High-dose dobutamine stress steady-state free precession (SSFP) cine MRI at 3T with patient adaptive local radiofrequency (RF) shimming using dual-source RF transmission.

PurposeTo prospectively assess the feasibility, image quality, and diagnostic accuracy of high-dose dobutamine stress magnetic resonance imaging (DSMR) using steady-state free precession (SSFP) cine imaging at 3T applying a dual-source radiofrequency (RF) excitation magnetic resonance imaging (MRI) system with parallel transmission and patient adaptive local RF shimming. Materials and MethodsDSMR using SSFP cine imaging was performed in 44 patients at 3T scheduled for a clinically indicated coronary angiography. The effect of conventional versus dual-source RF transmission was assessed regarding homogeneity of the B-1 field, contrast-to-noise ratios (CNRs) at rest, image quality, and diagnostic accuracy of DSMR using long and short axis. ResultsThe mean percentage of the intended flip angle within the heart increased from 889.1% with single-source to 103 +/- 5.6% (P < 0.001) dual-source RF transmission. CNR increased for dual-source particularly at the apex (63.4 +/- 24.2 vs. 36.5 +/- 16.5, P < 0.001) but also at the base of the left ventricle (LV) (50.1 +/- 14.8 vs. 39.3 +/- 15.8, P < 0.001). Image quality of dual-source was higher both at rest (2.8 +/- 0.5 vs. 2.6 +/- 0.7, P < 0.001) and stress (2.5 +/- 0.7 vs. 2.0 +/- 1.0, P < 0.001). The number of segments with severe artifacts or nondiagnostic image quality at stress was lower with dual-source RF transmission (8% vs. 27%, P < 0.001). The diagnostic accuracy of DSMR in coronary territories using dual-source RF transmission was significantly higher (77% vs. 65%, P=0.04). ConclusionPatient adaptive local RF shimming using dual-source RF transmission provided significantly improved image quality and higher diagnostic accuracy of SSFP during DSMR at 3T compared to conventional RF transmission. J. Magn. Reson. Imaging 2015;42:746-753.