- Meeting abstract
- Open Access
2140 Time-resolved contrast-enhanced whole-heart coronary MRA using 3DPR
© Lai et al; licensee BioMed Central Ltd. 2008
- Published: 22 October 2008
- Contrast Agent
- Signal Integration
- Optimal Time Point
- Signal Intensity Variation
- Signal Intensity Curve
In contrast-enhanced coronary MR angiography (CMRA), the transit time of the contrast agent is dependent on both the injection scheme and the blood circulation of the individual subject. Therefore, for the conventional protocol with Cartesian reconstruction, a bolus prescan and additional assessment are usually necessary to synchronize centre-k-space acquisition with the period of the highest blood signal. This work aimed to investigate the feasibility of time-resolved contrast-enhanced CMRA using 3DPR which eliminates the tedious planning task and enables automatic selection of the optimal time frame.
The center-k-space sample repeatedly measured in each k-space line was used to automatically determine the optimal time frame. First, the signal intensity variation as a function of the heartbeat number was derived by summing all the centre k-space samples acquired in each heartbeat and then low-pass filtered to eliminate modulations of respiratory and cardiac motion. Only signals acquired by the coil closest to the heart were used for the above calculation. Due to background suppression using inversion-recovery pulses, this signal intensity variation is correlated with the change of cardiac-blood-signal enhancement during the scan, which approximates coronary-blood-signal enhancement with slow contrast agent infusion. Next, by sliding the Kmax and Kmin apertures in temporal direction, signal integration over the two apertures were calculated in different aperture positions and the positions corresponding to the peak integration values were used to design the optimal tornado filter, based on which the optimal time frame was reconstructed.
The proposed technique enables time-resolved CMRA capturing the contrast kinetics in the heart. The repeatedly measured center-k-space sample can be exploited to track cardiac-blood-signal enhancement during the scan. The optimal tornado filter providing best contrast-enhancing effects can be automatically determined and used for reconstructing images for diagnosis.