3D Spiral UTE MRI for Bone Temperature Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current magnetic resonance (MR) based thermal therapies, such as MRI-guided focused ultrasound, struggle to monitor temperature changes in bone tissues effectively due to the short T2/T2* relaxation times of cortical bone, which makes it difficult to prevent overheating during procedures.
Innovation Solution
The implementation of a three-dimensional (3D) spiral ultrashort echo time (UTE) sequence for acquiring and analyzing MR data to detect changes in relaxation rates and magnetization density, allowing for the accurate monitoring of temperature changes in bone tissues during localized energy applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional MRI sequences with long echo times are used, then soft tissue temperature monitoring is effective, but bone tissue temperature monitoring is not possible due to short T2/T2* relaxation times
Solution Approach 1:
The patent changes the echo time parameter from conventional long TE to ultrashort TE (UTE) sequences with TE < 100 μs. This parameter change enables the MR sequence to capture signals from bone tissues that have short T2/T2* relaxation times, thereby extending temperature monitoring capability to bone tissues while maintaining soft tissue monitoring ability
Solution Approach 2:
The patent employs dynamic echo time adjustment where different echo times are used for different tissue types or different phases of the imaging sequence. This dynamic approach allows optimal signal acquisition from both soft tissues (using longer TE) and bone tissues (using ultrashort TE), achieving versatile temperature monitoring across different tissue types
2Productivity
If focused ultrasound sonications are performed frequently, then treatment effectiveness is improved, but bone temperature can reach dangerous levels due to slow heat dissipation
Solution Approach 1:
The patent implements real-time temperature monitoring using UTE MRI sequences during focused ultrasound treatment. The system continuously acquires MR signals and processes them to generate temperature maps, providing feedback that allows dynamic adjustment of ultrasound power and treatment parameters to prevent bone overheating while maintaining treatment effectiveness
Solution Approach 2:
The patent replaces conventional thermal monitoring methods (which cannot penetrate bone) with magnetic resonance-based thermal monitoring that can directly image bone temperature. This substitution enables safe frequency adjustment of ultrasound sonications based on real-time bone temperature data
3Measurement precision
If ultrashort echo time sequences are used, then bone tissue signal acquisition is enabled, but acquisition time increases compared to conventional sequences
Solution Approach 1:
The patent segments the k-space acquisition into multiple spiral readouts that are interleaved in time. By acquiring different portions of k-space at different echo times within a single TR period, the system enables comprehensive bone tissue imaging without requiring proportionally longer total acquisition time, thus maintaining efficiency while improving bone detectability
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 rapid and accurate temperature monitoring of bone tissues, preventing overheating and ensuring safety during focused ultrasound treatments by rapidly acquiring volumetric data and correlating MR signal changes with temperature characteristics.
Implementation Method 1
acquiring magnetic resonance (MR) data corresponding to bone tissue in an area of interest of a subject that is heated from the application of localized energy
Implementation Method 2
detecting, from the acquired magnetic resonance data, a change in MR response signal due to a change in at least one of relaxation rate and magnetization density caused by heating of the bone tissue
Implementation Method 3
Temperatures in the soft tissues may be monitored by exploiting the temperature dependence of the proton resonant frequency (PRF) in water
Data Source
AI summary
In one aspect, in accordance with one embodiment, a method includes acquiring magnetic resonance (MR) data corresponding to bone tissue in an area of interest of a subject that is heated from the application of localized energy. The acquiring includes applying a three-dimensional (3D) ultra-short echo time (UTE) spiral acquisition sequence. The method also includes detecting, from the acquired magnetic resonance data, a change in MR response signal due to a change in at least one of relaxation rate and magnetization density caused by heating of the bone tissue; and determining, based at least in part on the change in the MR response signal, that the temperature of the bone tissue has changed.