Potential pitfalls of functional MRI using conventional gradient-recalled echo techniques

NMR Biomed. 1994 Mar;7(1-2):69-74. doi: 10.1002/nbm.1940070111.


The conventional gradient-recalled echo technique, FLASH, has widely been used for functional MRI. FLASH results at 4 T with short TEs of 10-20 ms mimic those at 1.5 T with TEs of 25-50 ms or longer. Under these conditions, large venous vessels dominate the activated area; however, the use of longer TEs at 4 T reveals activation in gray matter areas as well as large vessels. Inflow effects of large vessels can be greatly reduced with centric-reordering of phase-encoding steps and inter-image delay. Finger and toe movement paradigms show that functional activation maps are consistent with classical somatotopic maps, and are specific to the tasks. Navigator-based motion correction generates functional maps with larger activation areas by reducing physiological noise.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Brain / anatomy & histology
  • Brain / blood supply
  • Brain / physiology
  • Cerebral Veins / physiology
  • Fingers / physiology
  • Humans
  • Image Processing, Computer-Assisted
  • Magnetic Resonance Imaging / methods*
  • Motor Cortex / anatomy & histology*
  • Motor Cortex / blood supply
  • Motor Cortex / physiology*
  • Movement / physiology
  • Oxygen / blood
  • Sensitivity and Specificity


  • Oxygen