. FDG PET/CT imaging characteristics, including tracer uptake patterns, kidney volumes, and extrarenal imaging findings, were reviewed in combination with clinical data and conventional imaging results.

RESULTS

Of the 31 patients, 19 (61%) showed focal FDG uptake. The remaining 12 study participants showed a diffuse FDG uptake pattern. After volumetric approximation, the affected kidneys were found to be significantly enlarged. Patients who showed a focal uptake pattern had a higher frequency of abscess formation requiring drainage. ACP patients showing diffuse tracer uptake patterns had a more benign clinical course. Seven patients had suspected extrarenal coinfections, and FDG PET/CT successfully confirmed the clinical suspicion in five cases. FDG PET/CT was as sensitive as CT in identifying the six patients (19%) who developed abscesses. Notably, FDG PET/CT findings caused a modification to the initial antibiotic regimen in nine patients (29%).

CONCLUSIONS

FDG PET/CT may be clinically useful in the assessment of patients with ACP who have a progressive disease course.

Computed Tomographic Estimation of Relationship between Renal Volume and Body Weight of an Individual

INTRODUCTION

Knowledge of normal range of size and volume of abdominal organs plays a vital role in clinical practices as various medical conditions affects the abdominal organs causing alteration in their dimensions.

AIM

The present retrospective study was done to establish the normal range of renal volume in study population and to see the correlation between renal volume and body weight of an individual.

MATERIALS AND METHODS

Computed tomographic evaluations of kidneys were performed on 140 kidneys of 70 individuals who had undergone abdominal CT scan for indications other than renal disease. We also excluded the patients diagnosed to have renal cysts, hydronephrosis or other renal diseases on CT examination. Renal length, width and depth were measured. Renal volume of both the kidneys was calculated by formula Kidney Volume (KV) =Л/6 x Renal length (L) x Renal width (W) x Renal depth (D). Various body parameters like age, weight, sex were also recorded in the data sheet.

RESULTS

Mean renal volume for the right kidney was 83.26±18.33 cm³ for females (33 females out of 70) and 103.92±23.27 cm³ for males (37 males out of 70). However, mean renal volume for the left kidney was 89.17±19.41 cm³ in females and 106±26.79 cm³ in males. Left renal volume was apparently more than right renal volume, though statistically insignificant. In males, mean kidney volume was found to be 104.96 cm³ whereas in females, it was found to be 86.21 cm³. Kidney volume was found to be significantly greater in males than females among study population (t=3.79, p=0.0001). Renal volume significantly correlated with age and body weight of an individual.

CONCLUSION

This study is a sincere attempt to establish a normograms of renal volume in study population. For the clinical assessment of renal pathologies, knowledge of renal volume is a vital parameter. In study group, most significant parameter associated with renal volume is body weight which can be used as an adjunct while evaluating renal pathological conditions. Of all the radiological imaging techniques, abdominal coronal computed tomography scan provides most accurate renal measurements.

Automated renal cortical volume measurement for assessment of renal function in patients undergoing radical nephrectomy

BACKGROUND

Renal volume change greatly affects renal function after nephrectomy. Although various measuring techniques were reported, no standard measuring method is available. In this study, we examined the computational automated volumetric method, and evaluated the volumetric change to assess the functional outcome in patients undergoing radical nephrectomy. We developed the predictive equation for postoperative renal function from volume alternation and validated the performance.

METHODS

Thirty-two patients undergoing radical nephrectomy participated in this study. Renal volume was calculated using three different methods [ellipsoid method, conventional manual voxel count method for renal parenchyma (manual RPV), and automated voxel count method for renal cortex (automated RCV)] through newly developed imaging software. Statistical analysis was performed to evaluate the correlation between renal functional alternation 7 days after the nephrectomy and renal volumetric change. A simple predictive equation for the postoperative renal function by renal volume loss was developed and externally validated through another 12 cases.

RESULTS

The automated RCV method had the strongest correlation between renal function alternation and RCV change (R = 0.82), than manual RPV (R = 0.69) and ellipsoid method (R = 0.50). Subsequently, a simple equation for postoperative renal function by renal volume alternation was developed: predicted postoperative estimated glomerular filtration rate (eGFR) from renal volume change = preoperative eGFR × (postoperative renal volume / preoperative renal volume). In the external validation cohort, automated RCV demonstrated the predictive performance of the constructed equations for renal function (R = 0.77).

CONCLUSIONS

The computational automated RCV measurements is a simple estimation of renal functional outcome for patients undergoing radical nephrectomy.

Measurement and Estimation of Renal Size by Computed Tomography in Korean Children

Adequate organ growth is an important aspect of growth evaluation in children. Renal size is an important indicator of adequate renal growth; computed tomography (CT) can closely estimate actual kidney size. However, insufficient data are available on normal renal size as measured by CT. This study aimed to evaluate the relationships of anthropometric indices with renal length and volume measured by CT in Korean pediatric patients. Renal length and volume were measured using CT images in 272 pediatric patients (age < 18 years) without renal disease. Data for anthropometric indices-including height, weight, and body surface area (BSA)-were obtained using medical records. Using the equation for an ellipsoid, renal volume was calculated in cubic centimeters. Height showed greatest correlation with renal length on stepwise multiple linear regression analysis; BSA showed the strongest significant correlation with renal volume. The mean renal size for each age group and height group was determined; it showed a tendency to increase with age and height. This is the first Korean study to report the relationship between body indices and renal size measured by CT. These results can serve as normative standards for assessing adequate renal growth.