Scan time Saving Uniformity Correction Technique for In-vivo 7T MR Brain 23Na Imaging

Principal Investigator: Alexander Lin

Authors: Sanghoon Kim, Alexander Lin
Lay Abstract

Materials and Methods
Sequence: UTE_3D Sequence. TR/TE: 12.8/0.27, FA: 25.

When we calculate a sensitivity map for the uniformity correction, we need to get low pass filtered volume coil (birdcage) and array coil (32ch) images. To reduce the scan time and increase SNR in the volume coil image, we obtained lower resolution images and used interpolated one. We measured line profiles from the center slice of the in vivo images using Matlab and custom image analysis scripts to confirm the uniformity correction effect.

Results
Due to the large voxel size, we can confirm that the lower resolution images were less noisy (Fig. 1) while preserving overall anatomic morphology. The uniformity correction results with lower resolution images show almost identical results high resolution one (Fig. 2). Using the 4mm iso-cubic resolution volume coil images, we could get 2mm and 3mm iso-cubic voxel total sodium concentration (TSC) map within 12 min 30s and 6min 30s, respectably (Fig. 3).

Conclusion
We demonstrated the feasibility of using lower resolution volume coil images for uniformity correction. It provides similar uniformity correction results when we compare with high resolution data while reducing scan time significantly. Our approach can be applied to the brain cancer patient practically.

Scientific Abstract

Materials and Methods
Sequence: UTE_3D Sequence. TR/TE: 12.8/0.27, FA: 25.

When we calculate a sensitivity map for the uniformity correction, we need to get low pass filtered volume coil (birdcage) and array coil (32ch) images. To reduce the scan time and increase SNR in the volume coil image, we obtained lower resolution images and used interpolated one. We measured line profiles from the center slice of the in vivo images using Matlab and custom image analysis scripts to confirm the uniformity correction effect.

Results
Due to the large voxel size, we can confirm that the lower resolution images were less noisy (Fig. 1) while preserving overall anatomic morphology. The uniformity correction results with lower resolution images show almost identical results high resolution one (Fig. 2). Using the 4mm iso-cubic resolution volume coil images, we could get 2mm and 3mm iso-cubic voxel total sodium concentration (TSC) map within 12 min 30s and 6min 30s, respectably (Fig. 3).

Conclusion
We demonstrated the feasibility of using lower resolution volume coil images for uniformity correction. It provides similar uniformity correction results when we compare with high resolution data while reducing scan time significantly. Our approach can be applied to the brain cancer patient practically.

Clinical Implications
In a clinical setting, reducing the scan time is occasionally more critical than best quality images. Our approach can provide an alternative solution for those cases in which timing is critical.

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