Temperature-controlled magnetic resonance imaging method and apparatus

A magnetic resonance imaging (MRI) equipment, comprising:

• a radio frequency transmitting coil, a magnet for imaging by the MRI equipment, a gradient coil, a temperature sensor, a heating element, a filter board, a temperature control device, a heating power supply and a relay output, wherein:
• said temperature sensor is used to measure the temperature of the magnet, so as to acquire the current value of the magnet temperature;
• said temperature control device is used to store a preset set temperature of the magnet, and to send a control signal to the heating power supply using a proportional/integral/differential PID parameter, so as to control the output power of the heating element to the magnet;
• wherein:
• said MRI equipment also comprises:
• a memory module, for storing a corresponding relationship between a preset magnet temperature drifting trend and the cumulative energy of gradient pulses;
• a calculation module, for obtaining said corresponding relationship from the memory module, for determining a magnet temperature corresponding to the current value of the cumulative energy of the gradient pulses according to the current value of the cumulative energy of the gradient pulses and said corresponding relationship, and for using said magnet temperature as the current predicted value of the magnet temperature;
• an accumulator, for receiving the current predicted value of the magnet temperature from the calculation module, for weighting the current measured value of the magnet temperature measured by the temperature sensor (4) and the current predicted value of the magnet temperature from the calculation module by preset weight coefficients, so as to obtain an actual temperature of the magnet;
• and
• said temperature control device is further used to receive the actual temperature of the magnet from the accumulator, to calculate the difference between the actual temperature of said magnet and the set temperature of said magnet, to adjust the PID parameter according to said difference, and is used to generate a control signal for keeping the magnet temperature constant according to said adjusted PID parameter.

A method for improving the imaging quality of nuclear magnetic resonance imaging (MRI) equipment, wherein the method comprises:

• presetting a corresponding relationship between a frequency drifting interference of MRI signals within an imaging field of view and the cumulative energy of gradient pulses;
• determining the frequency drifting interference corresponding to the current value of the cumulative energy of the gradient pulses according to the current value of the cumulative energy of the gradient pulses and said preset corresponding relationship, taking said frequency drifting interference as the current predicted value of the frequency drifting interference, and taking said current predicted value of the frequency drifting interference as a reference input signal to an adaptive filter, so as to obtain an output signal;
• and
• filtering out said output signal from the MRI signals obtained by scanning with the MRI equipment, so as to acquire the MRI signals for image reconstruction.

Magnetic resonance imaging MRI equipment, comprising:

• a memory module, for storing a preset corresponding relationship between the frequency drifting interference of MRI signals within an imaging field of view and the cumulative energy of gradient pulses;
• a calculation module, for receiving the corresponding relationship from the memory module, calculating the frequency drifting interference according to the current value of the cumulative energy of the gradient pulses and said corresponding relationship provided by the memory module, taking said frequency drifting interference as the current predicted value of the frequency drifting interference and sending it to an adaptive filter;
• the adaptive filter, for receiving the current predicted value of the frequency drifting interference from the calculation module, so as to obtain an output signal according to the input current predicted value of the frequency drifting interference;
• and
• a first accumulator, for receiving the output signal from the adaptive filter, so as to filter out said output signal from the MRI signals obtained by scanning with the MRI equipment, and to acquire the MRI signals for image reconstruction.