DELAYED DATA-ACQUISITION FOR OPTIMAL PET ACTIVATION STUDIES WITH OXYGEN-15-WATER IN CEREBRAL ARTERIOVENOUS MALFORMATION

In the clinical application of activation PET studies with O-15-water, optimal PET images are required when the high activity of a nearby le sion might affect the activated area. Methods: To determine the optima l time for data acquisition of PET images, we performed serial dynamic PET measurements in five patients with cerebral arteriovenous malform ation (AVM). All AVMs were closest to the motor cortices, and the acti vation task was opponent finger movement contralateral to the AVM. Act ivation PET and MR images were coregisterated for localization of acti vated foci. Results: Time-activity curves of the nidus and normal cort ex from the dynamic PET data demonstrated a discrepancy in peak time a nd significant radioactivity increase in the nidus during the early ph ase. Elimination of the initial PET data provided better contrast in a ctivated foci without affecting the calculated cerebral blood flow of other areas. Conclusion: Delayed data acquisition can avoid interferen ce of the AVM nidus with the activated area.