Synthetic MRI with Magnetic Resonance Spin TomogrAphy in Time-Domain (MR-STAT): Results from a Prospective Cross-Sectional Clinical Trial

Background Magnetic Resonance Spin TomogrAphy in Time-domain (MR-STAT) can reconstruct whole-brain multi-parametric quantitative maps (eg, T-1, T-2) from a 5-minute MR acquisition. These quantitative maps can be leveraged for synthetization of clinical image contrasts. Purpose The objective was to assess image quality and overall diagnostic accuracy of synthetic MR-STAT contrasts compared to conventional contrast-weighted images. Study Type Prospective cross-sectional clinical trial. Population Fifty participants with a median age of 45 years (range: 21-79 years) consisting of 10 healthy participants and 40 patients with neurological diseases (brain tumor, epilepsy, multiple sclerosis or stroke). Field Strength/Sequence 3T/Conventional contrast-weighted imaging (T-1/T-2 weighted, proton density [PD] weighted, and fluid-attenuated inversion recovery [FLAIR]) and a MR-STAT acquisition (2D Cartesian spoiled gradient echo with varying flip angle preceded by a non-selective inversion pulse). Assessment Quantitative T-1, T-2, and PD maps were computed from the MR-STAT acquisition, from which synthetic contrasts were generated. Three neuroradiologists blinded for image type and disease randomly and independently evaluated synthetic and conventional datasets for image quality and diagnostic accuracy, which was assessed by comparison with the clinically confirmed diagnosis. Statistical Tests Image quality and consequent acceptability for diagnostic use was assessed with a McNemar's test (one-sided alpha = 0.025). Wilcoxon signed rank test with a one-sided alpha = 0.025 and a margin of Delta = 0.5 on the 5-level Likert scale was used to assess non-inferiority. Results All data sets were similar in acceptability for diagnostic use (>= 3 Likert-scale) between techniques (T(1)w:P = 0.105, PDw:P = 1.000, FLAIR:P = 0.564). However, only the synthetic MR-STAT T-2 weighted images were significantly non-inferior to their conventional counterpart; all other synthetic datasets were inferior (T(1)w:P = 0.260, PDw:P = 1.000, FLAIR:P = 1.000). Moreover, true positive/negative rates were similar between techniques (conventional: 88%, MR-STAT: 84%). Data Conclusion MR-STAT is a quantitative technique that may provide radiologists with clinically useful synthetic contrast images within substantially reduced scan time. Evidence Level: 1 Technical Efficacy: Stage 2

Automated summary

This study evaluated the image quality and diagnostic accuracy of synthetic MR-STAT contrasts compared to conventional contrast-weighted images. The results showed that synthetic MR-STAT T-2 weighted images were superior to their conventional counterpart, while other synthetic datasets were inferior. The true positive/negative rates were similar between the techniques. This suggests that MR-STAT is a quantitative technique that can provide radiologists with clinically useful synthetic contrast images within a shorter scan time.