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Testud B, Fabiani N, Demortière S, Mchinda S, Medina NL, Pelletier J, Guye M, Audoin B, Stellmann JP, Callot V. Contribution of the MP2RAGE 7T Sequence in MS Lesions of the Cervical Spinal Cord. AJNR Am J Neuroradiol 2023; 44:1101-1107. [PMID: 37562829 PMCID: PMC10494945 DOI: 10.3174/ajnr.a7964] [Citation(s) in RCA: 1] [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] [Received: 04/17/2023] [Accepted: 07/06/2023] [Indexed: 08/12/2023]
Abstract
BACKGROUND AND PURPOSE The detection of spinal cord lesions in patients with MS is challenging. Recently, the 3D MP2RAGE sequence demonstrated its usefulness at 3T. Benefiting from the high spatial resolution provided by ultra-high-field MR imaging systems, we aimed to evaluate the contribution of the 3D MP2RAGE sequence acquired at 7T for the detection of MS lesions in the cervical spine. MATERIALS AND METHODS Seventeen patients with MS participated in this study. They were examined at both 3T and 7T. The MR imaging examination included a Magnetic Imaging in MS (MAGNIMS) protocol with an axial T2*-WI gradient recalled-echo sequence ("optimized MAGNIMS protocol") and a 0.9-mm isotropic 3D MP2RAGE sequence at 3T, as well as a 0.7-mm isotropic and 0.3-mm in-plane-resolution anisotropic 3D MP2RAGE sequences at 7T. Each data set was read by a consensus of radiologists, neurologists, and neuroscientists. The number of lesions and their topography, as well as the visibility of the lesions from one set to another, were carefully analyzed. RESULTS A total of 55 lesions were detected. The absolute number of visible lesions differed among the 4 sequences (linear mixed effect ANOVA, P = .020). The highest detection was observed for the two 7T sequences with 51 lesions each (92.7% of the total). The optimized 3T MAGNIMS protocol and the 3T MP2RAGE isotropic sequence detected 41 (74.5%) and 35 lesions (63.6%), respectively. CONCLUSIONS The 7T MP2RAGE sequences detected more lesions than the 3T sets. Isotropic and anisotropic acquisitions performed comparably. Ultra-high-resolution sequences obtained at 7T improve the identification and delineation of lesions of the cervical spinal cord in MS.
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Affiliation(s)
- B Testud
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - N Fabiani
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - S Demortière
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
- Department of Neurology (S.D., J.P., B.A.), Assistance Publique-Hopitaux de Marseille, Hôpital Universitaire Timone, Marseille, France
| | - S Mchinda
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - N L Medina
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - J Pelletier
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
- Department of Neurology (S.D., J.P., B.A.), Assistance Publique-Hopitaux de Marseille, Hôpital Universitaire Timone, Marseille, France
| | - M Guye
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - B Audoin
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
- Department of Neurology (S.D., J.P., B.A.), Assistance Publique-Hopitaux de Marseille, Hôpital Universitaire Timone, Marseille, France
| | - J P Stellmann
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
| | - V Callot
- From the Center for Magnetic Resonance in Biology and Medicine (B.T., N.F., S.D., S.M., N.L.M., J.P., M.G., B.A., J.P.S., V.C.), Aix-Marseille University, Centre national de la recherche scientifique, Marseille, France
- Assistance Publique-Hopitaux de Marseille (B.T., N.F., S.D., S.M., N.L.M., J,P., M.G., B.A., J.P.S., V.C.), Hôpital Universitaire Timone, CEMEREM, Marseille, France
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Duhamel G, Prevost VH, Cayre M, Hertanu A, Mchinda S, Carvalho VN, Varma G, Durbec P, Alsop DC, Girard OM. Validating the sensitivity of inhomogeneous magnetization transfer (ihMT) MRI to myelin with fluorescence microscopy. Neuroimage 2019; 199:289-303. [PMID: 31141736 DOI: 10.1016/j.neuroimage.2019.05.061] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [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: 01/07/2019] [Revised: 05/22/2019] [Accepted: 05/23/2019] [Indexed: 11/30/2022] Open
Abstract
Inhomogeneous Magnetization Transfer (ihMT) is a development from the MT MRI technique. IhMT can be considered as a dipolar order relaxation time (T1D) weighted imaging modality whose signal has shown an enhanced selectivity for myelin-rich structures. However, a formal validation of the ihMT sensitivity relative to a gold standard myelin density measurement has not yet been reported. To address this need, we compared ihMT MRI with green fluorescence protein (GFP) microscopy, in a study performed on genetically-modified plp-GFP mice, considered as a reference technique for myelin-content assessment. Various ihMT protocols consisting of variable T1D-filtering and radiofrequency power temporal distributions, were used for comparison with fluorescence microscopy. Strong and significant linear relationships (r2 (0.87-0.96), p < 0.0001) were found between GFP and ihMT ratio signals across brain regions for all tested protocol variants. Conventional MT ratios showed weaker correlations (r2 (0.24-0.78), p ≤ 0.02) and a much larger signal fraction unrelated to myelin, hence corresponding to a much lower specificity for myelin. T1D-filtering reduced the ihMT signal fraction not attributed to myelin by almost twofold relative to zero filtering suggesting that at least half of the unrelated signal has a substantially shorter T1D than myelin. Overall, these results strongly support the sensitivity of ihMT to myelin content.
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Affiliation(s)
- G Duhamel
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France.
| | - V H Prevost
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France
| | - M Cayre
- Aix Marseille Univ, CNRS, IBDM - UMR 7288, Marseille, France
| | - A Hertanu
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France
| | - S Mchinda
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France
| | - V N Carvalho
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France
| | - G Varma
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - P Durbec
- Aix Marseille Univ, CNRS, IBDM - UMR 7288, Marseille, France
| | - D C Alsop
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, 02215, USA
| | - O M Girard
- Aix Marseille Univ, CNRS, CRMBM - UMR 7339, Marseille, France
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Varma G, Girard OM, Mchinda S, Prevost VH, Grant AK, Duhamel G, Alsop DC. Low duty-cycle pulsed irradiation reduces magnetization transfer and increases the inhomogeneous magnetization transfer effect. J Magn Reson 2018; 296:60-71. [PMID: 30212729 DOI: 10.1016/j.jmr.2018.08.004] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 07/27/2018] [Accepted: 08/18/2018] [Indexed: 06/08/2023]
Abstract
Intense off-resonant RF irradiation can lead to saturation of the macromolecular pool magnetization and enhance bound pool dipolar order responsible for the inhomogeneous magnetization transfer (ihMT) effect, but the intensity of RF power in human imaging studies is limited by safety constraints on RF heating. High RF intensities can still be achieved if applied in short pulses with low duty-cycle. Here we investigate the benefits of low duty-cycle irradiation for MT and ihMT studies with both theoretical and experimental methods. Solutions for pulsed irradiation of a two-pool model including dipolar order effects were implemented. Experiments were conducted at 3 T in the brain and through the calf of healthy human subjects. 2D echo planar images were acquired following a preparation of RF irradiation with a 2 s train of 5 ms pulses repeated from between 10 to 100 ms for duty-cycles (DCs) of 50% to 5%, and at varying offset frequencies, and time averaged RF powers. MT and ihMT data were measured in regions of interest within gray matter, white matter and muscle, and fit to the model. RF irradiation effects on signal intensity were reduced at 5% relative to 50% DCs. This reduced RF effect was much larger for single than dual frequency irradiation. 5% DC irradiation reduced single and dual frequency MT ratios but increased ihMT ratios up to 3 fold in brain tissues. Muscle ihMT increased by an even larger factor, depending on the frequency and applied power. The model predicted these changes with duty-cycle. The model fit the data well and constrained model parameters. Low duty-cycle pulsed irradiation reduces MT effects and markedly increases dipolar order effects. This approach is an attractive method to enhance ihMT signal-to-noise ratio and demonstrates a measurable ihMT effect in muscle tissue at 3 T under acceptable specific absorption rates. The effects of duty-cycle changes demonstrated in a separate MT/ihMT preparation provide a route for new applications in magnetization-prepared MRI sequences.
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Affiliation(s)
- G Varma
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA.
| | - O M Girard
- Aix Marseille Univ, CNRS, CRMBM, Marseille, France
| | - S Mchinda
- Aix Marseille Univ, CNRS, CRMBM, Marseille, France
| | - V H Prevost
- Aix Marseille Univ, CNRS, CRMBM, Marseille, France
| | - A K Grant
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
| | - G Duhamel
- Aix Marseille Univ, CNRS, CRMBM, Marseille, France
| | - D C Alsop
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02115, USA
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Van Obberghen E, Mchinda S, le Troter A, Prevost VH, Viout P, Guye M, Varma G, Alsop DC, Ranjeva JP, Pelletier J, Girard O, Duhamel G. Evaluation of the Sensitivity of Inhomogeneous Magnetization Transfer (ihMT) MRI for Multiple Sclerosis. AJNR Am J Neuroradiol 2018; 39:634-641. [PMID: 29472299 DOI: 10.3174/ajnr.a5563] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Accepted: 12/22/2017] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Inhomogeneous magnetization transfer is a new endogenous MR imaging contrast mechanism that has demonstrated high specificity for myelin. Here, we tested the hypothesis that inhomogeneous magnetization transfer is sensitive to pathology in a population of patients with relapsing-remitting MS in a way that both differs from and complements conventional magnetization transfer. MATERIALS AND METHODS Twenty-five patients with relapsing-remitting MS and 20 healthy volunteers were enrolled in a prospective MR imaging research study, whose protocol included anatomic imaging, standard magnetization transfer, and inhomogeneous magnetization transfer imaging. Magnetization transfer and inhomogeneous magnetization transfer ratios measured in normal-appearing brain tissue and in MS lesions of patients were compared with values measured in control subjects. The potential association of inhomogeneous magnetization transfer ratio variations with the clinical scores (Expanded Disability Status Scale) of patients was further evaluated. RESULTS The magnetization transfer ratio and inhomogeneous magnetization transfer ratio measured in the thalami and frontal, occipital, and temporal WM of patients with MS were lower compared with those of controls (P < .05). The mean inhomogeneous magnetization transfer ratio measured in lesions was lower than that in normal-appearing WM (P < .05). Significant (P < .05) negative correlations were found between the clinical scores and inhomogeneous magnetization transfer ratio measured in normal-appearing WM structures. Weaker nonsignificant correlation trends were found for the magnetization transfer ratio. CONCLUSIONS The sensitivity of the inhomogeneous magnetization transfer technique for MS was highlighted by the reduction in the inhomogeneous magnetization transfer ratio in MS lesions and in normal-appearing WM of patients compared with controls. Stronger correlations with the Expanded Disability Status Scale score were obtained with the inhomogeneous magnetization transfer ratio compared with the standard magnetization transfer ratio, which may be explained by the higher specificity of inhomogeneous magnetization transfer for myelin.
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Affiliation(s)
- E Van Obberghen
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - S Mchinda
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - A le Troter
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - V H Prevost
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - P Viout
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - M Guye
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - G Varma
- Department of Radiology (G.V., D.C.A.), Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - D C Alsop
- Department of Radiology (G.V., D.C.A.), Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts
| | - J-P Ranjeva
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - J Pelletier
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
- Aix-Marseille University (J.P.), Assistance Publique des Hôpitaux de Marseille (APHM), Hôpital de La Timone, Pôle de Neurosciences Cliniques, Service de Neurologie, Marseille, France
| | - O Girard
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
| | - G Duhamel
- From Aix-Marseille Université (E.V.O., S.M., A.l.T., V.H.P., P.V., M.G., J.-P.R., J.P., O.G., G.D.), Centre de Résonance Magnétique Biologique et Médicale (CRMBM), UMR 7339 Centre National de Recherche Scientifique (CNRS), Marseille, France
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