T2-weighted thin-section imaging with the multislab three-dimensional RARE technique.
A novel three-dimensional (3D) RARE (rapid acquisition with relaxation enhancement) sequence was implemented on a clinical imager. In this technique, multiple slabs are excited in the same way as in the multisection spin-echo sequence, and each slab is further phase encoded into eight sections along the section-slab direction. With a 16-echo RARE sequence, 128 excitations cover the 256 X 256 X 8 3D k space. With a TR of 2,500 msec, 10 slabs can be excited sequentially at each TR, yielding 80 sections in 5 minutes. Slabs were overlapped to give contiguous sections after discarding of the aliased sections at slab edges. This relatively fast sequence makes contiguous thin-section T2-weighted imaging possible, an impractical achievement with the much longer spin-echo method. Compared with 3D Fourier transform gradient-echo imaging, the sensitivity of 3D RARE sequences to magnetic susceptibility is reduced. The clinical potential of T2-weighted 3D imaging is illustrated with high-resolution brain, spine, and temporomandibular joint images.
Oshio
K
K
Department of Radiology, Brigham & Women's Hospital, Boston, MA 02115.
Jolesz
F A
FA
Melki
P S
PS
Mulkern
R V
RV
D001921:Brain / Q000033:anatomy & histology; D002358:Cartilage, Articular / Q000033:anatomy & histology; D002555:Cerebrospinal Fluid; D003391:Cranial Nerves / Q000033:anatomy & histology; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D012815:Signal Processing, Computer-Assisted; D013116:Spinal Cord / Q000033:anatomy & histology; D013126:Spinal Nerve Roots / Q000033:anatomy & histology; D013704:Temporomandibular Joint / Q000033:anatomy & histology; D013997:Time Factors