Clinical application of respiratory navigator echo triggered black blood contrast cardiac MRI

Objective: To investigate the application of respiratory navigator echo triggered black blood contrast FSE in cardiac MRI. Methods: The respiratory navigator echo trigger technique combining with black blood FSE (NAV-FSE) was tested on 11 volunteers and 5 patients in free breathing, using breath-hold FSE (BH-FSE) with the same imaging protocals as control. The imaging efficiency and the image sharpness were compared between NAV-FSE and BH-FSE and t-test was used for the statistics. Results: All NAV-FSE acquisitions were completed in sixteen subjects while 4 BH-FSE acquisitions failed because of poor breath holding. The efficiencies of NAV-FSE were (42.95 ± 11.50)%, (56.14 ± 11.40)% and (55.25 ± 14.70)% when echo train length (ETL) were 24, 16 and 8, respectively. When ETL were 16 and 24, the sharpness of NAV-FSE (0.43 ± 0.02 vs 0.36 ± 0.02) and BH-FSE (0.36 ± 0.03 vs 0.35 ± 0.02) were statistically different (t =4.26, 5.53, respectively; P <0.05). NAV-FSE could have a shorter ETL setting without consideration of breath holding. Conclusion: The navigator echo trigger technique could be compatible with black blood contrast FSE to image the heart without the restriction of breath holding and it allows to optimize the parameters to improve the image quality. (authors)