Patent ID: 8570036

Claim:
A magnetic resonance imaging (MRI) apparatus for magnetic resonance angiography (MRA) comprising a coil assembly configured to sequentially transmit a plurality of consecutive radio frequency (RF) pulses α1° θ1° , α2° θ2° , −α1° θ1° , and −α2° θ2° one after another, wherein α1°, α2°, −α1°, and −α2° are the flip angles of the RF pulses, and wherein θ1° and θ2° are the phases of the RF pulses, wherein the four consecutive RF pulses are transmitted for refocusing transverse magnetization of spins and to cause the transverse magnetization of the spins to change to longitudinal magnetization after the refocusing of the transverse magnetization of the spins, wherein a combination of the flip angles α1°, α2°, −α1°, and −α2° of the RF pulses α1° θ1° , α2° θ2° , −α1° θ1° , and −α2° θ2° corresponds to any of the following combinations: (α1°, α2°, −α1°, −α2°)=(180°−Δd1°, 180°+Δd2°, −(180°−Δd1°), −(180°+Δd2°)); (α1°, α2°, −α1°, −α2°)=(180°+Δd1°, −(180°−Δd2°), −(180°+Δd1°), 180°−Δd2°); (α1°, α2°, −α1°, −α2°)=(−(180°−Δd1°), −(180°+Δd2°), 180°−Δd1°, 180°+Δd2°); (α1°, α2°, −α1°, −α2°)=(−(180°+Δd1°), 180°−Δd2°, 180°+Δd1°, −(180°−Δd2°)); (α1°, α2°, −α1°, −α2°)=(180°+Δd1°, 180°−Δd2°, −(180°+Δd1°), −(180°−Δd2°)); (α1°, α2°, −α1°, −α2°)=(180°−Δd1°, −(180°+Δd2°), −(180°−Δd1°), 180°+Δd2°); (α1°, α2°, −α1°, −α2°)=(−(180°+Δd1°), −(180°−Δd2°), 180°+Δd1°, 180°−Δd2°); and (α1°, α2°, −α1°, −α2°)=(−(180°−Δd1°), 180°+Δd2°, 180°−Δd1°, −(180°+Δd2°)), where Δd1° is an angle greater than 0° and less than 180° and Δd2° is an angle greater than 0° and less than 180°, and wherein said coil assembly is further configured to: transmit an RF pulse β° δ° , wherein β° is the flip angle, and δ° is the phase of RF pulse, wherein the RF pulse β° δ° is transmitted prior to the RF pulse α1° θ1° , and transmit an RF pulse −β° δ° , wherein −β° is the flip angle, and δ° is the phase of RF pulse, wherein the RF pulse −β° δ° is transmitted after the RF pulse −α2° θ2° .