2D-SENSE in isotropic slow infusion contrast-enhanced whole-heart coronary magnetic resonance angiography at 3 T
Journal of Cardiovascular Magnetic Resonance volume 12, Article number: P50 (2010)
To evaluate the SNR & CNR performance of 2D-SENSE enhanced whole-heart coronary MRA post contrast in comparison to a conventional T2Prep approach in patients.
Eleven patients with established cardiovascular disease were studied on a commercial 3 T Philips system with a 32-channel cardiac surface coil.
Baseline free-breathing 3D whole-heart coronary MRA with an adiabatic T2prep (TE = 50 ms) was first performed. The duration of the acquisition window was adjusted to the heart-rate of the patients with a TR/TE = 3.3/1.07 ms and a flip angle(α) of 20°. 1D-SENSE (2 times accelerated) was applied in the left-right(LR) direction. The acquired isotropic voxel size was 1.3 × 1.3 × 1.3 mm3.
Subsequently, 0.2 mmol/kg dose of Gd-BOPTA was injected at 0.3 cc/sec, and inversion-recovery (TI = 200 ms) whole-heart 2D-SENSE contrast-enhanced (CE)-MRA started 2 min after injection. Spatial/temporal resolution as well as volumetric coverage/scanning time remained unchanged relative to the baseline scan. However, post-contrast, a SENSE acceleration factor of 2 × 2 was used in the FH and LR directions. Rather than using 2D-SENSE to abbreviate scanning time, it was exploited to maximize SNR post-contrast by minimizing the signal readout bandwidth (TR/TE = 6.6/1.71 ms) and by optimizing α(= 25°). Based on a numerical simulation, the 2D-SENSE CE-MRA should improve SNR more than 2-fold vs. baseline.
Both scans were combined with a 3D noise scan (30 sec duration) to support SNR and CNR quantification on images acquired with SENSE. SNR, CNR, vessel length and sharpness were quantified and compared for the pre- and post-contrast acquisitions.
The quantitative results are shown in Tables 1 &2. 2D-SENSE CE-MRA resulted in a 3-fold/7-fold increase in SNR/CNR vs. baseline. However, this did not translate into improved vessel sharpness or longer visible vessel length. Representative images from a patient are shown in Figure 1. Figure 2 shows 2D-SENSE CE-MRA and the corresponding X-ray coronary angiogram from a patient with RCA disease.
Slow-infusion in combination with 2D-SENSE could be successfully exploited to substantially improve SNR and CNR in isotropic whole-heart coronary MRA at 3 T. Further methodological advances will help translate the considerable SNR and CNR advantage into an improved visible vessel length, vessel conspicuity and spatial resolution. This will be critical for larger patient studies that include a direct comparison with the x-ray coronary angiography.
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Yu, J., Jahnke, C., Schnackenburg, B. et al. 2D-SENSE in isotropic slow infusion contrast-enhanced whole-heart coronary magnetic resonance angiography at 3 T. J Cardiovasc Magn Reson 12 (Suppl 1), P50 (2010). https://doi.org/10.1186/1532-429X-12-S1-P50