Extended-coverage MRI coil with opposed-solenoid elements
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Solution Overview
Problem
Conventional opposed-solenoid antennas used in MRI applications have limited longitudinal coverage, which reduces their effectiveness in survey imaging in coronal or sagittal planes, particularly in intravascular imaging where extended coverage is necessary.
Innovation Solution
The development of multi-element extended-coverage imaging coils, comprising opposed-solenoid and single-loop antenna elements with optimized uneven spacing, which increases the homogeneity and extent of the coverage area, including configurations with four or six elements, to enhance longitudinal coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional opposed-solenoid antenna configurations are used, then the imaging coil provides a substantially homogenous region of sensitivity within the gap, but the longitudinal coverage area is limited
Solution Approach 1:
The imaging coil is divided into multiple opposed-solenoid antenna elements (first, second, third, and fourth elements) arranged along the longitudinal axis. Each element consists of solenoid windings separated by gaps, with adjacent elements having opposite current directions. This segmentation allows the coverage areas of individual elements to additively combine, extending the total longitudinal coverage while maintaining homogeneity within each element's gap region.
Solution Approach 2:
Multiple opposed-solenoid antenna elements are combined along the longitudinal axis with their coverage areas overlapping and adding together. The flux lines from each element contribute to the overall coverage, creating an extended longitudinal coverage area that combines the homogenous regions of sensitivity from all elements while maintaining the opposed-solenoid configuration benefits.
2Area of stationary object
If the area of longitudinal coverage is extended, then survey imaging in coronal or sagittal planes becomes more effective, but the homogeneity of the sensitivity region may be reduced
Solution Approach 1:
Each opposed-solenoid antenna element maintains its own local homogenous region of sensitivity within its gap, with current directions optimized for that specific region. The adjacent elements have opposite current directions to maximize their individual homogenous coverage areas. By positioning elements with optimized spacing, the local homogeneity of each element is preserved while their combined coverage extends the total longitudinal area.
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
The multi-element coils provide improved longitudinal coverage and homogeneity, enabling more effective imaging in intravascular applications by extending the coverage area beyond conventional opposed-solenoid antennas, facilitating both low-resolution survey imaging and high-resolution examination imaging.
Implementation Method 1
Opposed-solenoid antenna configurations are based on groups of loops (e.g., helical loops) separated by a gap, with current being driven in opposite directions on either side of the gap. Within the gap, field lines protrude beyond the diameter of the loops, providing a substantially homogenous region of sensitivity
Data Source
AI summary
Extended-coverage magnetic resonance imaging coils with optimized homogeneity in longitudinal sensitivity are described. One exemplary coil includes four elements, where two of the elements are opposed-solenoid imaging elements and two of the elements are single loop imaging elements.