A Comparison between Different Imaging Strategies for Diffusion Measurements with the Centric Phase-Encoded TurboFLASH Sequence

• Published in: Journal of magnetic resonance (1997) Vol. 124; no. 2; pp. 323 - 342
• Main Authors: Coremans, J., Spanoghe, M., Budinsky, L., Sterckx, J., Luypaert, R., Eisendrath, H., Osteaux, M.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.1997
• Subjects: Animals; Brain - pathology; Brain Mapping - instrumentation; Cerebral Infarction - diagnosis; Cerebral Infarction - physiopathology; Computer Simulation; Diffusion; Female; Image Processing, Computer-Assisted - instrumentation; Magnetic Resonance Imaging - instrumentation; Phantoms, Imaging; Rats; Rats, Wistar; Subtraction Technique - instrumentation
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1006/jmre.1996.1025

The study compared the results of three centrally reordered phase-encoded turboFLASH sequences for diffusion-weighted imaging (DWI). The sequences were conventional turboFLASH, turboFLASH with subtraction ofT1-related effects, and turboFLASH with correction forT1-related effects during the imaging period only. The relative merits were studied with respect to image quality and accuracy by computer simulation and by experimental validation on phantoms and onin vivorat brain. AT1-related underestimation of the diffusion coefficient ranging from −30% (T1≈ 200 ms) to −5% (T1≈ 1 s) was found to exist for the conventional sequence. Image artifacts, caused by longitudinal relaxation during the imaging period, are reflected in calculated diffusion maps. When the correction sequence is used, the artifacts and the systematic errors are reduced but longitudinal relaxation during the delay between preparation and imaging periods remains large enough to induce significant errors (−15% forT1≈ 200 ms to −3% forT1≈ 1 s). The subtraction sequence eliminates the influence ofT1effects on the calibrations, but leads to identical artifacts for all diffusion-weighted images.