Synchronous acquisition and calibration method for three-dimensional multi-parameter weighted magnetic resonance imaging

Abstract

The invention discloses a synchronous acquisition and calibration method for three-dimensional multi-parameter weighted magnetic resonance imaging. A three-dimensional / two-dimensional fast multi-echo water-fat separation sequence and a signal debugging method, a pre-scanning method, a scanning method, a data preprocessing method and an image reconstruction method thereof can obtain a water-fat separation image and T2 weighted (T1 weighted or PD weighted) image by one-time scanning. The three-dimensional multi-parameter weighted synchronous scanning and calibration method can maximize the number of images obtained in a single scan, including, an in-phase image, a reverse-phase image, a fat image, a fat-pressed image water, a conventional T2 weighted (or T1 weighted / PD weighted ) image, and a T2weighted images, significantly shortens clinical scanning time and increases the selectivity of clinical scanning schemes, and has less reliance on the hardware performance of an MRI system.

Description

technical field [0001] The invention relates to the technical field of magnetic resonance, in particular to a method for synchronous acquisition and calibration of three-dimensional multi-parameter weighted magnetic resonance imaging. Background technique [0002] Clinically, transverse relaxation time (T2) weighted fat suppression images are beneficial to improve the contrast and resolution of human anatomical details, thereby improving the diagnosis rate of diseases, and are often used in conjunction with T2 weighted images. However, the inversion recovery method will reduce the image signal-to-noise ratio of other human tissues and lesions at the same time, and the frequency-selective liposuction is easily disturbed by the inhomogeneity of the magnetic field and the radio frequency field. As an advanced imaging technology, the chemical shift phase-encoded water-lipid separation imaging technology is the best choice for T2-weighted fat suppression imaging in clinical pract...

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Problems solved by technology

However, the early data acquisition and processing methods lack universal applicability on imaging systems with insufficient hardware performance, and the use of bipolar gradients can cause the chemical shift phase between the three-point Dixon echo groups to deviate from the preset value. Large, the asymmetry effect of the echo amplitude waveform is more significant, the field drift effect causes layer selection errors and causes image blurring, and the long-term exponential term of the eddy current field can also cause high-order phase errors, which cannot be refocused by 180° Elimination of pulse and linear phase correction; especially, phase winding is usually unavoidable at low field strength due to the long interval of FSE echo time and chemical shift encoding echo and the magnetic field uniformity is not high enough, T2 *The relaxation effect cannot be ignored, which leads to incomplete separation of water and fat; in addition, it is difficult for the early two-dimensional imaging method to obtain high-resolution images in the layer selection direction when the gradient strength is not high, while the three-dimensional imaging method is easily affected by the magnet and radio frequency system. The impact of unstable performance

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