Causes and solutions of artifacts caused by array spatial sensitivity encoding technique in brain MRI(PDF)
《中国医学物理学杂志》[ISSN:1005-202X/CN:44-1351/R]
- Issue:
- 2019年第9期
- Page:
- 1039-1044
- Research Field:
- 医学影像物理
- Publishing date:
Info
- Title:
- Causes and solutions of artifacts caused by array spatial sensitivity encoding technique in brain MRI
- Author(s):
- ZHU Xi; YE Jing; WANG Zhijun; SUN Jiquan; ZHU Qingqiang; XIA Wei
- Clinical Medical College, Yangzhou University, Yangzhou 225000, China
- Keywords:
- ; Keywords: magnetic resonance imaging; brain; T1 FLAIR; artifact; array spatial sensitivity encoding technique
- PACS:
- R312；R445.2
- DOI:
- DOI:10.3969/j.issn.1005-202X.2019.09.009
- Abstract:
- Abstract: Objective To explore the cause of unexplained high signal artifacts in T1 FLAIR sequence of brain magnetic resonance imaging (MRI) and optimize the sequence. Methods A total of 300 clinical cases and 60 water phantoms were selected and divided into group A, B and C for MRI examination. For the 3 clinical groups, with 100 clinical cases in each group, routine parameters were adopted in group A; the ASSET acceleration factor in group B was decreased to 1.50; and in group C, ASSET option was removed and the number of excitation was abated to 1. The water phantoms were also grouped in the same way and the same scanning parameters were adopted in the corresponding groups. The number of cases with image artifacts was recorded, and the image quality was analyzed objectively and subjectively. Results For the 3 clinical groups, there were 12 cases in group A, 7 in group B and 0 in group C having image artifacts. The multiple comparison with Bonferroni test showed that statistical significances were found between group A and group C, group B and group C, but not between group A and group B. The signal-to-noise ratios of brain parenchyma in 3 groups were 37.6±10.2, 38.7±10.4 and 37.2±12.0, respectively. The objective comparison of image quality revealed that the difference among 3 groups was trivial, without statistical significance (P>0.05). The total score of the subjective evaluation of image quality in group A, B and C was 395, 424 and 455, respectively, and the Kruskal-Wallis test for the statistical analysis on the total score showed that there were statistical differences among 3 groups. Moreover, Mann-Whitney U test was used for the comparisons between group A and group B, group A and group C, group B and group C, and the test results showed that the differences between these groups were statistical significant. The objective evaluation of image quality and the number of cases with image artifacts in water phantom groups were coincided with those of clinical groups. Conclusion Giving up ASSET and reducing NEX to 1, or decreasing acceleration factor properly when setting T1 FLAIR sequence of brain MRI can ensure the image quality and eliminate unexplained high signal artifacts.
Last Update: 2019-09-23