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Final Program


Program-At-A-Glance

Oral Abstracts Session

Virtual Recording

Session: Oral Abstracts Science Session 5

Improved precision of high b-value in vivo cardiac diffusion tensor imaging on a commercial ultrahigh performance gradient system

Saturday, February 7, 2026
11:40 AM - 11:50 AM  
Location: Americas I and Hall 3 (2nd Lower Level)
Background: Cardiac diffusion tensor imaging (cDTI) enables noninvasive characterization of myocardial microstructure. However, cDTI in vivo has been limited by heterogeneous cDTI parameter maps due to limited gradient performance. Conventional clinical systems with maximum gradient strengths of 40-80 mT/m restrict b-values to approximately 500 s/mm2 before echo times become prohibitively long. Higher b-values using commercially available ultrahigh performance gradient systems (≥200 mT/m) reduce tissue diffusivity as previously found1. With the recent availability of commercial ultrahigh-performance gradients, we hypothesized that b=1000 s/mm2 (b1000) cDTI would yield more precise cDTI maps via lower standard deviations compared to b=500 s/mm2 (b500) cDTI maps in healthy volunteers.

Methods: Twenty-one volunteers were recruited and cDTI was performed on a 3T MRI scanner with ultrahigh-performance gradients (MAGNETOM Cima.X, Siemens Healthineers, Forchheim, Germany). Second-order motion-compensated diffusion-prepared spin echo were performed with the following parameters: 12 diffusion directions, 8 averages, b0=50 s/mm2 with 1 average, 2.7 x 2.7 x 8 mm3 resolution, TR=1RR interval. Each subject underwent b500 and b1000 cDTI with identical imaging parameters, except TE = 59 ms for b500 and TE=79 ms for b1000. cDTI maps of mean diffusivity (MD), fractional anisotropy (FA), and helix angle (HA) were generated and helix angle transmurality (HAT) was calculated using custom pipelines. Precision was quantified as the within-map standard deviation of these parameters. Paired statistical testing was used to compare cDTI metrics between b500 and b1000 acquisitions, where p< 0.05 was considered statistically significant.

Results: Qualitatively, b1000 maps demonstrated smoother myocardial tissue distributions and clearer transmural helical angle transitions compared with b500 (Figure 1). Importantly, precision was substantially improved. Standard deviations were lower in b1000 for both MD (0.24±0.06 vs. 0.37±0.09×10-3 mm2/s, p< 0.001) and FA (0.087±0.017 vs. 0.136±0.034, p< 0.001) (Figure 2). The b1000 images produced significantly lower mean MD compared to b500 images (1.42±0.05 vs. 1.51±0.09×10-3 mm2/s, p< 0.001), lower mean FA (0.298±0.016 vs. 0.329±0.023, p< 0.001), and more negative HAT (-0.83±0.09 vs. -0.79±0.08 °/%, p=0.048).

Conclusion: In vivo cDTI with b1000 s/mm2 is feasible on a commercially available clinical 3T MRI with ultrahigh-performance gradients and yields significantly more precise measurements than conventional b=500 s/mm2 acquisitions. We showcase here that higher diffusion weighting increases sensitivity. We also show that cDTI metrics decrease, in line with other studies using higher b-values1,2,3. These findings highlight the potential for high b-value cDTI to advance myocardial tissue characterization and underscore the promise of ultrahigh-performance gradient systems for enabling next-generation cardiac microstructural imaging.

Figure 1: Comparison of cardiac diffusion tensor imaging (DTI) parameter maps of the b=500 s/mm2 compared to b=1000 s/mm2 images. Qualitatively, images can be seen to be more homogenous in b=1000 s/mm2 mean diffusivity (MD), fractional anisotropy (FA) and helix angle (HA) maps. Notably, HA maps can be seen to have smoother gradient on the inferolateral wall in b=1000 s/mm2 image.
Figure 2: A) Standard deviations across the left ventricle were lower for mean diffusivity (MD) in b=1000 s/mm2 images compared to b=500 s/mm2 images (0.24±0.06 vs. 0.37±0.09×10-3 mm2/s, p<0.001). FA (0.087±0.017 vs. 0.136±0.034, p<0.001). B) Standard deviations across the left ventricle were lower for fractional anisotropy (FA) in b=1000 s/mm2 images compared to b=500 s/mm2 images (0.087±0.017 vs. 0.136±0.034, p<0.001). p<0.05 was considered statistically significant after paired t-test.
Figure 3: A) The b=1000 s/mm2 images produced significantly lower mean diffusivity (MD) compared to b=500 s/mm2 images (1.42±0.05 vs. 1.51±0.09×10-3 mm2/s, p<0.001). B) The b=1000 s/mm2 images produced significantly lower fractional anisotropy (FA) (0.298±0.016 vs. 0.329±0.023, p<0.001). C) The b=1000 s/mm2 images produced significantly more negative HAT (-0.83±0.09 vs. -0.79±0.08 °/%, p=0.048). p<0.05 was considered statistically significant after paired t-test.