MRI Continuous Travel Interruption for Breath-Hold Artifact Reduction
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Solution Overview
Problem
Magnetic resonance imaging (MRI) techniques face inefficiencies when acquiring data from examination regions affected by patient breathing motions, particularly in continuous travel methods, leading to movement artifacts, incomplete data acquisition, and reduced resolution due to breath-hold limitations and inhomogeneous measurement conditions.
Innovation Solution
The method involves interrupting and resuming the continuous travel of the examination region, allowing for controlled breath-hold periods and precise movement adjustments to ensure complete data acquisition without braking or acceleration phases, enabling high-quality image data sets by moving the region back by a predetermined distance before interruption and allowing for additional preparation or data acquisition during the pause.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous travel through the magnetic resonance apparatus is maintained to improve productivity, then measurement speed increases, but movement artifacts and data quality deteriorate due to patient breathing motions
Solution Approach 1:
The patent implements periodic interruption of the continuous travel, creating alternating phases of movement and pause. During pause phases, breath-hold commands are issued to acquire data without breathing-induced motion artifacts. This periodic action allows the system to maintain overall productivity while periodically eliminating the harmful effects of patient breathing motions during critical measurement phases.
Solution Approach 2:
The patent issues breath-hold commands to patients in advance during the pause phases, preparing them for the next data acquisition phase. This preliminary action ensures that when the continuous travel resumes and data acquisition begins, the patient is already in the appropriate physiological state (breath-hold) to minimize motion artifacts, thereby improving data quality before the measurement actually occurs.
2Measurement precision
If breath-hold duration is extended to improve measurement precision, then movement artifacts reduce, but patient capability and comfort worsen due to physiological limitations
Solution Approach 1:
The patent divides the continuous measurement process into multiple segments separated by pause phases. Instead of requiring one long breath-hold, the measurement is segmented into several shorter breath-hold periods interspersed with rest periods where the table continues to move. This segmentation allows patients to maintain breath-holds within their physiological comfort limits while still achieving high measurement precision through multiple short acquisitions.
Solution Approach 2:
The patent employs periodic alternation between measurement phases (requiring breath-hold) and pause phases (allowing normal breathing). This periodic action breaks down the demanding continuous breath-hold into manageable periodic intervals, maintaining measurement precision through repeated short breath-holds while respecting patient physiological limitations and comfort.
3Adaptability or versatility
If measurement volume is expanded to improve adaptability, then larger examination regions can be covered, but measurement precision worsens due to inhomogeneous basic magnetic field and gradient field nonlinearities
Solution Approach 1:
The patent segments the large examination region into multiple smaller measurement volumes that are acquired sequentially during different pause phases. Each small measurement volume is measured with optimal precision under homogeneous magnetic field conditions, and the segments are later combined to form the complete large-field-of-view image. This segmentation allows the system to maintain high measurement precision for each segment while achieving overall adaptability for large examination regions.
Solution Approach 2:
The patent resolves the spatial contradiction by introducing the time dimension. Instead of attempting to measure the entire large field of view simultaneously (which would compromise precision), the system measures different spatial segments at different time points during the continuous travel. This dimensional transformation allows large FOV adaptability to be achieved without sacrificing the measurement precision that requires small, homogeneous measurement volumes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for high-quality data acquisition from regions affected by breathing motions, reducing movement artifacts and improving resolution by optimizing the speed and breath-hold duration based on patient capabilities, ensuring comprehensive and efficient data collection.
Implementation Method 1
the examination subject is positioned in a comparably strong, static, homogeneous basic magnetic field (field strengths of 0.2 Tesla to 7 Tesla or more) in a magnetic resonance apparatus so that its nuclear spins orient along the basic magnetic field
Implementation Method 2
Radio-frequency excitation pulses are radiated into the examination subject, that cause the nuclear spins to behave so as to emit magnetic resonance signals that are measured
Implementation Method 3
For spatial coding of the measurement data, rapidly-switched (activated) magnetic gradient fields are superimposed on the basic magnetic field
Data Source
AI summary
In a method and apparatus for the acquisition of measurement data of an examination region of an examination subject (in particular a patient) during continuous travel of the examination region through a magnetic resonance apparatus for the generation of an image data set, the continuous travel is interrupted and resumed at least once. The examination region is moved back by a predeterminable distance counter to the travel direction of the continuous travel before interrupting the continuous travel. Moving the examination region back makes it possible to interrupt and resume an acquisition of measurement data given (otherwise) continuous travel of the examination region, without loss of measurement data. The time during the interruption can be used advantageously for preparation of an acquisition of measurement data in the portion of the examination region of the patient that is to be examined after the interruption of the continuous travel. In particular, during the interruption a patient can be prepared to hold his or her breath for an acquisition of additional measurement data that follows the interruption. The continuous travel can be interrupted arbitrarily often.