Trigger-adapted MR Data Acquisition Timing
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Solution Overview
Problem
During cardio MRI measurements, the selected imaging sequence of a magnetic resonance apparatus may be terminated due to exceeding the maximum available RF output if the patient's heartbeat becomes faster, leading to inadequate MR data acquisition.
Innovation Solution
A method is implemented to detect physiological triggers like heartbeats and synchronize MR data acquisition, ensuring that the imaging sequence is timed with a sufficient buffer to prevent exceeding the maximum RF output by checking the condition RR≥RR(0)−(dRR−dRR (B1)) and adjusting the timing intervals between preparation and readout pulses to maintain the average RF output below a predefined maximum value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the imaging sequence is synchronized to the trigger without additional time buffer, then the measurement time is shortened and productivity is improved, but the maximum RF output is exceeded and the sequence is terminated
Solution Approach 1:
The patent introduces a preliminary time buffer dRR between the readout module and the next preparation pulse, calculated based on the minimum expected RR interval. This preliminary action ensures that even when the heartbeat interval shortens, the RF output has sufficient time to decay before the next pulse, preventing maximum RF output exceedance and sequence termination while maintaining efficient timing.
Solution Approach 2:
The patent applies beforehand cushioning by adding an additional safety margin dRR(B1) to the time buffer calculation. This creates a cushioned time interval that accounts for variations in heartbeat rhythm, ensuring that the RF output never exceeds the maximum limit even under adverse conditions (fastest expected heartbeat), thereby guaranteeing sequence completion reliability.
2Reliability
If the time interval between readout module and preparation pulse is increased, then the maximum RF output is not exceeded, but the measurement time increases and productivity decreases
Solution Approach 1:
The patent implements dynamic timing adjustment by calculating the time buffer dRR based on the actual measured RR interval from the trigger signal, rather than using a fixed conservative value. The buffer is dynamically adapted to each heartbeat interval, allowing shorter buffers when the heartbeat is regular and longer buffers when the heartbeat interval shortens, thus maintaining RF output compliance while maximizing measurement speed.
Solution Approach 2:
The patent changes the timing parameter dRR dynamically based on the measured RR interval and the minimum expected RR interval. By adjusting this parameter adaptively rather than using a static value, the system achieves optimal balance between preventing RF output exceedance and maintaining high measurement productivity across varying physiological conditions.
Data Source
AI summary
In trigger-adapted MR data acquisition, a trigger from the object undergoing investigation is detected, by which a periodically repeated procedure of the object is detected. An imaging sequence is performed multiple times dependent on the trigger in order to acquire MR data. The imaging sequence includes at least one preparation pulse and a subsequent readout module, the readout module ending a first time period before an end of the procedure. The respective imaging sequence is performed only if RR≥RR(0)−(dRR−dRR(B1)), wherein dRR(B1) is a second time period, RR corresponds is a first time interval between a trigger that is currently being detected and a trigger that was detected immediately before the currently detected trigger, and RR(0) is a second time interval that corresponds to a predefined time interval between two directly succeeding triggers.