G Marchal

Catholic University of Louvain, Лувен-ла-Нев, Walloon, Belgium

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Publications (326)666.37 Total impact

  • European Radiology 09/2014; 8(8):1497-1498. DOI:10.1007/s003300050581 · 4.01 Impact Factor
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    ABSTRACT: Intrahepatic air embolism can occur during liver transplantation, jeopardizing the posttransplant outcome. Until now, the role of the procurement in the origin of intrahepatic air remains unclear; it might be underestimated. In this pilot study using magnetic resonance imaging (MRI), we observed a substantial amount of air trapped in porcine livers during multiorgan procurement. We quantified the amount of air, examining whether it could be reduced by avoiding direct contact of air with the lumen of the hepatic vasculature during procurement and back-table preparation. Five livers (control group) were procured according to standard techniques for comparison with 6 livers (modified group) where air could not enter into the livers due to clamping of the vasculature. MRI was performed during continuous machine perfusion (MP) preservation there after. We counted the number of black signal voids on T(2)*-weighted images, which were indicative of air bubbles within the hepatic contour. Additionally, an MRI contrast agent (gadolinium-diethylene triamine pentaacetic acid [Gd-DTPA]) was injected into the hepatic artery and circulated by MP. Insufficiently perfused areas with less contrast enhancement were analyzed quantitatively in T(1)-weighted images and expressed as the percentage of total liver volume. The images of the control livers showed more air bubbles compared with the modified group (45 ± 27 vs 6 ± 3; P = .004). The percentage of insufficiently perfused areas was higher among the control compared with the modified group (28.0 ± 15.8% vs 2.6 ± 4.6%; P = .047) on first-pass postcontrast T(1)-weighted images. After recirculating the contrast agent, insufficiently perfused areas showed similar localizations and contours within every liver. These data suggested that a substantial amount of air enters into the hepatic microcirculation through direct contact of air with the hepatic vasculature during standard procurement and back-table preparation. Avoiding opening the hepatic vessels to air substantially reduced this phenomenon.
    Transplantation Proceedings 12/2010; 42(10):4409-14. DOI:10.1016/j.transproceed.2010.07.016 · 0.98 Impact Factor

  • EJC Supplements 03/2010; 8(3):239-239. DOI:10.1016/S1359-6349(10)70641-8 · 9.39 Impact Factor
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    ABSTRACT: Screening mammography is one of the most challenging radiological techniques and this is partly due to the difficulty in detecting microcalcifications (MCs) against an anatomical background of varying mammographic tissue density. Further complicating factors in the detection of MCs include the small size and their resemblance to other bright structures in the breast. A number of different microcalcification simulating materials are available and these are often incorporated in test objects used to study some aspects of an imaging system, for example, optimal beam quality selection in digital mammography. Aluminum (Al) has similar x-ray attenuation properties to MCs and therefore Al is extensively used in test objects. However, to the best of our knowledge, the suitability of Al as a substitute material for MCs has not been studied explicitly. The aim of this study was therefore to demonstrate that spectral optimization studies for MCs can be performed with Al sheets. The approach used was twofold. First, contrasts generated by Al and MCs at several exposure settings were compared, and secondly an optimization study was performed with both Al and MCs as the contrasting target using an amorphous selenium (a-Se) based digital mammography unit. Specimens from stereotactic vacuum-assisted breast biopsies of non-palpable lesions with mammographic evidence of MCs were obtained from clinical routine patients. Contrasts generated by these MCs and by Al sheets were measured for Mo/Mo, Mo/Rh and W/Rh anode/filter combinations, for different polymethylmethacrylate (PMMA) thicknesses at the extremes of the x-ray tube voltages used clinically. A linear regression was then applied between the two measurements of contrast; the ratio of the angular coefficient q obtained from the fitted regression lines for Al and MCs ranged from 0.96 to 0.99 for Mo/Mo and Mo/Rh combinations at 2 and 4 cm PMMA, respectively, and from 0.83 at 4 cm PMMA to 1.14 at 7 cm PMMA for the W/Rh combination. For the optimization study, the signal-difference-to-noise ratio (SDNR) measured using the MCs was plotted as a function of mean glandular dose (MGD) for 4 cm PMMA, for the three different anode/filter combinations. The W/Rh combination always gave the highest SDNR for a given MGD. The SDNR and MGD were then used to define the common figure of merit SNR(2)/MGD; the setting that maximized this measure at 4 cm PMMA was 27 kV and a W/Rh combination. These results demonstrate a close correspondence between the attenuation properties of Al and extracted MC material over the energy range studied for the Mo/Mo, Mo/Rh and W/Rh anode/filter combinations. Furthermore, it was found that the exposure parameters that maximized the figure of merit for the MC specimen agree with results found in studies that used Al sheets as a substitute for the MC.
    Physics in Medicine and Biology 02/2010; 55(4):1057-68. DOI:10.1088/0031-9155/55/4/010 · 2.76 Impact Factor
  • F Zanca · D P Chakraborty · G Marchal · H Bosmans ·
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    ABSTRACT: Although the receiver operating characteristic (ROC) method is the acknowledged gold-standard for imaging system assessment, it ignores localisation information and differentiation between multiple abnormalities per case. As the free-response ROC (FROC) method uses localisation information and more closely resembles the clinical reporting process, it is being increasingly used. A number of methods have been proposed to analyse the data that result from an FROC study: jackknife alternative FROC (JAFROC) and a variant termed JAFROC1, initial detection and candidate analysis (IDCA) and ROC analysis via the reduction of the multiple ratings on a case to a single rating. The focus of this paper was to compare JAFROC1, IDCA and the ROC analysis methods using a clinical FROC human data set. All methods agreed on the ordering of the modalities and all yielded statistically significant differences of the figures-of-merit, i.e. p < 0.05. Both IDCA and JAFROC1 yielded much smaller p-values than ROC. The results are consistent with a recent simulation-based validation study comparing these and other methods. In conclusion, IDCA or JAFROC1 analysis of FROC human data may be superior at detecting modality differences than ROC analysis.
    Radiation Protection Dosimetry 02/2010; 139(1-3):52-6. DOI:10.1093/rpd/ncq030 · 0.91 Impact Factor
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    ABSTRACT: To compare the effective dose levels of cone beam computed tomography (CBCT) for maxillofacial applications with those of multi-slice computed tomography (MSCT). The effective doses of 3 CBCT scanners were estimated (Accuitomo 3D, i-CAT, and NewTom 3G) and compared to the dose levels for corresponding image acquisition protocols for 3 MSCT scanners (Somatom VolumeZoom 4, Somatom Sensation 16 and Mx8000 IDT). The effective dose was calculated using thermoluminescent dosimeters (TLDs), placed in a Rando Alderson phantom, and expressed according to the ICRP 103 (2007) guidelines (including a separate tissue weighting factor for the salivary glands, as opposed to former ICRP guidelines). Effective dose values ranged from 13 to 82 microSv for CBCT and from 474 to 1160 microSv for MSCT. CBCT dose levels were the lowest for the Accuitomo 3D, and highest for the i-CAT. Dose levels for CBCT imaging remained far below those of clinical MSCT protocols, even when a mandibular protocol was applied for the latter, resulting in a smaller field of view compared to various CBCT protocols. Considering this wide dose span, it is of outmost importance to justify the selection of each of the aforementioned techniques, and to optimise the radiation dose while achieving a sufficient image quality. When comparing these results to previous dosimetric studies, a conversion needs to be made using the latest ICRP recommendations.
    European journal of radiology 09/2009; 71(3):461-8. DOI:10.1016/j.ejrad.2008.06.002 · 2.37 Impact Factor
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    ABSTRACT: We aimed to examine different intratumoral changes after single-dose and fractionated radiotherapy, using diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) MRI in a rat rhabdomyosarcoma model. Four WAG/Rij rats with rhabdomyosarcomas in the flanks received single-dose radiotherapy of 8 Gy, and four others underwent fractionated radiotherapy (five times 3 Gy). In rats receiving single-dose radiotherapy, a significant perfusion decrease was found in the first 2 days post-treatment, with slow recuperation afterwards. No substantial diffusion changes could be seen; tumor growth delay was 12 days. The rats undergoing fractionated radiotherapy showed a similar perfusion decrease early after the treatment. However, a very strong increase in apparent diffusion coefficient occurred in the first 10 days; growth delay was 18 days. DW-MRI and DCE-MRI can be used to show early tumoral changes induced by radiotherapy. Single-dose and fractionated radiotherapy induce an immediate perfusion effect, while the latter induces more intratumoral necrosis.
    European Radiology 07/2009; 19(11):2663-71. DOI:10.1007/s00330-009-1451-1 · 4.01 Impact Factor
  • X Wu · H Wang · F Chen · L Jin · J Li · Y Feng · F DeKeyzer · J Yu · G Marchal · Y Ni ·
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    ABSTRACT: Rat model of reperfused partial liver infarction (RPLI) has been increasingly used in studying new diagnostics and therapeutics. To characterize the RPLI model using magnetic resonance imaging (MRI), microangiography, and histopathology. RPLI was induced in eight rats by occluding hepatic inflow to the right liver lobe for 3 hours. MRI was performed at a 1.5 T clinical scanner 6 hours after reperfusion to obtain T2-weighted (T2WI), T1-weighted (T1WI), contrast-enhanced (CE) T1WI, diffusion-weighted imaging (DWI) with apparent diffusion coefficient (ADC) maps, T1-weighted dynamic contrast-enhanced (T1-DC) perfusion-weighted imaging (PWI), and T2*-weighted dynamic susceptibility contrast-enhanced (T2*-DSC) PWI images. Rats were sacrificed for microangiography and histomorphology. In vivo morphological and functional MRI parameters, including maximum initial slope (MIS), K value, relative blood flow (rBF), relative blood volume (rBV), time to peak (TTP), and mean transit time (MTT), were matched with postmortem findings. The infarcted lobe was conspicuous from normal liver with lower and higher signal intensity on T1WI (P=0.018) and T2WI (P=0.001), respectively. Contrast between infarcted and normal liver reversed on CE-T1WI after gadolinium injection. The infarction averaged 37.5% of total liver volume. DWI and ADC maps were able to detect subtle perfusion-related differences (P<0.05). With T1-DC-PWI, increased extravasation and vascular permeability were reflected by significantly greater MIS (P=0.034) and K value (P=0.014) in infarction. T2*-DSC-PWI showed lower rBF and rBV with shorter TTP and MTT in infarcted liver (P<0.05). In vivo MRI findings corresponded well with postmortem outcomes. RPLI in rats could be characterized by multiparametric MRI and postmortem assessments, with insight into the no-reflow phenomenon, which implies its further application for preclinical assessments of new pharmaceutics.
    Acta Radiologica 04/2009; 50(3):276-87. DOI:10.1080/02841850802647021 · 1.60 Impact Factor
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    ABSTRACT: The purpose of this study is to compare Contrast Detail Curves (CDCs) of unprocessed and processed digital images. Images of a CDMAM (contrast detail for mammography) phantom had been acquired at 29 kV Tungsten-Rhodium anode-filter combination and 100 mAs; unprocessed images were subsequently processed using five clinically available image processing algorithms. Scoring of CDMAM images was then performed using human observers and automatic reading. Five observers conducted a four-alternative forced-choice experiment on a set of four images, for each processing condition. For the automatic analysis of CDMAM images the CDCOM software program was used. Contrast Detail Curves were then computed both for the human and automatic reading by fitting a psychometric curve, after applying a smoothing algorithm (Gaussian filter). For both types of readings the CDCs from processed and unprocessed images were compared. We verified the statistical significance of the difference Delta between contrast threshold measurements at 0.1 mm target size (Figure of Merit, FoM), for unprocessed and processed images and for each image processing algorithm separately. The non-parametric bootstrap method was used. No statistical significant difference is found between raw and processed images. This study shows that CDMAM images may not be appropriate in assessing image processing algorithms.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2009; 7258. DOI:10.1117/12.811732 · 0.20 Impact Factor
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    ABSTRACT: The purpose was to find the correlation between a Figure of Merit (FoM) calculated from a new (simple) test object for Quality Control in digital mammography and CDMAM threshold thicknesses. The FoM included the signal difference to noise ratio, modulation transfer function of the complete system (including scatter and grid) and normalized noise power spectrum. The pre-programmed exposure settings for clinical work were used, as was done for the CDMAM acquisitions. The FoM is calculated from 2 images only (an image from the QC test object and an image of a corresponding homogeneous plate imaged with the same exposure settings). This FoM was evaluated in frequencies that match with the diameters of the gold disks in the CDMAM phantom. Computerized CDMAM analysis uses 16 images per system. The software program "cdcom" (www.euref.org) was used for the 4-AFC experiment. All matrices were averaged, smoothed with a Gaussian filter and psychometric curves were fitted through the correctly detected fractions to obtain the threshold thickness with a detectability of 62.5% for all diameters. Images have been acquired on 10 different systems (2 computed radiography (CR) systems, 6 direct radiology (DR) systems and 2 photon counting systems). The reproducibility of the QC metrics from images of the new phantom was assessed. The standard error on the mean of the FoM was for the highest frequency 8.1% for a CR system and 5.6% for a DR system. The main component in this error is due to the NNPS and the limited number of independent pixels used in this analysis. Parameters calculated from both phantoms are sensitive to variation in mean glandular dose levels. Present results show a weak correlation (R2=0.60) between the FoM at 5lp/mm and CDMAM threshold values for the 0.1mm objects when all system data are pooled. If evaluated for separate systems, the correlation holds promise for automated, periodic performance evaluations of digital mammography systems with the simplified phantom.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2009; 7263. DOI:10.1117/12.811752 · 0.20 Impact Factor
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    J. Jacobs · F. Zanca · J. Verschakelen · G. Marchal · H. Bosmans ·
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    ABSTRACT: Until recently, the specifications of medical grade monochrome LCD monitors outperformed those of color LCD monitors. New generations of color LCD monitors, however, show specifications that are in many respects similar to those of monochrome monitors typically used in diagnostic workstations. The aim of present study was to evaluate the impact of different medical grade monitors in terms of detection of simulated lung nodules in chest x-ray images. Specifically, we wanted to compare a new medical grade color monitor (Barco Coronis 6MP color) to a medical grade grayscale monitor (Barco Coronis 3MP monochrome) and a consumer color monitor (Philips 200VW 1.7MP color) by means of an observer performance experiment. Using the free-response acquisition data paradigm, seven radiologists were asked to detect and locate lung nodules (170 in total), simulated in half of the 200 chest X-ray images used in the experiment. The jackknife free-response receiver operating characteristic (JAFROC) analysis of the data showed a statistically significant difference between at least two monitors, F-value=3.77 and p-value =0.0481. The different Figure of Merit values were 0.727, 0.723 and 0.697 for the new color LCD monitor, the medical grade monitor and the consumer color monitor respectively. There was no difference between the needed reading times but there was a difference between the mean calculated Euclidian distances between the position marked by the observers and the center of the simulated nodule, indicating a better accuracy with both medical grade monitors. Present data suggests that the new generation of medical grade color monitors could be used as diagnostic workstations.
    Proceedings of SPIE - The International Society for Optical Engineering 02/2009; 7263. DOI:10.1117/12.813702 · 0.20 Impact Factor
  • M Lieben · A Van Steen · G Marchal ·

    JBR-BTR: organe de la Société royale belge de radiologie (SRBR) = orgaan van de Koninklijke Belgische Vereniging voor Radiologie (KBVR) 01/2009; 92(3):160-1.
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    ABSTRACT: To compare the predictive value of the prenatal observed to expected (o/e) lung volume as measured by fetal magnetic resonance imaging (MRI), based on an algorithm using either the gestational age or fetal body volume (FBV), for neonatal survival of fetuses with isolated congenital diaphragmatic hernia (CDH). We included 53 fetuses with a prenatal diagnosis of isolated CDH, 26 without and 27 with prenatal tracheal occlusion, who were assessed by fetal MRI, liveborn after 32 weeks, and in whom follow-up until discharge from the neonatal care unit was available. Measurements of lung volumes were expressed as a percentage of the appropriate mean (o/e total fetal lung volume (TFLV) x 100) either for gestational age or for FBV. Measurements of FBV were expressed as a percentage of the appropriate mean (o/e FBV x 100) for gestation. Fetuses with prenatal intervention were all assessed > or = 24 h after balloon removal. Regression analysis was used to examine the effect on postnatal survival of either o/e TFLV based on gestational age or based on FBV, gestation at delivery, side of CDH, intrathoracic position of the liver and prenatal intervention. Receiver-operating characteristics (ROC) curves were constructed for the prediction of survival by o/e TFLV based on gestational age and o/e TFLV based on FBV, for all fetuses, as well as for those with o/e FBV between 90 and 110% and those with values beyond that range. A power calculation for the number of fetuses needed to show a difference between the ROC curves was performed. Regression analysis demonstrated that o/e TFLV based on gestational age and on FBV were the only independent predictors of postnatal survival. The area under the ROC curve for prediction of postnatal survival from the o/e TFLV based on gestational age was 0.811, and for that based on FBV it was 0.868 (P < 0.001 for both). For fetuses with o/e FBV between 90 and 110%, and those with values < 90% and > 110%, the area for measurements based on gestational age was 0.895 and 0.733, respectively; when based on FBV it was 0.906 and 0.833 (P < 0.01 for all). A minimum of 273 patients would be needed to provide a probability of 90% of detecting a difference between the areas under both ROC curves. In fetuses with isolated CDH, lung volume as measured by fetal MRI was significantly correlated with survival. Prediction tended to be better by o/e TFLV based on FBV rather than gestational age. The difference in the prediction of survival between o/e TFLV based on FBV or gestational age was dependent on fetal biometry.
    Ultrasound in Obstetrics and Gynecology 10/2008; 32(5):633-9. DOI:10.1002/uog.6139 · 3.85 Impact Factor
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    ABSTRACT: GCA carries an increased risk of developing thoracic aortic aneurysms. Previous work with fluorodeoxyglucose (FDG)-PET has shown that the aorta is frequently involved in this type of vasculitis. We wanted to investigate whether there is a correlation between the extent of vascular FDG uptake during the acute phase of GCA and the aortic diameter at late follow-up. All patients with biopsy-proven GCA who ever underwent an FDG-PET scan in our centre were asked to undergo a CT scan of the aorta. The diameter of the aorta was measured at six different levels (ascending aorta, aortic arch, descending aorta, abdominal suprarenal, juxtarenal and infrarenal aorta) and the volumes of the thoracic and of the abdominal aorta were calculated. Forty-six patients agreed to participate (32 females, 14 males). A mean of 46.7 +/- 29.9 months elapsed between diagnosis and CT scan. All aortic dimensions were significantly smaller in women than in men, except for the diameter of the ascending aorta. Patients who had an increased FDG uptake in the aorta at diagnosis of GCA, had a significantly larger diameter of the ascending aorta (P = 0.025) and descending aorta (P = 0.044) and a significantly larger volume of the thoracic aorta (P = 0.029). In multivariate analysis, FDG uptake at the thoracic aorta was associated with late volume of the thoracic aorta (P = 0.039). GCA-patients with increased FDG uptake in the aorta may be more prone to develop thoracic aortic dilatation than GCA patients without this sign of aortic involvement.
    Rheumatology (Oxford, England) 09/2008; 47(8):1179-84. DOI:10.1093/rheumatology/ken119 · 4.48 Impact Factor
  • F Zanca · C Van Ongeval · J Jacobs · G Marchal · H Bosmans ·
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    ABSTRACT: This study presents a quantitative method for evaluating the detectability of microcalcifications in digital mammography. Four hundred and twenty microcalcifications (with various morphology, size and contrast), simulated with a previously validated method, were used for the creation of image datasets. Lesions were inserted into 163 regions of interests of 59 selected raw digital mammograms with various anatomical backgrounds and acquired with a Siemens Novation DR. After processing, these composite images were scored by experienced radiologists, who located multiple simulated lesions and rated them under conditions of free-search. For statistical analysis, free-response receiver-operating characteristic curves are plotted; the use of jackknife free-response receiver-operating characteristic method has also been investigated. The main advantage of this methodology is that the exact number of inserted microcalcifications is well known and that the lesions are fully characterised in terms of pathology, size, morphology and peak contrast. A first application has been the evaluation of the effect of anatomical background on microcalcifications detection. Preliminary findings in this study indicate that this method may be a promising tool to evaluate factors that have an influence on the detectability of lesions, such as the clinical processing or the viewing conditions.
    Radiation Protection Dosimetry 04/2008; 129(1-3):214-8. DOI:10.1093/rpd/ncn049 · 0.91 Impact Factor
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    F Chen · Q Liu · H Wang · Y Suzuki · N Nagai · J Yu · G Marchal · Y Ni ·
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    ABSTRACT: This stroke experiment was designed to define the mismatch between perfusion-weighted imaging (PWI) and diffusion-weighted imaging (DWI) in MRI by applying early or instantly acquired PWI. Eight rats were induced with stroke through photothrombotic occlusion of the middle cerebral artery and scanned serially between 1 h and day 3 after induction using DWI and PWI with a 1.5 T MR scanner. The relative lesion volumes (rLV) on MRI and triphenyl tetrazolium chloride-stained specimens were defined as the proportion of lesion volume over brain volume. Discrepancies in the rLV between PWI- and DWI-derived apparent diffusion coefficient (ADC) maps were expressed by subtraction of the ADC from PWI, resulting in three possible patterns: (i) (PWI-ADC > 10% of PWI) denoting a mismatch; (ii) (-(10% of PWI) <or= PWI-ADC <or= 10% of PWI) denoting a match; and (iii) (PWI-ADC < -(10% of PWI)) denoting a reverse mismatch. The differences were compared with the minuend being either early PWI (ePWI) or instant PWI (iPWI) and the subtrahend being instant ADC (iADC). The occurrence and evolution of PWI-ADC patterns were analysed. Over time, PWI-ADC discrepancies evolved from mismatch, through to match, to reversed mismatch. The PWI-ADC mismatch still existed 3 days after MCA occlusion in one to three of the eight cases. The rLVs and mismatch incidences between the ePWI-iADC and iPWI-iADC models were linear correlated. A higher mismatch rate occurred in iPWI-iADC within day 1 and in ePWI-iADC at day 3. Both ePWI and iPWI proved useful to define PWI-ADC patterns within day 1. At day 3, iPWI appeared more adequate.
    The British journal of radiology 03/2008; 81(963):192-8. DOI:10.1259/bjr/70940134 · 2.03 Impact Factor
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    ABSTRACT: Using magnetic resonance imaging, the apparent diffusion coefficient (ADC) is an indicator to assess cerebral ischemia. The aim of this porcine study was to evaluate whether ADC assessed hepatic ischemia during ex vivo hypothermic machine perfusion (HMP) as well as in vivo. Ex vivo: ADC of normal versus warm ischemic (WI) livers was assessed during HMP and subsequent rewarming to mimic ischemia-reperfusion injury. As the preservation solution, we used either an acellular solution or diluted blood. WI was induced in the left lobe or in the whole liver and compared 2-hour WI and non-WI. In vivo: One liver was scanned with the left lobe vessels occluded for 2-hour WI and subsequently for 3 hour reperfusion to compare with the right lobe without WI. Aspartate aminotransferase (AST) in the perfusate and morphology were used as surrogates of WI. In all WI livers, AST reached high levels and histology showed severe injury. Ex vivo ADC during acellular perfusion showed negligible differences between the livers with versus without WI, namely, 0.75 x 10(-3) or 0.88 x 10(-3) mm(2)/s during HMP. Ex vivo ADC using sanguineous perfusion showed 1.11 x 10(-3) or 0.83 x 10(-3) mm(2)/s during HMP in regions with versus without WI, respectively, a difference that remained stable during the whole experiment. ADC in vivo decreased from the physiological level of 1.07 x 10(-3) mm(2)/s to 0.75 x 10(-3) mm(2)/s in the first 30 minutes of WI, whereas ADC in the non-WI liver remained constant. ADC in vivo decreased during hepatic ischemia, as previously seen in cerebral ischemia. However, the effect of WI on ADC was less clear during ex vivo HMP.
    Transplantation Proceedings 11/2007; 39(8):2643-6. DOI:10.1016/j.transproceed.2007.08.003 · 0.98 Impact Factor
  • Y. Ni · M. Van de Putte · H. Fonge · A. Verbruggen · P. de Witte · G. Marchal ·

    Contrast Media & Molecular Imaging 11/2007; 2(6):276-276. DOI:10.1002/cmmi.161 · 2.92 Impact Factor
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    ABSTRACT: Integrated positron emission tomography (PET) and computed tomography (CT) is a new imaging modality offering anatomic and metabolic information. The purpose was to evaluate retrospectively the accuracy of integrated PET-CT in the staging of a suggestive lung lesion, comparing this with the accuracy of CT alone, PET alone and visually correlated PET-CT. Fifty patients undergoing integrated PET-CT for staging of a suggestive lung lesion were studied. Their tumor, node, metastasis (TNM) statuses were determined with CT, PET, visually correlated PET-CT and integrated PET-CT. These TNM stages were compared with the surgical TNM status. Integrated PET-CT was the most accurate imaging technique in the assessment of the TNM status. Integrated PET-CT predicted correctly the T status, N status, M status and TNM status in, respectively, 86%, 80%, 98%, 70% versus 68%, 66%,88%, 46% with CT, 46%, 70%, 96%, 30% with PET and 72%, 68%, 96%, 54% with visually correlated PET-CT. T status and N status were overstaged, respectively, in 8% and 16% with integrated PET-CT, in 20% and 28% with CT, in 16% and 20% with PET, in 12% and 20% with visually correlated PET-CT and understaged in 6% and 4% with integrated PET-CT, versus 12% and 6% with CT, 38% and 10% with PET and 12% with visually correlated PET-CT. Integrated PET-CT improves the staging of lung cancer through a better anatomic localization and characterization of lesions and is superior to CT alone and PET alone. If this technique is not available, visual correlation of PET and CT can be a valuable alternative.
    European Radiology 02/2007; 17(1):23-32. DOI:10.1007/s00330-006-0284-4 · 4.01 Impact Factor
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    ABSTRACT: The purpose of the study was to determine prospectively the diagnostic value of a computed radiography (CR) system by comparing mammographic hard copy images with screen-film mammography (SFM). A series of 100 patients, who came for diagnostic investigation, underwent two-view SFM (Lorad M-IV Platinum) and digital mammography with a CR system (AGFA CR system). The images were obtained by double exposure, i.e. same view without removing compression of the corresponding breast. The CR images were processed with dedicated processing for mammography. Six radiologists read sets of SFM and CR images. The primary efficacy parameter was the overall diagnostic value. The secondary efficacy parameters were lesion conspicuity and lesion details (for masses and micro-calcifications), tissue visibility at chest wall and at skin line, axillary details, overall density and sharpness impression and the overall noise impression. These parameters were scored by a 7-point scoring system. "CR non-inferior to SFM" was concluded if the lower confidence interval bound exceeded 80%. The confidence interval for the overall diagnostic value was between 96.4% and 100%. Pooled analysis of the ten features for image quality comparison demonstrated for all but one feature (lesion details of the calcifications) CR non-inferiority to SFM.
    European Radiology 07/2006; 16(6):1360-6. DOI:10.1007/s00330-005-0134-9 · 4.01 Impact Factor

Publication Stats

7k Citations
666.37 Total Impact Points


  • 2006-2010
    • Catholic University of Louvain
      Лувен-ла-Нев, Walloon, Belgium
  • 1970-2010
    • Universitair Ziekenhuis Leuven
      • Department of Radiology
      Louvain, Flanders, Belgium
  • 2008-2009
    • Universitair Ziekenhuis Ghent
      Gand, Flanders, Belgium
  • 1978-2009
    • University of Leuven
      • • Biomedical Sciences Group
      • • Division of Radiology
      Louvain, Flanders, Belgium
  • 2005
    • Hospital of Saint Raphael
      New Haven, Connecticut, United States
  • 1993
    • Ecole Supérieure d'Aéronautique et des technologies
      L’Ariana, Ariana, Tunisia