Van De Luijtgaarden M.W.M.,University of Amsterdam |
Jager K.J.,University of Amsterdam |
Segelmark M.,Linkoping University |
Pascual J.,Hospital Del Mar |
And 19 more authors.
Nephrology Dialysis Transplantation | Year: 2016
Background Although previous studies suggest similar patient survival for peritoneal dialysis (PD) and haemodialysis (HD), PD use has decreased worldwide. We aimed to study trends in the choice of first dialysis modality and relate these to variation in patient and technique survival and kidney transplant rates in Europe over the last 20 years. Methods We used data from 196 076 patients within the European Renal Association-European Dialysis and Transplant Association (ERA-EDTA) Registry who started renal replacement therapy (RRT) between 1993 and 2012. Trends in the incidence rate and prevalence on Day 91 after commencing RRT were quantified with Joinpoint regression. Crude and adjusted hazard ratios (HRs) for 5-year dialysis patient and technique survival were calculated using Cox regression. Analyses were repeated using propensity score matching to control for confounding by indication. Results PD prevalence dropped since 2007 and HD prevalence stabilized since 2009. Incidence rates of PD and HD decreased from 2000 and 2009, respectively, while the incidence of kidney transplantation increased from 1993 onwards. Similar 5-year patient survival for PD versus HD patients was found in 1993-97 [adjusted HR: 1.02, 95% confidence interval (95% CI): 0.98-1.06], while survival was higher for PD patients in 2003-07 (HR: 0.91, 95% CI: 0.88-0.95). Both PD (HR: 0.95, 95% CI: 0.91-1.00) and HD technique survival (HR: 0.93, 95% CI: 0.87-0.99) improved in 2003-07 compared with 1993-97. Conclusions Although initiating RRT on PD was associated with favourable patient survival when compared with starting on HD treatment, PD was often not selected as initial dialysis modality. Over time, we observed a significant decline in PD use and a stabilization in HD use. These observations were explained by the lower incidence rate of PD and HD and the increase in pre-emptive transplantation. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA.
Chappell M.,Norwegian University of Science and Technology |
Haberg A.K.,Norwegian University of Science and Technology |
Kristoffersen A.,St. Olavs Hospital HF
Magnetic Resonance Imaging | Year: 2011
Research on the functions of the human brain requires that functional magnetic resonance imaging (MRI) moves towards producing images with less distortion and higher temporal and spatial resolution. This study compares passband balanced steady-state free precession (bSSFP) acquisitions with and without parallel imaging (PI) to investigate whether combining PI with this pulse sequence is a viable option for functional MRI. Such a novel combination has the potential to offer the distortion-free advantages of bSSFP with the reduced acquisition time of PI. Scans were done on a Philips 3T Intera, using the installed bSSFP pulse sequence, both with and without the sensitivity encoding (SENSE) PI option. The task was a visual flashing checkerboard, and the viewing window covered the visual cortex. Sensitivity comparisons with and without PI were done using the same manually drawn region of interest for each time course of the subject, and comparing the z-score summary statistics: number of voxels with z>2.3, the mean of those voxels, their 90th percentile and their maximum value. We show that PI greatly improves the temporal resolution in bSSFP, reducing the volume acquisition time by more than half in this study to 0.67 s with 3-mm isotropic voxels. At the same time, a statistically significant increase was found for the maximum z-score using bSSFP with PI as compared to without it (P=02). This improvement can be understood in terms of physiological noise, as demonstrated by noise measurements. This produces observed increases in the overall temporal signal to noise of the functional time series, giving greater sensitivity to functional activations with PI. This study demonstrates for the first time the possibility of combining PI with bSSFP to achieve distortion-free functional images without loss of sensitivity and with high temporal resolution. © 2011 Elsevier Inc.
Kristoffersen A.,St. Olavs Hospital HF
Magnetic Resonance in Medicine | Year: 2011
In human brain diffusion measurements, there are deviations from monoexponential signal decay at high values of the diffusion-weighting factor b. This is known as non-Gaussian diffusion and can provide novel kinds of image contrast. We evaluated quantitatively the goodness-of-fit of five popular diffusion models. Because of the Rician signal distribution and physiological noise, the measurement errors are unknown. This precludes standard π 2 testing. By repeating the measurement 25 times, the errors were estimated. Hypothesis testing based on the residual after least squares curve fitting was then carried out. Systematic errors originating from the Rician signal bias were eliminated in the fitting procedure. We performed diffusion measurements on four healthy volunteers with b-values ranging from 0 to 5000 s/mm 2. The data were analyzed voxelwise. The null hypothesis of a given model being adequate was rejected, if the residual after fitting exceeded a limit that corresponds to a significance level of 1%. The fraction of rejected voxels depended strongly on the number of free model parameters. The rejected fraction was: monoexponential model with two parameters, 94%; statistical model with three parameters, 29%; stretched exponential model with three parameters, 35%; cumulant model with three parameters, 48%; cumulant model with four parameters, 11%; biexponential model with four parameters, 2.9%. Copyright © 2011 Wiley Periodicals, Inc.
Agency: Cordis | Branch: FP7 | Program: MC-ITN | Phase: FP7-PEOPLE-ITN-2008 | Award Amount: 3.71M | Year: 2009
The scope of the present consortium is to provide technology and training for the integration of ultrasound and biophotonics based imaging with magnetic resonance imaging (MRI), Computed Tomography (CT) and Positron Emission Tomography (PET) to define the specs of an Integrated Interventional Imaging Operating System (III OS) aimed at minimal invasive treatment of common life-threatening disorders, e.g., cancer, cardiovascular disease and structural heart defects. Effective therapy of these conditions will require a range of safe surgical and interventional devices used with the necessary visualization and tracking under real-time image guidance. The consortium includes a critical mass of industrial and university research institute partners with high expertise in design, development, and manufacture of these devices and instruments. To ensure medical the safety and economical usability of the system and to allow an optimal integration into the future hospital workflow, 6 university hospitals will contribute their clinical and administrative expertise to the consortium in the fields of Interventional Radiology/Cardiology, Anaesthesia, Oncology, General and Cardiovascular Surgery and preclinical Image guided procedures. The consortium of the IIIOS research and training process includes two Biomedical Technology Societies: DGBMT and SMIT&MEDIS Foundation in Rumania providing expert networking and conference organization. The is involved in the consortium and will play a key role in the exchange of knowledge and expertise to the new member states of the EU through hosting conferences such SMIT 2009 in Sinaia (www.smit2009.com).
Amundsen T.,St. Olavs Hospital HF |
Amundsen T.,Norwegian University of Science and Technology |
Sundstrom S.,St. Olavs Hospital HF |
Gederaas O.A.,Norwegian University of Science and Technology |
Haaverstad R.,University of Bergen
Acta Oncologica | Year: 2014
Background. On the basis of our own experience and literature search, we hypothesised that a canine olfactory test may be useful for detecting lung cancer in an unselected population of patients suspected to have lung cancer. Material and methods. We conducted a prospective study of 93 patients consecutively admitted to hospital with suspected lung cancer. Exhaled breath and urine were sampled before the patients underwent bronchoscopy. The canine olfactory test was performed in a double-blinded manner. Sensitivity and specificity were outcome measures. Results. With 99% sensitivity, the olfactory test demonstrated that dogs have the ability to distinguish cancer patients from healthy individuals. With an intensified training procedure, the exhaled breath and urine tests showed sensitivity rates of 56-76% and specificity rates of 8.3-33.3%, respectively, in our heterogeneous study population. Conclusion. Although the olfactory test appears to be a promising tool for the detection of cancer, the main challenge is to determine whether the test can sufficiently discriminate between patients at risk, patients with benign disease, and patients with malignant disease. We need to gain a deeper understanding of this test and further refine it before applying it as a screening tool for lung cancer in clinical settings. © 2014 Informa Healthcare.