Method for controlling radio frequency excitation and gradient pulse characteristics in a magnetic resonance imaging system

Claim 1

A method for controlling radial frequency pulse excitation and gradient pulses applied during a scan cycle in a magnetic resonance imaging (MRI) system, said system including a magnet (magnets), excitation and detection units, a controller comprising a main channel and a plurality of output channels, said MRI system operated responsive to operating data including: instructions, timing information and RF pulse pattern data provided by a central processing unit (CPU), said method comprising the steps of: transmitting said operating data from the CPU to the controller; storing said operating data received from said CPU in said main channel and said output channels, controlling the scan cycle with the controller using said operating data received from said CPU; commencing the scan cycle when said instructions and timing information included in the operating data are received from the CPU by said main channel and when the RF pulse data is received by at least some of said plurality of output channel; said controlling step, including the steps of: transmitting instructions and timing information for controlling the output of the received RF pulse pattern data from the at least some of said output channels responsive to the instructions and timing information stored in said main channel after receipt from said CPU; and controlling said excitation units of the MRI system with said RF pulse pattern data; wherein the step of transmitting data from said CPU to said main channel and to said output channels further includes the steps of: transferring scan sequence cycle control from said CPU to said main channel after receipt by said controller of said operating data from the CPU; energizing the excitation units of the MRI system responsive to said operating data to perform a scan sequence cycle while control of the scan sequence cycle is in said main channel after transfer of control from said CPU to said main channel; returning scan sequence cycle control to said CPU from said main channel at the end of said scan sequence cycle whereby the scan sequence cycle is accomplished under control of said controller instead of said CPU, and defining said scan sequence cycle using the timing information transferred from said CPU to said main channel; and further including the step of transferring said instructions and timing information from said main channel to said output channels, said last named transferring step including: selecting the at least some of said output channels, providing said instructions to a data field in said main channel, and timing information to a timing field in said main channel for selecting starting addresses in said selected output channels to output pattern data, providing said instructions to a data run field in said main channel for selecting either a "run" or a "standby" condition for said selected output channels, and providing an address and control field in said main channel for instructions for activating the selected output channels to control desired ones of said MRI system units.

Claim 2

A method for controlling radial frequency pulse excitation and gradient pulses applied during a scan cycle in a magnetic resonance imaging (MRI) system, said system including a magnet (magnets), excitation and detection units, a controller comprising a main channel and a plurality of output channels, said MRI system operated responsive to operating data including: instructions, timing information and RF pulse pattern data provided by a central processing unit (CPU), said method comprising the steps of: transmitting said operating data from the CPU to the controller; storing said operating data received from said CPU in said main channel and said output channels, controlling the scan cycle with the controller using said operating data received from said CPU; commencing the scan cycle when said instructions and timing information included in the operating data are received from the CPU by said main channel and when the RF pulse data is received by at least some of said plurality of output channel; said controlling step, including the steps of: transmitting instructions and timing information for controlling the output of the received RF pulse pattern data from the at least some of said output channels responsive to the instructions and timing information stored in said main channel after receipt from said CPU; and controlling said excitation units of the MRI system with said RF pulse pattern data; wherein the step of transmitting data from said CPU to said main channel and to said output channels further includes the steps of: transferring scan sequence cycle control from said CPU to said main channel after receipt by said controller of said operating data from the CPU; energizing the excitation units of the MRI system responsive to said operating data to perform a scan sequence cycle while control of the scan sequence cycle is in said main channel after transfer of control from said CPU to said main channel; returning scan sequence cycle control to said CPU from said main channel at the end of said scan sequence cycle whereby the scan sequence cycle is accomplished under control of said controller instead of said CPU, and defining said scan sequence cycle using the timing information transferred from said CPU to said main channel; and further including the step of transferring said instructions and timing information from said main channel to said output channels, said last named transferring step including: selecting the at least some of said output channels, providing said instructions to a data field in said main channel, and timing information to a timing field in said main channel for selecting starting addresses in said selected output channels to output pattern data, providing said instructions to a data run field in said main channel for selecting either a "run" or a "standby" condition for said selected output channels, and providing an address and control field in said main channel for instructions for activating the selected output channels to control desired ones of said MRI system units.