Fast and fully automatic calibration of frequency offset for balanced steady-state free precession cardiovascular magnetic resonance at 3.0 Tesla

Background: this study proposed a fast and fully automatic calibration system to suppress the dark banding artifacts in balanced steady-state free precession (bssfp) cardiovascular magnetic resonance (cmr) at 3.0 t. methods. twenty-one healthy volunteers (18 men,3 women; mean age 24.9 years) participated in this study after providing institutionally approved consent. the optimal frequency was obtained using sweep scans of transition-band low flip-angle bssfp (bssfp-l),performed with three conditions: breath-hold plus electrocardiography (ecg) triggering (bh + ecg),breath-hold only (bh),and free breathing (fb). a real-time feedback system was implemented to allow the performing of bssfp-l calibration scanning and conventional cine bssfp within one breath-hold. for each scan condition,the optimal phase was estimated using 20-point and 10-point spline fitting. results: linear regression analysis indicated high correlation between the optimal phases obtained using bh and fb and those obtained using bh + ecg (r§ssup§2§esup§ = 0.91 to 0.98,n = 21). the optimal phases obtained using 10-point datasets showed high correlation with the 20-point bh + ecg datasets (r§ssup§2§ esup§ = 0.92 to 0.99,n = 21); although the within-subject coefficient of variation (wscv) was larger using 10-point fitting. the variation of repeated measurements was largest with fb acquisition and smallest with bh + ecg acquisition. the optimal frequency obtained by offline calculation and by real-time feedback calibration significantly reduced dark-band artifacts in cine bssfp images (both p <.01). conclusions: the proposed real-time feedback calibration method for bssfp imaging is rapid and fully automatic. this method could greatly reduce dark-band artifacts in bssfp images and facilitate clinical cmr at 3.0 t. © 2013 tang et al.; licensee biomed central ltd.