Combined outer volume suppression and T2 preparation sequence for coronary angiography.
PURPOSE
To develop a magnetization preparation sequence for simultaneous outer volume suppression (OVS) and T2 weighting in whole-heart coronary magnetic resonance angiography.


METHODS
A combined OVS and T2 preparation sequence (OVS-T2 Prep) was designed with a nonselective adiabatic 90° tipdown pulse, two adiabatic 180° refocusing pulses, and a 2D spiral -90° tipup pulse. The OVS-T2 Prep preserves the magnetization inside an elliptic cylinder with T2 weighting, while saturating the magnetization outside the cylinder. Its performance was tested on phantoms and on 13 normal subjects with coronary magnetic resonance angiography using 3D cones trajectories.


RESULTS
Phantom studies showed expected T2 -dependent signal amplitude in the spatial passband and suppressed signal in the spatial stopband. In vivo studies with full-field-of-view cones yielded a passband-to-stopband signal ratio of 3.18 ± 0.77 and blood-myocardium contrast-to-noise ratio enhancement by a factor of 1.43 ± 0.20 (P < 0.001). In vivo studies with reduced-field-of-view cones showed that OVS-T2 Prep well suppressed the aliasing artifacts, as supported by significantly reduced signal in the regions with no tissues compared to the images acquired without preparation (P < 0.0001).


CONCLUSION
OVS-T2 Prep is a compact sequence that can accelerate coronary magnetic resonance angiography by suppressing signals from tissues surrounding the heart while simultaneously enhancing the blood-myocardium contrast.
['Luo|Jieying|J|', 'Addy|Nii Okai|NO|', 'Ingle|R Reeve|RR|', 'Hargreaves|Brian A|BA|', 'Hu|Bob S|BS|', 'Nishimura|Dwight G|DG|', 'Shin|Taehoon|T|']
D000328:Adult D016477:Artifacts D017023:Coronary Angiography D003331:Coronary Vessels D005260:Female D006801:Humans D007089:Image Enhancement D007090:Image Interpretation, Computer-Assisted D021621:Imaging, Three-Dimensional D018810:Magnetic Resonance Angiography D008297:Male D012680:Sensitivity and Specificity D012815:Signal Processing, Computer-Assisted
outer volume suppression T2 Prep cones imaging coronary MR angiography radiofrequency pulse design