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US 10,591,561 B2Granted
Pulse sequences for low field magnetic resonance
AssigneeHyperfine Research, Inc.
InventorsLaura Sacolick, Matthew Scot Rosen, Gregory L. Charvat, Jonathan M. Rothberg, Mathieu Sarracanie
Life of this patent
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Abstract
A low-field magnetic resonance imaging (MRI) system. The system includes a plurality of magnetics components comprising at least one first magnetics component configured to produce a low-field main magnetic field B0 and at least one second magnetics component configured to acquire magnetic resonance data when operated, and at least one controller configured to operate one or more of the plurality of magnetics components in accordance with at least one low-field zero echo time (LF-ZTE) pulse sequence.
Claims35
A low-field magnetic resonance imaging (MRI) system, comprising:
- a plurality of magnetics components comprising:
- a B0 magnetic component configured to produce a low-field main magnetic field B0;
- at least one gradient coil configured to, when operated, provide spatial encoding of emitted magnetic resonance signals;
- and
- at least one radio frequency component configured to acquire magnetic resonance data when operated;
- and
- at least one controller that operates one or more of the plurality of magnetics components in accordance with at least one pulse sequence having a plurality of pulse repetition periods over which magnetic resonance signals are produced and detected, wherein the at least one controller is configured to operate the at least one gradient coil to produce a gradient field throughout each of the plurality of pulse repetition periods, and
- wherein the at least one controller is configured to apply at least one RF pulse, and wherein applying the at least one RF pulse comprises generating at least one RF pulse of a duration and amplitude to deflect a net magnetization vector of a subject being imaged by an angle smaller than 30 degrees.
5 more elements
A low-field magnetic resonance imaging (MRI) system comprising:
- a plurality of magnetics components comprising at least one first magnetics component configured to produce a low-field main magnetic field B0 and at least one second magnetics component configured to acquire magnetic resonance data when operated;
- and
- at least one controller that operates one or more of the plurality of magnetics components in accordance with at least one pulse sequence, wherein the at least one controller is configured to operate the one or more of the plurality of magnetics components in accordance with the pulse sequence at least in part by performing a set of acts including:
- (A) applying a plurality of gradient fields;
- (B) while applying the plurality of gradient fields:
- applying at least one RF pulse comprising generating at least one RF pulse of a duration and amplitude to deflect a net magnetization vector of a subject being imaged by an angle smaller than 30 degrees;
- and
- after a threshold amount of time elapses after application of the at least one RF pulse, acquiring a magnetic resonance signal;
- and
- (C) adjusting strengths of at least one of the plurality of gradient fields to at least one other value.
7 more elements
A low-field magnetic resonance imaging (MRI) comprising:
- a plurality of magnetics components comprising at least one first magnetics component configured to produce a low-field main magnetic field B0 and at least one second magnetics component configured to acquire magnetic resonance data when operated;
- and
- at least one controller that operates one or more of the plurality of magnetics components in accordance with at least one pulse sequence, wherein the at least one controller is configured to operate the one or more of the plurality of magnetics components in accordance with the pulse sequence at least in part by performing a set of acts including:
- (A) applying a plurality of gradient fields;
- (B) while applying the plurality of gradient fields:
- applying at least one RF pulse, wherein applying the at least one RF pulse comprises pre-emphasizing, based at least on a transfer function of a transmit coil of the low-field MRI system, the at least one RF pulse to obtain at least one pre-emphasized RF pulse, and transmitting the at least one pre-emphasized RF pulse using the transmit coil;
- and
- after a threshold amount of time elapses after application of the at least one RF pulse, acquiring a magnetic resonance signal;
- and
- (C) adjusting strengths of at least one of the plurality of gradient fields to at least one other value.
7 more elements
A low-field magnetic resonance imaging (MRI) system, comprising:
- a plurality of magnetics components comprising at least one first magnetics component configured to produce a low-field main magnetic field B0 and at least one second magnetics component configured to acquire magnetic resonance data when operated;
- and
- at least one controller that operates one or more of the plurality of magnetics components in accordance with at least one pulse sequence, wherein the controller is configured to operate the one or more of the plurality of magnetics components in accordance with the at least one pulse sequence at least in part by performing a set of acts including:
- (A) applying an RF pulse;
- (B) after applying the RF pulse, applying a plurality of gradient fields;
- (C) after applying the plurality of gradient fields, acquiring a magnetic resonance signal while applying one of the plurality of gradient fields;
- (D) after acquiring the magnetic resonance signal, refocusing a magnetic moment of a subject being imaged at least in part by applying gradient fields with strengths and/or polarities selected such that a sum of the field strengths of each gradient field across a duration of a pulse repetition period of the at least one pulse sequence is zero.
4 more elements
A low-field magnetic resonance imaging (MRI) comprising:
- a plurality of magnetics components comprising:
- a B0 magnetic component configured to produce a low-field main magnetic field B0;
- at least one gradient coil configured to, when operated, provide spatial encoding of emitted magnetic resonance signals;
- and
- at least one radio frequency component configured to acquire magnetic resonance data when operated;
- and
- at least one controller that operates one or more of the plurality of magnetics components in accordance with at least one pulse sequence having a plurality of pulse repetition periods over which magnetic resonance signals are produced and detected, wherein the at least one controller is configured to operate the at least one gradient coil to produce a gradient field throughout each of the plurality of pulse repetition periods and,
- wherein the at least one controller is configured to apply at least one RF pulse, and wherein applying the at least one RF pulse comprises pre-emphasizing, based at least on a transfer function of a transmit coil of the low-field MRI system, the at least one RF pulse to obtain at least one pre-emphasized RF pulse, and transmitting the at least one pre-emphasized RF pulse using the transmit coil.
5 more elements
Dependencies are inferred from the claim text.