Abstract
Displacement-encoded imaging with stimulated echoes (DENSE) and harmonic phase imaging (HARP) employ 1-1 spatial modulation of magnetization to cosine modulate the longitudinal magnetization as a function of position at end diastole. Later in the cardiac cycle they sample the cosine-modulated signal and compute myocardial strain from the signal phase. The sampled signal generally includes three distinct echoes: 1) a displacement-encoded stimulated echo, 2) the complex conjugate of the displacement-encoded echo, and 3) an echo arising from T1 relaxation. If the T1-relaxation and complex conjugate echoes are suppressed, then a phase image representing just the displacement-encoded echo can be reconstructed. In the present study, the use of cosine and sine modulation to eliminate (CANSEL) the T1-relaxation and complex conjugate echoes was investigated. With the use of CANSEL, it was demonstrated that DENSE accurately measures through-plane as well as in-plane components of tissue motion. Also, DENSE with CANSEL artifact suppression can provide increased signal-to-noise ratio (SNR) secondary to reduced intravoxel dephasing by using relatively low displacement-encoding frequencies. For applications that employ DENSE imaging with multiple acquisitions, the CANSEL technique can suppress artifact-generating echoes without placing constraints on the displacement-encoding frequency and direction.
Original language | English (US) |
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Pages (from-to) | 774-781 |
Number of pages | 8 |
Journal | Magnetic Resonance in Medicine |
Volume | 52 |
Issue number | 4 |
DOIs | |
State | Published - Oct 2004 |
Externally published | Yes |
Keywords
- Displacement encoding using stimulated echoes (DENSE)
- Harmonic phase imaging (HARP)
- Heart
- Mice
- MRI
- Myocardial tagging
- Stimulated echoes
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging
- Radiological and Ultrasound Technology