Limits...
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 UTE images at 9.4 T showing the heart and the liver of a mouse. Images were acquired before and after injection of USPIO at 50, 200 and 500 μmol Fe/kg, without cardiac or respiratory synchronization. The small arrow indicates the aortic arch and the dashed arrow indicates the liver
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: 3D UTE images at 9.4 T showing the heart and the liver of a mouse. Images were acquired before and after injection of USPIO at 50, 200 and 500 μmol Fe/kg, without cardiac or respiratory synchronization. The small arrow indicates the aortic arch and the dashed arrow indicates the liver

Mentions: Images were acquired in a zone extending from the liver to the neck. Three different concentrations of contrast agents were used, and the images acquired at 9.4 T pre- and post contrast agent injection with UTE sequences are shown in Fig. 2. Before injecting the contrast agent, the blood vessels and the blood inside the ventricles were not readily visible. After injection of the contrast agent, whatever the concentration injected, the blood in the various blood vessels was visible with the UTE sequence with an intense signal. This signal was highly homogeneous, whether in zones with high turbulence, such as the aortic arch (Fig. 2, small arrow), or in blood vessels with slow-flow, such as the jugular veins. No artefact related to blood flow or movement was visible on the images.Fig. 2


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 UTE images at 9.4 T showing the heart and the liver of a mouse. Images were acquired before and after injection of USPIO at 50, 200 and 500 μmol Fe/kg, without cardiac or respiratory synchronization. The small arrow indicates the aortic arch and the dashed arrow indicates the liver
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Fig2: 3D UTE images at 9.4 T showing the heart and the liver of a mouse. Images were acquired before and after injection of USPIO at 50, 200 and 500 μmol Fe/kg, without cardiac or respiratory synchronization. The small arrow indicates the aortic arch and the dashed arrow indicates the liver
Mentions: Images were acquired in a zone extending from the liver to the neck. Three different concentrations of contrast agents were used, and the images acquired at 9.4 T pre- and post contrast agent injection with UTE sequences are shown in Fig. 2. Before injecting the contrast agent, the blood vessels and the blood inside the ventricles were not readily visible. After injection of the contrast agent, whatever the concentration injected, the blood in the various blood vessels was visible with the UTE sequence with an intense signal. This signal was highly homogeneous, whether in zones with high turbulence, such as the aortic arch (Fig. 2, small arrow), or in blood vessels with slow-flow, such as the jugular veins. No artefact related to blood flow or movement was visible on the images.Fig. 2

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