Evaluation of axial gradient Echo spiral MRI of the spine at 1.5 T

Abstract

Axial gradient echo T2*-weighed MRI of the spine is a valuable diagnostic tool with several advantages over axial T2-weighted TSE MRI, but it suffers from a low signal-to-noise ratio (SNR) and inconsistent image quality. This work investigates the potential of spiral MRI to reduce artifacts and produce improved SNR and image quality in axial T2*-weighted gradient echo MRI of the spine of pediatric patients. For the purposes of image quality evaluation, 15 pediatric patients were recruited among those scheduled for a routine spine or brain exam at 1.5 T. Pediatric spine images were rated by three pediatric neuroradiologists on a subjective scale of 1–5 using four image quality criteria. Image quality scores were evaluated using non-parametric Wilcoxon signed-rank testing and a mixed effects logistic regression model. Significant differences were found in the image quality scores in favor of spiral MRI. The odds of spiral images receiving an overall image quality score higher than 3 was 16.3 times greater than the odds of Cartesian images receiving a score higher than 3 (p < 0.001, 95% CI of 4.6 to 86) as calculated using a mixed effects logistic regression model. A quantitative comparison was also performed on a single volunteer to illustrate the SNR benefit of spiral MRI. In conclusion, spiral MRI was found to provide equal or better image quality than Cartesian MRI in axial T2*-weighted gradient echo MRI in the spine of a small cohort of pediatric patients at 1.5 T.