Filip Claus

Universitair Ziekenhuis Leuven, Louvain, Flanders, Belgium

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Publications (69)215.38 Total impact

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    ABSTRACT: Objectives To assess the relationship between the position of the stomach and the volume of herniated organs into the thorax, and the observed-to-expected total fetal lung volume (o/e TFLV), which is a measure of pulmonary hypoplasia in fetuses with isolated left sided congenital diaphragmatic hernia (LCDH).Methods Single-center study on archived MR images of fetuses evaluated for isolated LCDH over an 11-year period. We retrieved the gestational age at MR examination, the o/e TFLV and liver position. Images were also reviewed to retrospectively determine the position of the stomach as well as the proportion of the volume of fetal liver, stomach and other viscera into the thorax, to the total thorax volume. The latter measurements were done by a single operator. Following confirmation of reproducibility, we correlated intra-thoracic organ volumes and stomach position to the o/e TFLV.Results205 fetuses underwent 259 MR examinations. The reproducibility of organ volume measurements was excellent (range of ICC: 0.928-0.997). The average time spent on each intra-thoracic organ volume ranged from 2.28-5.13 min. From all herniated organs, the liver-to-thoracic volume ratio (LiTR) correlated best to o/e TFLV (R = −0.429, p < 0.0001). Stomach volume did not correlate though as a categorical variable, the position of the stomach was inversely related to the o/e TFLV.Conclusions We observed an inverse relationship between lung volume and the amount of liver herniated as well as the position of the stomach into the chest.
    Ultrasound in Obstetrics and Gynecology 10/2014; · 3.56 Impact Factor
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    ABSTRACT: Objective To report a recent update on fetuses with right-sided congenital diaphragmatic hernia (RCDH) in the era of fetal surgery.DesignRetrospective review of prospectively collected data.SettingFetal treatment centres in Leuven and Barcelona.PopulationConsecutive cases of RCDH between 2002 and 2012.Methods Data on prenatal imaging, genetic testing, pregnancy and neonatal outcomes were extracted from our databases, including structural and genetic anomalies, candidate outcome predictors such as lung size, liver herniation ratio, polyhydramnios, cervical length, preterm prelabour rupture of membranes and gestational age at birth.Main outcome measuresSurvival and oxygen dependency at discharge.ResultsTen out of 86 fetuses with RCDH had associated abnormalities. Of 76 isolated pregnancies, eight women opted for termination of pregnancy, most with severe hypoplasia and one was lost to follow up. Nineteen pregnancies were expectantly managed and delivered at a mean gestational age of 36.0 ± 3.0 weeks. Survival at discharge was 53% (10/19), one being oxygen dependent. In the fetal surgery group (n = 48), mean gestational age at delivery was 34.5 ± 3.0 weeks. In our recent experience not previously published (n = 23) survival rate was 52 and 39% were oxygen dependent at discharge. Pooling these data with earlier reported observations by our group we observed a 42% survival rate in 57 fetuses. Lung size on magnetic resonance imaging and an interval of >24 hours between reversal of tracheal occlusion and delivery were predictors of outcome.Conclusions Right-sided CDH seems to have a poorer outcome than that reported for fetuses with left-sided CDH with similar lung size before birth. Survival rates after expectant management with observed/expected lung-to-head ratio values ≤45 and ≤30% were 17 and 0%, respectively. In those undergoing fetal surgery (observed/expected lung-to-head ratio ≤45%) there was an apparent increase (42%).
    BJOG An International Journal of Obstetrics & Gynaecology 09/2014; · 3.76 Impact Factor
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    ABSTRACT: The purpose of this study was to retrospectively assess the incidence of bowel wall oedema on computed tomography (CT) in patients with renal cell carcinoma (RCC) treated with sunitinib, and to investigate its association with diarrhoea.
    European Radiology 08/2014; · 4.34 Impact Factor
  • L Bonne, M Bex, R Oyen, F Claus
    05/2014; 97(3):193-4.
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    ABSTRACT: Objective To determine the bias induced by matching fetuses by gestational age (GA) or by fetal body volume (FBV) when calculating the observed/expected total fetal lung volume (o/e TFLV) in isolated congenital diaphragmatic hernia (CDH). Methods Single-center, retrospective study on archived magnetic resonance (MR) images of isolated CDH fetuses over a 10-year's period. We retrieved the TFLV, GA and o/e TFLVGA, delineated FBV to obtain TFLVFBV. We correlated o/e TFLVFBV and o/e TFLVGA by Bland Altman analysis. All outliers were manually identified to retrieve specific clinical features. Results377 MR examinations from 225 fetuses were identified. The average time spent on FBV measurement was 16.12 ± 4.95 min. Reproducibility of FBV measurement was 0.998 and the interobserver intraclass correlation coefficient was 0.999. FBV was highly correlated with GA (R = 0.94, p < 0.0001). There was a good agreement between o/e TFLVGA or o/e TFLVFBV, with a mean difference = −1.10% and 95%-limits-of-agreement of −8.58 to 6.39. There were no outliers in fetuses that had an o/e TFLV<25%. Discrepancies induced by different methods were more likely in woman with BMI≥25 kg/m2 (+16.49%), fetuses with an estimated fetal weight (EFW)≤10th percentile (+21.33%) or EFW>90th percentile (+14.82%). Conclusions Discrepancies are more likely in fetuses with an abnormal EFW or in overweighted mothers. The clinical relevance of using FBV rather than GA for calculation of the o/e TFLV might be limited, as there was no discrepancy between both methods in fetuses with small lungs (<25%), the group of interest for lung volume assessment.
    Ultrasound in Obstetrics and Gynecology 03/2014; · 3.56 Impact Factor
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    ABSTRACT: Our aim was to analyze the apparent contraction of meshes in vivo after abdominal wall reconstruction and evaluate histological and biomechanical properties after explantation. Nine New Zealand female rabbits underwent repair of two full-thickness 25 × 30-mm midline defects in the upper and lower parts of the abdomen. These were primarily overlaid by 35 × 40-mm implants of a polyvinylidene fluoride (PVDF) DynaMesh (n = 6) or polypropylene meshes Ultrapro (n = 6) and Marlex (n = 6). Edges of the meshes were secured with iron(II,III) oxide (Fe3O4)-loaded PVDF sutures. Magnetic resonance images (MRIs) were taken at days 2, 30 and 90 after implantation. The perimeter of the mesh was traced using a 3D spline curve. The apparent surface area or the area within the PVDF sutures was compared with the initial size using the one-sample t test. A two-way repeat analysis of variance (ANOVA) was used to compare the apparent surface area over time and between groups. PVDF meshes and sutures with Fe3O4 could be well visualized on MRI. DynaMesh and Marlex each had a 17 % decrease in apparent surface area by day 2 (p < 0.001 and p = 0.001), respectively, which persisted after day 90. Whereas there was a decrease in apparent surface area in Ultrapro, it did not reach significance until day 90 (p = 0.01). Overall, the apparent surface area decreased 21 % in all meshes by day 90. No differences in histological or biomechanical properties were observed at day 90. There was a reduction in the apparent surface area between implantation and day 2, indicating that most mesh deformation occurs prior to tissue in-growth.
    International Urogynecology Journal 01/2014; · 2.17 Impact Factor
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    ABSTRACT: Postmortem MRI (pmMRI) is increasingly used in perinatology, typically as an alternative or complement to conventional necropsy for central nervous system anomalies. Overall it provides reliable information on structural malformations, but was shown to be of limited use in examining fetal heart. We aimed to assess the fetal heart on 3-Tesla pmMRI in a consecutive series of fetuses with structural congenital heart defects (CHD) and to determine diagnostic evaluation limits in case of CHD. A single center database was retrospectively reviewed. Only fetuses having CHD of functional significance were included. Fetal cardiac anatomy was assessed on T2-weighted 3D multiplanar reconstructed images acquired using isovolumetric voxel size (0.3-0.8mm(3) ) that allows to visualize cardiac structures in situ in multiple fetal body planes. Cardiac pathology was classified into complex and isolated CHD. Based on clinically relevant findings pmMRI was considered either diagnostic or not diagnostic. A total of 24 fetuses were included in this study. The median gestational age (GA) was 22weeks and 2days (range 12w5d-34w6d). The median delay between delivery of the fetus and MR was 6hours30minutes (range 1h30min-19h). PmMRI was diagnostic for 12 out of 13 (92.3%) complex-CHD and for six out of eleven (54.5%) isolated-CHD. In case of valvular malformation a tentative diagnosis was reached in 7/11 cases (64%) based on indirect features. Postmortem MRI is a valid diagnostic tool for CHD in fetuses beyond 16 weeks up to term. This article is protected by copyright. All rights reserved.
    Prenatal Diagnosis 11/2013; · 2.68 Impact Factor
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    ABSTRACT: The intrarenal resistive index is routinely measured in many renal-transplantation centers for assessment of renal-allograft status, although the value of the resistive index remains unclear. In a single-center, prospective study involving 321 renal-allograft recipients, we measured the resistive index at baseline, at the time of protocol-specified renal-allograft biopsies (3, 12, and 24 months after transplantation), and at the time of biopsies performed because of graft dysfunction. A total of 1124 renal-allograft resistive-index measurements were included in the analysis. All patients were followed for at least 4.5 years after transplantation. Allograft recipients with a resistive index of at least 0.80 had higher mortality than those with a resistive index of less than 0.80 at 3, 12, and 24 months after transplantation (hazard ratio, 5.20 [95% confidence interval {CI}, 2.14 to 12.64; P<0.001]; 3.46 [95% CI, 1.39 to 8.56; P=0.007]; and 4.12 [95% CI, 1.26 to 13.45; P=0.02], respectively). The need for dialysis did not differ significantly between patients with a resistive index of at least 0.80 and those with a resistive index of less than 0.80 at 3, 12, and 24 months after transplantation (hazard ratio, 1.95 [95% CI, 0.39 to 9.82; P=0.42]; 0.44 [95% CI, 0.05 to 3.72; P=0.45]; and 1.34 [95% CI, 0.20 to 8.82; P=0.76], respectively). At protocol-specified biopsy time points, the resistive index was not associated with renal-allograft histologic features. Older recipient age was the strongest determinant of a higher resistive index (P<0.001). At the time of biopsies performed because of graft dysfunction, antibody-mediated rejection or acute tubular necrosis, as compared with normal biopsy results, was associated with a higher resistive index (0.87 ± 0.12 vs. 0.78 ± 0.14 [P=0.05], and 0.86 ± 0.09 vs. 0.78 ± 0.14 [P=0.007], respectively). The resistive index, routinely measured at predefined time points after transplantation, reflects characteristics of the recipient but not those of the graft. (ClinicalTrials.gov number, NCT01879124 .).
    New England Journal of Medicine 11/2013; 369(19):1797-806. · 54.42 Impact Factor
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    ABSTRACT: A mathematical model to estimate membrane tensions (Mt) at the urogenital hiatus and midpelvis in patients with and without prolapse is proposed. For that purpose the complex structures of the pelvic floor were simplified and, based on assumptions concerning geometry and loading conditions, Laplace's law was used to calculate Mt. The pelvic cavity is represented by an ellipsoid in which the midpelvic and hiatal sections are described by an ellipse. The downwards forces within the pelvis (Fin) are in equilibrium with the support forces within its walls (Fw). Fin is the abdominal pressure (PABD) multiplied by the area A of the ellipse. The force inside the tissues (Fw) is distributed along the circumference of the ellipse C. The Mt can be approximated as Mt = (PABD.A)/C (N/m). Mt-α accounts for the angle α which describes tissue orientation with respect to the anatomical section and is calculated as Mt-α = Mt/sin(α). We conducted a retrospective study on archived magnetic resonance imaging scans (n = 20) and ultrasound images in patients with (n = 50) or without prolapse (n = 50) and measured actual geometrical variables. PABD was measured in patients with and without prolapse (n = 20). Mt at the urogenital hiatus at rest is 0.35 N/cm. They significantly increase with the Valsalva manoeuvre, by a factor of 2.3 (without prolapse) to 3.6 (with prolapse). Calculated Mt are much lower than what is reported for the abdominal cavity. Prolapse patients have significantly larger Mt, which during the Valsalva manoeuvre increase more than in healthy subjects.
    International Urogynecology Journal 10/2013; · 2.17 Impact Factor
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    ABSTRACT: With this pictorial essay we aimed to provide gestational age specific reference ranges of relevant fetal structures using micro- ultrasound, as well as its correlation with postmortem MRI and whole body sections. Time-mated pregnant rabbits (n = 24) were assessed once at various gestational ages in the second half of pregnancy (15, 17, 21-23, 25-28 and 30-31 days; term = 31 days). We obtained biometric data, together with Doppler flow patterns in the ductus venosus (DV), umbilical artery (UA) and umbilical vein. After euthanasia, micro-ultrasound images were compared with images obtained by 9.4 Tesla MRI and whole body paraffin sections at 15,23,26 and 28 days. We constructed biometric normative curves, which showed a significant correlation with gestational age. The pulsatility index (PI) in the UA decreased with gestation (PI = 5.746 - 0.2969(GA) + 0.004931(GA)(2) ; R(2) = 0.30), whereas pulsatility index for veins (PIV) in the DV remained constant (median PIV = 0.82 (0.60-1.12)). In this report we provide an anatomical atlas of fetal thoracic development using both micro-ultrasound and MRI. We describe anatomical fetal leporine development as can be visualized by micro-ultrasound and MR imaging. The reported reference ranges may be useful for researchers using the fetal rabbit model. This article is protected by copyright. All rights reserved.
    Prenatal Diagnosis 10/2013; · 2.68 Impact Factor
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    ABSTRACT: Preclinical and histological data show overexpression of the type 1 cannabinoid receptor (CB1R) in prostate carcinoma (PCa). In a prospective study, the feasibility of 18F-MK-9470 positron emission tomography (PET) imaging in patients with primary and metastatic PCa was evaluated. Eight patients were included and underwent 18F-MK-9470 PET/CT imaging. For five patients with primary PCa, dynamic PET/CT imaging was performed over three acquisition intervals (0 to 30, 60 to 90 and 120 to 150 min post-injection). In malignant and benign prostate tissue regions, time activity curves of the mean standardized uptake value (SUVmean) were determined as well as the corresponding area under the curve to compare 18F-MK-9470 uptake over time. Muscle uptake of 18F-MK-9470 was used as reference for non-specific binding. Magnetic resonance imaging (MRI) was used as anatomical reference and for delineating intraprostatic tumours. Histological and immunohistochemical (IHC) examination was performed on the whole-mount histopathology sections of four patients who underwent radical prostatectomy to assess the MRI-based tumour versus benign tissue classification. For three patients with proven advanced metastatic disease, two static PET/CTs were performed 1 and 3 h post-injection. 18F-MK-9470 uptake was evaluated in bone lesions of metastatic PCa by comparing SUVmean values of metastases with these of the contralateral bone tissue. F-MK-9470 uptake was significantly higher in benign and malignant prostate tissue compared to muscle, but it did not differ between both prostate tissue compartments. IHC findings of corresponding prostatic histopathological sections indicated weak CB1R expression in locally confined PCa, which was not visualized with 18F-MK-9470 PET. Metastases in the axial skeleton could not be detected while some metastases in the appendicular skeleton showed higher 18F-MK-9470 uptake as compared to the uptake in contralateral normal bone. F-MK-9470 PET could not detect local PCa or bone metastases in the axial skeleton but was able to visualize metastases in the appendicular skeleton. Based on these pilot observations, it seems unlikely that CB1R PET will play a significant role in the evaluation of PCa.
    EJNMMI research. 08/2013; 3(1):59.
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    ABSTRACT: In this manuscript we report 3 cases of severe lower urinary tract obstruction diagnosed before 20 weeks of pregnancy. All cases had a very similar prenatal presentation with a megacystis, bilateral hydro-ureteronephrosis and increased echogenicity of the kidneys. High-resolution postmortem magnetic resonance imaging (MRI), following termination of pregnancy, enabled accurate investigation of the underlying cause of the urinary tract obstruction, by depicting the presence of an urethral valve, urethral atresia and cloacal dysgenesis. Postmortem fetal MRI provides high anatomical detail and is very suitable to investigate congenital anomalies of the lower urinary tract. In case (timely or consented) conventional autopsy is not possible, MRI is an excellent alternative.
    Fetal Diagnosis and Therapy 06/2013; · 2.30 Impact Factor
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    ABSTRACT: Diabetic muscle infarction is a rare microangiopathic complication occurring in patients with advanced diabetes mellitus. Diabetic patients with chronic kidney disease stage Vd are prone to develop this complication. The presenting symptom is a localized painful swelling of the affected limb. Symptoms usually resolve spontaneously during the following weeks, but frequent relapse can occur and in some cases swelling may lead to compartment syndrome. Biochemical blood analyses show an elevated C-reactive protein, but creatine kinase is often normal. Diagnosis can be made on clinical presentation and imaging, with magnetic resonance imaging as the gold standard. Histology is often not contributive. Treatment consists of rest, analgesics, rigorous glycemic control and low-dose aspirin. Severe cases of compartment syndrome require fasciotomy. In the current paper, we present two diabetic patients with cystic fibrosis, who are treated with automated peritoneal dialysis and suffered from episodic lower limb infarction. We subsequently review 48 episodes of diabetic muscle infarction previously reported in the literature in patients with end-stage renal disease.
    Case Reports in Nephrology. 05/2013; 2013.
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    ABSTRACT: OBJECTIVE: To report on the feasibility of assessing cardiac structures on post-mortem 3-tesla MRI (pmMRI) and to provide morphometric data in fetuses without cardiac abnormalities. METHODS: Retrospective single center study on 3T pmMRI of 39 consecutive fetuses without cardiac abnormalities (13-38 weeks of gestation). Fetal cardiac anatomy was assessed and measurements of cardiac structures were performed on T2-weighted 3D multiplanar reconstructed images. Linear regression analysis was performed to examine changes of cardiac dimensions during gestation. RESULTS: The four-chamber view of the fetal heart could be obtained and the measurements of cardiac chambers and ventricular walls could be performed in all 39 cases. The aorta and the pulmonary artery were visualized and their diameters were measured in 38 (97.4%) fetuses, ductus arteriosus in 32 (82%). All measurements showed strong linear correlation with gestational age. The relationship of the diameters of the pulmonary artery, aorta, and ductus arteriosus remained constant over pregnancy. All these observations are consistent with what is known from prenatal ultrasound. CONCLUSIONS: The present study proves the feasibility of visualizing normal cardiac structures on 3-tesla pmMRI in fetuses beyond 14 weeks. We provide morphometric data that may enable diagnostic evaluation of cardiac abnormalities on pmMRI. © 2013 John Wiley & Sons, Ltd.
    Prenatal Diagnosis 03/2013; · 2.68 Impact Factor
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    ABSTRACT: We report the prenatal sonographic detection of a fetus with megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly. Only 14 patients have been reported in the literature so far, all but one were diagnosed postnatally. The polymicrogyria in the frontoparietal lobe was confirmed by prenatal magnetic resonance imaging. Additionally, a hypoplastic thymus as seen in a 22q11 deletion was present. Although polymicrogyria along with pre-axial polydactyly has been described in 22q11 deletion, the diagnosis of Di George syndrome was ruled out. The etiology of megalencephaly, polymicrogyria, postaxial polydactyly and hydrocephaly has not been revealed yet. A dominant as well as recessive inheritance has been suggested. © 2013 John Wiley & Sons, Ltd.
    Prenatal Diagnosis 01/2013; · 2.68 Impact Factor
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    ABSTRACT: Purpose: From independently conducted free-response receiver operating characteristic (FROC) and receiver operating characteristic (ROC) experiments, to study fixed-reader associations between three estimators: the area under the alternative FROC (AFROC) curve computed from FROC data, the area under the ROC curve computed from FROC highest rating data, and the area under the ROC curve computed from confidence-of-disease ratings.Methods: Two hundred mammograms, 100 of which were abnormal, were processed by two image-processing algorithms and interpreted by four radiologists under the FROC paradigm. From the FROC data, inferred-ROC data were derived, using the highest rating assumption. Eighteen months afterwards, the images were interpreted by the same radiologists under the conventional ROC paradigm; conventional-ROC data (in contrast to inferred-ROC data) were obtained. FROC and ROC (inferred, conventional) data were analyzed using the nonparametric area-under-the-curve (AUC), (AFROC and ROC curve, respectively). Pearson correlation was used to quantify the degree of association between the modality-specific AUC indices and standard errors were computed using the bootstrap-after-bootstrap method. The magnitude of the correlations was assessed by comparison with computed Obuchowski-Rockette fixed reader correlations.Results: Average Pearson correlations (with 95% confidence intervals in square brackets) were: Corr(FROC, inferred ROC) = 0.76[0.64, 0.84] > Corr(inferred ROC, conventional ROC) = 0.40[0.18, 0.58] > Corr (FROC, conventional ROC) = 0.32[0.16, 0.46].Conclusions: Correlation between FROC and inferred-ROC data AUC estimates was high. Correlation between inferred- and conventional-ROC AUC was similar to the correlation between two modalities for a single reader using one estimation method, suggesting that the highest rating assumption might be questionable.
    Medical Physics 10/2012; 39(10):5917-29. · 3.01 Impact Factor
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    Ultrasound in Obstetrics and Gynecology 09/2012; 40(S1). · 3.56 Impact Factor
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    ABSTRACT: Congenital thoracic malformations (CTMs) are a heterogeneous group of rare disorders that may involve the airways or lung parenchyma. The authors have focused on the condition that causes the most controversy, namely, congenital cystic adenomatoid malformation (CCAM). The reported incidence is 3.5 and 0.94 per 10,000 live births for CTMs and CCAMs respectively. Ultrasound is the antenatal imaging modality of choice for screening for CCAMs whilst magnetic resonance imaging is complimentary for morphological and volumetric evaluation of the foetal lung. Most CCAMs are detected antenatally with only a small proportion presenting postnatally. Only a few CCAMs cause foetal problems, with foetal hydrops being the best predictor of death. Although many CCAMs regress during pregnancy, most remain detectable postnatally by CT scans. Surgical excision of symptomatic lesions is relatively straightforward, but management of asymptomatic lesions is controversial. Some surgeons adopt a "wait and see" approach operating only on those patients who develop symptoms, but others operate on asymptomatic patients usually within the first year of life. Due to the potential of malignant transformation, children should have long term follow up. There is an urgent need to delineate the natural history of antenatally detected CCAMs to guide future management.
    Paediatric Respiratory Reviews 09/2012; 13(3):162-70; quiz 170-1. · 2.22 Impact Factor
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    International Journal of Urology 08/2012; · 1.80 Impact Factor

Publication Stats

282 Citations
215.38 Total Impact Points

Institutions

  • 1970–2014
    • Universitair Ziekenhuis Leuven
      • • Department of Radiology
      • • Department of Gynaecology and obstetrics
      Louvain, Flanders, Belgium
  • 2013
    • Fondazione IRCCS Ca' Granda - Ospedale Maggiore Policlinico
      Milano, Lombardy, Italy
  • 2011–2012
    • KU Leuven
      • • Department of Reproduction, Development and Regeneration
      • • Faculty of Medicine
      Leuven, VLG, Belgium
    • Heillig Hart Ziekenhuis Lier
      Flanders, Belgium