Evaluation of combined late gadolinium‐enhancement and functional cardiac magnetic resonance imaging using spiral real‐time acquisition

Abstract

The purpose of the current study was to implement and validate joint real‐time acquisition of functional and late gadolinium‐enhancement (LGE) cardiac magnetic resonance (MR) images during free breathing. Inversion recovery cardiac real‐time images with a temporal resolution of 50 ms were acquired using a spiral trajectory (IR‐CRISPI) with a pre‐emphasis based on the gradient system transfer function during free breathing. Functional and LGE cardiac MR images were reconstructed using a low‐rank plus sparse model. Late gadolinium‐enhancement appearance, image quality, and functional parameters of IR‐CRISPI were compared with clinical standard balanced steady‐state free precession breath‐hold techniques in 10 patients. The acquisition of IR‐CRISPI in free breathing of the entire left ventricle took 97 s on average. Bland–Altman analysis and Wilcoxon tests showed a higher artifact level for the breath‐hold technique (p = 0.003), especially for arrhythmic patients or patients with dyspnea, but an increased noise level for IR‐CRISPI of the LGE images (p = 0.01). The estimated transmural extent of the enhancement differed by not more than 25% and did not show a significant bias between the techniques (p = 0.50). The ascertained functional parameters were similar for the breath‐hold technique and IR‐CRISPI, that is, with a minor, nonsignificant (p = 0.16) mean difference of the ejection fraction of 2.3% and a 95% confidence interval from −4.8% to 9.4%. IR‐CRISPI enables joint functional and LGE imaging in free breathing with good image quality but distinctly shorter scan times in comparison with breath‐hold techniques.

Do Disinfectant Solutions during Gargling Reach the Pharynx?

“…Ten consecutive spiral arms, equidistantly spread across k-space (i.e., increment of 36°), were combined to build one undersampled frame. In consecutive frames, the k-space gaps were filled according to the golden ratio, i.e., the entire sampling pattern was rotated by 360°/(5*((sqrt(5))+1)) ≈ 22.25° [24, 26]. Images were reconstructed offline in MATLAB using a low-rank plus sparse model [27].…”

Fast measurement of the gradient system transfer function at 7 T

“…Its first‐order terms can be used to calculate actual k‐space trajectories and apply them in image‐reconstruction algorithms, 11–13 or to achieve a superior gradient pre‐emphasis 14,15 . The GSTF‐based correction methods have, for example, recently been shown to enable the use of spiral trajectories for functional 16 or real‐time imaging 17,18 . The GSTF can be determined from the field response to a broadband input waveform.…”

“…14,15 The GSTF-based correction methods have, for example, recently been shown to enable the use of spiral trajectories for functional 16 or real-time imaging. 17,18 The GSTF can be determined from the field response to a broadband input waveform. The field response can be measured either with a field camera, consisting of multiple NMR probes, 19 or with a phantom-based thin-slice approach that does not require additional hardware.…”