HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Li, Q.-S. Articles by Becker, L. C. Search for Related Content PubMed PubMed Citation Articles by Li, Q.-S. Articles by Becker, L. C.

Technetium-99m Methoxyisobutyl Isonitrile (RP30) for Quantification of Myocardial Ischemia and Reperfusion in Dogs

Division of Cardiology, Department of Medicine, and Division of Nuclear Medicine, Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, Maryland

Correspondence: For reprints contact: Lewis C. Becker, MD, Johns Hopkins Medical Institutions, Halsted 500, 600 N. Wolfe St., Baltimore, MD 21205.

ABSTRACT

This study was done to determine whether [^99mTc]methoxyisobutyl isonitrile (RP30), a nonredistributing myocardial perfusion agent, could be used to quantify regional myocardial blood flow distribution during ischemia and reperfusion, employing sequential injections of tracer, tomographic imaging, and appropriate image subtraction. Dogs underwent transient (6 min) coronary artery occlusion, followed by two paired injections of RP30 and radioactive microspheres combined with tomographic imaging, the first during coronary occlusion and the second after 60 min of reperfusion. To obtain a true image representative of reperfusion, the first set of images was corrected for ^99mTc decay and subtracted from the second. During occlusion, tissue microsphere content and scintigraphic RP30 activity in the center of the ischemic region (both expressed as a fraction of the nonischemic region) were closely correlated, although RP30 consistently exceeded microsphere content (0.43 ± .03 vs. 0.24 ± 0.04, p < 0.01). Direct tissue counting of RP30 confirmed its relative excess in ischemic myocardium. Reperfusion was successful in 7/8 dogs, with an increase in RP30 activity to 0.98 ± 0.04 compared to 0.89 ± 0.03 for microspheres (p = N.S.). In one dog with microsphere-documented persistent ischemia, the RP30 defect was still present after reflow. Our results indicate that because of the lack of myocardial clearance and redistribution, repeat injections of RP30 can be used to quantify serial changes in regional myocardial blood flow.

FOOTNOTES

^* Present address: Cujetna Cesta 13, 41000 Zagreb, Yugoslavia.

This article has been cited by other articles:

				A. Ayalew, P.-Y. Marie, P. Menu, P.-M. Mertes, S. Audonnet, V. Jouan, P. Olivier, G. Karcher, D. Ungureanu-Longrois, and A. Bertrand 201Tl and 99mTc-MIBI Retention in an Isolated Heart Model of Low-Flow Ischemia and Stunning: Evidence of Negligible Impact of Myocyte Metabolism on Tracer Kinetics J. Nucl. Med., April 1, 2002; 43(4): 566 - 574. [Abstract] [Full Text] [PDF]

				U. Sechtem Imaging myocardial area at risk and final infarct size Eur. Heart J. Suppl., June 1, 2001; 3(suppl_C): C36 - C46. [PDF]

				G. Ambrosio, S. Betocchi, L. Pace, M. A. Losi, P. Perrone-Filardi, A. Soricelli, F. Piscione, J. Taube, F. Squame, M. Salvatore, et al. Prolonged Impairment of Regional Contractile Function After Resolution of Exercise-Induced Angina: Evidence of Myocardial Stunning in Patients With Coronary Artery Disease Circulation, November 15, 1996; 94(10): 2455 - 2464. [Abstract] [Full Text]

				R. Medrano, R. W. Lowry, J. B. Young, D. G. Weilbaecher, L. H. Michael, I. Afridi, Z.-X. He, J. J. Mahmarian, and M. S. Verani Assessment of Myocardial Viability With 99mTc Sestamibi in Patients Undergoing Cardiac Transplantation: A Scintigraphic/Pathological Study Circulation, September 1, 1996; 94(5): 1010 - 1017. [Abstract] [Full Text]

				T. D. Miller, T. F. Christian, M. R. Hopfenspirger, D. O. Hodge, B. J. Gersh, and R. J. Gibbons Infarct Size After Acute Myocardial Infarction Measured by Quantitative Tomographic 99mTc Sestamibi Imaging Predicts Subsequent Mortality Circulation, August 1, 1995; 92(3): 334 - 341. [Abstract] [Full Text]

				R. J. Gibbons, D. R. Holmes, G. S. Reeder, K. R. Bailey, M. R. Hopfenspirger, B. J. Gersh, and The Mayo Coronary Care Unit and Catheterization La Immediate Angioplasty Compared with the Administration of a Thrombolytic Agent Followed by Conservative Treatment for Myocardial Infarction N. Engl. J. Med., March 11, 1993; 328(10): 685 - 691. [Abstract] [Full Text]