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Interrelations of T 1 and diffusion of water in acute cerebral ischemia of the rat
Author(s) -
Kettunen Mikko I.,
Gröhn Olli H.J.,
Lukkarinen Jouko A.,
Vainio Pauli,
Silvennoinen M. Johanna,
Kauppinen Risto A.
Publication year - 2000
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 - 10.1002/1522-2594(200012)44:6<833::aid-mrm3>3.0.co;2-f
Subject(s) - ischemia , anesthesia , medicine , occlusion , middle cerebral artery , cardiology
Interrelation of T 1 and diffusion of water was studied in rat models of acute global and focal cerebral ischemia. Cortical T 1 , as quantified with an inversion recovery method, increased by 4–7% within a few minutes of global ischemia at 4.7 and 9.4 T, but a significantly smaller change was detected at 1.5 T. The initial T 1 change occurred within seconds of cardiac arrest, much earlier than the extensive diffusion drop after 1–2 min. Thus, the initial increase in T 1 upon acute cerebral ischemia is directly caused by cessation of blood flow. In transient middle cerebral artery occlusion (MCAO), prolonged T 1 relaxation was detected within 10 min, with a subsequent increase during the course of ischemia. Spin density did not change during the first hour, showing that T 1 increase was not caused by net accumulation of water. Interestingly, partial recovery of T 1 upon release of MCAO, occurring independent of long‐term tissue outcome, was observed only in concert with diffusion recovery. Magn Reson Med 44:833–839, 2000. © 2000 Wiley‐Liss, Inc.