Abstract:
:To achieve optimal image quality and highest spatial resolution for inner ear imaging with a 3D gradient echo sequence, it is necessary to minimize susceptibility dephasing effects by using very short TE. Fractional RF pulses and echoes can yield short TE for moderate spatial resolution; however, for voxel size of less than 1 mm, TE is limited by the phase encode gradients. We present a method to obtain very short effective TE by using short triangular shaped phase encode gradients to sample the central portions of k-space and progressively longer trapezoidal gradients for the outer portions of k-space. A 3D pulse sequence employing the modified phase encoding scheme for both in-plane and slice phase encoding directions was implemented and tested on phantoms and in vivo. The effective TE equals the minimal TE used for the central k-space portions. Submillimeter resolution (0.35 x 0.35 x 0.7 mm3) images of the inner ear were obtained with effective TE of 3.2 ms and were compared with standard 3D images with TE of 8 ms. With this pronounced TE reduction, the susceptibility artifacts at air/fluid interfaces are significantly reduced.
journal_name
Magn Reson Medjournal_title
Magnetic resonance in medicineauthors
Ying K,Schmalbrock P,Clymer Bdoi
10.1002/mrm.1910330112subject
Has Abstractpub_date
1995-01-01 00:00:00pages
82-7issue
1eissn
0740-3194issn
1522-2594journal_volume
33pub_type
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更新日期:1999-09-01 00:00:00
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