Robust single-shot acquisition of high resolution whole brain ASL images by combining time-dependent 2D CAPIRINHA sampling with spatio-temporal TGV reconstruction

NeuroImage

Kristian Bredies¹  Danny JJ. Wang²  Matthias Schloegl²  Rudolf Stollberger³  Stefan M. Spann³  Christoph S. Aigner⁴  Xingfeng Shao⁴ 

[1] Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA;Mary Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA;Institute of Medical Engineering, Graz University of Technology, Stremayrgasse 16, 8010, Graz, Austria;;Laboratory of FMRI Technology (LOFT), Mark &

关键词: Arterial spin labeling;    ASL;    Cerebral blood flow;    CBF;    Spatio-temporal reconstruction;    Total generalized variation (TGV);   

DOI  :  

来源: DOAJ

【 摘 要 】

For ASL perfusion imaging in clinical settings the current guidelines recommends pseudo-continuous arterial spin labeling with segmented 3D readout. This combination achieves the best signal to noise ratio with reasonable resolution but is prone to motion artifacts due to the segmented readout. Motion robust single-shot 3D acquisitions suffer from image blurring due to the T2 decay of the sampled signals during the long readout. To tackle this problem, we propose an accelerated 3D-GRASE sequence with a time-dependent 2D-CAIPIRINHA sampling pattern. This has several advantages: First, the single-shot echo trains are shortened by the acceleration factor; Second, the temporal incoherence between measurements is increased; And third, the coil sensitivity maps can be estimated directly from the averaged k-space data. To obtain improved perfusion images from the undersampled time series, we developed a variational image reconstruction approach employing spatio-temporal total-generalized-variation (TGV) regularization. The proposed ASL-TGV method reduced the total acquisition time, improved the motion robustness of 3D ASL data, and the image quality of the cerebral blood flow (CBF) maps compared to those by a standard segmented approach. An evaluation was performed on 5 healthy subjects including intentional movement for 2 subjects. Single-shot whole brain CBF-maps with high resolution 3.1 × 3.1 × 3 mm and image quality can be acquired in 1min 46sec. Additionally high quality CBF- and arterial transit time (ATT) -maps from single-shot multi-post-labeling delay (PLD) data can be gained with the proposed method. This method may improve the robustness of 3D ASL in clinical settings, and may be applied for perfusion fMRI.

【 授权许可】

Unknown