These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Influence of patient height and weight and type of stress on myocardial count density during SPECT imaging with thallium-201 and technetium 99m-sestamibi.
    Author: O'Connor MK, Bothun E, Gibbons RJ.
    Journal: J Nucl Cardiol; 1998; 5(3):304-12. PubMed ID: 9669585.
    Abstract:
    BACKGROUND: The aim of this study was to determine the variability in myocardial activity with 99mTc-labeled sestamibi and 201Tl tomographic imaging, and to correlate this variability with patient anthropometric data and type of stress. METHODS AND RESULTS: Conventional tomographic acquisition (all-purpose collimator, 30 views, 40 sec/view) was performed in 249 patients (155 with 99mTc-sestamibi, 84 with 201Tl). Normal myocardium was identified in three short-axis tomographic slices between the base and mid-ventricle. To exclude abnormal myocardium, all myocardial activity below an 85% threshold of peak counts was excluded. The average counts per pixel in the remaining myocardium was determined. All data were normalized to a collimator sensitivity of 8.1 counts/min/kBq and corrected for decay. Myocardial count densities in both 201Tl and 99mTc-sestamibi studies exhibited a high degree of variability and varied by factors of 3 to 4 and 2.5 to 3 respectively, between the 10th and 90th percentile of count densities. All 99mTc-sestamibi studies showed an inverse correlation (R approximately 0.7) between myocardial count density and patient weight. For stress 201Tl studies in male patients, a similar inverse correlation (R = 0.63) was found between patient weight and myocardial count density. No correlation was found for female patients. For rest 99mTc-sestamibi studies, the average myocardial count density was 1245 +/- 297 counts/pixel for a 1.11 GBq (30 mCi) injection. This was similar with pharmacologic stress (1224 +/- 297 counts/pixel per 1.11 GBq (30 mCi), but significantly higher with exercise (1569 +/- 363 counts/pixel per 1.11 GBq (30 mCi) (p < 0.005). 201Tl studies averaged 327 +/- 97 counts/pixel (111 MBq [3 mCi] injection) with exercise and 374 +/- 145 counts/pixel/111 MBq (3 mCi) with pharmacologic stress (p = NS). Redistribution studies after exercise/pharmacologic stress (with a 37 MBq [1 mCi] reinjection) averaged 267 +/- 83 counts/pixel (148 MBq [3+1 mCi]). CONCLUSIONS: Measured count densities in the myocardium demonstrate a high degree of variability that is only weakly correlated with patient anthropometric data. Nevertheless, knowledge of the mean values of myocardial activity as a function of administered dose may be useful in the optimization of rapid imaging procedures for 99mTc-based perfusion agents.
    [Abstract] [Full Text] [Related] [New Search]