| Autor: |
Franson, Dominique, Ahad, James, Liu, Yuchi, Fyrdahl, Alexander, Truesdell, William, Hamilton, Jesse, Seiberlich, Nicole |
| Předmět: |
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| Zdroj: |
Magnetic Resonance in Medicine; Feb2023, Vol. 89 Issue 2, p536-549, 14p |
| Abstrakt: |
Purpose: Through‐time spiral GRAPPA is a real‐time imaging technique that enables ungated, free‐breathing evaluation of the left ventricle. However, it requires a separate fully‐sampled calibration scan to calculate GRAPPA weights. A self‐calibrated through‐time spiral GRAPPA method is proposed that uses a specially designed spiral trajectory with interleaved arm ordering such that consecutive undersampled frames can be merged to form calibration data, eliminating the separate fully‐sampled acquisition. Theory and Methods: The proposed method considers the time needed to acquire data at all points in a GRAPPA calibration kernel when using interleaved arm ordering. Using this metric, simulations were performed to design a spiral trajectory for self‐calibrated GRAPPA. Data were acquired in healthy volunteers using the proposed method and a comparison electrocardiogram‐gated and breath‐held cine scan. Left ventricular functional values and image quality are compared. Results: A 12‐arm spiral trajectory was designed with a temporal resolution of 32.72 ms/cardiac phase with an acceleration factor of 3. Functional values calculated using the proposed method and the gold‐standard method were not statistically significantly different (paired t‐test, p < 0.05). Image quality ratings were lower for the proposed method, with statistically significantly different ratings (Wilcoxon signed rank test, p < 0.05) for two of five image quality aspects rated (level of artifact, blood‐myocardium contrast). Conclusions: A self‐calibrated through‐time spiral GRAPPA reconstruction can enable ungated, free‐breathing evaluation of the left ventricle in 71 s. Functional values are equivalent to a gold‐standard cine technique, although some aspects of image quality may be inferior due to the real‐time nature of the data collection. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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