Arrival Time Correction for DSC MRI Perfusion Accuracy
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Solution Overview
Problem
Current dynamic susceptibility contrast (DSC) MRI techniques struggle to accurately measure cerebral blood volume in patients with perfusion deficits, such as acute stroke, due to assumptions of uniform perfusion, leading to inaccurate calculations of permeability and underestimation of blood-brain barrier disruption.
Innovation Solution
The implementation of an arrival time correction (ATC) method that adjusts for time shifts, amplitude scales, and signal changes in the MRI system to generate corrected contrast agent concentration curves, accounting for variations in contrast delivery and perfusion deficits, thereby improving the accuracy of cerebral blood volume measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If DSC MRI assumes uniform perfusion to simplify calculations, then device complexity is reduced, but measurement precision of cerebral blood volume deteriorates in patients with perfusion deficits
Solution Approach 1:
The patent applies local quality by introducing voxel-specific arrival time parameters (arrival time shift and arrival time stretch) that allow each voxel to be treated individually based on its perfusion characteristics. This enables the calculation to account for local perfusion variations in stroke patients while maintaining the overall DSC MRI framework, thus improving measurement precision without excessively increasing complexity.
Solution Approach 2:
The patent changes the parameters of the perfusion model by adding arrival time correction parameters (shift and stretch) to the standard DSC MRI calculation. These parameter changes allow the model to adapt to non-uniform perfusion conditions in stroke patients, improving the accuracy of cerebral blood volume measurements while keeping the computational approach manageable.
2Loss of time
If DSC MRI uses standard permeability calculation without arrival time correction, then processing time is reduced, but measurement precision of blood-brain barrier disruption deteriorates
Solution Approach 1:
The patent applies preliminary action by calculating arrival time shift and stretch parameters from the contrast agent concentration curves before performing the final permeability calculation. This preliminary correction of arrival times ensures that subsequent permeability measurements are accurate even in patients with perfusion deficits, without requiring excessive additional processing time.
Solution Approach 2:
The patent introduces arrival time correction parameters as intermediary variables that mediate between the raw DSC MRI signal and the final permeability calculation. These intermediary parameters capture the effects of non-uniform perfusion and allow the final permeability measurement to be accurate without requiring a complete redesign of the calculation process.
3Measurement precision
If DSC MRI applies leakage correction for BBB disruption, then measurement precision of cerebral blood volume is improved, but device complexity increases due to additional correction terms
Solution Approach 1:
The patent applies local quality by implementing leakage correction at the voxel level using the arrival time corrected concentration curves. Each voxel's leakage is calculated independently based on its specific arrival time parameters, allowing accurate correction for blood-brain barrier disruption without requiring a completely complex global model.
Solution Approach 2:
The patent uses the arrival time correction parameters as intermediaries that simplify the leakage correction process. By first correcting arrival times, the subsequent leakage calculation becomes more straightforward and accurate, reducing the overall complexity of the correction model while improving measurement precision.
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 ATC method enhances the ability to detect blood-brain barrier disruption and improves the accuracy of cerebral blood volume measurements in patients with perfusion deficits, as demonstrated by improved ROC curve performance and clinical relevance.
Implementation Method 1
employing magnetic fields (Gx, Gy, and Gz) that have the same direction as the polarizing field B0, but which have a gradient along the respective x, y, and z axes
Implementation Method 2
A NMR signal is emitted by the excited spins after the excitation signal B1 is terminated
Implementation Method 3
dynamic susceptibility contrast (DSC) MRI is used to measure cerebral blood volume (CBV)
Data Source
AI summary
A system and method for generating dynamic susceptibility contrast information from medical imaging data acquired using a magnetic resonance imaging (MRI) system and from a subject having received a dose of a contrast agent. A plurality of images are acquired of the subject. Using the images, an arrival time correction (ATC) is determined that includes a value for at least one of a time shift variable, a time stretch variable, and an amplitude scale variable. The ATC is applied to a model of dynamic susceptibility contrast that relates a measure of signal change over time with a correction term to dynamic susceptibility contrast information to create a corrected model of dynamic susceptibility contrast including the ATC. At least one contrast agent concentration curve is generated from the plurality of images using the corrected model.