- Workshop presentation
- Open Access
Sodium imaging of the heart at 7T: design, evaluation and application of a four-channel transmit/receive surface coil array
© Graessl et al; licensee BioMed Central Ltd. 2013
- Published: 30 January 2013
- Chronic Heart Disease
- Voxel Model
- Adequate Image Quality
- Loop Element
- Sodium Imaging
Insight of physiological processes and cellular metabolism makes 23Na-MRI conceptually appealing as non-invasive imaging discipline. Several studies report the applicability of 23Na-MRI for the detection and assessment of acute and chronic heart disease due to increased sodium concentration after myocardial infarctions. Bi-exponential decay of the signal and a low SNR compared to 1H-MRI makes 23Na-MRI unattractive for clinical use. With a high SNR and fast imaging technologies ultrahigh field MRI brings 23Na-MRI back into focus, asking for dedicated radiofrequency (RF) technology.
The reflection coefficient of each element was measured to be better than -18 dB, transmission coefficients were found to be below -16 dB. The SAR values fell well within the limits provided by the IEC 60601-2-33 for input power of 10W in normal mode. In vivo studies yielded a rather uniform signal intensity across the heart leading to adequate image quality. An intense signal caused by the high 23Na-concentration of the ribs was observed. The cardiac triggered acquisitions showed a SNR of 38 in the blood-pool and 24 in the septum resulting in a blood/myocardium contrast of 3,3.
Our results demonstrate that 23Na-MRI of the heart is feasible at 7.0 T. The proposed RF coil design yielded adequate image quality within clinically acceptable scan times for free breathing, cardiac triggered acquisitions. Using an even larger number of TX/RX channels would help to further boost SNR and spatial resolution together with scan time shortening.
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