Use of an Enhanced Gradient System for Diffusion MR Imaging with Motion-Artifact Reduction

Acta Radiologica - Tập 36 Số 4-6 - Trang 662-670 - 1995
Sara Brockstedt1, C. Thomsen2, Ronnie Wirestam1, John De Poorter3, Carlos De Wagter3, Leif G. Salford4, S. Holtås5, Freddy Ståhlberg1,5
1Department of Radiation Physics, University Hospital, Lund, Sweden
2Danish Research Centre of Magnetic Resonance, Hvidovre Hospital, Hvidovre, Denmark
3MR Department, University Hospital, Ghent, Belgium
4Experimental Neuro-Oncology, Department of Neurosurgery, University Hospital, Lund, Sweden
5MR Division, Department of Diagnostic Radiology, University Hospital, Lund, Sweden

Tóm tắt

Purpose: A spin-echo diffusion-sensitized pulse sequence using high gradients (23 mT/m) is introduced. Material and Methods: In order to minimize motion artefacts, velocity-compensating gradients, ECG-triggering and post-processing with phase correction and raw data averaging using navigator echoes was performed. The in vitro ratio of diffusion coefficients for water and acetone was determined and the water self-diffusion coefficient at different temperatures was evaluated. The pulse sequence was tested in 7 healthy volunteers and in 2 tumour patients with astrocytomas of grades I—II and III—IV. Both single-slice and multi-slice techniques were used. Results: The incorporation of phase correction clearly improved the quality of both diffusion-encoded images and the calculated diffusion maps. Mean values of the diffusion coefficients in vivo were for CSF 2.66×10−9 m2/s and for white and grey matter 0.69×10−9 m2/s and 0.87×10−9 m2/s, respectively. Conclusion: Velocity-compensating gradients in combination with a high gradient strength were shown to be useful for in vivo diffusion MR imaging.

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Thông tin xuất bản

Acta Radiologica

Tập 36 Số 4-6

662-670

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