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Orcel T, Chau HT, Turlin B, Chaigneau J, Bannier E, Otal P, Frampas E, Leguen A, Boulic A, Saint-Jalmes H, Aubé C, Boursier J, Bardou-Jacquet E, Gandon Y. Evaluation of proton density fat fraction (PDFF) obtained from a vendor-neutral MRI sequence and MRQuantif software. Eur Radiol 2023; 33:8999-9009. [PMID: 37402003 DOI: 10.1007/s00330-023-09798-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2022] [Revised: 03/29/2023] [Accepted: 04/21/2023] [Indexed: 07/05/2023]
Abstract
OBJECTIVE To validate the proton density fat fraction (PDFF) obtained by the MRQuantif software from 2D chemical shift encoded MR (CSE-MR) data in comparison with the histological steatosis data. METHODS This study, pooling data from 3 prospective studies spread over time between January 2007 and July 2020, analyzed 445 patients who underwent 2D CSE-MR and liver biopsy. MR derived liver iron concentration (MR-LIC) and PDFF was calculated using the MRQuantif software. The histological standard steatosis score (SS) served as reference. In order to get a value more comparable to PDFF, histomorphometry fat fraction (HFF) were centrally determined for 281 patients. Spearman correlation and the Bland and Altman method were used for comparison. RESULTS Strong correlations were found between PDFF and SS (rs = 0.84, p < 0.001) or HFF (rs = 0.87, p < 0.001). Spearman's coefficients increased to 0.88 (n = 324) and 0.94 (n = 202) when selecting only the patients without liver iron overload. The Bland and Altman analysis between PDFF and HFF found a mean bias of 5.4% ± 5.7 [95% CI 4.7, 6.1]. The mean bias was 4.7% ± 3.7 [95% CI 4.2, 5.3] and 7.1% ± 8.8 [95% CI 5.2, 9.0] for the patients without and with liver iron overload, respectively. CONCLUSION The PDFF obtained by MRQuantif from a 2D CSE-MR sequence is highly correlated with the steatosis score and very close to the fat fraction estimated by histomorphometry. Liver iron overload reduced the performance of steatosis quantification and joint quantification is recommended. This device-independent method can be particularly useful for multicenter studies. CLINICAL RELEVANCE STATEMENT The quantification of liver steatosis using a vendor-neutral 2D chemical-shift MR sequence, processed by MRQuantif, is well correlated to steatosis score and histomorphometric fat fraction obtained from biopsy, whatever the magnetic field and the MR device used. KEY POINTS • The PDFF measured by MRQuantif from 2D CSE-MR sequence data is highly correlated to hepatic steatosis. • Steatosis quantification performance is reduced in case of significant hepatic iron overload. • This vendor-neutral method may allow consistent estimation of PDFF in multicenter studies.
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Affiliation(s)
- T Orcel
- Department of Radiology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
| | - H T Chau
- Department of Radiology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
- NUMECAN, INSERM U1099, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
| | - B Turlin
- NUMECAN, INSERM U1099, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
- Department of Pathology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
| | - J Chaigneau
- HIFIH, UPRES EA3859, Angers University Hospital, 4 Rue Larrey, 49993, Angers, France
| | - E Bannier
- Department of Radiology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
- EMPENN U746 Unit/Project, INSERM/INRIA, IRISA, University of Rennes, Beaulieu Campus, UMR CNRS 6074, 35042, Rennes, France
| | - P Otal
- Department of Radiology, Toulouse University Hospital, 1 Av Pr J. Poulhes, 31059, Toulouse, France
| | - E Frampas
- Department of Radiology, Nantes University Hospital, 1 Pl. Alexis-Ricordeau, 44000, Nantes, France
| | - A Leguen
- Department of Radiology, Bretagne-Atlantique Hospital, 20 Bd Général Maurice Guillaudot, 56000, Vannes, France
| | - A Boulic
- Department of Radiology, Bretagne Sud Hospital, 5 Avenue de Choiseul, 56322, Lorient, France
| | - H Saint-Jalmes
- INSERM U1099, LTSI, University of Rennes, Beaulieu Campus, 35042, Rennes, France
| | - C Aubé
- HIFIH, UPRES EA3859, Angers University Hospital, 4 Rue Larrey, 49993, Angers, France
- Department of Radiology, Angers University Hospital, 4 Rue Larrey, 49993, Angers, France
| | - J Boursier
- HIFIH, UPRES EA3859, Angers University Hospital, 4 Rue Larrey, 49993, Angers, France
- Department of Hepatology-GastoeEnterology, Angers University Hospital, 4 Rue Larrey, 49993, Angers, France
| | - E Bardou-Jacquet
- NUMECAN, INSERM U1099, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
- Department of Hepatology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France
| | - Y Gandon
- Department of Radiology, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France.
- NUMECAN, INSERM U1099, Rennes University Hospital, 2 Rue H. Le Guilloux, 35033, Rennes, France.
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Ghemame M, Cathelineau C, Carsin-Nicol B, Eliat PA, Saint-Jalmes H, Ferré JC, Mouriaux F. Ex vivo porcine model for eye, eyelid, and orbit movement analysis of 4-mm ferromagnetic foreign bodies in MRI. Graefes Arch Clin Exp Ophthalmol 2021; 260:311-318. [PMID: 34173880 DOI: 10.1007/s00417-021-05258-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/11/2021] [Accepted: 05/27/2021] [Indexed: 11/25/2022] Open
Abstract
PURPOSE Ferromagnetic foreign bodies (FFB) present during magnetic resonance imaging (MRI) explorations can lead to tissue injury due to movement, especially in and around the eyes. Ferromagnetic foreign bodies located in the intraocular area, eyelids, and orbit are thus prohibited from undergoing MRI. The aim of the study was to analyze movement of 4-mm ferromagnetic foreign bodies in MRI in the eye, eyelid, and orbit using computed tomography (CT) scan. METHOD We developed a porcine model using 12 quarters of fresh porcine heads. Each porcine head included one whole orbit with the ocular globe, orbital fat, muscles, and eyelids. Four-millimeter FFB were implanted in the eye within 2 days post-slaughter, and images were acquired within 5 days post-slaughter. Four-millimeter FFB movement was analyzed after 1.5-Tesla (T) MRI. Four locations were tested: intravitreous, suprachoroidal, intraorbital fat, and intrapalpebral. Movement analysis was assessed using computed tomography (CT) scan. RESULTS The intravitreous ferromagnetic ball moved 14.0 ± 8.8 mm (p < 0.01), the suprachoroidal ball moved 16.8 ± 5.4 mm (p < 0.01), the intraorbital fat ball moved 5.8 ± 0.9 mm (p > 0.05), and the intrapalpebral ball moved 2.0 ± 0.4 mm (p > 0.05). CONCLUSION The ex vivo porcine model was able to study FFB movement. The 4-mm ferromagnetic balls moved in intravitreous and in suprachoroidal locations after MRI.
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Affiliation(s)
- M Ghemame
- Department of Ophthalmology, Rennes University Hospital, F-35000, Rennes, France.
| | - C Cathelineau
- Department of Neuroradiology, Rennes University Hospital, F-35033, Rennes, France
| | - B Carsin-Nicol
- Department of Neuroradiology, Rennes University Hospital, F-35033, Rennes, France
| | - P-A Eliat
- CNRS, Inserm, BIOSIT- UMS 3480, US_S 018, F-35000, Rennes, France
| | - H Saint-Jalmes
- University of Rennes, Rennes University Hospital, CLCC Eugène Marquis, Inserm, LTSI - UMR 1099, F-35000, Rennes, France
| | - J-C Ferré
- Department of Neuroradiology, Rennes University Hospital, F-35033, Rennes, France
- University of Rennes, Rennes University Hospital, Inria, CNRS, INSERM, IRISA, Empenn ERL U-1228, F-35000, Rennes, France
| | - F Mouriaux
- Department of Ophthalmology, Rennes University Hospital, F-35000, Rennes, France
- University of Rennes, INSERM, UMR 1241, Nutrition, Métabolismes et Cancer (NuMeCan), Rennes, France
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Largent A, Barateau A, Nunes J, Lafond C, Greer P, Dowling J, Baxter J, Saint-Jalmes H, Acosta O, de Crevoisier R. 45 A comparison of pseudo-CT generation methods for prostate MRI-based dose planning: deep learning, patch-based, atlas-based and bulk-density methods. Phys Med 2019. [DOI: 10.1016/j.ejmp.2019.09.126] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Beaumont J, Saint-Jalmes H, Acosta O, Kober T, Tanner M, Ferré JC, Salvado O, Fripp J, Gambarota G. Multi T1-weighted contrast MRI with fluid and white matter suppression at 1.5 T. Magn Reson Imaging 2019; 63:217-225. [PMID: 31425812 DOI: 10.1016/j.mri.2019.08.010] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2019] [Revised: 08/11/2019] [Accepted: 08/15/2019] [Indexed: 11/16/2022]
Abstract
INTRODUCTION The fluid and white matter suppression sequence (FLAWS) provides two T1-weighted co-registered datasets: a white matter (WM) suppressed contrast (FLAWS1) and a cerebrospinal fluid (CSF) suppressed contrast (FLAWS2). FLAWS has the potential to improve the contrast of the subcortical brain regions that are important for Deep Brain Stimulation surgery planning. However, to date FLAWS has not been optimized for 1.5 T. In this study, the FLAWS sequence was optimized for use at 1.5 T. In addition, the contrast-enhancement properties of FLAWS image combinations were investigated using two voxel-wise FLAWS combined images: the division (FLAWS-div) and the high contrast (FLAWS-hc) image. METHODS FLAWS sequence parameters were optimized for 1.5 T imaging using an approach based on the use of a profit function under constraints for brain tissue signal and contrast maximization. MR experiments were performed on eleven healthy volunteers (age 18-30). Contrast (CN) and contrast to noise ratio (CNR) between brain tissues were measured in each volunteer. Furthermore, a qualitative assessment was performed to ensure that the separation between the internal globus pallidus (GPi) and the external globus pallidus (GPe) is identifiable in FLAWS1. RESULTS The optimized set of sequence parameters for FLAWS at 1.5 T provided contrasts similar to those obtained in a previous study at 3 T. The separation between the GPi and the GPe was clearly identified in FLAWS1. The CN of FLAWS-hc was higher than that of FLAWS1 and FLAWS2, but was not different from the CN of FLAWS-div. The CNR of FLAWS-hc was higher than that of FLAWS-div. CONCLUSION Both qualitative and quantitative assessments validated the optimization of the FLAWS sequence at 1.5 T. Quantitative assessments also showed that FLAWS-hc provides an enhanced contrast compared to FLAWS1 and FLAWS2, with a higher CNR than FLAWS-div.
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Affiliation(s)
- J Beaumont
- Univ Rennes, CLCC Eugène Marquis, Inserm, LTSI-UMR1099, F-35000 Rennes, France; CSIRO, the Australian eHealth Research Centre, Herston, Queensland, Australia.
| | - H Saint-Jalmes
- Univ Rennes, CLCC Eugène Marquis, Inserm, LTSI-UMR1099, F-35000 Rennes, France
| | - O Acosta
- Univ Rennes, CLCC Eugène Marquis, Inserm, LTSI-UMR1099, F-35000 Rennes, France
| | - T Kober
- Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland; Department of Radiology, University Hospital (CHUV), Lausanne, Switzerland; LTS5, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - M Tanner
- Invicro, A Konica Minolta Company, London, UK
| | - J C Ferré
- Univ Rennes, Inria, CNRS, INSERM, IRISA, VISAGES ERL U-1228, F-35000 Rennes, France; CHU Rennes, Department of Neuroradiology, F-35033 Rennes, France
| | - O Salvado
- CSIRO, Data61, Herston, Queensland, Australia
| | - J Fripp
- CSIRO, the Australian eHealth Research Centre, Herston, Queensland, Australia
| | - G Gambarota
- Univ Rennes, CLCC Eugène Marquis, Inserm, LTSI-UMR1099, F-35000 Rennes, France
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Largent A, Barateau A, Nunes J, Lafond C, Greer P, Dowling J, Saint-Jalmes H, Acosta O, De Crevoisier R. PO-1007 Comparison of deep learning with three other methods to generate pseudo-CT for MRI-only radiotherapy. Radiother Oncol 2019. [DOI: 10.1016/s0167-8140(19)31427-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Largent A, Barateau A, Nunes J, Lafond C, Greer P, Dowling JA, Saint-Jalmes H, Acosta O, Crevoisier R. 29 Pseudo-CT generation for MRI-only radiotherapy treatment planning: comparison between patch-based, atlas-based and bulk density methods. Phys Med 2018. [DOI: 10.1016/j.ejmp.2018.09.042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Simoncini C, Rolland Y, Morgenthaler V, Jurczuk K, Saint-Jalmes H, Eliat PA, Kretowski M, Bezy-Wendling J. Blood Flow Simulation in Patient-Specific Segmented Hepatic Arterial Tree. Ing Rech Biomed 2017. [DOI: 10.1016/j.irbm.2017.04.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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Rondeau-Mouro C, Kovrlija R, Gambarota G, Saint-Jalmes H. μ-ViP: Customized virtual phantom for quantitative magnetic resonance micro-imaging at high magnetic field. J Magn Reson 2017; 275:73-79. [PMID: 28024256 DOI: 10.1016/j.jmr.2016.12.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/08/2016] [Accepted: 12/09/2016] [Indexed: 06/06/2023]
Abstract
The applications of Magnetic Resonance micro-Imaging (MRμI) cover nowadays a wide range of fields. However few of them present quantitative measurements when the sample of interest changes over time or in case of a long acquisition time. In this domain, two challenges have to be overcome: the introduction of a phantom as a reference signal and the guarantee that this signal is stable over the experiment duration while some conditions such as temperature and/or the moisture are varied. The aim of the present study was to implement a dedicated experimental set-up to generate a virtual phantom (ViP) signal in a vertical-bore 11.7 T NMR spectrometer, equipped with a micro-imaging probe. This study shows that the generation of a micro-imaging-dedicated ViP (μ-ViP) signal is of great benefit for on-line quality control of the spectrometer performance during acquisition in the case of real-time experiments. Thus, μViP represents a step towards improvement of the magnetic resonance signal quantification in small samples.
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Affiliation(s)
- C Rondeau-Mouro
- Irstea, UR OPAALE, 17 avenue de Cucillé, CS 64427, F-35044 Rennes, France; Université Bretagne Loire, France.
| | - R Kovrlija
- Irstea, UR OPAALE, 17 avenue de Cucillé, CS 64427, F-35044 Rennes, France; Université Bretagne Loire, France
| | - G Gambarota
- INSERM, UMR 1099, Rennes, France; LTSI, Université de Rennes 1, 35000 Rennes, France
| | - H Saint-Jalmes
- INSERM, UMR 1099, Rennes, France; LTSI, Université de Rennes 1, 35000 Rennes, France; CRLCC, Centre Eugène Marquis, Rennes, France
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Marchand A, Hitti E, Monge F, Saint-Jalmes H, Guillin R, Duvauferrier R, Gambarota G. MRI quantification of diffusion and perfusion in bone marrow by intravoxel incoherent motion (IVIM) and non-negative least square (NNLS) analysis. Magn Reson Imaging 2014; 32:1091-6. [DOI: 10.1016/j.mri.2014.07.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2013] [Revised: 05/24/2014] [Accepted: 07/25/2014] [Indexed: 01/21/2023]
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Abstract
Prospective synchronization of MRI acquisitions on living organisms involves the monitoring of respiratory and heart motions. The electrocardiogram (ECG) signal is conventionally used to measure the cardiac cycle. However, in some circumstances, obtaining an uncorrupted ECG signal recorded on small animals with radio frequency (RF) pulses and gradient switching is challenging. To monitor respiratory motion, an air cushion associated with a pressure sensor is commonly used but the system suffers from bulkiness. For many applications, the physiological gating information can also be derived from an MR navigated signal. However, a compact device that can simultaneously provide respiratory and cardiac information, for both prospective gating and physiological monitoring, is desirable. This is particularly valid since small volume coils or dedicated cardiac RF coil arrays placed directly against the chest wall are required to maximize measurement sensitivity. An optic-based device designed to synchronize MRI acquisitions on small animal's respiratory and heart motion was developed using a transmit-receive pair of optical fibers. The suitability of the developed device was assessed on mice ( n = 10) and was based on two sets of experiments with dual cardiac and respiratory synchronization. Images acquired with prospective triggering using the optical-based signal, ECG, and the pressure sensor during the same experiment were compared between themselves in the first set. The second set compared prospective technique using optical-based device and ECG to a retrospective technique. The optical signal that was correlated to both respiratory and heart motion was totally unaffected by radiofrequency pulses or currents induced by the magnetic field gradients used for imaging. Mice heart MR images depict low-visible motion artifacts with all sensors or techniques used. No significant SNR differences were found between each series of image. Full fiber-optic-based signal derived from heart and respiratory motion was suitable for prospective triggering of heart MR imaging. The fiber optic device performed similarly to the ECG and air pressure sensors, while providing an advantage for imaging with dedicated cardiac array coils by reducing bulk. It can be an attractive alternative for small animal MRI in difficult environments such as limited space and strong gradient switching.
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Rengle A, Baboi L, Saint-Jalmes H, Sablong R, Beuf O. Optical cardiac and respiratory device for synchronized MRI on small animal. ACTA ACUST UNITED AC 2008; 2007:2046-9. [PMID: 18002388 DOI: 10.1109/iembs.2007.4352722] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Respiratory and cardiac motion must be overcome if MRI of the thorax or abdomen is to be performed satisfactorily. An optical-based device designed to synchronize MRI acquisition on small animal was developed using a pair of optical fibers. Light from a laser diode was focused into the transmit fiber and impinged upon the moving skin. The reflected light was detected by the receive fiber and then caries to a light-voltage photodiode, were the signal was amplified and filtered. The recorded optical-based signals are well correlated with both respiratory and heart motions. The signal amplitude recorded on both rats and mice were large enough to perform an easy adjustment of gating level with good differentiation between cardiac and respiratory signal. The device developed using thin fibers is simple to use even when space available around the mice is limited (narrow coils). The signal is totally unaffected by radiofrequency impulsions or magnetic field gradients used for imaging. This optical-based trigger system was used successfully for dual cardiac and respiratory synchronization of rat and mice for heart and liver examinations at 4.7T.
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Affiliation(s)
- A Rengle
- CREATIS-LRMN, CNRS, UMR 5220, Villeurbanne, France
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Rengle A, Armenean M, Bolbos R, Goebel JC, Pinzano-Watrin A, Saint-Jalmes H, Gillet P, Beuf O. A dedicated two-element phased array receiver coil for high resolution MRI of rat knee cartilage at 7T. ACTA ACUST UNITED AC 2007; 2007:3886-9. [DOI: 10.1109/iembs.2007.4353182] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Armenean C, Beuf O, Armenean M, Pilleul F, Perrin E, Saint-Jalmes H. IRM Interventionnelle : Risques de brûlure du patient et du radiologue. ACTA ACUST UNITED AC 2007; 88:599-600. [PMID: 17464262 DOI: 10.1016/s0221-0363(07)89863-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- C Armenean
- Laboratoire de RMN, CNRS UMR 5012, Université Claude Bernard LYON1, CPE, Domaine Scientifique de la DOUA, Villeurbanne Cedex, France.
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Oulmane F, Detti V, Grenier D, Perrin E, Saint-Jalmes H. Radiofrequency power deposition near metallic wires during MR imaging: feasibility study using T1-weighted thermal imaging. Annu Int Conf IEEE Eng Med Biol Soc 2007; 2007:3894-3897. [PMID: 18002850 DOI: 10.1109/iembs.2007.4353184] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The presence of metallic conductors (implants, wires or catheters) is prohibited in MR imaging for safety purpose with respect to radiofrequency (RF) power deposition caused by RF excitation B1 field. This work describes the use of T1-weigthed MR imaging for estimating a thermal map around a metallic (copper) wire located in the center of a MR imaging unit during an imaging sequence. The experimental set up and the methodology used for capturing the elevation of temperature created by radiofrequency power deposition around the wire is presented. A proof of its efficiency to followup temperature elevation about 0,5 degrees C in a milimetric region of interest (pixel size: 1 x 1 mm2, slice thickness 5 mm) located around the wire is given, leading to further developments of MR imaging in presence of metallic implants, coils or catheters.
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Affiliation(s)
- F Oulmane
- Creatis-LRMN Laboratory, UMR CNRS INSA UCBL 5220, INSERM U630, Université de Lyon, France
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Benoit-Cattin H, Collewet G, Belaroussi B, Saint-Jalmes H, Odet C. The SIMRI project: a versatile and interactive MRI simulator. J Magn Reson 2005; 173:97-115. [PMID: 15705518 DOI: 10.1016/j.jmr.2004.09.027] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2004] [Revised: 09/10/2004] [Indexed: 05/02/2023]
Abstract
This paper gives an overview of SIMRI, a new 3D MRI simulator based on the Bloch equation. This simulator proposes an efficient management of the T2* effect, and in a unique simulator integrates most of the simulation features that are offered in different simulators. It takes into account the main static field value and enables realistic simulations of the chemical shift artifact, including off-resonance phenomena. It also simulates the artifacts linked to the static field inhomogeneity like those induced by susceptibility variation within an object. It is implemented in the C language and the MRI sequence programming is done using high level C functions with a simple programming interface. To manage large simulations, the magnetization kernel is implemented in a parallelized way that enables simulation on PC grid architecture. Furthermore, this simulator includes a 1D interactive interface for pedagogic purpose illustrating the magnetization vector motion as well as the MRI contrasts.
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Affiliation(s)
- H Benoit-Cattin
- CREATIS, UMR CNRS #5515, U 630 Inserm, Université Claude Bernard Lyon 1, INSA Lyon, Bât. B. Pascal, 69621 Villeurbanne, France.
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Beuf O, Pilleul F, Armenean M, Hadour G, Saint-Jalmes H. In vivo colon wall imaging using endoluminal coils: Feasibility study on rabbits. J Magn Reson Imaging 2004; 20:90-6. [PMID: 15221813 DOI: 10.1002/jmri.20059] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To assess in vivo distal colon wall magnetic resonance imaging (MRI) feasibility on rabbits using an endoluminal radio frequency (RF) coil on a 1.5-T clinical scanner. MATERIALS AND METHODS The endoluminal coil signal-to-noise ratio (SNR) was compared to a clinical four-element phased-array body coil. High-resolution (HR) MRI of rabbit colon walls was performed on six rabbits. The imaging protocol combined T1-weighted fast low-angle-shot (FLASH) sequences with and without fat saturation (FS), T2-weighted True-Fast imaging with steady state precession (Fisp), turbo spin-echo (TSE), and T1-weighted FLASH FS after contrast media injection. Images were compared to histological sections. Catheter tracking using an endoluminal coil in addition to external coils was also evaluated on two rabbits. RESULTS HR images allow visualization and identification of rabbit colon wall layers. Real-time tracking allows a clear visualization and a good positioning of the endoluminal coil within the rabbit. CONCLUSION Compared to a clinical multielement array coil, a dedicated endoluminal RF coil provides an important SNR increase at the region of interest (ROI). Very HR images of in vivo rabbit colon walls were achieved providing detailed information on the different wall layers. This technique could be considered on humans for accurate tumoral and inflammatory bowel disease diagnosis.
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Affiliation(s)
- O Beuf
- Laboratoire de RMN, CNRS UMR 5012, Université Claude Bernard Lyon I-ESCPE, France
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Germain D, Vahala E, Ehnholm GJ, Vaara T, Ylihautala M, Savart M, Laurent A, Tanttu J, Saint-Jalmes H. MR temperature measurement in liver tissue at 0.23 T with a steady-state free precession sequence. Magn Reson Med 2002; 47:940-7. [PMID: 11979573 DOI: 10.1002/mrm.10147] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
MRI can be used for monitoring temperature during a thermocoagulation treatment of tumors. The aim of this study was to demonstrate the suitability of a 3D steady-state free precession sequence (3D Fast Imaging with Steady-State Precession, 3D TrueFISP) for MR temperature measurement at 0.23 T, and to compare it to the spin-echo (SE) and spoiled 3D gradient-echo (3D GRE) sequences. The optimal flip angle for the TrueFISP sequence was calculated for the best temperature sensitivity in the image signal from liver tissue, and verified from the images acquired during the thermocoagulation of excised pig liver. Factors influencing the accuracy of the measured temperatures are discussed. The TrueFISP results are compared to the calculated values of optimized SE and 3D GRE sequences. The accuracy of TrueFISP in the liver at 0.23 T, in imaging conditions used during thermocoagulation procedures, is estimated to be +/-3.3 degrees C for a voxel of 2.5 x 2.5 x 6 mm(3) and acquisition time of 18 s. For the SE and GRE sequences, with similar resolution and somewhat longer imaging time, the uncertainty in the temperature is estimated to be larger by a factor of 2 and 1.2, respectively.
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Affiliation(s)
- D Germain
- Center for Research in Interventional Imaging, Jouy en Josas, France
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18
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Abstract
Thermal therapy of tumour including hyperthermia and thermal ablation by heat or cold delivery requires on line monitoring. Due to its temperature sensitivity, Magnetic Resonance Imaging (MRI) allows thermal mapping at the time of the treatment. The different techniques of MR temperature monitoring based on water proton resonance frequency (PRF), longitudinal relaxation time T1, diffusion coefficient and MR Spectroscopic Imaging (MRSI) are reviewed and debated. The PRF method appears the most widely used and the most efficient at high magnetic field in spite of important drawbacks. The T1 method is the easiest method of visualisation of qualitative temperature distribution and quantitative measurement seems possible in the tissue surrounding the tumour up to a temperature of 45-65 degrees C. Despite its high temperature sensitivity, application of the diffusion method in vivo is restricted due to its high motion sensitivity. The recent MRSI technique seems very promising provided acquisition times can be reduced. Results from the literature indicate that MR temperature monitoring in vivo can be achieved in vivo with a precision of about 3 degrees C in 13 s for a voxel of 16 mm3 (1.5 x 1.5 x 7 mm) in 1.5 T scanners.
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Affiliation(s)
- D Germain
- Centre de Recherche en Imagerie Interventionnelle (Cr2i, APHP-INRA), Domaine de Vilvert, 78352, Jouy en Josas, France.
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19
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Darquié A, Poline JB, Poupon C, Saint-Jalmes H, Le Bihan D. Transient decrease in water diffusion observed in human occipital cortex during visual stimulation. Proc Natl Acad Sci U S A 2001; 98:9391-5. [PMID: 11459931 PMCID: PMC55431 DOI: 10.1073/pnas.151125698] [Citation(s) in RCA: 146] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2001] [Indexed: 01/10/2023] Open
Abstract
Using MRI, we report the observation of a transient decrease of the apparent diffusion coefficient (ADC) of water in the human brain visual cortex during activation by a black and white 8-Hz-flickering checkerboard. The ADC decrease was small (<1%), but significant and reproducible, and closely followed the time course of the activation paradigm. Based on the known sensitivity of diffusion MRI to cell size in tissues and on optical imaging studies that have revealed changes in the shape of neurons and glial cells during activation, the observed ADC findings have been tentatively ascribed to a transient swelling of cortical cells. These preliminary results suggest a new approach to produce images of brain activation with MRI from signals directly associated with neuronal activation, and not through changes in local blood flow.
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Affiliation(s)
- A Darquié
- Service Hospitalier Frédéric Joliot, Commissariat à l'Energie Atomique, 4 Place du Général Leclerc, 91401 Orsay Cedex, France
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20
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Germain D, Chevallier P, Laurent A, Savart M, Wassef M, Saint-Jalmes H. MR monitoring of laser-induced lesions of the liver in vivo in a low-field open magnet: temperature mapping and lesion size prediction. J Magn Reson Imaging 2001. [PMID: 11169802 DOI: 10.1002/1522-2586(200101)13:1<42::aid-jmri1007>3.0.co;2-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The aims of this study were, firstly, to monitor temperature with magnetic resonance (MR) during laser ablations performed in pig livers in vivo in a low-field open scanner (0.23T) and, secondly, to study the feasibility of lesion size prediction. Spin-echo (SE) images of 29 sec acquired during laser applications allowed calculation of temperature maps using T1 and M(0) temperature sensitivity. Temperature was also measured with thermocouples. Images of prediction of tissue damage were calculated using temperature maps and Arrhenius model. T2W sequences were acquired after the ablations. Animals were sacrificed immediately. Lesions were photographed macroscopically. Lesion surfaces were measured and compared in T2W images, temperature images, damage prediction images, and macroscopic pictures. A correlation exists between temperature measured with MR and with thermocouples (rho = 0.878; P < 0.001, Spearman test). Mean surface of predicted damaged tissue is consistent with mean early necrosis measured in macroscopic pictures. Early T2W images underestimate mean necrosis size. J. Magn. Reson. Imaging 2001;13:42-49.
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Affiliation(s)
- D Germain
- Centre de Recherche en Imagerie Interventionnelle, Jouy en Josas, France.
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21
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Germain D, Chevallier P, Laurent A, Savart M, Wassef M, Saint-Jalmes H. MR monitoring of laser-induced lesions of the liver in vivo in a low-field open magnet: temperature mapping and lesion size prediction. J Magn Reson Imaging 2001; 13:42-9. [PMID: 11169802 DOI: 10.1002/1522-2586(200101)13:1<42::aid-jmri1007>3.0.co;2-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The aims of this study were, firstly, to monitor temperature with magnetic resonance (MR) during laser ablations performed in pig livers in vivo in a low-field open scanner (0.23T) and, secondly, to study the feasibility of lesion size prediction. Spin-echo (SE) images of 29 sec acquired during laser applications allowed calculation of temperature maps using T1 and M(0) temperature sensitivity. Temperature was also measured with thermocouples. Images of prediction of tissue damage were calculated using temperature maps and Arrhenius model. T2W sequences were acquired after the ablations. Animals were sacrificed immediately. Lesions were photographed macroscopically. Lesion surfaces were measured and compared in T2W images, temperature images, damage prediction images, and macroscopic pictures. A correlation exists between temperature measured with MR and with thermocouples (rho = 0.878; P < 0.001, Spearman test). Mean surface of predicted damaged tissue is consistent with mean early necrosis measured in macroscopic pictures. Early T2W images underestimate mean necrosis size. J. Magn. Reson. Imaging 2001;13:42-49.
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Affiliation(s)
- D Germain
- Centre de Recherche en Imagerie Interventionnelle, Jouy en Josas, France.
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22
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Abstract
Relaxation times estimation methods play a central role in various problems, such as magnetic resonance (MR) hardware calibration, tissue characterization, or temperature measurement. Previous studies have proposed optimization criteria to estimate the relaxation time T1 faster than with a multipoint method leading to two-point methods. In this paper, the class of optimized two-point methods is extended to gradient-echo (GE) sequence offering new advantages over spin-echo (SE) or inversion recovery (IR) sequences. Two GE acquisitions, with optimal flip angles theta1 and theta2 minimizing both the total scan time and the variance in the computed T1 image were applied to estimate T1, and the results were compared with those of SE sequence with optimized paired repetition times T(R1) and T(R2). First, phantom studies were carried out with five tissue-like samples on a 0.5T scanner. Then in vivo, human brain T1 image were calculated using both optimized GE and SE two-point methods. More precise T1 GE estimates than those for SE were found thanks to high signal-to-noise ratio (SNR) per unit of time, but with a small bias. These results also concern the temperature variation measurement methods, based on T1 estimation. Preliminary experimental data for temperature measurement are given.
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Affiliation(s)
- J Imran
- Université de Technologie de Compiègne, Division Imagerie Médicale, CIMA, Compiègne, France.
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23
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Gobin L, Blanchot L, Saint-Jalmes H. Integrating the digitized backscattered image to measure absorption and reduced-scattering coefficients in vivo. Appl Opt 1999; 38:4217-27. [PMID: 18323904 DOI: 10.1364/ao.38.004217] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Measurement of absorption and reduced-scattering optical coefficients microa and micros' is possible when a steady-state backscattered image is used on a sample surface. A new method for processing the backscattered image, acquired with a CCD, has been developed. The image is integrated to decrease sensitivity to noise. The resulting curve is defined as the integral reflectance. The curve is then fitted with a relaxation model to evaluate microa and micros'. We have validated the method with calibrated scattering and absorption phantoms. The integral reflectance method is then applied to measurements of the microa and micros' coefficients of human skin in vivo.
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Affiliation(s)
- L Gobin
- Laboratoire d'Etude et de Recherche en Instrumentation Signaux et Systèmes, Université Paris XII, Bâtiment P2, 61 avenue De Gaulle, 94010 Créteil Cedex, France.
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24
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Lévêque S, Boccara AC, Lebec M, Saint-Jalmes H. Ultrasonic tagging of photon paths in scattering media: parallel speckle modulation processing. Opt Lett 1999; 24:181-3. [PMID: 18071447 DOI: 10.1364/ol.24.000181] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Tagging of photon trajectories in scattering media is possible by application of a localized ultrasonic field to the sample and by measurement of the induced speckle modulation. Instead of using a single optical detector, which integrates the signal of many speckle grains, we propose a more efficient detection scheme that uses a CCD camera and parallel lock-in detection to record the full modulation of the speckle. The advantage of this multiplex detection is demonstrated, as well as the imaging capabilities of the process for biological tissues.
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25
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Abstract
We present a new microscopy system for imaging in turbid media that is based on the spatial coherence gate principle and generates in parallel a complete two-dimensional head-on image without scanning. This system has been implemented in a commercial microscope and preserves the lateral resolution of the optics used. With a spatially incoherent source, speckle-free images with diffraction-limited resolution are recorded at successive depths with shot-noise-limited detection. The setup comprises a photoelastic modulator for path difference modulation and a two-dimensional CCD array and uses a multiplexed lock-in detection scheme.
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26
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Gleyzes P, Boccara AC, Saint-Jalmes H. Multichannel Nomarski microscope with polarization modulation: performance and applications. Opt Lett 1997; 22:1529-31. [PMID: 18188288 DOI: 10.1364/ol.22.001529] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Using a two-dimensional CCD array, a photoelastic modulator, and a commercial Nomarski microscope, we built a differential polarization interferometer. Multichannel lock-in detection of the signal allowed us to reach a shot-noise limit corresponding to 5-pm path differences for a few seconds of recording time. This interferometer was used as a surface profilometer as well as a system for imaging through scattering media.
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27
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Guillot G, Trokiner A, Darrasse L, Dupas A, Ferdossi F, Kassab G, Hulin J, Rigord P, Saint-Jalmes H. NMR imaging applied to various studies of porous media. Magn Reson Imaging 1991. [DOI: 10.1016/0730-725x(91)90382-v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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28
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Bittoun J, Saint-Jalmes H, Querleux BG, Darrasse L, Jolivet O, Idy-Peretti I, Wartski M, Richard SB, Leveque JL. In vivo high-resolution MR imaging of the skin in a whole-body system at 1.5 T. Radiology 1990; 176:457-60. [PMID: 2367660 DOI: 10.1148/radiology.176.2.2367660] [Citation(s) in RCA: 91] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
High-resolution magnetic resonance (MR) images of the skin were acquired with a whole-body MR system at 1.5 T by adding a specific imaging module: A saddle-shaped surface gradient coil was connected in place of one of the gradient coils of the system, and a surface radio-frequency coil with a 1.5-cm radius was placed at the center of the gradient coil. The images, acquired in 3 minutes 25 seconds, represent a field of view of 18 x 50 mm2, which corresponds to a pixel size of 70 x 390 micro2; the section thickness was 1.2 mm. With this spatial resolution, the different layers of the skin are clearly delineated: Epidermis appears as a high-signal-intensity layer, while dermis appears hypointense due to its very short T2. Pilosebaceous units appear as inclusions of epidermis inside dermis. The high quality of the images obtained enables in vivo MR characterization of skin.
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Affiliation(s)
- J Bittoun
- Centre Inter-Etablissements de Résonance Magnétique, Université, Paris-Sud, Hôpital de Bicêtre, France
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30
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Abstract
A new design for an axial magnetic field gradient is described. Implemented in a four-coil configuration, it requires far less power than the conventional Maxwell pair, while maintaining the same field linearity. A practical design tool with a set of curves giving coil dimensions is proposed. Two realizations dedicated to NMR imaging are described and compared with the equivalent Maxwell pair. Substantial power reductions are achieved; in these cases, dc power is reduced by a factor of 5 and switching power by a factor of 15.
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