This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map 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 Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Dilsizian, V. Articles by Bonow, R. O. Search for Related Content PubMed PubMed Citation Articles by Dilsizian, V. Articles by Bonow, R. O.

Circulation, Vol 85, 1032-1038, Copyright © 1992 by American Heart Association

ARTICLES

Differential uptake and apparent 201Tl washout after thallium reinjection. Options regarding early redistribution imaging before reinjection or late redistribution imaging after reinjection

V Dilsizian and RO Bonow
Cardiology Branch, National Heart, Lung, and Blood Institute, Institutes of Health, Bethesda, MD 20892.

BACKGROUND. Because thallium reinjection enhances the identification of viable myocardium, many laboratories have adopted the routine practice of performing reinjection imaging instead of 3-4-hour redistribution imaging. This approach assumes that the stress-reinjection protocol provides the necessary information regarding both exercise-induced ischemia and myocardial viability. Because apparent "washout" of thallium may occur between redistribution and reinjection studies, we examined the limitations created by eliminating 3-4-hour redistribution images. METHODS AND RESULTS. We studied 50 patients with chronic stable coronary artery disease by exercise thallium tomography, radionuclide angiography, and coronary arteriography. Immediately after the 3-4-hour redistribution images, 1 mCi thallium was injected at rest, and images were reacquired both 10 minutes and 24 hours after reinjection. The stress, redistribution, reinjection, and 24-hour images were then analyzed quantitatively, and the magnitude of change in regional thallium activity after reinjection was termed "differential uptake." Of the 127 abnormal myocardial regions on the stress images, 55 (43%) demonstrated either complete or partial reversibility on 3-4-hour redistribution images. After reinjection, 14 of these regions (25%) demonstrated apparent thallium washout due to low differential uptake of thallium, which was only 46 +/- 20% of that observed in normal regions. As a result, the relative thallium activity, which was 55 +/- 13% during stress (relative to normal regions) and increased significantly to 75 +/- 13% on 3-4-hour redistribution studies (p less than 0.001), decreased to only 58 +/- 13% after thallium reinjection. At 24 hours, redistribution again developed in all 14 regions, resulting in a relative thallium activity of 71 +/- 16% (p less than 0.03), which was similar to that achieved on 3-4-hour redistribution images. Twelve of the 14 regions (86%) exhibiting apparent washout after reinjection were supplied by a totally occluded coronary artery, of which eight (67%) had normal wall motion at rest. In contrast, only 41% of the regions with either improved or unchanged thallium uptake after reinjection were supplied by a totally occluded coronary artery (p less than 0.05). CONCLUSIONS. These data indicate that regions with thallium defects that are reversible on 3-4-hour redistribution images may demonstrate apparent washout of thallium after reinjection due to low differential uptake. Although this occurs in only a small fraction of regions (8%) identified as abnormal on exercise images, these regions represent approximately 25% of regions showing redistribution. Such defects would appear irreversible if redistribution imaging is not performed before reinjection. However, these same myocardial regions also redistribute further after reinjection and are identified as reversible on 24-hour images. Thus, one of two imaging options, either stress-redistribution-reinjection imaging or stress-reinjection-24-hour imaging, may be used for a comprehensive assessment of myocardial ischemia and viability.

This article has been cited by other articles:

				A. N. Kitsiou, S. L. Bacharach, M. L. Bartlett, G. Srinivasan, R. M. Summers, A. A. Quyyumi, and V. Dilsizian 13N-ammonia myocardial blood flow and uptake: Relation to functional outcome of asynergic regions after revascularization J. Am. Coll. Cardiol., March 1, 1999; 33(3): 678 - 686. [Abstract] [Full Text] [PDF]

				J. E. Udelson Steps Forward in the Assessment of Myocardial Viability in Left Ventricular Dysfunction Circulation, March 10, 1998; 97(9): 833 - 838. [Full Text] [PDF]

				G. Srinivasan, A. N. Kitsiou, S. L. Bacharach, M. L. Bartlett, C. Miller-Davis, and V. Dilsizian [18F]Fluorodeoxyglucose Single Photon Emission Computed Tomography : Can It Replace PET and Thallium SPECT for the Assessment of Myocardial Viability? Circulation, March 10, 1998; 97(9): 843 - 850. [Abstract] [Full Text] [PDF]

				M.G. Niemeyer, A.F.M. Kuijper, J.G. Meeder, M.J.M. Cramer, A.J.M. Cleophas, E.E. van der Wall, and M. G. Niemeyer Comparison of Thallium Scintigraphy and Positron Emission Tomography Angiology, October 1, 1997; 48(10): 843 - 853. [Abstract] [PDF]

				A. I. McGhie and A. Weyman Searching for Hibernating Myocardium: Time to Reevaluate Investigative Strategies? Circulation, December 1, 1996; 94(11): 2685 - 2688. [Full Text]