Determination of cognitive hemispheric lateralization by functional transcranial Doppler cross-validated by functional MRI

• Published in: Stroke (1970) Vol. 30; no. 5; pp. 939 - 945
• Main Authors: SCHMIDT, P, KRINGS, T, WILLMES, K, ROESSLER, F, REUL, J, THRON, A
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.05.1999; American Heart Association, Inc
• Subjects: Adult; Biological and medical sciences; Brain Mapping; Cerebral circulation. Blood-brain barrier. Choroid plexus. Cerebrospinal fluid. Circumventricular organ. Meninges; Cerebral Cortex - blood supply; Cerebral Cortex - diagnostic imaging; Cerebral Cortex - physiology; Cerebrovascular Circulation - physiology; Cognition - physiology; Echoencephalography; Electric Stimulation; Female; Functional Laterality - physiology; Fundamental and applied biological sciences. Psychology; Humans; Magnetic Resonance Imaging - standards; Magnetics; Male; Reproducibility of Results; Space Perception - physiology; Ultrasonography, Doppler, Transcranial; Vertebrates: nervous system and sense organs; Sonography; Human; Regional blood flow; Exploration; Cognition; Duplex ultrasonography; Nuclear magnetic resonance imaging; Transcranial route; Cerebral hemisphere; Medical imagery; Hemodynamics; Laterality; Comparative study; Brain (vertebrata)
• ISSN: 0039-2499; 1524-4628
• DOI: 10.1161/01.str.30.5.939

Changes of blood flow velocity in the right and left middle cerebral artery (MCA) induced by cognitive demands are detectable by means of "functional" transcranial Doppler sonography (fTCD). Functional MRI (fMRI) is an alternative method for mapping brain activity. The purpose of this study was to determine whether fTCD can detect hemispheric lateralization and to cross-validate fTCD with fMRI. Bilateral continuous MCA monitoring of 14 healthy, right-handed subjects with TCD was performed while the subjects underwent a visuospatial task, and the hemispheric blood flow velocity shift was calculated. Identical stimulus and response patterns were used in fMRI. Blood oxygenation level-dependent fMRI was performed with the use of a gradient-echo echo-planar sequence on a 1.5-T scanner. Statistical maps were computed on a voxel-by-voxel basis, hemispheric ratios for activated pixels were computed, and a group study was performed separately for the male and female subgroups. Statistical analyses (t test) showed a significantly higher mean peak blood flow velocity increase (P<0.05) of the right MCA (111.3+/-7.0%) compared with the left MCA (107.1+/-6.1%). fMRI demonstrated bilateral activation in the superior parietal lobulus (Brodmann area 7) with a right/left ratio of 1.95. Concordant differences between the female and male subgroups could be visualized with both methods. Both methods succeeded in discriminating a blood flow shift to the right hemisphere induced by a complex cognitive visuospatial task. fMRI cross-validates the findings of fTCD. Our study suggests that fTCD can investigate the close relationship between brain activity and blood flow and lateralize higher cognitive functions reliably.