Fig 1.
Design and simulations of the new whole-body RF-coil.
(a-d) Electromagnetic field modelling results for the designed whole-body coil. (a) Coronal view and (b) transversal view of the 10g local SAR maps showing hotspots in the chest wall and shoulders. (c) Predicted B1+ efficiency map. Note the uniformity of excitation across the heart and liver. (d) Direct comparison of B1+ variability across the heart between surface transmit (Tx) coil and the whole-body Tx coil. (e) A photograph of the new apparatus installed on our 7T MRI scanner. The extension of the patient table with the integrated whole-body coil rests on a custom-build support frame and connects to the existing motorized patient bed from the service end of the scanner.
Table 1.
Comparison of the SNR and peak B1+ between three combinations of RF transmit and receive coils in a phantom placed 10 cm away from the surface RF-coil.
Fig 2.
Transverse in vivo maps of (a, b) PCr and (c, d) 2,3-DPG signals acquired using the body coil in (a, c) transceiver mode and (b, d)using the combined whole-body transmit and 16-channel local receive setup. All maps are overlaid on 1H localizer images registered to the CSI grid. Note that the signals outside the body are from a concentrated fiducial mounted in the centre of the receive array.
Fig 3.
Representative in vivo 31P-MR spectra acquired with the 3D-UTE-CSI protocol in (a) human heart and (b) liver using the combined coil setup. (c) PCr metabolite map in transverse view through the chest without the saturation pulses. (d) Shows the ratio of PCr signal from acquisitions with and without the saturation bands applied to reduce skeletal muscle signal.
Fig 4.
(a) Representative Bloch-Siegert, 2D, transverse B1+ map overlaid on 1H localizer image registered to the CSI grid. (b) A histogram of measured B1+ variability across all four subjects normalized to individual subject median B1+. A fitted normal distribution function (red line) is also depicted. All voxels with sufficient SNR were used for analysis.