Taui, A high-resolution metabolic imaging biomarker for myocardium
نویسندگان
چکیده
Background Contrast-enhanced H2O T1-weighted cardiovascular MRI is usually interpreted using tracer paradigms; e.g., the extra-/intravascular contrast agent (CA) partition coefficient. However, the signal molecule is water, not CA. Consequently, the myocardial extracellular volume fraction (ECV) is underestimated in proportion to its magnitude. Even more importantly, intercompartmental water exchange kinetics are inaccessible. The mean intracellular water molecule lifetime [taui] is assumed effectively 0; though it is a fraction of a second. For cylindrical myocytes with mean cytolemmal water permeability coefficient PW and diameter d: taui = 4(PW/d). taui -1 is linearly related to PW and to d . However, PW dominates and is itself dominated by active trans-membrane water cycling. Thus, taui -1 is proportional to the driving cytolemmal ATPase ion pump activity.
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