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Positive contrast high-resolution 3D-cine imaging of the cardiovascular system in small animals using a UTE sequence and iron nanoparticles at 4.7, 7 and 9.4 T.

Trotier AJ, Lefrançois W, Van Renterghem K, Franconi JM, Thiaudière E, Miraux S - J Cardiovasc Magn Reson (2015)

Bottom Line: UTE imaging generated positive contrast and higher SNR and CNR whatever the magnetic field and the USPIO concentration used compared to pre-contrast images.We have demonstrated that by combining the injection of iron nanoparticles with 3D-cine UTE sequences, it was possible to generate a strong positive contrast between blood and surrounding tissues.These properties were exploited to produce images of the cardiovascular system in small animals at high magnetic fields with a high spatial and temporal resolution.

View Article: PubMed Central - PubMed

Affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS/Université de Bordeaux, 146 rue Léo Saignat, Cedex 33076, Bordeaux, France. trotier@rmsb.u-bordeaux2.fr.

ABSTRACT

Background: To show that 3D sequences with ultra-short echo times (UTEs) can generate a positive contrast whatever the magnetic field (4.7, 7 or 9.4 T) and whatever Ultra Small Particles of Iron Oxide (USPIO) concentration injected and to use it for 3D time-resolved imaging of the murine cardiovascular system with high spatial and temporal resolutions.

Methods: Three different concentrations (50, 200 and 500 μmol Fe/kg) of USPIO were injected in mice and static images of the middle part of the animals were acquired at 4.7, 7 and 9.4 T pre and post-contrast with UTE (TE/TR = 0.05/4.5 ms) sequences. Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) of blood and static tissus were evaluated before and after contrast agent injection. 3D-cine images (TE/TR = 0.05/3.5 ms, scan time < 12 min) at 156 μm isotropic resolution of the mouse cardiopulmonary system were acquired prospectively with the UTE sequence for the three magnetic fields and with an USPIO dose of 200 μmol Fe/kg. SNR, CNR and signal homogeneity of blood were measured. High spatial (104 μm) or temporal (3.5 ms) resolution 3D-cine imaging (scan time < 35 min) isotropic resolution were also performed at 7 T with a new sequence encoding scheme.

Results: UTE imaging generated positive contrast and higher SNR and CNR whatever the magnetic field and the USPIO concentration used compared to pre-contrast images. Time-resolved 3D acquisition enables high blood SNR (66.6 ± 4.5 at 7 T) and CNR (33.2 ± 4.2 at 7 T) without flow or motion artefact. Coronary arteries and aortic valve were visible on images acquired at 104 μm resolution.

Conclusions: We have demonstrated that by combining the injection of iron nanoparticles with 3D-cine UTE sequences, it was possible to generate a strong positive contrast between blood and surrounding tissues. These properties were exploited to produce images of the cardiovascular system in small animals at high magnetic fields with a high spatial and temporal resolution. This approach might be useful to measure the functional cardiac parameters or to assess anatomical modifications to the blood vessels in cardio-vascular disease models.

No MeSH data available.


Related in: MedlinePlus

Acquisition scheme of the 3D ECG-triggered UTE sequence used to reconstruct either 10 High Spatial Resolution cine images or 40 High Temporal Resolution cine images. a Blocks of 4 Free Induction Decays (FIDs) corresponding to 4 k-space trajectories (named « 1-2-3-4 » for the first R-R interval, « 5-6-7-8 » for the second R-R interval…) were repeatedly acquired 10 times along one R-R interval. b (up) Point surface showing the end-point of the acquired half-projections in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane, acquired 10 times for one R-R interval. The reconstructed images display high space resolution (HSR) and lower time resolution. c (up) Point surface showing the ends of the first acquired half-projection of each block in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane of the end-point of trajectories. The reconstructed images display higher time resolution (HR) at the expense of space-resolution. d Projections on the kx-ky plane of the end-point of the second trajectories of each block used for HTR2, 6,… images in red, the third trajectories of each block used for HTR3, 7, … images in green and the fourth trajectories of each block used for HTR4, 8, … images in magenta
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Fig1: Acquisition scheme of the 3D ECG-triggered UTE sequence used to reconstruct either 10 High Spatial Resolution cine images or 40 High Temporal Resolution cine images. a Blocks of 4 Free Induction Decays (FIDs) corresponding to 4 k-space trajectories (named « 1-2-3-4 » for the first R-R interval, « 5-6-7-8 » for the second R-R interval…) were repeatedly acquired 10 times along one R-R interval. b (up) Point surface showing the end-point of the acquired half-projections in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane, acquired 10 times for one R-R interval. The reconstructed images display high space resolution (HSR) and lower time resolution. c (up) Point surface showing the ends of the first acquired half-projection of each block in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane of the end-point of trajectories. The reconstructed images display higher time resolution (HR) at the expense of space-resolution. d Projections on the kx-ky plane of the end-point of the second trajectories of each block used for HTR2, 6,… images in red, the third trajectories of each block used for HTR3, 7, … images in green and the fourth trajectories of each block used for HTR4, 8, … images in magenta

Mentions: The acquisition scheme of the triggered prospective sequence is shown on Fig. 1. The proposed encoding scheme allows to reconstruct with the same acquisition datas, either Ncine = R-Rinterval/(4 x TR) High Spatial Resolution images (HSR), or Ncine = R-Rinterval/TR High Temporal Resolution (HTR) images.Fig. 1


Positive contrast high-resolution 3D-cine imaging of the cardiovascular system in small animals using a UTE sequence and iron nanoparticles at 4.7, 7 and 9.4 T.

Trotier AJ, Lefrançois W, Van Renterghem K, Franconi JM, Thiaudière E, Miraux S - J Cardiovasc Magn Reson (2015)

Acquisition scheme of the 3D ECG-triggered UTE sequence used to reconstruct either 10 High Spatial Resolution cine images or 40 High Temporal Resolution cine images. a Blocks of 4 Free Induction Decays (FIDs) corresponding to 4 k-space trajectories (named « 1-2-3-4 » for the first R-R interval, « 5-6-7-8 » for the second R-R interval…) were repeatedly acquired 10 times along one R-R interval. b (up) Point surface showing the end-point of the acquired half-projections in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane, acquired 10 times for one R-R interval. The reconstructed images display high space resolution (HSR) and lower time resolution. c (up) Point surface showing the ends of the first acquired half-projection of each block in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane of the end-point of trajectories. The reconstructed images display higher time resolution (HR) at the expense of space-resolution. d Projections on the kx-ky plane of the end-point of the second trajectories of each block used for HTR2, 6,… images in red, the third trajectories of each block used for HTR3, 7, … images in green and the fourth trajectories of each block used for HTR4, 8, … images in magenta
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4493959&req=5

Fig1: Acquisition scheme of the 3D ECG-triggered UTE sequence used to reconstruct either 10 High Spatial Resolution cine images or 40 High Temporal Resolution cine images. a Blocks of 4 Free Induction Decays (FIDs) corresponding to 4 k-space trajectories (named « 1-2-3-4 » for the first R-R interval, « 5-6-7-8 » for the second R-R interval…) were repeatedly acquired 10 times along one R-R interval. b (up) Point surface showing the end-point of the acquired half-projections in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane, acquired 10 times for one R-R interval. The reconstructed images display high space resolution (HSR) and lower time resolution. c (up) Point surface showing the ends of the first acquired half-projection of each block in a 3D k-space and (bottom) the corresponding projections on the kx-ky plane of the end-point of trajectories. The reconstructed images display higher time resolution (HR) at the expense of space-resolution. d Projections on the kx-ky plane of the end-point of the second trajectories of each block used for HTR2, 6,… images in red, the third trajectories of each block used for HTR3, 7, … images in green and the fourth trajectories of each block used for HTR4, 8, … images in magenta
Mentions: The acquisition scheme of the triggered prospective sequence is shown on Fig. 1. The proposed encoding scheme allows to reconstruct with the same acquisition datas, either Ncine = R-Rinterval/(4 x TR) High Spatial Resolution images (HSR), or Ncine = R-Rinterval/TR High Temporal Resolution (HTR) images.Fig. 1

Bottom Line: UTE imaging generated positive contrast and higher SNR and CNR whatever the magnetic field and the USPIO concentration used compared to pre-contrast images.We have demonstrated that by combining the injection of iron nanoparticles with 3D-cine UTE sequences, it was possible to generate a strong positive contrast between blood and surrounding tissues.These properties were exploited to produce images of the cardiovascular system in small animals at high magnetic fields with a high spatial and temporal resolution.

View Article: PubMed Central - PubMed

Affiliation: Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS/Université de Bordeaux, 146 rue Léo Saignat, Cedex 33076, Bordeaux, France. trotier@rmsb.u-bordeaux2.fr.

ABSTRACT

Background: To show that 3D sequences with ultra-short echo times (UTEs) can generate a positive contrast whatever the magnetic field (4.7, 7 or 9.4 T) and whatever Ultra Small Particles of Iron Oxide (USPIO) concentration injected and to use it for 3D time-resolved imaging of the murine cardiovascular system with high spatial and temporal resolutions.

Methods: Three different concentrations (50, 200 and 500 μmol Fe/kg) of USPIO were injected in mice and static images of the middle part of the animals were acquired at 4.7, 7 and 9.4 T pre and post-contrast with UTE (TE/TR = 0.05/4.5 ms) sequences. Signal-to-Noise Ratio (SNR) and Contrast-to-Noise Ratio (CNR) of blood and static tissus were evaluated before and after contrast agent injection. 3D-cine images (TE/TR = 0.05/3.5 ms, scan time < 12 min) at 156 μm isotropic resolution of the mouse cardiopulmonary system were acquired prospectively with the UTE sequence for the three magnetic fields and with an USPIO dose of 200 μmol Fe/kg. SNR, CNR and signal homogeneity of blood were measured. High spatial (104 μm) or temporal (3.5 ms) resolution 3D-cine imaging (scan time < 35 min) isotropic resolution were also performed at 7 T with a new sequence encoding scheme.

Results: UTE imaging generated positive contrast and higher SNR and CNR whatever the magnetic field and the USPIO concentration used compared to pre-contrast images. Time-resolved 3D acquisition enables high blood SNR (66.6 ± 4.5 at 7 T) and CNR (33.2 ± 4.2 at 7 T) without flow or motion artefact. Coronary arteries and aortic valve were visible on images acquired at 104 μm resolution.

Conclusions: We have demonstrated that by combining the injection of iron nanoparticles with 3D-cine UTE sequences, it was possible to generate a strong positive contrast between blood and surrounding tissues. These properties were exploited to produce images of the cardiovascular system in small animals at high magnetic fields with a high spatial and temporal resolution. This approach might be useful to measure the functional cardiac parameters or to assess anatomical modifications to the blood vessels in cardio-vascular disease models.

No MeSH data available.


Related in: MedlinePlus