- Meeting abstract
- Open Access
130 Contrast-enhanced whole-heart coronary MR angiography at 3.0 T: comparison to steady-state free precession technique at 1.5 T
© Liu et al; licensee BioMed Central Ltd. 2008
- Published: 22 October 2008
- Coronary Segment
- Matrix Coil
- Imaging Coronary Artery
- Volunteer Information
- Average Acquisition Time
Contrast-enhanced whole-heart MRA using slow infusion of a high-relaxivity extravascular contrast agent has been shown to be a promising technique for imaging coronary arteries at 3.0 T (Bi X, Carr J, Li D. MRM 2007, 58: 1–7). Steady-state free precession (SSFP) is the most commonly used method for coronary MRA at 1.5 T. A direct comparison of the two techniques will be useful to demonstrate the advantages of coronary MRA at 3.0 T.
To compare contrast-enhanced whole-heart MRA at 3.0 T and non-contrast SSFP coronary MRA at 1.5 T in the same volunteers.
Ten healthy volunteers (mean age 51 years) were recruited for this study and each subject underwent both 3.0 T and 1.5 T coronary MRA in random order. The interval of the two examinations was within two weeks. No beta-blocker or nitroglycerine was administrated to any subject.
All studies were performed on two Siemens whole-body scanners (1.5 T: Avanto; 3.0 T: Tim Trio; Siemens Medical Solutions). Segmented 3D SSFP and 3D contrast-enhanced FLASH techniques were employed at 1.5 T and 3.0 T, respectively. All data were collected with real-time motion adaptive navigator respiratory gating, ECG triggering, and fat saturation. T2 preparation (40 msec) was applied at 1.5 T to improve the blood-myocardial contrast. At 3.0 T, signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were optimized by applying a non-selective inversion pulse (TI = 200 msec), accompanied by slowly injecting (0.3 ml/sec) of 0.2 mmol/kg body weight of MultiHance (Bracco Imaging SpA, Milan, Italy). The same number of partitions (120–144), spatial resolution (1.4 × 1.4 × 0.9 mm3), GRAPPA (factor of 2), and 12 channel matrix coil were used in 3.0 T and 1.5 T coronary MRA.
SNR and CNR of coronary arteries were measured from original images by a radiologist blinded to all study and volunteer information. The image quality and coverage of coronary anatomy were evaluated independently by two observers using original images of the coronary MRA. The image quality was graded as 1, poor; 2, fair; 3, good; and 4, excellent. The coverage of coronary arteries was assessed based on the number of coronary segments according to the classification of the American Heart Association.
Contrast-enhanced whole-heart coronary MRA at 3.0 T demonstrated higher CNR, less acquisition time, and better depiction of coronary segments, especially for small branches such as diagonal branch, marginal branch, and posterior descending branch compared to SSFP coronary MRA at 1.5 T. Patient studies are required to evaluate the clinical value of contrast-enhanced whole-heart coronary MRA at 3.0 T.
This article is published under license to BioMed Central Ltd.