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Background: Late gadolinium enhancement (LGE) imaging is well validated for the diagnosis and quantification of myocardial infarction (MI). 2D LGE imaging involves multiple breath‐holds for acquisition of short‐axis slices to cover the left ventricle (LV). 3D LGE methods cover the LV in a single breath‐hold; however, breath‐hold duration is typically long with images susceptible to motion artifacts. Purpose/Hypothesis: To assess a single breath‐hold 3D mDIXON LGE pulse sequence for image quality and quantitation of MI. Study Type: Prospective. Population: Ninety‐ two patients with prior MI. Field Strength/Sequence: 1.5T cardiac MRI protocol using both conventional 2D phase sensitive inversion recovery and 3D mDIXON LGE imaging 10 minutes following contrast administration in random order to avoid bias. Assessment: Data were analyzed qualitatively for image quality (three observers). Quantitative assessment of myocardial scar mass (full‐width half‐maximum), scar transmurality, and contrast‐to‐noise ratio measurements were performed. Time for 2D and 3D LGE imaging was recorded. Statistical Tests: Paired Student's t‐test, Wilcoxon rank test, Cohen κ statistic, Pearson correlation, linear regression, and Bland–Altman analysis. Results: Image quality scores were comparable between 3D and 2D LGE (1.4 ± 0.6 vs. 1.3 ± 0.5; P = 0.162). 3D LGE was associated with greater scar tissue mass (3D: 18.9 ± 17.5 g vs. 2D: 17.8 ± 16.2 g P = 0.03), although this difference was less pronounced when scar tissue was expressed as %LV mass (3D: 13.4 ± 9.9% vs. 2D: 12.7 ± 9.5% P = 0.07). For 3D vs. 2D scar mass there was a strong and significant positive correlation; Bland–Altman analysis showed mean mass bias of 1.1 g (95% confidence interval [CI]: –5.7 to 7.9). Segmental level agreement of scar transmurality between 3D and 2D LGE at the clinical viability threshold of 50% transmurality was excellent (κ = 0.870). 3D image acquisition (15.6 ± 1.4 sec) was just 5% of time required for 2D images (311.6 ± 43.2 sec) P < 0.0001. Data Conclusion: Single breath‐hold 3D mDIXON LGE imaging allows quantitative assessment of MI mass and transmurality, with comparable image quality, in vastly shorter overall acquisition time compared with standard 2D LGE imaging. Level of Evidence: 1 Technical Efficacy: Stage 2

Purpose To demonstrate the feasibility of an automatic adaptive acquisition sequence. Magnetic resonance perfusion pulse sequences often leave potential acquisition time unused in patients with lower heart-rates (HR) and smaller body size. Materials and Methods A perfusion technique was developed that automatically adapts to HR and field-of-view by maximizing in-plane spatial resolution while maintaining temporal resolution every cardiac cycle. Patients (n = 10) and volunteers (n = 10) were scanned with both a standard resolution and adaptive method. Image quality was scored, signal-to-noise ratio (SNR) calculated, and width of dark-rim artifact (DRA) measured. Results The acquired spatial resolution of the adaptive sequence (1.92 × 1.92 mm2 ± 0.34) was higher than the standard resolution (2.42 × 2.42 mm2) (P

Purpose: To evaluate the performance of 4D flow MR in the thoracic aorta with 8- and 32-channel coil arrays using k-t BLAST and SENSE acceleration techniques and compare this to a conventional 2D SENSE approach. Materials and Methods: Fifteen healthy subjects and eight patients underwent magnetic resonance imaging (MRI) at 3.0T using: 1) 2D SENSE phase contrast velocity mapping as the reference standard and 2) 4D-flow pulse sequences accelerated with SENSE and k-t BLAST, using both 8- and 32-channel coil arrays. Data processing was performed using GT Flow. Image quality of the magnitude images and pathline visualization were graded and mean scan times, flow, peak velocity, stroke volume, and image quality were compared between techniques. Results: Mean scan times were significantly lower for 4D-flow sequences accelerated with k-t BLAST compared to SENSE (5.5 vs. 25.2 min; P 0.05); the lowest bias being observed with the 4D 32 channel k-t BLAST sequence. There were no significant differences in measured flow, peak velocity, or stroke volume with any of the four investigated 4D acquisition techniques compared to reference technique values (P > 0.05). In patients, there were no significant differences in flow, peak velocity, or stroke volume measurements between 32-channel 4D k-t BLAST and the reference acquisition. Conclusion: 4D flow MR using k-t BLAST and 32 channel coils allows a reduction in total scan time while improving overall image quality compared to a standard 2D SENSE and 4D SENSE acquisitions. The use of 32 channels rather than 8 channels with the 4D k-t BLAST was also preferable in terms of image quality.

Purpose Intramyocardial hemorrhage and area at risk are both prognostic markers in acute myocardial infarction (AMI). Myocardial T2 and T2* mapping have been used to detect such tissue changes at 1.5T but these techniques are challenging at 3.0T due to additional susceptibility variation. We studied T2 and T2* myocardial mapping techniques at 3.0T on a system employing B1 shimming and compared two different methods of B0 shimming. Materials and Methods Fifteen volunteers and six AMI patients were scanned on a 3T system. Volume and image-based (IB) B0 shimming techniques were implemented. Single breath-hold, multiecho gradient, and spin echo sequences were employed from which T2* and T2 maps were calculated. Results In volunteers, there was no significant difference in mean values obtained with volume or IB shimming for T2 mapping (39.1 ± 6.0 msec vs. 39.4 ± 6.1 msec; P > 0.05) or for T2* mapping (24.2 ± 6.7 msec vs. 24.1 ± 5.2 msec; P > 0.05). There were no significant regional differences in mean T2 values between septal, anterior, and posterior segments with either shimming technique (all P > 0.05); but there were significant regional differences in mean T2* values using volume shimming (27.8 ± 5.2 msec vs. 28.4 ± 5.8 msec vs. 15.9 ± 8.3 msec; P 0.05). Conclusion At 3.0T, cardiac T2 mapping is robust. Although T2* mapping is prone to more regional heterogeneity this can be reduced by using IB instead of conventional volume B0 shimming. J. Magn. Reson. Imaging 2015;41:1013–1020. © 2014 Wiley Periodicals, Inc.