2007-05-08 Vesa Oikonen - D R A F T

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Partial volume and spillover effects in cardiac PET studies

Analytical method

Henze et al. (1983) suggested an analytical method to correct for the spillover and recovery fractions. The method was validated by Herrero et al. (1988). The method needs the cardiac dimensions: myocardial wall thickness and cavity diameter, which may not always be available. The method also assumes 10% vascular space, which is also corrected.

This correction can be applied to the regional data before modeling, for example by using heartcor.

Geometrical model

The spillover and partial volume effects are taken into account in compartment models by assuming a geometrical model (Hutchins et al., 1990) and based on that


, where C_PET(t) is the measured myocardial PET concentration as a function of time, C_LV(t) is the measured concentration in the middle of left ventricular cavity, representing also true arterial concentration, and (1-F_LV) is
regional recovery coefficient (between 0 and 1). This method is easy to implement, but it ignores the partial volume effect on the outer side of myocardial wall (Hutchins et al., 1992).

Model for [¹⁵O]H₂O

Iida et al. (1991, 1992) proposed a model for quantification of myocardial blood flow (MBF) with [¹⁵O]H₂O and PET, where the recovery coefficients in both myocardial and LV regions and the spillover fractions from blood to myocardium and from myocardium to blood were included in the model parameters.

This model can be applied to the regional data by using fitmbf.

Further reading

For a short review on general methods to account for spillover and partial volume effects, see for example Feng et al. (1996).


 

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Feng D, Li X, Huang S-C. A new double modeling approach for dynamic cardiac PET studies using noise and spillover contaminated LV measurements. IEEE Trans Biomed Eng. 1996; 43(3): 319-327.

Henze E, Huang S-C, Ratib O, Hoffman E, Phelps ME, Schelbert HR. Measurements of regional tissue and blood-pool radiotracer concentrations from serial tomographic images of the heart. J Nucl Med. 1983; 24: 987-996.

Herrero P, Markham J, Myears DW, Weinheimer CJ, Bergmann SR. Measurement of myocardial blood flow with positron emission tomography: correction for count spillover and partial volume effects. Math Comput Modeling 1988; 11: 807-812.

Hutchins GD, Schwaiger M, Rosenspire KC, Krivokapich J, Schelbert H, Kuhl DE. Noninvasive quantification of regional myocardial blood flowin the human heart using N-13 ammonia and dynamic positron emission tomographic imaging. J Am Coll Cardiol. 1990; 15(5): 1032-1042.

Hutchins GD, Caraher JM, Raylman RR. A region of interest strategy for minimizing resolution distortions in quantitative myocardial PET studies. J Nucl Med. 1992; 33: 1243-1250.

Iida H, Rhodes CG, de Silva R, Yamamoto Y, Araujo LI, Maseri A, Jones T. Myocardial tissue fraction - correction for partial volume effects and measure of tissue viability. J Nucl Med. 1991; 32: 2169-2175.

Iida H, Rhodes CG, de Silva R, Araujo LI, Bloomfield P, Lammertsma AA, Jones T. Use of the left ventricular time-activity curve as a noninvasive input function in dynamic oxygen-15-water positron emission tomography. J Nucl Med. 1992; 33: 1669-1677.

Oikonen V. Model equations for myocardial perfusion studies with [¹⁵O]H2O PET. http://www.turkupetcentre.net/reports/tpcmod0005.pdf

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