Automatic Renal Segmentation in DCE-MRI using Convolutional Neural Networks

Kidney function evaluation using dynamic contrast-enhanced MRI (DCE-MRI) images could help in diagnosis and treatment of kidney diseases of children. Automatic segmentation of renal parenchyma is an important step in this process. In this paper, we propose a time and memory efficient fully automated segmentation method which achieves high segmentation accuracy with running time in the order of seconds in both normal kidneys and kidneys with hydronephrosis. The proposed method is based on a cascaded application of two 3D convolutional neural networks that employs spatial and temporal information at the same time in order to learn the tasks of localization and segmentation of kidneys, respectively. Segmentation performance is evaluated on both normal and abnormal kidneys with varying levels of hydronephrosis. We achieved a mean dice coefficient of 91.4 and 83.6 for normal and abnormal kidneys of pediatric patients, respectively

Wars, disasters and kidneys

This paper summarizes the impact that wars had on the history of nephrology, both worldwide and in the Ghent Medical Faculty notably on the definition, research and clinical aspects of acute kidney injury. The paper briefly describes the role of 'trench nephritis' as observed both during World War I and II, supporting the hypothesis that many of the clinical cases could have been due to Hantavirus nephropathy. The lessons learned from the experience with crush syndrome first observed in World War II and subsequently investigated over many decades form the basis for the creation of the Renal Disaster Relief Task Force of the International Society of Nephrology. Over the last 15 years, this Task Force has successfully intervened both in the prevention and management of crush syndrome in numerous disaster situations like major earthquakes

The influence of perfusion solution on renal graft viability assessment

BACKGROUND: Kidneys from donors after cardiac or circulatory death are exposed to extended periods of both warm ischemia and intra-arterial cooling before organ recovery. Marshall’s hypertonic citrate (HOC) and Bretschneider’s histidine-tryptophan-ketoglutarate (HTK) preservation solutions are cheap, low viscosity preservation solutions used clinically for organ flushing. The aim of the present study was to evaluate the effects of these two solutions both on parameters used in clinical practice to assess organ viability prior to transplantation and histological evidence of ischemic injury after reperfusion. METHODS: Rodent kidneys were exposed to post-mortem warm ischemia, extended intra-arterial cooling (IAC) (up to 2 h) with preservation solution and reperfusion with either Krebs-Hensleit or whole blood in a transplant model. Control kidneys were either reperfused directly after retrieval or stored in 0.9% saline. Biochemical, immunological and histological parameters were assessed using glutathione-S-transferase (GST) enzymatic assays, polymerase chain reaction and mitochondrial electron microscopy respectively. Vascular function was assessed by supplementing the Krebs-Hensleit perfusion solution with phenylephrine to stimulate smooth muscle contraction followed by acetylcholine to trigger endothelial dependent relaxation. RESULTS: When compared with kidneys reperfused directly post mortem, 2 h of IAC significantly reduced smooth muscle contractile function, endothelial function and upregulated vascular cellular adhesion molecule type 1 (VCAM-1) independent of the preservation solution. However, GST release, vascular resistance, weight gain and histological mitochondrial injury were dependent on the preservation solution used. CONCLUSIONS: We conclude that initial machine perfusion viability tests, including ischemic vascular resistance and GST, are dependent on the perfusion solution used during in situ cooling. HTK-perfused kidneys will be heavier, have higher GST readings and yet reduced mitochondrial ischemic injury when compared with HOC-perfused kidneys. Clinicians should be aware of this when deciding which kidneys to transplant or discard

Pkd2 dosage influences cellular repair responses following ischemia-reperfusion injury

Autosomal dominant polycystic kidney disease (ADPKD) results from mutations in either PKD1 or PKD2 and accounts for 10% of all patients on renal replacement therapy. The kidney disease phenotype is primarily characterized by cyst formation, but there are also prominent interstitial changes (inflammation, apoptosis, proliferation, and fibrosis). Using a model of unilateral ischemia-reperfusion injury, we tested the hypothesis that Pkd2 heterozygous kidneys are more sensitive to injury and that this could lead to interstitial inflammation and fibrosis. Baseline tubular proliferation in heterozygous kidneys was twofold higher than in wild-type kidneys. The magnitude and duration of tubular and interstitial proliferative responses was consistently greater in injured heterozygous compared with wild-type kidneys at all time points. Conversely, tubular p21 expression in heterozygotes was lower at baseline and following injury at all time points. Significantly more neutrophils and macrophages were detected in injured Pkd2 heterozygous kidneys at 2 days, correlating with increased expression of the cytokines interleukin (IL)-1 beta and keratinocyte-derived chemokine and resulting in interstitial fibrosis at 28 days. We conclude that Pkd2 dosage influences both susceptibility and nature of the repair responses following injury. Polycystin-2 is therefore likely to play multiple roles in regulating tubular cell viability, repair, and remodeling in the mature kidney

The economic implications of HLA matching in cadaveric renal transplantation.

Abstract Background: The potential economic effects of the allocation of cadaveric kidneys on the basis of tissue-matching criteria are controversial. We analyzed the economic costs associated with the transplantation of cadaveric kidneys with various numbers of HLA mismatches and examined the potential economic benefits of a local, as compared with a national, system designed to minimize HLA mismatches between donor and recipient in first cadaveric renal transplantations. Methods: All data were supplied by the U.S. Renal Data System. Data on all payments made by Medicare from 1991 through 1997 for the care of recipients of a first cadaveric renal transplant were analyzed according to the number of HLA-A, B, and DR mismatches between donor and recipient and the duration of cold ischemia before transplantation. Results: Average Medicare payments for renal-transplant recipients in the three years after transplantation increased from $60,436 per patient for fully HLA-matched kidneys (those with no HLA-A, B, or DR mismatches) to$80,807 for kidneys with six HLA mismatches between donor and recipient, a difference of 34 percent (P\u3c0.001). By three years after transplantation, the average Medicare payments were $64,119 for transplantations of kidneys with less than 12 hours of cold-ischemia time and$74,997 for those with more than 36 hours (P\u3c0.001). In simulations, the assignment of cadaveric kidneys to recipients by a method that minimized HLA mismatching within a local geographic area (i.e., within one of the approximately 50 organ-procurement organizations, which cover widely varying geographic areas) produced the largest cost savings ($4,290 per patient over a period of three years) and the largest improvements in the graft-survival rate (2.3 percent) when the potential costs of longer cold-ischemia time were considered. Conclusions: Transplantation of better-matched cadaveric kidneys could have substantial economic advantages. In our simulations, HLA-based allocation of kidneys at the local level produced the largest estimated cost savings, when the duration of cold ischemia was taken into account. No additional savings were estimated to result from a national allocation program, because the additional costs of longer cold-ischemia time were greater than the advantages of optimizing HLA matching

Ex vivo renal perfusion and autotransplantation in treatment of calculous disease or abdominal aortic aneurysm.

Two more indications are described for temporary ex vivo perfusion of kidneys with revascularization of these organs as autografts to orthotopic or heterotopic locations. One of the patients had staghorn calculi which were removed from a solitary kidney. The other patient had both kidneys autografted in the course of a surgical procedure on an extensive abdominal aortic aneurysm

Ex vivo perfusion, arteriography, and autotransplantation procedures for kidney salvage

Three kidneys with arterial lesions that would have been difficult or impossible to repair by standard vascular reconstruction were removed, perfused by the Belzer technique, and returned to host after partial or complete autotransplantation. The fact that kidneys can be studied, dissected, repaired, and constantly salvaged with this technique should have important implications in several aspects of urologic operations

Beyond Gift and Bargain: Some Suggestions for Increasing Kidney Exchanges

Each year, thousands of people in the United States die from end stage renal disease (ESRD), despite the fact that we have the medical knowledge necessary to save them. The reason is simple: these people need a kidney transplant and we have too few kidneys. Given our current technology, the only way to meet the massive annual shortfall between the number of kidneys that are donated and the number of kidneys that are necessary to save the lives of those with ESRD is to increase the number of living donations. The debate on how to do so has often pitted those who favor creating a “free market” in human organs against those who believe that the selling of organs by human donors poses unacceptable evils and risks. Current law prohibits donors from being paid for kidneys. Once the donation has been made, however, the kidney will often change hands in exchange for money several times before reaching the patient. There are no serious proposals to ban such transactions. This article generally sympathizes with those who favor the free alienation of kidneys by donors in exchange for payment. The goal of this article, however, is not to make another charge across the no man’s land separating free-marketeers from prohibitionists. Rather, it aims to explore ways in which we can increase trust in order to foster a promising new development in transplant medicine: extended kidney exchange

Monitoring kidney optical properties during cold storage preservation with spatial frequency domain imaging.

Transplantation of kidneys results in delayed graft function in as many as 40% of cases. During the organ transplantation process, donor kidneys undergo a period of cold ischemic time (CIT), where the organ is preserved with a cold storage solution to maintain tissue viability. Some complications observed after grafting may be due to damage sustained to the kidney during CIT. However, the effects due to this damage are not apparent until well after transplant surgery has concluded. To this end, we have used spatial frequency domain imaging (SFDI) to measure spatially resolved optical properties of porcine kidneys over the course of 80-h CIT. During this time, we observed an increase in both reduced scattering (μs&') and absorption (μa) coefficients. The measured scattering b parameter increased until 24 h of CIT, then returned toward baseline during the remaining duration of the imaging sequence. These results show that the optical properties of kidney tissue change with increasing CIT and suggest that continued investigation into the application of SFDI to kidneys under CIT may lead to the development of a noninvasive method for assessing graft viability

Gender Bias and Organ Transplantation in Nepal

Women in Nepal are less likely to receive proper, high quality medical care than their male relatives. Live-donor kidney transplantation provides a compelling example of such disparities, as 84% of recipients are male, 75% of donors are female and most kidneys are transferred from mother to son and from wife to husband. In the case of transplantation, women are not just denied healthcare, they are also responsible for the health of their male kin. Based on semi-structured ethnographic interviews with transplant patients, organ donors, dialysis patients and relatives, this paper elaborates on the social and economic factors that have created an extreme gender bias in transplantation. We argue that women, whose livelihoods largely depend on their husbands, donate kidneys out of self-protection and a sense of duty. Conversely, men receive kidneys but rarely donate them to women, because the health of men is a more productive economic investment than the health of women. We reject the notion that wives are directly coerced or pressured into donating kidneys to their husbands. Rather, we argue that female kidney donors make thoughtful, independent decisions that serve their best interests, and allow them to assert some control over their lives. It is, however, Nepal’s patriarchal society that both necessitates and limits such assertions of power