Double-slice imaging method in NMR imaging apparatus

A double-slice IMAG method in a nuclear magnetic resonance (NMR) imaging apparatus for obtaining images of slices of an object lying in a space where a static magnetic field is applied, said method comprising the steps of;

• selectively exciting magnetizations in a slice of said object by applying a first synthesized RF magnetic field pulse (HA) in a presence of a gradient magnetic field, said first synthesized RF magnetic field pulse (HA) being synthesized according to the following formula and from a first 90.degree. RF magnetic field pulse (HC) in which cosine Fourier components are dominant in comparison with sine Fourier components and a second 90.degree. RF magnetic field pulse (HS) in which sine Fourier components are dominant in comparison with cosine Fourier components:
• HA=K.multidot.HC+L.multidot.HS
• wherein K.sup.2 +L.sup.2 =1, and each of
• K and L is a real number;
• collecting first echo signals of magnetizations excited by said first synthesized RF magnetic field pulse (HA);
• selectively exciting magnetizations in said slice by applying a second synthesized RF magnetic field pulse (HB) in the presence of said gradient magnetic field, said second synthesized RF magnetic field pulse (HB) being synthesized according to the following formula and from said first 90.degree. RF magnetic field pulse (HC) and said second 90.degree. RF magnetic field pulse (HS):
• HB=M.multidot.HC+N.multidot.HS
• wherein M.sup.2 +N.sup.2 =1, and each of
• M and N is a real number;
• collecting second echo signals of magnetizations excited by said second synthesized RF magnetic field pulse (HB);
• reconstructing a first image corresponding to a first sub-slice from data of said first and second echo signals;
• ad
• reconstructing a second image corresponding to a second sub-slice from data of said first and second echo signals.

A double-slice imaging method in a nuclear magnetic resonance (NMR) imaging apparatus for obtaining images of slices of an object lying in a space where a static magnetic field is applied, said method comprising the steps of:

• selecting exciting magnetizations in a slice of said object by applying a first RF magnetic field pulse amplitude-modulated by a first waveform to said object in a presence of a gradient magnetic field, cosine Fourier components of said first waveform being dominant in comparison with sine Fourier components;
• collecting first echo signals of magnetizations excited by said first RF magnetic field pulse;
• selectively exciting magnetizations in said slice by applying a second RF magnetic field pulse amplitude-modulated by a second waveform to said object in a presence of said gradient magnetic field, sine Fourier components of said second waveform being dominant in comparison with cosine Fourier components so that a slice profile of magnetizations excited by said second RF magnetic field pulse forms two separate peaks at positions of a fist sub-slice of said slice and a second sub-slice of said slice, respectively;
• collecting second echo signals of magnetizations excited by said second RF magnetic field pulse;
• processing an imaging calculating on data (A) of said first echo signals to obtain a first provisional image data (G.multidot.A);
• processing an imaging calculation on data (B) of said second echo signals to obtain a second provisional image data (G.multidot.B);
• and
• processing a slice separation calculation on said first and second provisional image data (G.multidot.A and G.multidot.B) to obtain an image of said first sub-slice and an image of said second sub-slice, respectively.