Single-shot versus interleaved echo-planar MR -imaging: Application to visualization of cardiac valve leaflets
✍ Scribed by Clarence P. Davis; Graerne C. McKinnon; Jorg F. Debatin; Stefan Duewell; Gustav K. Von Schulthess
- Book ID
- 102907238
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 701 KB
- Volume
- 5
- Category
- Article
- ISSN
- 1053-1807
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✦ Synopsis
Visualization of the cardiac valves with standard magnetic resonance (MR) imaging is not adequate because of long acquisition times. Echo-planar imaging @PI) can, however, be performed with a temporal resolution (30-50 msec) comparable to that of echocardiography. The authors evaluated the feasibility of real-time imaging of cardiac valve motion with ultrafast MR techunteers and three patients with mitral stenosis and regurgitation were studied with a 1.5-T whole-body imager. Two different EPI sequences were assessed: a standard single-shot gradiquence and a fast imaging technique based on multiple-shot EPI with interleaved k-space acquisition (ICEPI). Fat-suppressed images with an in-plane resolution of 3.7 x 3.7 mm were obtained equally spaced through the cardiac cycle. Half-k-space acquisition was used. Morphologic evaluation was superior with IGEPI, owing to the better intracavitary signal homogeneity (P < .01). and the mitral valve leaflets were easier to identify on systolic images. IGEPI provided adequate valve visibility in all three patients.
niques. Eight healthy v01ent-echo EPI (GEPI) SC-
CONVENTIONAL MAGNETIC resonance IMR) imaging provides excellent morphologic information and is a clinically accepted modality for the evaluation of congenital heart disease (1-3) and disease processes affecting the pericardium. the paracardiac structures, and the thoracic aorta (4-9). Furthermore, the inherent motion sensitivity of MR imaging permits the assessment of cardiac flow.
For MR imaging to become more useful in cardiac diagnosis, it must si- multaneously provide both morphologic and functional information currently available only from a combination of echocardiography. coronary angiography. and nuclear medicine studies. A limitation of conventional MR imaging in the heart is the relatively long acquisition times. This limitation may be overcome with ultrafast imaging (10.1 1). In fact, echo-planar imaging (EPI) (12) can be performed with a temporal resolution as brief as 40-50 msec.
The visualization of moving heart ' Examination time is given for 24 heart phases.