MRI Lung Ventilation Quantification via Density and Volume Analysis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic resonance imaging (MRI) methods for lung ventilation face challenges such as torso movement during breathing and susceptibility artifacts, making it difficult to accurately determine relative and quantitative lung ventilation, especially when comparing different patients.
Innovation Solution
A method that acquires multiple lung-representing image data sets at different breathing phases to calculate localized, quantitative ventilation by determining density changes and lung volume, using spin-echo or minimized echo time gradient-echo methods to minimize signal losses, and employing three-dimensional or two-dimensional imaging with navigator echoes to track volume changes, allowing for accurate ventilation measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If gradient-echo based methods are used at field strength of about 1.5 tesla, then imaging speed is improved, but susceptibility artifacts increase causing signal losses
Solution Approach 1:
The patent changes the imaging parameter from gradient-echo to spin-echo based methods, which fundamentally alters the pulse sequence timing and echo formation mechanism. This parameter change eliminates susceptibility artifacts while maintaining acceptable imaging speed for ventilation measurement
Solution Approach 2:
The patent uses minimal echo time gradient-echo methods as a compromise solution when spin-echo is not feasible, accepting some signal loss but maintaining the ability to capture ventilation changes. This is a practical trade-off that sacrifices some quality for speed when necessary
2Device complexity
If only relative change in ventilation is measured, then measurement simplicity is improved, but comparability between different patients deteriorates
Solution Approach 1:
The patent introduces lung volume as an intermediary parameter that mediates between the simple relative ventilation measurement and the need for patient-specific quantification. By multiplying relative ventilation change with measured lung volume, the system generates absolute ventilation values that are comparable across patients while building upon the simpler relative measurement approach
Solution Approach 2:
The patent replaces the need for complex external volume measurement devices by using MRI itself to measure lung volume through image analysis. This substitution integrates volume measurement into the imaging process, enabling quantitative ventilation measurement without additional mechanical equipment
3Measurement precision
If three-dimensional image data sets are acquired, then localized ventilation measurement is improved, but acquisition time increases requiring breath-holding
Solution Approach 1:
The patent uses periodic breathing cycles as the basis for acquisition, acquiring images at specific phases of the breathing cycle rather than attempting to capture the entire cycle. This periodic sampling approach allows 3D imaging without requiring prolonged breath-holding, as each acquisition is timed to a specific breathing phase
Solution Approach 2:
The patent performs preliminary acquisition of 3D image data sets at key breathing phases (such as end-inspiration and end-expiration) to establish baseline volume and ventilation information. These preliminary 3D data sets are then used to inform subsequent faster 2D acquisitions, reducing the need for repeated breath-holding
4Object-affected harmful factors
If spin-echo based methods are used, then susceptibility artifacts are reduced, but imaging speed decreases
Solution Approach 1:
The patent employs periodic breathing cycle synchronization with spin-echo imaging, acquiring images at specific phases rather than continuously. This periodic approach reduces the total imaging time required while maintaining the artifact-reduction benefits of spin-echo methods
Solution Approach 2:
The patent uses dynamic adjustment of imaging parameters based on the breathing phase, optimizing the spin-echo sequence timing to match the physiological rhythm. This dynamic approach maintains image quality while reducing unnecessary acquisition time
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
Enables precise, quantitative, and localized determination of lung ventilation, overcoming the limitations of relative change measurements and susceptibility artifacts, allowing for accurate comparison across patients and reducing the need for breath-holding during data acquisition.
Implementation Method 1
magnetic resonance imaging... the lungs are basically composed of pulmonary alveoli, and the tissue of an alveolus encloses an air-filled space. This tissue has therein protons and, accordingly can be detected in a magnetic resonance measurement
Implementation Method 2
In order to avoid such artifacts, it is possible to use spin-echo based methods, or the gradient-echo based methods have to be implemented with a minimal echo time
Implementation Method 3
gradient-echo based methods starting at a field strength of about 1.5 tesla... these methods have to be used with minimized echo time
Data Source
AI summary
In a method for determining the ventilation of a lung of an object under examination by magnetic resonance imaging, at least two first lung-representing image data sets are acquired at different intervals of the breathing phase. The density change of the lung tissue is automatically determined from the signal difference between the image signals of the first image data sets in at least one corresponding region of the first lung-representing image data set. The lung or the thorax volume is automatically determined using at least two of the first image data sets, or using at least an additional second lung-representing image data set in a breathing phase that corresponds with the breathing phase of a first image data set. The localized, quantitative ventilation of the lung is automatically calculated depending on the density change of the lung tissue and the change of the lung or thorax volume.