Contribution of mitochondria to cardiac muscle water/macromolecule proton magnetization transfer

The contribution of mitochondria to water‐macromolecule proton magnetization transfer (MT) was evaluated in porcine heart tissue. An examination of isolated mitochondria in suspension, at the same concentration as found in heart tissue, revealed MT effects very similar in magnitude and bandwidth to those in intact heart tissue. Disruption of the gross structure of the mitochondria by freeze‐thawing or with detergent resulted in only ∼25% decreases in MT, which suggests that the structure of the mitochondria is not critical for these effects. The current data indicate that mitochondria macromolecules contribute significantly to MT in the intact heart. Magn Reson Med 50:1312–1316, 2003. Published 2003 Wiley‐Liss, Inc.