18 Questions
What is the ideal scenario for the main magnetic field (B0) across the imaging volume?
Having the same strength and direction at all points
What can field inhomogeneities cause in MRI images?
Distortions, artifacts, and signal loss
Why is field homogeneity crucial in spectroscopic MRI (MRS)?
For accurate measurement and quantification of metabolite concentrations
What is the process of adjusting the magnetic field to improve homogeneity?
Shimming
What can variations in magnetic field strength lead to in MRI images?
Geometric distortions and image warping
What can field inhomogeneities result in?
Signal loss or signal pile-up, reducing image contrast and diagnostic utility
What is the primary function of shim coils in MRI systems?
To produce a homo field
What type of shim coils compensate for linear field gradients along the x, y, and z axes?
First-Order Shim Coils
What is the purpose of shim coils in maintaining field homogeneity during MRI image acquisition?
To compensate for field inhomogeneities
What is the advantage of dynamic shim coils over other types of shim coils?
They can be adjusted in real-time during image acquisition
What is the result of inadequate shim coil compensation in MRI image acquisition?
Spatial distortions and signal loss
What is the location of shim coils in an MRI system?
Inside the aperture
What is the primary reason for optimizing shim settings in MRI systems?
To improve field homogeneity
In functional MRI studies, why is field homogeneity crucial?
To increase the sensitivity of BOLD signal detection
What is the main advantage of active shimming in MRI?
It generates additional magnetic fields to correct field distortions
Which of the following techniques is used to adjust the magnetic field gradients to compensate for field variations?
Gradient shimming
What is the primary consequence of inaccurate field mapping in quantitative MRI?
Errors in parameter estimation and misinterpretation of tissue properties
What is the purpose of dynamic shimming in MRI?
To continuously adjust shim settings during image acquisition
Test your understanding of magnetic field homogeneity in MRI systems, a crucial aspect of image quality and diagnostic accuracy. Learn about the ideal scenario and factors that affect field homogeneity. Improve your knowledge of MRI system performance!
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