Optimizing 4D abdominal MRI: image denoising using an iterative back-projection approach

Baudouin Denis de Senneville (1, 2) , Colleen Rosalie Cardiet (3) , Aurélien Trotier (3) , Emeline Ribot (3) , Luc Lafitte (1) , Laurent Facq (1) , Sylvain Miraux (3)

1 IMB - Institut de Mathématiques de Bordeaux
2 MONC - Modélisation Mathématique pour l'Oncologie
3 CRMSB - Centre de résonance magnétique des systèmes biologiques

4D-MRI is a promising tool for organ exploration, target delineation and treatment planning. Intra-scan motion artifacts may be greatly reduced by increasing the imaging frame rate. However, poor signal-to-noise ratios (SNR) are observed when increasing spatial and/or frame number per physiological cycle, in particular in the abdomen. In the current work, the proposed 4D-MRI method favored spatial resolution, frame number, isotropic voxels and large field-of-view (FOV) during MR-acquisition. The consequential SNR penalty in the reconstructed data is addressed retrospectively using an iterative back-projection (IBP) algorithm. Practically, after computing individual spatial 3D deformations present in the images using a deformable image registration (DIR) algorithm, each 3D image is individually enhanced by fusing several successive frames in its local temporal neighborood, these latter being likely to cover common independent informations. A tuning parameter allows one to freely readjust the balance between temporal resolution and precision of the 4D-MRI. The benefit of the method was quantitatively evaluated on the thorax of 6 mice under free breathing using a clinically acceptable duration. Improved 4D cardiac imaging was also shown in the heart of 1 mice. Obtained results are compared to theoretical expectations and discussed. The proposed implementation is easily parallelizable and optimized 4D-MRI could thereby be obtained with a clinically acceptable duration.

Mots clés: Cardiopulmonary MRI; Abdominal MRI; Iterative back- projection; Denoising; 4D-MRI

Domaines: Imagerie

Baudouin Denis de Senneville, Colleen Rosalie Cardiet, Aurélien Trotier, Emeline Ribot, Luc Lafitte, et al.. Optimizing 4D abdominal MRI: image denoising using an iterative back-projection approach. Physics in Medicine and Biology, inPress, ⟨10.1088/1361-6560/ab563e⟩. ⟨hal-02367839⟩