A Quantitative Fast Frequency Locking Magnetic Resonance Imaging Method

Abstract

The invention discloses a quantitative fast frequency-locked magnetic resonance imaging method. Data acquisition of magnetic resonance imaging signals corresponding to different spin lock pulses in acontinuous scanning period is completed, and the data fills the same position in K space, so that T1rhomapping images finally obtained corresponding to the different spin lock pulses have high matching degree and can be used for judging tissue fibrosis indexes and diagnosing a tissue edema state; the effects of arrhythmia, uneven breathing and the like on the quality of the T1rhomapping images areminimized, and physical state and ability to suspend breathing and the like of a tester are not strictly required, so that scanning time required to obtain the T1rhomapping images is greatly shortened and the research and promotion of a T1rhomapping imaging technology in the field of clinical medical detection is further developed; in addition, the spin lock pulses alternate in positive and negative phases in adjacent RF excitation pulses, thereby effectively reducing artifacts due to magnetic field uniformity.

Description

technical field [0001] The invention belongs to the technical field of medical diagnosis, and relates to a magnetic resonance scanning method that requires ECG and respiratory gating navigation for clinical heart and the like. Background technique [0002] Magnetic resonance imaging (MRI, Magnetic Resonance Imaging) has been widely used in clinical examination and experimental research of diseases in recent years. It detects T 1 Relaxation time (i.e. spin-lattice relaxation time) and T 2 The difference in relaxation time (spin-spin relaxation time) is obtained by Fourier transform to obtain images of related tissues, so as to display various tissues and the changes caused by different pathologies in the form of images. [0003] The spin-locked pulse refers to the transverse excitation magnetic field B under the MRI system 1 (B 1 ≥0) The low-amplitude radio frequency (RF) pulse generated by the action is a resonant and continuous radio frequency pulse wave with a specific ...

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Problems solved by technology

Although T can be obtained by the above method 1ρ mapping quantitative data, however, the above t 1ρ The mapping imaging method still has the following problems: (1) ECG and respiratory conditions often vary from person to person, poor ECG-respiratory triggering, unstable breath-hold time of patients, and arrhythmia of patients are easy to make the acquired T 1ρ There are artifacts in the mapping image, which affects the imaging quality; (2) often due to the magnet of the equipment (such as not meeting the requirements of B 1 required for the magnetic field), need to change B 1 (3) In order to meet the international guidelines for the specific absorption rate (SAR value) during scanning, the scanning time of the imaging process is relatively long (when the ECG is in good condition, a T 1ρ The total scanning time of the mapping image is about 40s; the overall T of the heart is obtained 1ρ The mapping image requires six T 1ρ mapping image, when the ECG is disordered, it is impossible to obtain a good quality image, and the scanning time will be prolonged, or even interrupted, so the total scanning time is much longer than 6 minutes), which requires high breath-holding ability of the patient, and is critical for doctors and patients. As far as patients with diseases are concerned, it is generally difficult to meet the requirements, so that T 1ρ Mapping technology is difficult to have application value

And the above T 1ρ Problems such as high image artifacts and poor patient cooperation or status in the mapping technology are also T 1ρ Reasons why it is difficult to make further progress in the development and promotion of mapping technology

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