Noncontrast MRI Perfusion Imaging for Real-Time CSF and Dural Lymphatic Flow
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Solution Overview
Problem
Conventional MRI methods for observing cerebrospinal fluid and dural lymphatic fluid perfusion are invasive, rely on foreign tracers, and provide indirect, non-real-time observations, failing to capture natural perfusion behavior.
Innovation Solution
An MRI apparatus and method using tag-on and tag-off pulse sequences to acquire data without contrast agents, generating perfusion images that depict fluid flow into and out of specific regions, combined with anatomical images to visualize fluid perfusion in real time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a gadolinium-based tracer is intrathecally injected to observe perfusion behavior, then the perfusion of dural lymphatic fluid can be observed, but the method becomes invasive and requires long-term repeated imaging over 12-48 hours
Solution Approach 1:
The patent extracts and eliminates the tracer substance from the imaging system, using endogenous water protons in the cerebrospinal fluid instead. This removes the need for invasive intrathecal injection and allows single-time-point imaging to capture perfusion behavior, resolving the contradiction between measurement capability and operational ease
Solution Approach 2:
The patent enables the cerebrospinal fluid to serve itself as the imaging target by utilizing its inherent water proton signals. The fluid's own magnetic resonance properties are exploited to generate contrast, eliminating the need for external tracer substances and repeated imaging sessions
2Measurement precision
If a gadolinium-based tracer is used to indirectly observe perfusion, then perfusion behavior can be detected, but the natural perfusion behavior without foreign substances cannot be observed
Solution Approach 1:
The patent removes the foreign tracer substance from the system and directly images the endogenous cerebrospinal fluid using its water proton signals. This eliminates the interference of foreign substances and allows observation of truly natural perfusion behavior, resolving the contradiction between detection capability and behavioral accuracy
Solution Approach 2:
The patent changes the imaging parameter from tracer signal detection to endogenous water proton signal detection. By exploiting the magnetic resonance properties of water protons naturally present in the cerebrospinal fluid, the method achieves both detection capability and natural behavior observation
3Loss of time
If imaging is performed every 12 hours to observe tracer disappearance, then perfusion changes over time can be captured, but real-time perfusion behavior cannot be observed
Solution Approach 1:
The patent enables continuous monitoring capability by using endogenous water protons that remain constantly present in the cerebrospinal fluid. Unlike tracers that require repeated imaging to track disappearance, the endogenous signals allow single-time-point imaging to capture perfusion dynamics, effectively providing continuous observation capability without temporal gaps
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 non-invasive, real-time visualization of cerebrospinal and dural lymphatic fluid perfusion without tracers, providing clear depiction of fluid movement and its surrounding tissues.
Implementation Method 1
An MRI apparatus is an imaging apparatus which magnetically excites nuclear spin of an object placed in a static magnetic field with a radio frequency (RF) pulse having the Larmor frequency and reconstructs an image on the basis of magnetic resonance (MR) signals emitted from the object due to the excitation
Implementation Method 2
a tag pulse for inverting a magnetization of an object is applied to a specific region
Data Source
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AI summary
In one embodiment, an MRI apparatus includes: a scanner that includes a static magnetic field magnet, a gradient coil, and a WB coil; and processing circuitry. The processing circuitry is configured to: cause the scanner to image, under a first imaging method, a tissue including a perfusion route of body fluid that removes waste products of the object the body fluid including neurofluid; generate an anatomical image of the tissue from first data acquired by imaging under the first imaging method; cause the scanner to image perfusion behavior of the body fluid in real time under a second imaging method using non-contrast perfusion imaging; generate a perfusion image indicating the perfusion behavior of the body fluid from second data acquired by imaging under the second imaging method; and generate a fused image by combining the anatomical image and the perfusion image.