- Workshop presentation
- Open Access
Feasibility and benefit of using a cryogenic radiofrequency coil for functional cardiac magnetic resonance imaging of mice at 9.4 T
© Dieringer et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Cardiac Magnetic Resonance
- Coil Array
- Intraobserver Variability
- Cardiac Morphology
- Myocardial Border
Cardiac morphology and function assessment by MRI is of increasing interest for a variety of mouse models in pre-clinical research. Signal-to-noise ratio (SNR) constraints, however, limit image quality and blood myocardium delineation, which crucially depend on high spatial resolution. Significant gains in SNR can be achieved with a cryogenically cooled RF probe. This study examines the feasibility and potential benefits of CMR in mice employing a 400 MHz cryogenic RF surface coil, compared with a conventional mouse heart coil array operating at room temperature.
Imaging was conducted using a 9.4T MR system (Bruker Biospin, Ettlingen, Germany). Two RF coil set-ups were used: a) a conventional linear polarized birdcage resonator (Bruker Biospin; inner diameter 72mm) for transmission in conjunction with a curved four channel receive only mouse cardiac coil array (Bruker Biospin) at room temperature (RT) and b) a cryogenic transceive quadrature RF surface coil (CryoProbe, CP, Bruker Biospin) of similar coil geometry as the RT surface coil (inner diameter 20mm) operating at 30 K (preamplifiers at 77 K). Ten C57BL/6N mice were imaged twice, once with the RT-coil and once with the CryoProbe. Short axis views were acquired for ten slices covering the whole heart using a self-gated bright-blood cine technique (IntraGate-FLASH, slice thickness=0.8 mm). For each coil two imaging protocols with TE/TR=1.3/8.5 ms and 20 frames were conducted: a) conventional spatial resolution (156x234x800 µm3, α=15°, NR=100, TA ~2 min) and b) high spatial resolution (69x115x800 µm3, α=20°, NR=170, TA ~4.5 min). The latter was used for cardiac function assessment. Intraobserver variability for the EDV, ESV and EDM of the left and right ventricle was evaluated using Bland-Altman analysis.
Cardiac morphology, cardiac chamber quantification and cardiac function assessment using a cryogenically cooled RF probe is feasible and affords significant SNR gains over the conventional approach. Hence, the use of a cryogenically cooled RF probe represents a valuable means of enhancing the capabilities of CMR of mice.
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