Paul E. Sijens

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1H MR spectra obtained by chemical shift imaging (CSI) of contrast-enhancing brain tumors before and after the administration of Gd-contrast agent were quantitated and compared with the results in normal brain tissue included in the volume of interest. Twenty-seven combined magnetic resonance imaging and spectroscopy (MRI, MRS) examinations of brain tumor(More)
In the non-invasive determination of the liver iron concentration several validated MRI methods are available, two of which are compared in this study. Twenty-eight patients were examined by MRI and evaluated by the methods of Kreeftenberg et al. [Kreeftenberg Jr HG, Mooyaart EL, Huizenga JR, Sluiter WJ, Kreeftenberg Sr HG. Quantification of liver iron(More)
Primary progressive multiple sclerosis (ppMS; n=4) patients and controls (n=4) were examined by 1H magnetic resonance spectroscopy (MRS) and diffusion tensor imaging (DTI) in order to map choline (Cho), creatine and N-acetylaspartate (NAA), the fractional anisotropy (FA) and the apparent diffusion constant (ADC). After chemical shift imaging (point-resolved(More)
AIM To assess and correlate the lipid content of various organs in obese subjects and in persons with a normal body weight. METHODS Magnetic resonance spectroscopy and a previously validated gradient echo magnetic resonance imaging method with Dixon's two point technique were used in this study to quantify fat in liver, pancreas as well as kidney. (More)
Fifteen percent loss in the peak area of choline containing compounds (Cho) was recently observed in 1H MR spectra of contrast-enhancing tumor at 5-10 min after Gd-contrast administration [Magn. Reson. Med. 37:222-225, 1997]. In this study, chemical shift imaging (CSI, 1500/135 ms PRESS) was used to assess the spectral changes in 47 Gd-enhancing glial brain(More)
Magnetic resonance spectroscopy was used to assess the presence of brain lactate and lipid signals, frequently associated with the presence of pathology, in healthy persons of 60–90 years old (n=540). Lactate and lipid signals were observed in, respectively, 25 and 6% of women, and 18 and 2% of men. Upon adjustment for age, and for MRI-detected cerebral(More)
To determine whether quantitative multivoxel MRS improves the accuracy of MRI in the assessment of breast lesions. Twenty-five consecutive patients with 26 breast lesions ≥1 cm assessed as BI-RADS 3 or 4 with mammography underwent quantitative multivoxel MRS and contrast-enhanced MRI. The choline (Cho) concentration was calculated using the unsuppressed(More)
The high divergence between the liver metabolite concentrations and pH values reported in previous quantitative 31P magnetic resonance studies, for instance phosphomonoester (0.7-3.8 mM) and phosphodiester (3.5-9.7 mM), has not been addressed in the literature. To assess what level of discrepancy can be caused by processing and metabolite integration, in(More)
Clinical hepatic diffusion weighted imaging (DWI) generally relies on mono-exponential diffusion. The aim was to demonstrate that mono-exponential diffusion in the liver is contaminated by microperfusion and that the bi-exponential model is required. Nineteen fasting healthy volunteers were examined with DWI (seven b-values) using fat suppression and(More)
The purpose was to assess changes in lactate content and other brain metabolites under visual stimulation in optical chiasm, optic radiations and occipital cortex using multiple voxel MR spectroscopy (MRS). H chemical shift imaging (CSI) examinations of transverse planes centered to include the above structures were performed in four subjects at an echo(More)