RT Journal Article SR Electronic T1 Histochemical Correlates of 15O-Water–Perfusable Tissue Fraction in Experimental Canine Studies of Old Myocardial Infarction JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1737 OP 1745 VO 41 IS 10 A1 Iida, Hidehiro A1 Tamura, Yoshikazu A1 Kitamura, Keishi A1 Bloomfield, Peter M. A1 Eberl, Stefan A1 Ono, Yukihiko YR 2000 UL http://jnm.snmjournals.org/content/41/10/1737.abstract AB A method has been proposed to quantitate the myocardial water-perfusable tissue fraction (PTF) in the area of hypoperfused asynergic segments using 15O-water (H215O) and PET. This study investigated the histochemical correlates of PTF (and perfusable tissue index, PTI) in a canine model of old myocardial infarction. Methods: Myocardial infarction was produced in 12 mongrel dogs, and PET was performed 1 mo later, providing quantitative parametric images of PTF, regional myocardial blood flow (MBF), and extravascular density from H215O, 15O-carbon monoxide, and transmission datasets. At the end of scanning, the myocardium was sectioned, and the PET images were compared directly with the corresponding myocardial sections. Results: The distribution of tissue necrosis identified by histochemical staining corresponded well with the defect in PTF but not in MBF. PTF agreed with the equilibrium images of myocardial H215O distribution, obtained after injection of a large bolus of H215O. The defect surface area identified on PTF agreed well quantitatively with the morphometric estimates of the surface area of myocardial infarction. PTI agreed with the absolute proportion of histochemically defined normal myocardium (0.87 ± 0.09 and 0.83 ± 0.08, respectively; P < 0.01). Both PTF and PTI decreased significantly in segments of myocardial infarction and showed a significant difference between the transmural and nontransmural myocardial infarction. Conclusion: The absolute mass and proportion of histochemically defined noninfarcted tissue may be quantitated with PTF and PTI in the area of myocardial infarction segments.