title: Perfusion imaging with a freely diffusible hyperpolarized contrast agent.
abstract: Contrast agents that can diffuse freely into or within tissue have numerous attractive features for perfusion imaging. Here we present preliminary data illustrating the suitability of hyperpolarized (13)C labeled 2-methylpropan-2-ol (also known as dimethylethanol, tertiary butyl alcohol and tert-butanol) as a freely diffusible contrast agent for magnetic resonance perfusion imaging. Dynamic (13)C images acquired in rat brain with a balanced steady-state free precession sequence following administration of hyperpolarized 2-methylpropan-2-ol show that this agent can be imaged with 2-4 s temporal resolution, 2 mm slice thickness, and 700 μm in-plane resolution while retaining adequate signal-to-noise ratio. (13)C relaxation measurements on 2-methylpropan-2-ol in blood at 9.4 T yield T(1) = 46 ± 4s and T(2) = 0.55 ± 0.03 s. In the rat brain at 4.7 T, analysis of the temporal dynamics of the balanced steady-state free precession image intensity in tissue and venous blood indicate that 2-methylpropan-2-ol has a T(2) of roughly 2-4s and a T(1) of 43 ± 24 s. In addition, the images indicate that 2-methylpropan-2-ol is freely diffusible in brain and hence has a long residence time in tissue; this in turn makes it possible to image the agent continuously for tens of seconds. These characteristics show that 2-methylpropan-2-ol is a promising agent for robust and quantitative perfusion imaging in the brain and body.
authors: Department of Radiology, Harvard Medical School, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA. akgrant@bidmc.harvard.edu
authors: Aaron K
authors: AK
authors: Grant
authors: Elena
authors: E
authors: Vinogradov
authors: Xiaoen
authors: X
authors: Wang
authors: Robert E
authors: RE
authors: Lenkinski
authors: David C
authors: DC
authors: Alsop
mesh_terms: D000818:Animals; D001931:Brain Mapping / Q000379:methods*; D002247:Carbon Isotopes; D002560:Cerebrovascular Circulation; D003287:Contrast Media / Q000493:pharmacokinetics*; D005682:Gadolinium; D006571:Heterocyclic Compounds / Q000493:pharmacokinetics; D007089:Image Enhancement / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D051381:Rats; D017208:Rats, Wistar; D059629:Signal-To-Noise Ratio; D020002:tert-Butyl Alcohol / Q000493:pharmacokinetics*
chemical_list: D002247:Carbon Isotopes; D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium; D020002:tert-Butyl Alcohol