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Dive into the research topics where Patricia J. Nelemans is active.

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Featured researches published by Patricia J. Nelemans.


Journal of the American College of Cardiology | 2012

Diagnostic Performance of Noninvasive Myocardial Perfusion Imaging Using Single-Photon Emission Computed Tomography, Cardiac Magnetic Resonance, and Positron Emission Tomography Imaging for the Detection of Obstructive Coronary Artery Disease: A Meta-Analysis

Caroline Jaarsma; Tim Leiner; Sebastiaan C.A.M. Bekkers; Harry J.G.M. Crijns; Joachim E. Wildberger; Eike Nagel; Patricia J. Nelemans; Simon Schalla

OBJECTIVES This study aimed to determine the diagnostic accuracy of the 3 most commonly used noninvasive myocardial perfusion imaging modalities, single-photon emission computed tomography (SPECT), cardiac magnetic resonance (CMR), and positron emission tomography (PET) perfusion imaging for the diagnosis of obstructive coronary artery disease (CAD). Additionally, the effect of test and study characteristics was explored. BACKGROUND Accurate detection of obstructive CAD is important for effective therapy. Noninvasive myocardial perfusion imaging is increasingly being applied to gauge the severity of CAD. METHODS Studies published between 1990 and 2010 identified by PubMed search and citation tracking were examined. A study was included if a perfusion imaging modality was used as a diagnostic test for the detection of obstructive CAD and coronary angiography as the reference standard (≥50% diameter stenosis). RESULTS Of the 3,635 citations, 166 articles (n = 17,901) met the inclusion criteria: 114 SPECT, 37 CMR, and 15 PET articles. There were not enough publications on other perfusion techniques such as perfusion echocardiography and computed tomography to include these modalities into the study. The patient-based analysis per imaging modality demonstrated a pooled sensitivity of 88% (95% confidence interval [CI]: 88% to 89%), 89% (95% CI: 88% to 91%), and 84% (95% CI: 81% to 87%) for SPECT, CMR, and PET, respectively; with a pooled specificity of 61% (95% CI: 59% to 62%), 76% (95% CI: 73% to 78%), and 81% (95% CI: 74% to 87%). This resulted in a pooled diagnostic odds ratio (DOR) of 15.31 (95% CI: 12.66 to 18.52; I(2) 63.6%), 26.42 (95% CI: 17.69 to 39.47; I(2) 58.3%), and 36.47 (95% CI: 21.48 to 61.92; I(2) 0%). Most of the evaluated test and study characteristics did not affect the ranking of diagnostic performances. CONCLUSIONS SPECT, CMR, and PET all yielded a high sensitivity, while a broad range of specificity was observed. SPECT is widely available and most extensively validated; PET achieved the highest diagnostic performance; CMR may provide an alternative without ionizing radiation and a similar diagnostic accuracy as PET. We suggest that referring physicians consider these findings in the context of local expertise and infrastructure.


Hypertension | 2007

Self-measurement of blood pressure at home reduces the need for antihypertensive drugs: a randomized, controlled trial.

Willem J. Verberk; Abraham A. Kroon; Jacques W. M. Lenders; Alfons G. H. Kessels; Gert A. van Montfrans; Andries J. Smit; Paul-Hugo M. van der Kuy; Patricia J. Nelemans; Roger J. M. W. Rennenberg; Diederick E. Grobbee; Frank W. Beltman; Manuela A. Joore; Daniëlle E.M. Brunenberg; Carmen D. Dirksen; Theo Thien; Peter W. de Leeuw

It is still uncertain whether one can safely base treatment decisions on self-measurement of blood pressure. In the present study, we investigated whether antihypertensive treatment based on self-measurement of blood pressure leads to the use of less medication without the loss of blood pressure control. We randomly assigned 430 hypertensive patients to receive treatment either on the basis of self-measured pressures (n=216) or office pressures (OPs; n=214). During 1-year follow-up, blood pressure was measured by office measurement (10 visits), ambulatory monitoring (start and end), and self-measurement (8 times, self-pressure group only). In addition, drug use, associated costs, and degree of target organ damage (echocardiography and microalbuminuria) were assessed. The self-pressure group used less medication than the OP group (1.47 versus 2.48 drug steps; P<0.001) with lower costs (


BMC Health Services Research | 2008

Effects of intensive home visiting programs for older people with poor health status: A systematic review

Ans Bouman; Erik van Rossum; Patricia J. Nelemans; Gertrudis I. J. M. Kempen; Paul Knipschild

3222 versus


Journal of Magnetic Resonance Imaging | 2000

Three‐dimensional contrast‐enhanced moving‐bed infusion‐tracking (MoBI‐track) peripheral MR angiography with flexible choice of imaging parameters for each field of view

Tim Leiner; Kai Yiu J.A.M. Ho; Patricia J. Nelemans; Michiel W. de Haan; Joseph M.A. van Engelshoven

4420 per 100 patients per month; P<0.001) but without significant differences in systolic and diastolic OP values (1.6/1.0 mm Hg; P=0.25/0.20), in changes in left ventricular mass index (-6.5 g/m(2) versus -5.6 g/m(2); P=0.72), or in median urinary microalbumin concentration (-1.7 versus -1.5 mg per 24 hours; P=0.87). Nevertheless, 24-hour ambulatory blood pressure values at the end of the trial were higher in the self-pressure than in the OP group: 125.9 versus 123.8 mm Hg (P<0.05) for systolic and 77.2 versus 76.1 mm Hg (P<0.05) for diastolic blood pressure. These data show that self-measurement leads to less medication use than office blood pressure measurement without leading to significant differences in OP values or target organ damage. Ambulatory values, however, remain slightly elevated for the self-pressure group.


European Radiology | 2005

Contemporary imaging techniques for the diagnosis of renal artery stenosis

Tim Leiner; M.W. de Haan; Patricia J. Nelemans; J.M.A. van Engelshoven; G.B.C Vasbinder

BackgroundHome visiting programs have been developed aimed at improving the health and independent functioning of older people. Also, they intend to reduce hospital and nursing home admission and associated cost. A substantial number of studies have examined the effects of preventive home visiting programs on older people living in the community; the findings have been inconsistent. The objective of this review was to assess the effectiveness of intensive home visiting programs targeting older people with poor health or otherwise with functional impairments.MethodsA search for literature was based on included trials from four reviews on the effectiveness of home visits published after 2000 and on a database search of Cinahl, the Cochrane Central Register of Controlled Trials, Embase, Medline and PsycINFO from 2001 onwards. We also manually searched reference lists from potentially relevant papers. Randomized controlled trials were included assessing the effectiveness of intervention programs consisting of at least four home visits per year, an intervention duration of 12 months or more, and targeting older people (aged 65 years and over) with poor health. Two reviewers independently abstracted data from full papers on program characteristics and outcome measures; they also evaluated the methodological quality.ResultsThe search identified 844 abstracts; eight papers met the inclusion criteria. Seven trials were of sufficient methodological quality; none of the trials showed a significant favorable effect for the main analysis comparing the intervention group with the control group on mortality, health status, service use or cost. The inclusion of less-intensive intervention programs for frail older persons would not have exerted a great influence on the findings of our review.ConclusionWe conclude that home visiting programs appear not to be beneficial for older people with poor health within the health care setting of Western countries.


European Journal of Cancer | 2002

The role of ultrasonography as an adjunct to mammography in the detection of breast cancer. a systematic review.

Karin Flobbe; Patricia J. Nelemans; A.G.H. Kessels; Geerard L. Beets; M.F. von Meyenfeldt; J.M.A. van Engelshoven

A technique to image peripheral arteries with flexible choice of scan parameters for separate stations was developed based on moving‐bed single‐bolus three‐dimensional gradient‐recalled echo magnetic resonance angiography. A volunteer study yielded higher signal‐ and contrast‐to‐noise ratios, less venous enhancement, and better subjective interpretability compared with imaging with fixed parameters for each station. Additionally, six patients were imaged to test the feasibility of the new method in a clinical setting. Imaging peripheral arteries with the new technique in volunteers yielded better image quality and is feasible for patients. J. Magn. Reson. Imaging 2000;11:368–377.


Stroke | 2014

Diagnosing Intracranial Aneurysms With MR Angiography: Systematic Review and Meta-Analysis

Anna M. Sailer; Bart A.J.M. Wagemans; Patricia J. Nelemans; Rick de Graaf; Willem H. van Zwam

Renal artery stenosis (RAS) is a potentially curable cause of renovascular hypertension (RVH) and is caused by either atherosclerosis or fibromuscular dysplasia (FMD) in the vast majority of patients. Although intra-arterial digital subtraction angiography (IA-DSA) is still considered the standard of reference test for the anatomical diagnosis of RAS, noninvasive techniques such as MR angiography, CT angiography, and color-aided duplex ultrasonography are promising alternatives that also allow functional characterization of RAS. We provide an overview of these techniques and discuss their relative merits and shortcomings. Analysis of high-quality studies shows that both MR and CT angiography are significantly more accurate for the diagnosis of at least 50% atherosclerotic RAS than ultrasonographic techniques. The primary strength of ultrasonography at present is its suggested ability to predict functional recovery based on preinterventional resistance index measurements. A still unresolved issue is the detection of FMD. Because missing RVH may have serious consequences the most important requirement for a screening test is that it has high sensitivity.


Value in Health | 2010

The Impact of Differences in EQ-5D and SF-6D Utility Scores on the Acceptability of Cost-Utility Ratios: Results across Five Trial-Based Cost-Utility Studies

Manuela A. Joore; Danielle Brunenberg; Patricia J. Nelemans; Emiel F.M. Wouters; Petra Kuijpers; Adriaan Honig; Daniëlle C. M. Willems; Peter W. de Leeuw; Johan L. Severens; Annelies Boonen

The aim of this review was to summarise the diagnostic performance of ultrasonography as an adjunct to mammography in the detection of breast cancer and to identify clinical indications. A systematic review was performed of all publications in MEDLINE and EMBASE between 1990 and 2000 on the role of ultrasonography as an adjunct to mammography. 22 studies were included, showing a large variety of indications for ultrasonography and variations in the diagnostic performance of mammography and ultrasonography. There were six studies comparing a combined diagnosis of mammography and ultrasonography together with mammography alone, of which three studies had an increased sensitivity at the cost of a lower specificity. The methods of selecting the study population and interpretation of ultrasonography significantly influenced the diagnostic performance of mammography and ultrasonography relative to each other (P=0.003, P=0.03, respectively). Based on the studies reviewed, little evidence-based support was found to confirm the well recognised value of ultrasonography as an adjunct to mammography in the detection of breast cancer in clinical practice. Furthermore, no clinical indications for additional ultrasonography could be defined. The heterogeneity in the diagnostic performance in these studies may be explained by the methods of patient selection and ultrasonography interpretation, as well as by their poor quality.


Journal of Cardiothoracic Surgery | 2013

Preoperative thrombin generation is predictive for the risk of blood loss after cardiac surgery: a research article

Yvonne P.J. Bosch; Raed Al Dieri; Hugo ten Cate; Patricia J. Nelemans; Saartje Bloemen; Coenraad Hemker; Patrick W. Weerwind; Jos G. Maessen; Baheramsjah Mochtar

Background and Purpose— The aim of this study was to evaluate the sensitivity and specificity of MR angiography (MRA) in the diagnosis of ruptured and unruptured intracranial aneurysms. Methods— A systematic search was performed on 4 electronic databases on relevant articles that were published from January 1998 to October 2013. Inclusion criteria were met by 12 studies that compared MRA with digital subtraction angiography as reference standard. Two independent reviewers evaluated the methodological quality of the studies. Data from eligible studies were extracted and used to construct 2×2 contingency tables on a per-aneurysm level. Pooled estimates of sensitivity and specificity were calculated for all studies and subgroups of studies. Heterogeneity was tested, and risk for publication bias was assessed. Results— Included studies were of high methodological quality. Studies with larger sample size tended to have higher diagnostic performance. Most studies used time-of-flight MRA technique. Among the 960 patients assessed, 772 aneurysms were present. Heterogeneity with reference to sensitivity and specificity was moderate to high. Pooled sensitivity of MRA was 95% (95% confidence interval, 89%–98%), and pooled specificity was 89% (95% confidence interval, 80%–95%). False-negative and false-positive aneurysms detected on MRA were mainly located at the skull base and middle cerebral artery. Freehand 3-dimensional reconstructions performed by the radiologist significantly increased diagnostic performance. Studies performed on 3 Tesla showed a trend toward higher performance (P=0.054). Conclusions— Studies on diagnostic performance of MRA show high sensitivity with large variation in specificity in the detection of intracranial aneurysms.


European Radiology | 2009

Morphological MRI criteria improve the detection of lymph node metastases in head and neck squamous cell carcinoma: multivariate logistic regression analysis of MRI features of cervical lymph nodes

R. B. J. de Bondt; Patricia J. Nelemans; Frans C. H. Bakers; Jan Casselman; C. Peutz-Kootstra; B. Kremer; Paul A. M. Hofman; R.G.H. Beets-Tan

OBJECTIVE This article investigates whether differences in utility scores based on the EQ-5D and the SF-6D have impact on the incremental cost-utility ratios in five distinct patient groups. METHODS We used five empirical data sets of trial-based cost-utility studies that included patients with different disease conditions and severity (musculoskeletal disease, cardiovascular pulmonary disease, and psychological disorders) to calculate differences in quality-adjusted life-years (QALYs) based on EQ-5D and SF-6D utility scores. We compared incremental QALYs, incremental cost-utility ratios, and the probability that the incremental cost-utility ratio was acceptable within and across the data sets. RESULTS We observed small differences in incremental QALYs, but large differences in the incremental cost-utility ratios and in the probability that these ratios were acceptable at a given threshold, in the majority of the presented cost-utility analyses. More specifically, in the patient groups with relatively mild health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the EQ-5D to estimate utility. While in the patient groups with worse health conditions the probability of acceptance of the incremental cost-utility ratio was considerably larger when using the SF-6D to estimate utility. CONCLUSIONS Much of the appeal in using QALYs as measure of effectiveness in economic evaluations is in the comparability across conditions and interventions. The incomparability of the results of cost-utility analyses using different instruments to estimate a single index value for health severely undermines this aspect and reduces the credibility of the use of incremental cost-utility ratios for decision-making.

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Michiel W. de Haan

Maastricht University Medical Centre

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