The higher signal-to-noise ratio (SNR) of 3-Tesla magnetic resonance imaging (3T MRI) contributes to an
improvement in the spatial and temporal resolution. However, T1-weighted images of the brain obtained by the
spin-echo (SE) method using 3T MRI are unsuitable for clinical use because of the inhomogeneity of the radio frequency
(RF) field B1 non-uniformity. And it is clear by SE method. In addition, the prolongation of the longitudinal relaxation
time (T1) of most tissues leads to a decrease in the T1 contrast. Therefore, many hospitals that utilize 3TMRI use the
GRE method instead of the SE method in order to obtain an adequate T1 contrast, as can be obtained using FLASH (fast
low angle shot), and high uniformity of images. Further, many studies have been performed to improve the non
uniformity using techniques such as spatial presaturation. However, when filters are used, the high intensity of the
influence in susceptible regions, signal deficits, and original contrast are lost, and a distortion can be clearly observed
when the GRE method is used. Therefore, we obtained the T1-weighted images by using the partial flip angle SE method
instead of the GRE method or SE method.
We attempted to improve the image non-uniformity by using the partial flip angle SE method. Using this method, we
could improve the image uniformity and also realize an adequate T1 contrast. As a result, the uniformity was found to
improve by 6% and it became 82.6% at 110°. These results indicate that the use of the partial flip angle SE method is
effective for obtaining adequate uniformity in the T1-weighted images of the brain.