Comparison of functional MR and H215O positron emission tomography in stimulation of the primary visual cortex

M. A. Kraut, S. Marenco, B. J. Soher, D. F. Wong, R. N. Bryan

Research output: Contribution to journalArticlepeer-review


PURPOSE: To locate spoiled gradient-echo functional MR signal changes in relation to brain parenchyma. METHODS: The region of the primary visual cortex was evaluated using functional MR and H215O positron emission tomography in each of six male subjects who were being visually stimulated by means of red light-emitting diode flash goggles. RESULTS: The positron emission tomography technique demonstrated substantially greater relative signal change with visual stimulation than did the functional MR technique. Furthermore, the functional MR signal changes were concentrated in loci around the periphery of brain parenchyma exhibiting increased radiotracer activity, as opposed to being collocated. CONCLUSIONS: Signal changes found using functional MR based on gradient-echo techniques reflect primarily phenomena occurring within small veins and underrepresent activity intrinsic to brain parenchyma, thus introducing potential inaccuracies in locating regions of activated brain tissue. Positron emission tomography, however, directly measures changes in metabolically related activity within the parenchyma.

Original languageEnglish (US)
Pages (from-to)2101-2107
Number of pages7
JournalAmerican Journal of Neuroradiology
Issue number10
StatePublished - 1995


  • Magnetic resonance, functional
  • Positron emission tomography

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Clinical Neurology


Dive into the research topics of 'Comparison of functional MR and H<sub>2</sub><sup>15</sup>O positron emission tomography in stimulation of the primary visual cortex'. Together they form a unique fingerprint.

Cite this