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Cerebral perfusion assessment by bolus tracking using hyperpolarized 13 C
Author(s) -
Johansson E.,
Månsson S.,
Wirestam R.,
Svensson J.,
Petersson J.S.,
Golman K.,
Ståhlberg F.
Publication year - 2004
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20013
Subject(s) - depolarization , cerebral blood flow , nuclear magnetic resonance , chemistry , perfusion , cerebral blood volume , hyperpolarization (physics) , bolus (digestion) , nuclear medicine , medicine , nuclear magnetic resonance spectroscopy , anesthesia , physics
Cerebral perfusion was assessed with 13 C MRI in a rat model after intravenous injections of the 13 C‐labeled compound bis ‐1,1‐(hydroxymethyl)‐1‐ 13 C‐cyclopropane‐D 8 in aqueous solutions hyperpolarized by dynamic nuclear polarization (DNP). Since the tracer acted as a direct signal source, several of the problems associated with techniques based on traditional dynamic susceptibility contrast (DSC) MRI contrast agents were avoided. Maps of cerebral blood flow (CBF), cerebral blood volume (CBV), and mean transit time (MTT) were calculated. The MTT was determined to be 2.8 ± 0.8 sec. However, arterial partial‐volume effects in the animal model prevented accurate absolute quantification of CBF and CBV. It was demonstrated that depolarization of the hyperpolarized 13 C tracer via relaxation and the imaging sequence had little influence on CBF assessment when the time resolution of the imaging sequence was short compared to the MTT. However, CBV and MTT were increasingly underestimated as MTT or the depolarization rate increased if depolarization was not taken into account. With a modified bolus‐tracking theory depolarization could be compensated for, assuming that the depolarization rate was known. Three separate compensation methods were investigated experimentally and by numerical simulations. Magn Reson Med 51:464–472, 2004. © 2004 Wiley‐Liss, Inc.