انتشارات / RCMCI
تاریخ: 2003/12/23
توسط: Dr Mohammad Ali Oghabian
منتشر شده در: Iranian J of Radiology, VOL1, No 3-4,
فایل های پیوست: iranjradiol-16900.pdf
URL منتشر شده: https://www.sid.ir/en/journal/ViewPaper.aspx?ID=14002

 

 

Oghabian M A, Riahi-Alam N, Mehdipour S

Abstract

We introduce a new method of measuring transmit and receive RF inhomogeneity
in different RF coils of MRI systems. In this method a single slice of a uniform phantom is
imaged from different flip angles, using a standard spin echo protocol. The signal intensity in
these images is then fitted to a mathematical model which describes the relationship between the signal intensity and flip angle of the spin echo images. The results of this curve
fitting process are two parameters, T(r) and R(r), whose variation with the spatial position
shows RF transmit, and receive non-uniformity, respectively.
In this approach a linear profile of B1 field distribution and receive sensitivity of RF coils are
achieved which is also applicable in vivo. The method can be used to assess any commercial
MR scanner and is highly recommended for the quality control (QC) of those MR scanners
which are devoid of complicated protocols such as SE(-2). Such systems are still running
in different clinics especially in the developing countries where the latest high performance
MR scanners are not available and many scanners lack standard maintenance services