MR imaging using nested pulse sequence involving IR pulse
First Claim
1. A method of magnetic resonance imaging for a plurality of slice planes of an object by carrying out a plurality of pulse sequences at a repetition time, each pulse sequence being applied to each slice plane and including an inversion sequence with an inversion pulse and an imaging sequence applied after an inversion time has passed from the application of the inversion sequence, and each slice including nuclear spins, the method comprising the steps of:
- manually specifying both the repetition time and the inversion time;
setting the plurality of pulse sequences according to both of the specified repetition time and the specified inversion time so that, during each inversion time of each specified pulse sequence, both of more than one inversion sequence and more than one imaging sequence belonging to pulse sequences other than the specified pulse sequence is allocated in a nesting way that allows the plurality of pulse sequences to be nested one in another during repeating a scan every repetition time, and the plurality of pulse sequences cause the nuclear spins included in each of the plurality of slice planes to be subjected to magnetic actions during the same time interval within the repetition time by allocating two kinds of waiting time periods between the applications of the inversion sequence and the imaging sequence; and
performing a multislice scan for the plurality of slice planes using the set pulse sequences.
0 Assignments
0 Petitions
Accused Products
Abstract
In addition to the known MT (magnetization transfer) effect, an RMT (reverse MT) is newly found, which increases a detected MR signal strength. Both the MT and RMT effects can be explained with mutual interaction, such as phenomena of chemical exchange and/or cross relaxation, acted between a pool of water proton spins and another pool of macromolecule proton spins, for example, within an object. In order to enhance the MT or RMT effect, the frequency bandwidths of RF pulses, such as a 90° RF exciting pulse in a SE or FSE method, an inversion pulse in a FLAIR or fast FLAIR method, and others, are controlled. To enhance the MT effect, the bandwidth is controlled into a wider value (approx. more than 1250 Hz) than the normally (conventionally) used bandwidth, while to obtain the RMT effect, the bandwidth is controlled into a narrower value (approx. less than 1000 Hz) than the normally used bandwidth. Actively controlling the MT or RMT effect permits changed image contrast in MR imaging.
-
Citations
10 Claims
-
1. A method of magnetic resonance imaging for a plurality of slice planes of an object by carrying out a plurality of pulse sequences at a repetition time, each pulse sequence being applied to each slice plane and including an inversion sequence with an inversion pulse and an imaging sequence applied after an inversion time has passed from the application of the inversion sequence, and each slice including nuclear spins, the method comprising the steps of:
-
manually specifying both the repetition time and the inversion time;
setting the plurality of pulse sequences according to both of the specified repetition time and the specified inversion time so that, during each inversion time of each specified pulse sequence, both of more than one inversion sequence and more than one imaging sequence belonging to pulse sequences other than the specified pulse sequence is allocated in a nesting way that allows the plurality of pulse sequences to be nested one in another during repeating a scan every repetition time, and the plurality of pulse sequences cause the nuclear spins included in each of the plurality of slice planes to be subjected to magnetic actions during the same time interval within the repetition time by allocating two kinds of waiting time periods between the applications of the inversion sequence and the imaging sequence; and
performing a multislice scan for the plurality of slice planes using the set pulse sequences. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A magnetic resonance imaging system for a plurality of slice planes of an object by carrying out a plurality of pulse sequences at a repetition time, each pulse sequence being applied to each slice plane and including an inversion sequence with an inversion pulse and an imaging sequence applied after an inversion time has passed from the application of the inversion sequence, and each slice including nuclear spins, the system comprising:
-
a unit configured to receive both manually specified repetition time and inversion time;
a setting unit configured to specify the plurality of pulse sequences according to both of the specified repetition time and the specified inversion time, wherein the setting unit comprises first allocating means for allocating, during each inversion time of each specified pulse sequence, both of more than one inversion sequence and more than one imaging sequence belonging to pulse sequences other than the specified pulse sequence in a nesting way that allows the plurality of pulse sequences to be nested one in another during repeating a scan every repetition time, and second allocating means for allocating two kinds of waiting time periods between the applications of the inversion sequence and the imaging sequence so that the plurality of pulse sequences cause the nuclear spins included in each of the plurality of slice planes to be subjected to magnetic actions during the same time interval within the repetition time; and
a performing unit configured to perform a multislice scan for the plurality of slice planes using the set pulse sequences. - View Dependent Claims (7, 8, 9, 10)
-
Specification