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I Goethals

Publications and source records attributed to I Goethals.

At least 19 recordsLinked to original sources
PubMed2006

An adaptive input-output modeling approach for predicting the glycemia of critically ill patients.

In this paper we apply system identification techniques in order to build a model suitable for the prediction of glycemia levels of critically ill patients admitted to the intensive care unit. These patients typically show increased glycemia levels, and it has been shown that glycemia control by means of insulin therapy significantly reduces morbidity and mortality. Based on a real-life dataset from 15 critically ill patients, an initial input-output model is estimated which captures the insulin effect on glycemia under different settings. To incorporate patient-specific features, an adaptive modeling strategy is also proposed in which the model is re-estimated at each time step (i.e., every hour). Both one-hour-ahead predictions and four-hours-ahead simulations are executed. The optimized adaptive modeling technique outperforms the general initial model. To avoid data selection bias, 500 permutations, in which the patients are randomly selected, are considered. The results are satisfactory both in terms of forecasting ability and in the clinical interpretation of the estimated coefficients.

Aged↗
PubMed2006

Characteristics and profile of boys and girls with emotional and behavioural disorders in Flanders mental health institutes: a quantitative study.

BACKGROUND: In this article, we search for gender differences and outline a detailed gender profile for children and youngsters with emotional and behavioural disorders who are placed in Flemish residential care institutes. METHODS: Data were collected of all placements (517 children) in six residential and semi-residential mental health care centres for children and youngsters with emotional and behavioural disorders in East Flanders, Belgium. File data (gender, age, retention, current treatment, type of referral, education, intelligence, Diagnostic and Statistical Manual IV-diagnoses and medication use) were gathered. The Child Behaviour Check List (CBCL) was implemented and completed for each child. On the basis of the CBCL, a behaviour profile was developed by means of correlation tables (Pearson correlation coefficient) and cross tabulations. Finally, the profile was compared with the file data of the boys and the girls. RESULTS: Significant gender differences were found for type of referral, intelligence and diagnoses. The same profile was developed for both genders separately, based on variables Externalizing and Social Problems. The file data associated with the profile groups differ for boys and girls. CONCLUSIONS: The results of our study show the complexity and diversity of the needs of boys and girls with disruptive behaviour in Flemish residential care institutes. Flemish government has to be aware of the fact that the current referral system selects the children with outspoken externalizing and problematic behaviour towards special health care and special schools. They are relegated because the mainstream system is not equipped well enough to cope with their disruptive, aggressive behaviour. Even if governments are in favour of inclusive education, it seems that in practice a rest group is created, in which girls are selected through the same mechanisms as boys, in this case for the same reasons of negative externalizing behaviour and social problems. For this it seems appropriate that school and (semi)-residential institutes apply a specific and adapted methodology.

Adolescent↗
PubMed2006

Functional imaging, serotonin and the suicidal brain.

The involvement of the serotonergic system in the pathophysiology of suicidal behaviour has been established through indirect and direct research on serotonin and its metabolites and on serotonin transporters and receptors. Indirect research results include a reduced 5-HIAA in cerebrospinal fluid in violent suicide attempters and a blunted increase in prolactin after a fenfluramine challenge. Direct post-mortem research demonstrated an increase in 5-HT2A receptors. Direct in vivo functional imaging with PET or SPECT demonstrated a reduction in 5-HT2A binding index in suicide attempts in anxious and depressed suicide attempters and an increase in 5-HT2A binding in impulsive suicide attempters. These results are in keeping with 5-HT2A binding studies in depressed patients and impulsive animal research. Interestingly, both an increase and a decrease in 5-HT2A binding index seem to normalize with SSRI treatment.

Brain↗
PubMed2005

The effect of citalopram hydrobromide on 5-HT2A receptors in the impulsive-aggressive dog, as measured with 123I-5-I-R91150 SPECT.

PURPOSE: Involvement of the serotonergic system in impulsive aggression has been demonstrated in both human and animal studies. The purpose of the present study was to investigate the effect of citalopram hydrobromide (a selective serotonin re-uptake inhibitor) on the 5-HT(2A) receptor and brain perfusion in impulsive-aggressive dogs by means of single-photon emission computed tomography. METHODS: The binding index of the radioligand (123)I-5-I-R91150 was measured before and after treatment with citalopram hydrobromide in nine impulsive-aggressive dogs. Regional perfusion was measured with (99m)Tc-ethyl cysteinate dimer (ECD). Behaviour was assessed before treatment and again after 6 weeks of treatment. RESULTS: A correlation was found between decreased binding and behavioural improvement in eight out of nine dogs. The 5-HT(2A) receptor binding index was significantly reduced after citalopram hydrobromide treatment in all cortical regions but not in the subcortical area. None of the dogs displayed alterations in perfusion on the post-treatment scans. CONCLUSION: This study supports previous findings regarding the involvement of the serotonergic system in impulsive aggression in dogs in general. More specifically, the effect of treatment on the 5-HT(2A) receptor binding index could be demonstrated and the decreased binding index correlated with behavioural improvement.

Aggression↗
PubMed2004

Registration accuracy of 153Gd transmission images of the brain.

PURPOSE: The aim of the study was to determine the accuracy of non-rigid nine-parameter image registrations based on 153Gd transmission computed tomography (TCT) images as compared with those based on 99mTc-ethyl cysteinate dimer (ECD) images and to assess whether normalised mutual information (NMI) or count difference (CD) should be used. METHODS: TCT and ECD data were acquired in 25 randomly selected patients. Emission images were registered to an ECD template with a CD cost function. The same registration parameters were applied to the transmission images to create a TCT template. All TCT images were registered to the TCT template and the same registration parameters were applied to the ECD images. The procedure was repeated with NMI as cost function. Accuracy of both ECD-based and TCT-based registrations was assessed by comparing the normalisation parameter values and regional activities in the spatially normalised ECD images, using a mixed-model analysis of variance (ANOVA). Scheffe post hoc tests were performed. RESULTS: No significant differences were found between ECD/CD, ECD/NMI and TCT/CD, suggesting that ECD registration can be done with either CD or NMI, and that TCT registration using CD is equally as accurate as ECD registration. The accuracy of TCT registration with NMI was lower, with discrepancies occurring in the frontal inferior region and the cerebellum. The analysis of normalisation parameters indicated that z-scaling is underestimated and yz-rotation overestimated with TCT/NMI registration. CONCLUSION: We conclude that ECD registrations with CD or NMI are as accurate as TCT registrations with CD and that TCT registrations with NMI should be avoided.

Brain↗
PubMed2002

Leakage assessment in adjustable laparoscopic gastric banding: radiography versus (99m)Tc-pertechnetate scintigraphy.

The least invasive of all surgical weight-lowering procedures is the adjustable laparoscopic gastric banding (ALGB) technique. A rare complication (0.9%-1.8% of patients) but one that may require surgical revision is leakage of the gastric banding device. This paper reports on the usefulness of technetium-99m scintigraphy for the assessment of gastric band leaks as compared with radiography. Between March 1997 and October 2001, 23 obese patients (20 women and 3 men; mean age 35 years; range 23-60 years; mean body mass index before gastric banding procedure, 39.2 kg/m(2); range 29.3-52.1 kg/m(2)) were referred for exclusion of gastric banding leakage by means of radiography and (99m)Tc-pertechnetate scintigraphy. Both procedures were performed on the same day in all patients. Two patients underwent both procedures, respectively two and three times. A total of 27 radiographic and scintigraphic examinations were performed. Radiographs were judged positive for leakage when escape of contrast agent through a defect in the gastric banding device was visualised or when indirect criteria, e.g. smooth passage of barium suspension through the stoma after injection of contrast agent, were present. Scintigraphic images were judged positive when tracer disappearance out of the banding device and uptake in the thyroid gland as well as enhancement of the gastric mucosa were observed 30 min and/or 3 h post injection. Overall sensitivity, specificity and accuracy for radiography and (99m)Tc scintigraphy were 81.8% vs 81.8%, 75% vs 100% and 77.7% vs 92.6%. Leakage from the reservoir or the connecting tube is a late complication of ALGB. The presented data suggest that (99m)Tc-pertechnetate scintigraphy is more efficient than radiography in determining the presence of such leaks.

Adult↗
PubMed2002

The clinical value of nuclear medicine in the assessment of irradiation-induced and anthracycline-associated cardiac damage.

Two groups of patients, those treated for Hodgkin's disease and breast cancer, are particularly at risk of developing late myocardial damage, since radiotherapy (RT) techniques for both patient groups may include (large) parts of the heart, and adjuvant systemic therapy is frequently administered to these patients, in particular anthracycline-containing chemotherapy. Available literature on the monitoring and prediction of RT-induced and anthracycline-associated cardiac damage using nuclear medicine techniques is presented. Based on relevant studies, the risk of overall cardiac disease post-RT and overt congestive heart failure during anthracycline-containing chemotherapy is probably low. Conventional nuclear medicine imaging, i.e. myocardial perfusion scintigraphy, may be of complementary use to echocardiographical evaluation for routine follow-up after RT with modern techniques, in a subgroup of patients with known cardiovascular risk factors. Left ventricle ejection fraction (LVEF) measurements, as assessed by radionuclide angiography for the monitoring of anthracycline-associated cardiac injury, are not very sensitive and early detection will probably be enhanced by combining LVEF measurements with other cardiac function parameters. Also, it may be expected that nuclear medicine techniques using molecular radioligands will constitute an essential future step in the evaluation of subclinical cardiac injury afforded by the combined effect of RT and cardiotoxic chemotherapy.

Anthracyclines↗
PubMed2002

SPECT neuropsychological activation procedure with the Verbal Fluency Test in attempted suicide patients.

Performance on the Verbal Fluency Test, as a measure of the ability of initiating processes, is reduced in depressed suicidal patients. The hampered results in this prefrontal executive task parallel the reduction in prefrontal blood perfusion and metabolism in depressed subjects. A neuropsychological activation study with the verbal fluency paradigm could evaluate a possible blunted increase in perfusion in the prefrontal cortex in depressed suicidal patients. Twenty clinically depressed patients who had recently attempted suicide and 20 healthy volunteers were included in a single photon emission computed tomography (SPECT) split-dose activation study following a verbal fluency paradigm. Statistical parametric mapping was used to determine voxelwise significant changes. Differences in regional cortical activation between the letter fluency and category fluency tasks in attempted suicide patients were found. These patients showed a blunted increase in perfusion in the prefrontal cortex. Methodological restrictions concerning group uniformity, medication bias and subjective effort of the participants are discussed. Our findings indicate a blunted increase in prefrontal blood perfusion as a possible biological reason for reduced drive and loss of initiative in attempted suicide patients.

Adult↗
PubMed2001

99mTc-ECD brain perfusion SPET: variability, asymmetry and effects of age and gender in healthy adults.

Reliable and high-resolution reference data for regional cerebral blood flow measured with single-photon emission tomography (SPET) are necessary for optimal clinical and research use. Therefore, a large dataset of normal technetium-99m labelled ethylene cysteine dimer (ECD) perfusion SPET in carefully screened healthy volunteers with an age range spanning six decades was created, with correction for non-uniform attenuation and scatter and based on an anatomically standardised analysis. Eighty-nine healthy volunteers, stratified for gender (46 females, 43 males; age 20-81 years), were included. Twelve volunteers underwent repeated 99mTc-ECD SPET after 2.5+/-2.3 weeks. An automated whole-brain volume of interest analysis with MANOVA as well as voxelwise analysis using SPM99 was conducted. Average intersubject variability was 4.8% while intrasubject reproducibility was 3.0%. An age-related decline in tracer uptake was found in the anterior cingulate gyrus, bilateral basal ganglia, left prefrontal, left lateral frontal and left superior temporal and insular cortex (all P=0.001-0.02). There was an overall increase in right/left asymmetry with age, which was most pronounced in the frontal and temporal neocortex. The most significant correlations between AI and age decade were found in the prefrontal (R=0.35, P=0.001) and superior temporal neocortex (R=0.43, P<0.001). Women had significantly higher uptake in the right parietal cortex (P<0.001), while men showed higher uptake in the cerebellum and the left anterior temporal and orbitofrontal cortex (all P<0.01). This normative dataset allows age- and gender-specific patient and group assessment of 99mTc-ECD perfusion SPET under a wide variety of clinical circumstances in relation to normal variations and highlights the importance of both age- and gender-specific normal datasets for optimal analysis sensitivity.

Adult↗
PubMed2001

The classical stroop interference task as a prefrontal activation probe: a validation study using 99Tcm-ECD brain SPECT.

This study investigated the feasibility of brain single photon emission computed tomography (SPECT) functional imaging in a neuropsychological test setting, following a single-day protocol with a split-dose paradigm. The Stroop Color Word Test (SCWT) is an example of a well-documented prefrontal activation task. In a split-dose protocol, ten right-handed healthy volunteers were injected twice with 370 MBq 99Tcm-ethyl cysteinate dimer while performing consecutively both series of card-reading of the SCWT. Images were reconstructed using filtered back-projection and normalized to a standard template in Talairach coordinates. Statistical Parametric Mapping (SPM96) was used to determine voxelwise significant changes. A first activation cluster was found in the left medial prefrontal cortex, consisting of the gyrus cinguli anterior and the gyrus frontalis medius and superior. A second activation cluster included the right gyrus frontalis dorsalis and medius. These findings confirm to a large extent the results of previous functional magnetic resonance imaging, positron emission tomography studies of Stroop-like tasks. The choice and validity of various methodological characteristics of the experimental design leading to these results is critically discussed. It is concluded that brain SPECT activation with the Stroop Color Word Test under standard neuropsychological conditions in healthy volunteers, is both technically and practically feasible.

Adult↗
PubMed2001

Guidelines for brain radionuclide imaging. Perfusion single photon computed tomography (SPECT) using Tc-99m radiopharmaceuticals and brain metabolism positron emission tomography (PET) using F-18 fluorodeoxyglucose. The Belgian Society for Nuclear Medicine.

The purpose of these guidelines is to assist nuclear medicine practitioners in recommending, performing, interpreting, and reporting the results of brain perfusion SPECT studies using Tc-99m radiopharmaceuticals and brain metabolism PET studies using F-18 fluorodeoxyglucose (FDG). These guidelines have been adapted and extended from those produced by the Society of Nuclear Medicine (Juni et al., 1998) and the European Association of Nuclear Medicine by a Belgian group of experts in the field trained in neurology and/or nuclear medicine. Some indications are not universally approved (e.g. brain death), but largely supported by the literature. They have been included in these guidelines in order to provide recommendations and a standardised protocol.

Acetazolamide↗
PubMed1999

Vagus nerve stimulation for medically refractory epilepsy; efficacy and cost-benefit analysis.

INTRODUCTION: Vagus nerve stimulation is a novel treatment for patients with medically refractory epilepsy, who are not candidates for conventional epilepsy surgery, or who have had such surgery without optimal outcome. To date only studies with relatively short follow-up are available. In these studies efficacy increased with time and reached a maximum after a period of 6 to 12 months. Implantation of a vagus nerve stimulator requires an important financial investment but a cost-benefit analysis has not been published. PATIENTS AND METHODS: Our own experience with VNS in Gent comprises 15 patients with mean age of 29 years (range: 17-44 years) and mean duration of epilepsy of 18 years (range: 4-32 years). All patients underwent a comprehensive presurgical evaluation and were found not to be suitable candidates for resective epilepsy surgery. Mean post-implantation follow-up is 24 months (range: 7-43 months). In patients with follow-up of at least one year, efficacy of treatment in terms of seizure control and seizure severity was assessed one year before and after the implantation of a vagus nerve stimulator. Epilepsy-related direct medical costs (ERDMC) before and after the implantation were also compared. RESULTS: A mean reduction of seizure frequency from 14 seizures/month (range: 2-40/month) to 8 seizures/month (range: 0-30/month) was achieved (Wilcoxon signed rank test n = 14; p = 0.0016). Five patients showed a marked seizure reduction of > or = 50%; 6 became free of complex partial seizures, 3 of whom became entirely seizure free for more than 12 months; 2 patients had a worthwhile reduction of seizure frequency between 30-50%; in 2 patients seizure frequency reduction has remained practically unchanged. Seizure freedom or > or = 50% seizure reduction was achieved within the first 4 months after implantation in 6/11 patients. Before the implantation, the mean yearly epilepsy-related direct medical costs per patient were estimated to be 8830 US$ (n = 13; range: 1879-31,129 US$; sd = 7667); the average number of hospital admission days per year was 21 (range: 4-100; sd = 25.7). In the 12 months after implantation, ERDMC had decreased to 4215 US$ (range: 615-11,794 US$; sd = 3558) (Wilcoxon signed rank test n = 13; p = 0.018) and the average number of admission days to 8 (range: 0-35) (Wilcoxon signed rank test n = 13; p = 0.023). CONCLUSION: VNS is an effective treatment of refractory epilepsy and remains effective during long-term follow-up. Cost-benefit analysis suggests that the cost of VNS is saved within two years following implantation.

Adolescent↗