Eelco L.W. Giele

Eindhoven University of Technology

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Jacques A. den Boer

Eindhoven University of Technology

Arie Hasman

Amsterdam University Medical Centers

Jos M. A. van Engelshoven

Maastricht University

Jacobus A. de Priester

Zaans Medisch Centrum

Maarten H. L. Christiaans

Maastricht University

Alphons G.H. Kessels

Maastricht University Medical Centre

J. A. Blom

University of Twente

J.A. de Priester

Maastricht University

M. J. A. M. Geerlings

University Medical Center Utrecht

Hans P. van Hooff

Maastricht University Medical Centre

Cooperative Institutions

Maastricht University Medical Centre

Maastricht University

Eindhoven University of Technology

University Medical Center

Academic Medical Center

Catharina Ziekenhuis

Radboud University Nijmegen

University Medical Center Utrecht

Transnational University Limburg

University Surgical Associates

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Evaluation of two cortical fraction estimation algorithms for the calculation of dynamic magnetic resonance renograms

Computer Methods and Programs in Biomedicine (2002)

Eelco L.W. Giele Jacobus A. de Priester J. A. Blom Jacques A. den Boer Jos M. A. van Engelshoven

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10.1016/s0169-2607(01)00119-5

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Citations (4)

Reduction of noise in medullary renograms from dynamic MR images

Journal of Magnetic Resonance Imaging (2000)

Eelco L.W. Giele J.A. de Priester J. A. Blom Jacques A. den Boer Jos M. A. van Engelshoven

Dynamic magnetic resonance images of the kidney can be used to acquire separate renograms of the cortex and medulla. A high-quality cortical renogram can be determined directly from a region of interest (ROI) placed in the cortex. Due to partial volume effects, part of the signal from a ROI placed in the medulla is caused by cortical tissue. By subtracting a fraction of the cortical signal from the cortico-medullary signal, a purer medullary renogram can be obtained. A side effect of this subtraction is an increase in noise level. The noise level increases with larger partial volume fractions. Using a matched image filter, it is possible to exclude those areas from the ROI that have a high partial volume content, thus reducing the amount of cortical signal that has to be separated from the medullary signal. Noise reductions of up to 50% have been achieved in the medullary renogram, with an average reduction of 23%.

Medulla

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Partial volume

SIGNAL (programming language)

Region of interest

10.1002/(sici)1522-2586(200002)11:2<149::aid-jmri11>3.0.co;2-3

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Movement correction of the kidney in dynamic MRI scans using FFT phase difference movement detection

Journal of Magnetic Resonance Imaging (2001)

Eelco L.W. Giele J.A. de Priester J. A. Blom Jacques A. den Boer Jos M. A. van Engelshoven

Abstract To measure cortical and medullary MR renograms, regions of interest (ROIs) are placed on the kidney in images acquired using dynamic MRI. Since native kidneys move with breathing, and breath‐holding techniques are not feasible, movement correction is necessary. In this contribution we compare three correction methods, based on image matching, phase difference movement detection (PDMD), and cross‐correlation, respectively. The PDMD‐based method showed the best performance and was able to determine kidney movement in our test series in 68% of the scans with no visible deviation, and in 88% of the scans if a one‐pixel deviation is considered acceptable. J. Magn. Reson. Imaging 2001;14:741–749. © 2001 Wiley‐Liss, Inc.

Region of interest

Dynamic Contrast-Enhanced MRI

10.1002/jmri.10020

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Citations (34)

MR renography by semiautomated image analysis: Performance in renal transplant recipients

Journal of Magnetic Resonance Imaging (2001)

Jacobus A. de Priester Alphons G.H. Kessels Eelco L.W. Giele Jacques A. den Boer Maarten H. L. Christiaans

We evaluated a method of semiautomated analysis of dynamic MR image series in renal transplants. Nine patients were studied twice, with an average time interval of 7 days. MR examination consisted of a run of 256 T1-weighted coronal scans (GE; TR/TE/flip: = 11/3.4/60 degrees; slice thickness = 6 mm; temporal resolution = 2 seconds). Gadolinium-DTPA (0.05 mmol/kg) was injected with an injector pump (5 ml/seconds). MR renographs of the cortex and medulla were obtained by segmentation of the renal transplant and placement of two regions of interest (ROIs) overlying the peripheral and central renal parenchyma. In the first 100 frames of the renographs, analysis of variance (ANOVA) demonstrated significant intraclass correlation coefficients with mean values for the cortex and medulla of 0.47 and 0.59, respectively. We conclude that the procedure is a robust technique that generates meaningful signal curves.

Renal cortex

10.1002/jmri.1163

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Citations (48)

Automated quantitative evaluation of diseased and nondiseased renal transplants with MR renography

Journal of Magnetic Resonance Imaging (2002)

Jacobus A. de Priester Jacques A. den Boer Maarten H. L. Christiaans Alphons G.H. Kessels Eelco L.W. Giele

To present a method of automated parametric quantification of dynamic MR enhancement curves of renal transplants and evaluate the disease-discriminating properties of the resulting MR renography (MRR) data.This study included 27 patients with nondiseased renal transplants and eight patients with diseased renal transplants. The examination was repeated in 10 patients and the reproducibility of the enhancement parameters was estimated by analysis of variance (ANOVA). The disease-discriminating properties of the transplant volumes and enhancement parameters were tested with t-tests and logistic regression analysis.The enhancement parameters were reproducible. The mean medullary nephronal washout rate (lambda1) and cortical arterial blood volume (mu0) were lower in diseased renal transplants. The combination of these parameters was a strong predictor of renal transplant disease (area under ROC curve 0.98; 95% confidence interval 0.96-1.0).Automated parametric quantification of cortical and medullary enhancement is feasible and allows the accurate detection of nonsurgical disease in renal transplants by MRR.

10.1002/jmri.10217

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Citations (23)

MR renography: An algorithm for calculation and correction of cortical volume averaging in medullary renographs

Journal of Magnetic Resonance Imaging (2000)

Jacobus A. de Priester Jacques A. den Boer Eelco L.W. Giele Maarten H. L. Christiaans Alphons G.H. Kessels

We evaluated a mathematical algorithm for the generation of medullary signal from raw dynamic magnetic resonance (MR) data. Five healthy volunteers were studied. MR examination consisted of a run of 100 T1-weighted coronal scans (gradient echo; TR/TE 11/3.4 msec, flip angle 60°; slice thickness 6 mm; temporal resolution 2 seconds). Gadolinium-diethylene triamine pentaacetic acid (DTPA; 0.05 mmol/kg) was injected with an injector pump (5 ml/sec). Medullary MR renographs (MRRs) were calculated for regions of interest with strong and moderate cortical volume averaging (CVA). A reference medullary MRR, devoid of CVA, was obtained. Percentual signal differences between calculated and reference medullary MRRs were estimated for each consecutive scan. Run averaged values of these differences were calculated. Mean values, after subtraction of the resting state signal, were +0.2% (SD 9.7%) and +0.7% (SD 9.0%) for areas with strong and moderate CVA, respectively. We conclude that with this algorithm reliable extraction of medullary MRRs is feasible, providing a unique tool for clinical evaluation of medullary disease. J. Magn. Reson. Imaging 2000;12:453–459. © 2000 Wiley-Liss, Inc.

Flip angle

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10.1002/1522-2586(200009)12:3<453::aid-jmri11>3.0.co;2-z

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Citations (17)