Analysis of T2 limitations and off‐resonance effects on spatial resolution and artifacts in echo‐planar imaging

Farhad Farzaneh, Stephen J. Riederer, Norbert J. Pelc

Research output: Contribution to journalArticle

276 Scopus citations

Abstract

Several aspects of blipped echo‐planar imaging (EPI) are treated mathematically. An expression relating the necessary readout gradient strength and sampling time to the spatial resolution and readout duration is derived. It is shown how the net spatial resolution may be limited by the object's T2 characteristics and Bo field homogeneity, irrespective of the number of sampled points. Additionally, off‐resonance effects result in a loss of spatial resolution and image distortion to a considerably greater degree than in conventional two‐dimensional Fourier transform imaging. The extent of these effects is directly related to the time required to acquire the data matrix, and is therefore amplified when EPI is implemented on a standard commercial whole‐body system which because of limited gradient performance uses necessarily longer sampling durations. Specific hardware modifications to a standard commercial imager are considered to allow successful EPI implementation. EPI image characteristics are compared quantitatively with those of conventional methods. © 1990 Academic Press, Inc.

Original languageEnglish (US)
Pages (from-to)123-139
Number of pages17
JournalMagnetic Resonance in Medicine
Volume14
Issue number1
DOIs
StatePublished - Apr 1990

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging

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