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Computer-assisted Analysis of Three-dimensional MR Angiograms

Marcela Hernández-Hoyos, Maciej Orkisz, Philippe Puech, Catherine Mansard-Desbleds, Philippe Douek, Isabelle E. Magnin
2002 Radiographics  
The software tools required for postprocessing of magnetic resonance (MR) angiograms include the following functions: data handling, image visualization, and vascular analysis. A custom postprocessing software called Magnetic Resonance Angiography Computer Assisted Analysis (MARACAS) has been developed. This software combines the most commonly used three-dimensional visualization techniques with image processing methods for analysis of vascular morphology on MR angiograms. The main
more » ... of MARACAS are (a) implementation of a fast method for stenosis quantification on three-dimensional MR angiograms, which is clinically applicable in a personal computer-based system; and (b) portability to the most widespread platforms. The quantification is performed in three steps: extraction of the vessel centerline, detection of vessel boundaries in planes locally orthogonal to the centerline, and calculation of stenosis parameters on the basis of the resulting contours. Qualitative results from application of the method to data from patients showed that the vessel centerline correctly tracked the vessel path and that contours were correctly estimated. Quantitative results obtained from images of phantoms showed that the computation of stenosis severity was accurate. © RSNA, 2002 Abbreviations: DICOM ϭ Digital Imaging and Communications in Medicine, MARACAS ϭ Magnetic Resonance Angiography Computer Assisted Analysis, MIP ϭ maximum intensity projection, MPR ϭ multiplanar reformation, PC ϭ personal computer, 2D ϭ two-dimensional, 3D ϭ three-dimensional
doi:10.1148/radiographics.22.2.g02mr03421 pmid:11896231 fatcat:qbvaq3oufrapfepkktvwq4mwjy

ROI-Wise Material Decomposition in Spectral Photon-Counting CT [article]

Bingqing Xie and Pei Niu and Ting Su and Valérie Kaftandjian and Loic Boussel and Philippe Douek Feng Yang and Philippe Duvauchelle and Yuemin Zhu
2019 arXiv   pre-print
Spectral photon-counting X-ray CT (sCT) opens up new possibilities for the quantitative measurement of materials in an object, compared to conventional energy-integrating CT or dual energy CT. However, achieving reliable and accurate material decomposition in sCT is extremely challenging, due to similarity between different basis materials, strong quantum noise and photon-counting detector limitations. We propose a novel material decomposition method that works in a region-wise manner. The
more » ... d consists in optimizing basis materials based on spatio-energy segmentation of regions-of-interests (ROIs) in sCT images and performing a fine material decomposition involving optimized decomposition matrix and sparsity regularization. The effectiveness of the proposed method was validated on both digital and physical data. The results showed that the proposed ROI-wise material decomposition method presents clearly higher reliability and accuracy compared to common decomposition methods based on total variation (TV) or L1-norm (lasso) regularization.
arXiv:1912.02483v1 fatcat:bjqbapa4s5duvlf4fjdyzctyyi

Assessment of candidate elements for development of spectral photon-counting CT specific contrast agents

Johoon Kim, Daniel Bar-Ness, Salim Si-Mohamed, Philippe Coulon, Ira Blevis, Philippe Douek, David P. Cormode
2018 Scientific Reports  
Philippe Douek and David P. Cormode supervised the work as principal investigators. All authors contributed to the design of the experiments, as well as contributed to and approved the manuscript.  ...  Philippe Coulon and Ira Blevis optimized the image acquisition parameters (i.e. energy bin thresholds) and provided the details of the CT scanners and image reconstruction methods.  ...  Philippe Coulon and Dr. Ira Blevis are employees of Philips Healthcare, the manufacturer of the scanner.  ... 
doi:10.1038/s41598-018-30570-y pmid:30108247 pmcid:PMC6092324 fatcat:lfuk5bllezcknihlrhm4wesqj4

Ecg-Gated C-Arm Computed Tomography Using L1 Regularization

Vincent Auvray, Loic Boussel, Philippe Douek, Michael Grass, Cyril Mory, Francoise Peyrin, Simon Rit, Dirk Schäfer, Bo Zhang
2012 Zenodo  
Publication in the conference proceedings of EUSIPCO, Bucharest, Romania, 2012
doi:10.5281/zenodo.52226 fatcat:jv7mlzis5fd73gjmrbsozchiyy

RR22. Magnetic Resonance Imaging for Identifying Vulnerable Carotid Plaques

Antoine Millon, Jean-Louis Mathevet, Loic Boussel, Zahi Fayad, Peter Faries, Patrick Feugier, Philippe Douek
2012 Journal of Vascular Surgery  
Magnetic Resonance Imaging for Identifying Vulnerable Carotid Plaques Antoine Millon 1 , Jean-Louis Mathevet 1 , Loic Boussel 1 , Zahi Fayad 2 , Peter Faries 2 , Patrick Feugier 1 , Philippe Douek 1 .  ...  Douek: Nothing to disclose; P. Faries: Nothing to disclose; Z. Fayad: Nothing to disclose; P. Feugier: Nothing to disclose; J. Mathevet: Nothing to disclose; A. Millon: Nothing to disclose. RR23.  ... 
doi:10.1016/j.jvs.2012.03.231 fatcat:2ozw6qvpbjbs7kmwrememdw6ia

Multicolour imaging with spectral photon-counting CT: a phantom study

Salim Si-Mohamed, Daniel Bar-Ness, Monica Sigovan, Valérie Tatard-Leitman, David P Cormode, Pratap C Naha, Philippe Coulon, Lucie Rascle, Ewald Roessl, Michal Rokni, Ami Altman, Yoad Yagil (+2 others)
2018 European Radiology Experimental  
Consent for publication Not applicable Competing interests Philippe Coulon, Michal Rokni, Ewald Roessl, Yoad Yagil and Ami Altman are employees of Philips Healthcare, the manufacturer of the scanner.  ... 
doi:10.1186/s41747-018-0063-4 pmid:30327898 pmcid:PMC6191405 fatcat:guzz5rqhu5godhct5xwqmehiam

Diffusion and perfusion magnetic resonance imaging in brain tumors

Denis Le Bihan, Philippe Douek, Maria Argyropoulou, Robert Turner, Nicholas Patronas, Michael Fulham
1993 Topics in Magnetic Resonance Imaging (TMRI)  
Gliomas are the most common primary neoplasm of the brain, varying histologically from low grade to high-grade. Perfusion-weighted MRI techniques have permitted the creation of cerebral blood volume (CBV) value, leading to the qualitative and quantitative assessment of tumor vascularity. This research aimed at assessing the rCBV and the ADC values in core and peritumoral areas glioma brain tumors and determining of significance rCBV of values i Alpha I In evaluating brain tumor. Ten patients
more » ... h non-enhancing supratentorial gliomas were evaluated by diffusion weighted imaging (DWI) and standard dynamic susceptibility contrast-enhanced gradient echo during first pass of a bolus injection of contrast material before surgical resection. Six low-grade gliomas (WHO Grade II) and 4 high-grade gliomas (III, IV) were evaluated. Alpha Both the apparent diffusion coefficient (ADC) and relative cerebral blood volume (rCBV) values were calculated by a standard program on the solid portion of the tumor in the peritumoural area as well as contra lateral white matter. In perfusion, mean rCBVmax in high-grade and low-grade tumors were obtained (3.47±0.92), (2.37±0.49)-(1.66±0.68), (1.15±0.39) for core and peritumoral regions, respectively. In diffusion method, mean ADC in high-grade and low grade tumors were (0.53±0.07), (0.91±0.18)-(1.24±0.27), (1.007±0.33) for core and peritumoral regions, respectively. It was concluded that the values rCBVs are important in determining the grade of tumor and we propose that perfusion weighted imaging be done for all patients before surgery.
doi:10.1097/00002142-199300520-00005 fatcat:7cqhvcl2yvaghduw2z6fzuzbie

Spectral Photon-Counting CT Technology in Chest Imaging

Salim Aymeric Si-Mohamed, Jade Miailhes, Pierre-Antoine Rodesch, Sara Boccalini, Hugo Lacombe, Valérie Leitman, Vincent Cottin, Loic Boussel, Philippe Douek
2021 Journal of Clinical Medicine  
Acknowledgments: We are deeply grateful to Philip Robinson for his help in editing the manuscript, Adja Diaw, Daniel Bar-Ness for their help in experiments, Marjorie Villien, Philippe Coulon, Yoad Yagil  ... 
doi:10.3390/jcm10245757 pmid:34945053 pmcid:PMC8704215 fatcat:j7t7w3l5pbap3egs4j7hj6te7u

Assessment of complicated arterial bypass grafts: Value of contrast-enhanced subtraction magnetic resonance angiography

K. Bendib, Y. Berthezène, P. Croisille, J. Villard, Philippe C. Douek
1997 Journal of Vascular Surgery  
Purpose: To evaluate complicated aortoiliac and lower extremity arterial bypass grafts with contrast-enhanced subtraction magnetic resonance angiography (MRA). Methods: Twenty-three patients with 40 vascular grafts with either clinical symptoms or abnormal duplex findings were selected. They were examined using a fast Tl-weighted gradient-echo sequence. Twelve to 19 coronal sections of 5 to 8 mm were acquired before and after an intravenous bolus injection of gadolinium (0.1 mmol/kg) in 25 to
more » ... seconds. Final images were created by subtracting each precontrast section from its corresponding postcontrast section. The MRA was obtained after subtraction and maximum intensity projection. Results: MRA detected 38 grafts (95%) with 28 abnormalities. Two stenoses were overestimated. MRA had a sensitivity of 91% and a specificity of 92% for diagnosis of graft stenoses and occlusions. MRA brought out more information in five cases by demonstrating four nonthrombotic ectasias that were unseen by duplex sonography and one thrombotic ectasia that was unseen by x-ray angiography. Conclusions: MRA seems to compare favorably with x-ray angiography for the diagnosis of arterial bypass graft complications. A multicenter trial will be necessary to validate these preliminary results and to assess the exact role of MRA compared with the other established techniques. (J Vasc Surg 1997;26:1036-42.) Eighty percent of venous bypass graft stenoses occur during the first year after surgery, and almost all occur during the first 18 months. The incidence of this complication is 12% at 1 year and very often happens with no clinical symptoms (60%). 1 Thus a surveillance program must be set up to depict these failures in time to enable a corrective action for secondary patency. 2,3 Duplex sonography (DS) is the main follow-up method, and surveillance criteria such as anlde-brachial index, midgraft peak systolic flow velocity, velocity ratio before and after stenosis, and duplex scanning of the entire graft have been successfully tested. 4-6 X-ray angiography is performed after DS has diagnosed a complication and From the Dtpartement d'imagerie, and the Service de chirurgie cardio-vasculaire (Dr. Villard), Hopital Cardio-vasculaire et Pneumologique.
doi:10.1016/s0741-5214(97)70017-x pmid:9423720 fatcat:syen7bfeend4tpzmuevyeh6qc4

Virtual monoenergetic images from photon-counting spectral computed tomography to assess knee osteoarthritis

Christine Chappard, Juan Abascal, Cécile Olivier, Salim Si-Mohamed, Loic Boussel, Jean Baptiste Piala, Philippe Douek, Francoise Peyrin
2022 European Radiology Experimental  
Background Dual-energy computed tomography has shown a great interest for musculoskeletal pathologies. Photon-counting spectral computed tomography (PCSCT) can acquire data in multiple energy bins with the potential to increase contrast, especially for soft tissues. Our objectives were to assess the value of PCSST to characterise cartilage and to extract quantitative measures of subchondral bone integrity. Methods Seven excised human knees (3 males and 4 females; 4 normal and 3 with
more » ... is; age 80.6 ± 14 years, mean ± standard deviation) were scanned using a clinical PCSCT prototype scanner. Tomographic image reconstruction was performed after Compton/photoelectric decomposition. Virtual monoenergetic images were generated from 40 keV to 110 keV every 10 keV (cubic voxel size 250 × 250 × 250 μm3). After selecting an optimal virtual monoenergetic image, we analysed the grey level histograms of different tissues and extracted quantitative measurements on bone cysts. Results The optimal monoenergetic images were obtained for 60 keV and 70 keV. Visual inspection revealed that these images provide sufficient spatial resolution and soft-tissue contrast to characterise surfaces, disruption, calcification of cartilage, bone osteophytes, and bone cysts. Analysis of attenuation versus energy revealed different energy fingerprint according to tissues. The volumes and numbers of bone cyst were quantified. Conclusions Virtual monoenergetic images may provide direct visualisation of both cartilage and bone details. Thus, unenhanced PCSCT appears to be a new modality for characterising the knee joint with the potential to increase the diagnostic capability of computed tomography for joint diseases and osteoarthritis.
doi:10.1186/s41747-021-00261-x pmid:35190914 pmcid:PMC8861235 fatcat:uv2pixe5p5b25fwddkp6rc76g4

Spectral photon-counting CT imaging of colorectal peritoneal metastases: initial experience in rats

Arnaud Thivolet, Salim Si-Mohamed, Pierre-Emmanuel Bonnot, Christophe Blanchet, Vahan Képénékian, Loïc Boussel, Philippe Douek, Pascal Rousset
2020 Scientific Reports  
Computed tomography imaging plays a major role in the preoperative assessment of tumor burden by providing an accurate mapping of the distribution of peritoneal metastases (PM). Spectral Photon Counting Computed Tomography (SPCCT) is an innovative imaging modality that could overcome the current limitations of conventional CT, offering not only better spatial resolution but also better contrast resolution by allowing the discrimination of multiple contrast agents. Based on this capability, we
more » ... sted the feasibility of SPCCT in the detection of PM at different time of tumor growth in 16 rats inoculated with CC531 cells using dual-contrast injection protocols in two compartments (i.e. intravenous iodine and intraperitoneal gadolinium or the reverse protocol), compared to surgery. For all peritoneal regions and for both protocols, sensitivity was 69%, specificity was 100% and accuracy was 80%, and the correlation with surgical exploration was strong (p = 0.97; p = 0.0001). No significant difference was found in terms of diagnostic performance, quality of peritoneal opacification or diagnostic quality between the 2 injection protocols. We also showed poor vascularization of peritoneal metastases by measuring low concentrations of contrast agent in the largest lesions using SPCCT, which was confirmed by immunohistochemical analyses. In conclusion, SPCCT using dual-contrast agent injection protocols in 2 compartments is a promising imaging modality to assess the extent of PM in a rat model.
doi:10.1038/s41598-020-70282-w pmid:32770125 pmcid:PMC7414131 fatcat:pjb7fwba4fagvoaitf2vatcaoa

Spectral Photon-Counting Computed Tomography (SPCCT): in-vivo single-acquisition multi-phase liver imaging with a dual contrast agent protocol

Salim Si-Mohamed, Valérie Tatard-Leitman, Alexis Laugerette, Monica Sigovan, Daniela Pfeiffer, Ernst J. Rummeny, Philippe Coulon, Yoad Yagil, Philippe Douek, Loic Boussel, Peter B. Noël
2019 Scientific Reports  
Diagnostic imaging of hepatocellular carcinoma (HCC) requires a liver CT or MRI multiphase acquisition protocol. Patients would benefit from a high-resolution imaging method capable of performing multi-phase imaging in a single acquisition without an increase in radiation dose. Spectral Photon-Counting Computed Tomography (SPCCT) has recently emerged as a novel and promising imaging modality in the field of diagnostic radiology. SPCCT is able to distinguish between two contrast agents referred
more » ... o as multicolor imaging because, when measuring in three or more energy regimes, it can detect and quantify elements with a K-edge in the diagnostic energy range. Based on this capability, we tested the feasibility of a dual-contrast multi-phase liver imaging protocol via the use of iodinated and gadolinated contrast agents on four healthy New Zealand White (NZW) rabbits. To perform a dual-contrast protocol, we injected the agents at different times so that the first contrast agent visualized the portal phase and the second the arterial phase, both of which are mandatory for liver lesion characterization. We demonstrated a sensitive discrimination and quantification of gadolinium within the arteries and iodine within the liver parenchyma. In the hepatic artery, the concentration of gadolinium was much higher than iodine (8.5 ± 3.9 mg/mL versus 0.7 ± 0.1 mg/mL) contrary to the concentrations found in the liver parenchyma (0.5 ± 0.3 mg/mL versus 4.2 ± 0.3 mg/mL). In conclusion, our results confirm that SPCCT allows in-vivo dual contrast qualitative and quantitative multi-phase liver imaging in a single acquisition.
doi:10.1038/s41598-019-44821-z pmid:31186467 pmcid:PMC6559958 fatcat:jmxk7jlj2rcnlon3mgj6lq4lxa

Higher prevalence of incidental findings identified upon coronary calcium score assessment in type 2 and type 3 diabetes versus type 1 diabetes

Mélanie Gaudillière, Charlotte Marsot, Laetitia Balaire, Laure Groisne, Myriam Moret, Sylvie Villar-Fimbel, Philippe Douek, Philippe Moulin, Sybil Charrière, Andreas Zirlik
2021 PLoS ONE  
Supporting information S1 Author Contributions Conceptualization: Philippe Moulin, Sybil Charrière.  ... 
doi:10.1371/journal.pone.0251693 pmid:34029335 fatcat:2dbgaix7dveqxfs7bxxbshebh4

Feasibility of improving vascular imaging in the presence of metallic stents using spectral photon counting CT and K-edge imaging

Monica Sigovan, Salim Si-Mohamed, Daniel Bar-Ness, Julia Mitchell, Jean-Baptiste Langlois, Philippe Coulon, Ewald Roessl, Ira Blevis, Michal Rokni, Gilles Rioufol, Philippe Douek, Loic Boussel
2019 Scientific Reports  
Correct visualization of the vascular lumen is impaired in standard computed tomography (CT) because of blooming artifacts, increase of apparent size, induced by metallic stents and vascular calcifications. Recently, due to the introduction of photon-counting detectors in the X-ray imaging field, a new prototype spectral photon-counting CT (SPCCT) based on a modified clinical CT system has been tested in a feasibility study for improving vascular lumen delineation and visualization of coronary
more » ... tent architecture. Coronary stents of different metal composition were deployed inside plastic tubes containing hydroxyapatite spheres to simulate vascular calcifications and in the abdominal aorta of one New Zealand White (NZW) rabbit. Imaging was performed with an SPCCT prototype, a dual-energy CT system, and a conventional 64-channel CT system (B64). We found the apparent widths of the stents significantly smaller on SPCCT than on the other two systems in vitro (p < 0.01), thus closer to the true size. Consequently, the intra-stent lumen was significantly larger on SPCCT (p < 0.01). In conclusion, owing to the increased spatial resolution of SPCCT, improved lumen visualization and delineation of stent metallic mesh is possible compared to dual-energy and conventional CT.
doi:10.1038/s41598-019-56427-6 pmid:31882698 pmcid:PMC6934567 fatcat:fl6m23f2gfdade7zpgbhulnndu

Removing streak artifacts from ECG-gated reconstructions using deconvolution

Cyril Mory, Vincent Auvray, Bo Zhang, Michael Grass, Dirk Schäfer, Simon Rit, Françoise Peyrin, Philippe Douek, Loïc Boussel
2014 Journal of X-Ray Science and Technology  
4D cardiac computed tomography aims at reconstructing the beating heart from a series of 2D projections and the simultaneously acquired electrocardiogram. Each cardiac phase is reconstructed by exploiting the subset of projections acquired during this particular cardiac phase only. In these conditions, the Feldkamp, Davis and Kress method (FDK) generates large streak artifacts in the reconstructed volumes, hampering the medical interpretation. These artifacts can be substantially reduced by
more » ... nvolution methods. The aim of this paper is to compare two 4D cardiac CT reconstruction methods based on deconvolution, and to evaluate their practical benefits on two applications: cardiac micro CT and human cardiac C-arm CT. The first evaluated method builds upon inverse filtering. It has been proposed recently and demonstrated on 4D cardiac micro CT. The second one is an iterative deconvolution method, and turns out equivalent to an ECG-gated Iterative Filtered Back Projection (ECG-gated IFBP). Results are presented on simulated data in 2D parallel beam, 2D fan beam and 3D cone beam geometries. Both methods are efficient on the cardiac micro CT simulations, but insufficient to handle 4D human cardiac C-Arm CT simulations. Overall, ECG-gated IFPB largely outperforms the inverse filtering method.
doi:10.3233/xst-140423 pmid:24699351 fatcat:m4wtpp237bhp3c3jm4bsrlhtq4
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