Elimination Effect of Cross Excitation Artifacts using the Changes of Flip Angle in 3.0 T MRI

Abstract

Magnetic resonance imaging (MRI) shows high contrast and resolution on the soft tissues and nervous tissues without radiation hazard, which is used as an essential diagnostic test in the radiology. Cross excitation means to show artifacts upon the signal loss from overlapped radio frequency (RF) in some anatomical locations during the image acquisition process with RF pulse. To lower cross excitation artifacts, their images were analyzed by the changes of flip angle, TR, and TE. Ingenia 3.0T CX MRI by Philips was used for image acquisition. Self-developed water phantom used for quality control of MRI was used. SNR values at 40 degree of flip angle were 1,354 ±7.12 and 214 ± 2.10; those at 70 degree were 1,375 ± 7.31 and 305 ± 2.12; and those at 90 degree were 1,413 ± 7.93 and 357 ± 2.33, for water and artifact, respectively. CNR values were 1,140 ± 7.01, 1,070 ± 7.18, and 1,056 ± 7.12 at 40, 70 and 90 degree of flip angle, respectively (P 0.05). As f lip angle was lowered more, artifact was decreased more. In case of 90 degree of flip angle, artifact was decreased more as TR was longer. These results are anticipated to be used as the fundamental data to acquire more valued medical images in terms of diagnostics with MRI to diagnose various diseases.