Measuring the change in CBV upon cortical activation with high temporal resolution using look-locker EPI and Gd-DTPA
✍ Scribed by S.T. Francis; J.A. Pears; S. Butterworth; R.W. Bowtell; P.A. Gowland
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 273 KB
- Volume
- 50
- Category
- Article
- ISSN
- 0740-3194
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✦ Synopsis
Abstract
A method of simultaneously measuring the changes in cerebral blood volume (CBV) and T that occur on brain activation with high temporal resolution was developed. The method involves measuring the change in the longitudinal relaxation time (T~1~) that occurs following a bolus injection of Gd‐DTPA and converting this measurement to a change in blood volume assuming fast exchange. The sequence was optimized for the measurement of changes in CBV with high temporal resolution. A change in CBV of 27 ± 4% on activation of the primary visual cortex (V1) was measured across four subjects. The time course of changes in T showed a poststimulus undershoot (P = 0.008) corresponding approximately to a period over which CBV was still elevated above baseline, but falling (P = 0.01). The effects of perfusion, nonfulfillment of the assumption of fast exchange and of intrinsic T~1~ changes on activation on the model used to calculate the change in CBV are discussed. Magn Reson Med 50:483–492, 2003. © 2003 Wiley‐Liss, Inc.