Accuracy and Precision of the Computerized Brain Atlas Programme for Localization and Quantification in Positron Emission Tomography

Abstract

Summary:The computerized brain atlas programme (CBA) provides a powerful tool for the anatomical anal ysis of functional images obtained with positron emission tomography (PET). With a repertoire of simple transfor mations, the data base of the CBA is first adapted to the anatomy of the subject's brain represented as a set of magnetic resonance (MR) or computed tomography (CT) images. After this, it is possible to spatially standardize (reformat) any set of tomographic images related to the subject, PET images, as well as CT and MR images, by applying the inverse atlas transformations. From these reformatted images, statistical images, such as average images and associated error images corresponding to dif ferent groups of subjects, may be produced. In all these images, anatomical structures can be localized using the atlas data base and the functional values can be evaluated quantitatively. The purpose of this study was to deter mine the spatial and quantitative accuracy and precision of the calculated regional mean values. Therefore, the CBA was applied to regional CBF (rCBF) measurements with [ 11 C]fluoromethane and PET on 26 healthy male vol unteers during rest and during three different physiolog ical stimulation tasks. First, the spatial accuracy and pre cision of the reformation process were determined by measuring the spread of defined anatomical structures in the reformatted MR images of the subjects. Second, the mean global CBF and the mean rCBF in the average PET images were compared with the global CBF and rCBF in the original PET images. Our results demonstrate that the reformation process accurately transformed the individReceived July 24, 1989; revised November 24, 1989; accepted November 28, 1989. Address correspondence and reprint requests to Dr. R. J. Seitz at Department of Clinical Neurophysiology, Karolinska Hospital, Box 60500, S-10401 Stockholm, Sweden.Abbreviations used: CBA, computerized brain atlas pro gramme; CT, computed tomography; MR, magnetic resonance; PET, positron emission tomography; rCBF, regional CBF; rCMR, regional CMR; ROl, region of interest. For image types, see Table I. . O wing to this high sampling resolution, it was possible to differentiate the mean rCBF changes in adjacent activated fields such as the left motor hand area from the sensory hand area and the left premotor cortex. (c) By calculating the rela tion of the mean rCBF change to the SEM of the mean rCBF change on a pixel-by-pixel basis, areas with signif icant rCBF changes could be determined. By use of the CBA, it was found that there was a high intersubject con sistency in location of stimulation-induced rCBF changes. Furthermore, the rCBF changes in specifically stimulated areas were of similar magnitude among the subjects. It was shown that the stimulation-induced mean rCBF increases may be accompanied by mean rCBF de creases in other areas. Key Words: Computerized brain atlas-Magnetic resonance imaging-Physiological stim ulation-Positron emission tomography.Positron emission tomography (PET) is a no...

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“…PET studies that have demonstrated activation of the cerebellum include those examining motor learning [Seitz et al, 1990], motor control [Fox et al, 1985], and tactile learning [Roland et al, 1987], as well as somatosensory discrimination [O'Sullivan et al, 1994]. It has been postulated that the cerebellum is involved in higher cognitive processing mediated through its reciprocal connections with the prefrontal cortex [Middleton and Strick, 1994].…”

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