PURPOSE: Respiratory organ motion is still the major challenge of various image-guided treatments in the abdomen. Dynamic organ motion tracking, necessary for the treatment control, can be performed with volumetric time-resolved MRI that sequentially acquires one image and one navigator slice. Here, a novel imaging method is proposed for truly simultaneous high temporal resolution acquisition. METHODS: A standard balanced steady state free precession sequence was modified to simultaneously acquire two superimposed slices with different phase cycles, namely an image and a navigator slice. Instead of multiband RF pulses, two separate RF pulses were used for the excitation. Images were reconstructed using offline CAIPIRINHA reconstruction. Phantom and in vivo measurements of healthy volunteers were performed and evaluated. RESULTS: Phantom and in vivo measurements showed good image quality with high signal-to-noise ratio (SNR) and no reconstruction issues. CONCLUSION: We present a novel imaging method for truly simultaneous acquisition of image and navigator slices for four-dimensional (4D) MRI of organ motion. In this method, the time lag between the sequential acquisitions is eliminated, leading to an improved accuracy of organ motion models, while CAIPIRINHA reconstruction results in an improved SNR compared with an existing 4D MRI approach.
PURPOSE: Respiratory organ motion is still the major challenge of various image-guided treatments in the abdomen. Dynamic organ motion tracking, necessary for the treatment control, can be performed with volumetric time-resolved MRI that sequentially acquires one image and one navigator slice. Here, a novel imaging method is proposed for truly simultaneous high temporal resolution acquisition. METHODS: A standard balanced steady state free precession sequence was modified to simultaneously acquire two superimposed slices with different phase cycles, namely an image and a navigator slice. Instead of multiband RF pulses, two separate RF pulses were used for the excitation. Images were reconstructed using offline CAIPIRINHA reconstruction. Phantom and in vivo measurements of healthy volunteers were performed and evaluated. RESULTS: Phantom and in vivo measurements showed good image quality with high signal-to-noise ratio (SNR) and no reconstruction issues. CONCLUSION: We present a novel imaging method for truly simultaneous acquisition of image and navigator slices for four-dimensional (4D) MRI of organ motion. In this method, the time lag between the sequential acquisitions is eliminated, leading to an improved accuracy of organ motion models, while CAIPIRINHA reconstruction results in an improved SNR compared with an existing 4D MRI approach.
Authors: Frank Preiswerk; Matthew Toews; Cheng-Chieh Cheng; Jr-Yuan George Chiou; Chang-Sheng Mei; Lena F Schaefer; W Scott Hoge; Benjamin M Schwartz; Lawrence P Panych; Bruno Madore Journal: Magn Reson Med Date: 2016-10-13 Impact factor: 4.668
Authors: Jinsoo Uh; Matthew J Krasin; Yimei Li; Xingyu Li; Christopher Tinkle; John T Lucas; Thomas E Merchant; Chiaho Hua Journal: Int J Radiat Oncol Biol Phys Date: 2017-05-25 Impact factor: 8.013
Authors: Andrew Oar; Gary Liney; Robba Rai; Shrikant Deshpande; Li Pan; Meredith Johnston; Michael Jameson; Shivani Kumar; Mark Lee Journal: Phys Imaging Radiat Oncol Date: 2018-10-06
Authors: Elena H Tran; Björn Eiben; Andreas Wetscherek; Uwe Oelfke; Gustav Meedt; David J Hawkes; Jamie R McClelland Journal: Biomed Phys Eng Express Date: 2020-06-12