强大的T2估计与平衡的稳定状态自由前行
Oliver Bieri1,2, Claudia Weidensteiner1,2, Carl Ganter3
1Department of Biomedical Engineering, University of Basel, Allschwil, Switzerland.
Magnetic resonance in medicine
|February 27, 2024
概括
一个新的平衡稳态自由前行 (bSSFP) 信号模型表明T2独立于B1和磁化转移 (MT) 效应. 这种强大的T2量化方法对先进的MRI应用具有前景.
科学领域:
- 磁共振成像是一种磁共振成像技术.
- 生物物理学的生物物理.
背景情况:
- 平衡稳态自由前行 (bSSFP) 是一种广泛使用的MRI技术.
- 准确的T2量化对于各种诊断应用至关重要.
- B1 场不均性和磁化转移 (MT) 效应可以在T2测量中引入错误.
研究的目的:
- 为bSSFP开发一种新的信号表示.
- 为了证明T2量化与B1和MT效应的独立性.
- 在bSSFP成像中建立一个可靠的T2测量方法.
主要方法:
- 开发了一个新的bSSFP信号模型,显然依赖于T2和一个新的参数c.
- 通过重新定义T1和E1.1,将磁化转移效应纳入其中.
- 阶段循环bSSFP脑部扫描在3T时获得了不同的参数.
- 使用变量预测 (VARPRO) 方法估计了T2和c.
- 蒙特卡洛模拟评估了T2估计精度.
主要成果:
- 开发的模型证实了T2与TR的独立性,翻转角度,B1不均性和射频脉冲持续时间.
- 协议设置的变化主要影响了参数c的估计,而不是T2.
- 最初的实验验证实了理论预测.
结论:
- 新的bSSFP信号模型提供了独立于B1和MT效应的T2量化.
- 这种方法为准确的T2测量提供了潜在的强大方法.
- 建议对现有标准进行进一步的验证.
相关概念视频
Estimation of the Physical Quantities
4.3K
On many occasions, physicists, other scientists, and engineers need to make estimates of a particular quantity. These are sometimes referred to as guesstimates, order-of-magnitude approximations, back-of-the-envelope calculations, or Fermi calculations. The physicist Enrico Fermi was famous for his ability to estimate various kinds of data with surprising precision. Estimating does not mean guessing a number or a formula at random. Instead, estimation means using prior experience and sound...
4.3K
Pole and System Stability
296
The transfer function is a fundamental concept representing the ratio of two polynomials. The numerator and denominator encapsulate the system's dynamics. The zeros and poles of this transfer function are critical in determining the system's behavior and stability.
Simple poles are unique roots of the denominator polynomial. Each simple pole corresponds to a distinct solution to the system's characteristic equation, typically resulting in exponential decay terms in the system's...
Simple poles are unique roots of the denominator polynomial. Each simple pole corresponds to a distinct solution to the system's characteristic equation, typically resulting in exponential decay terms in the system's...
296
Net Torque Calculations
9.1K
When a mechanic tries to remove a hex nut with a wrench, it is easier if the force is applied at the farthest end of the wrench handle. The lever arm is the distance from the pivot point (the hex nut in this case) to the person’s hand. If this distance is large, the torque is higher. Only the component of the force perpendicular to the lever arm contributes to the torque. Therefore, pushing the wrench perpendicular to the lever arm is more advantageous. If multiple people apply force to...
9.1K
Rigid Body Equilibrium Problems - I
4.4K
A rigid body is said to be in static equilibrium when the net force and the net torque acting on the system is equal to zero. To solve for rigid body equilibrium problems, do the following steps.
4.4K
Torque Free Motion
482
The torque-free motion refers to the movement of a rigid body in space when no external torques are acting upon it. This type of motion can be observed in environments where there are no external forces or frictions, like in outer space. For example, a rotation of Mars in space is a torque-free motion. Mars is an axisymmetric object, meaning it has an axis of symmetry along which it rotates, designated as the z-axis. The rotating frame of reference is defined such that the center of mass of...
482
Multimachine Stability
153
Multimachine stability analysis is crucial for understanding the dynamics and stability of power systems with multiple synchronous machines. The objective is to solve the swing equations for a network of M machines connected to an N-bus power system.
In analyzing the system, the nodal equations represent the relationship between bus voltages, machine voltages, and machine currents. The nodal equation is given by:
In analyzing the system, the nodal equations represent the relationship between bus voltages, machine voltages, and machine currents. The nodal equation is given by:
153


