Undersampling to acquire nuclear magnetic resonance images.

In this paper, we present a method that permits the application of a direct digital receiver based on undersampling techniques to NMR and MRI scanners working with incoherent excitation pulses, and we evaluate the performance of such receivers in the acquisition and reconstruction of images. The method has been tested on a BRUKER BIOSPEC BMT 47/40, and the results show that undersampling can be used to process NMR and MRI signals, and that it correctly reconstructs images without loss of information, extending the range of applications of 'digital radio' techniques to NMR and MRI systems working with high-intensity magnetic fields. We also describe a series of tests performed to validate the application of undersampling to NMR systems and an algorithm to compensate the phase fluctuations due to the incoherent excitation pulses.

[1]  Emmanuel Ifeachor,et al.  Digital Signal Processing: A Practical Approach , 1993 .

[2]  J. A. Wepman,et al.  Analog-to-digital converters and their applications in radio receivers , 1995, IEEE Commun. Mag..

[3]  W. Edelstein,et al.  A signal-to-noise calibration procedure for NMR imaging systems. , 1984, Medical physics.

[4]  T W Redpath,et al.  Estimating achievable signal-to-noise ratios of MRI transmit-receive coils from radiofrequency power measurements: applications in quality control. , 2000, Physics in medicine and biology.

[5]  R. Henkelman.  Measurement of signal intensities in the presence of noise in MR images. , 1985, Medical physics.

[6]  H. V. Sorensen,et al.  An overview of sigma-delta converters , 1996, IEEE Signal Process. Mag..

[7]  M. T. Vlaardingerbroek,et al.  Magnetic Resonance Imaging: Theory and Practice , 1996 .

[8]  Ulrich L. Rohde,et al.  Communications Receivers: Principles and Design , 1988 .

[9]  E. Brigham,et al.  The fast Fourier transform and its applications , 1988 .

[10]  C-N. Chen,et al.  Biomedical magnetic resonance technology , 1989 .

[11]  Rodney G. Vaughan,et al.  The theory of bandpass sampling , 1991, IEEE Trans. Signal Process..

[12]  K. W. Cattermole,et al.  Principles of pulse code modulation , 1969 .

[13]  Hassane S. Mchaourab,et al.  ELECTRON PARAMAGNETIC RESONANCE DETECTION BY TIME-LOCKED SUBSAMPLING , 1998 .

[14]  H. Carr,et al.  The Principles of Nuclear Magnetism , 1961 .

[15]  E. McVeigh,et al.  Signal‐to‐noise measurements in magnitude images from NMR phased arrays , 1997 .