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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

3D ECG-gated cine image of a mouse heart at 156 μm isotropic resolution obtained before (at 7 T) and after injection of USPIO at 200 μmol Fe/kg (at 4.7, 7 and 9.4 T). Ten images per cardiac cycle were generated, the images at the end of diastole (left) and systole (right) are shown in two orientations (short axis: upper panels; long axis: lower panels). No respiratory gating was used
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Fig4: 3D ECG-gated cine image of a mouse heart at 156 μm isotropic resolution obtained before (at 7 T) and after injection of USPIO at 200 μmol Fe/kg (at 4.7, 7 and 9.4 T). Ten images per cardiac cycle were generated, the images at the end of diastole (left) and systole (right) are shown in two orientations (short axis: upper panels; long axis: lower panels). No respiratory gating was used

Mentions: 3D-cine images at 156 μm isotropic resolution were acquired prospectively with the UTE sequence for the three magnetic fields tested before and after contrast agent injection. The intermediate concentration of contrast agent (200 μmol Fe/kg) was used for the images shown in Fig. 4, but similar results were obtained with the highest concentration. Slices were extracted during systole and diastole in two orientations (short axis and long axis) and are shown for the three magnetic fields. The acquisition times for these images were around 12 min.Fig. 4


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)

3D ECG-gated cine image of a mouse heart at 156 μm isotropic resolution obtained before (at 7 T) and after injection of USPIO at 200 μmol Fe/kg (at 4.7, 7 and 9.4 T). Ten images per cardiac cycle were generated, the images at the end of diastole (left) and systole (right) are shown in two orientations (short axis: upper panels; long axis: lower panels). No respiratory gating was used
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig4: 3D ECG-gated cine image of a mouse heart at 156 μm isotropic resolution obtained before (at 7 T) and after injection of USPIO at 200 μmol Fe/kg (at 4.7, 7 and 9.4 T). Ten images per cardiac cycle were generated, the images at the end of diastole (left) and systole (right) are shown in two orientations (short axis: upper panels; long axis: lower panels). No respiratory gating was used
Mentions: 3D-cine images at 156 μm isotropic resolution were acquired prospectively with the UTE sequence for the three magnetic fields tested before and after contrast agent injection. The intermediate concentration of contrast agent (200 μmol Fe/kg) was used for the images shown in Fig. 4, but similar results were obtained with the highest concentration. Slices were extracted during systole and diastole in two orientations (short axis and long axis) and are shown for the three magnetic fields. The acquisition times for these images were around 12 min.Fig. 4

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