Quantitative relationship of stress Tc-99m sestamibi lung uptake with resting Tl-201 lung uptake and with indices of left ventricular dysfunction and coronary artery disease

Abstract

Increased stress Tc-99m sestamibi LHR correlates with rest Tl-201 LHR in patients with known or suspected CAD. Stress Tc-99m sestamibi lung uptake is also associated with invasively measured LV filling pressures.

Clinical Significance of Tetrofosm in Extracardiac Uptake During Myocardial Perfusion Imaging

“…The results of assessing Tc-99m sestamibi pulmonary-to heart ratio of activity on conventional images obtained 30-60 min after stress are ambiguous, while a few studies have suggested that measuring lung uptake of Tc-99m sestamibi on immediate post-stress images may be more valuable (Bacher-Stier et al, 2000;Choy & Leslie, 2001;Giubbini et al, 1995;Hurwitz et al, 1993;Hurwitz et al, 1996;Hurwitz et al, 1998;Hurwitz, 2000;Patel et al, 2004;Romanens et al, 2001;Saha et al, 1994). In addition, the methodology for calculating LHR among investigators varies; for example, a large ROI that enclosed the entire left ventricle or most of the left ventricle respectively and a fixed-size ROI in the left lung (Choy & Leslie, 2001;Patel et al, 2004). Other widely used methods are the following: a transmural segment of the myocardium is outlined containing the area of peak counts and a crescenting ROI placed over the left lung or alternatively, a fixed small rectangular ROI placed over maximal myocardial and left lung activity (Hurwitz et al, 1993;Hurwitz et al, 1996;Hurwitz et al, 1998;Hurwitz, 2000;Romanens et al, 2001).…”

“…Thus, the reported LHR normal values for Tc99m sestamibi vary significantly between 0.44 and 0.56, depended on the method of calculation and the time interval between radiotracer's injection and the acquisition of the image for the LHR calculation, although early post-stress calculated values are generally higher than those calculated during the standard acquisition time (Georgoulias et al, 2010a). In addition, conflicting results have been reported about the relation between the values of LHR measured in the delayed images and the presence of extensive myocardial ischaemia www.intechopen.com or severe CAD (Bacher-Stier et al, 2000;Choy & Leslie, 2001;Patel et al, 2004;Saha et al, 1994). On the other hand, the clinical value of Tc-99m sestamibi LHR obtained almost immediately after stress (exercise or vasodilatation), has been reported in several studies (Flamen et al, 1995;Münch et al, 1997;Nakajima et al, 1993).…”

“…For the quantification of Tc-99m tetrofosmin pulmonary uptake, in our Nuclear Medicine Laboratory we acquire early anterior planar images (1000 kcounts, matrix 256X256), 4-6 min after radiotracer injection at stress (early post-stress images), considering that Tc-99m tetrofosmin has a rapid clearance from the lungs. We then delineate two ROIs: one square, 15X15 pixels, placed over the left mid-lung area at the vicinity of the myocardium (at a distance of at least 3 pixels above the anterolateral wall -'lung ROI') and the other, manually drown irregular ROI, including the whole myocardial activity of the left ventricle ('myocardial ROI') (Choy & Leslie, 2001;Georgoulias et al, 2006;Patel et al, 2004) (Fig. 1).…”

“…The pulmonary/heart ratio was determined as the mean counts/pixel in the lung ROI divided by the mean counts/pixel in the myocardial ROI (Choy & Leslie, 2001;Giubbini et al, 1995;Homma et al, 1987;Hurwitz et al, 1992;Hurwitz et al, 1998;Kaul et al, 1998;Kurata et al, 1991;Liu et al, 1985;Patel et al, 2004;Tanigaki et al, 1998;Tsou et al, 2002). Our method for calculating Tc-99m tetrofosmin LHR is similar to that used by Choy & Leslie (Choy & Leslie, 2001) and Patel et al (Patel et al, 2004). This approach may underestimate the counts from the heart, if severe defects are present, thus potentially overestimating the LHR value.…”

Diastolic Filling Parameters Derived from Myocardial Perfusion Imaging Can Predict Left Ventricular End-Diastolic Pressure at Subsequent Cardiac Catheterization

“…201 Tl is still used as the rest imaging agent in dual-isotope stress and rest-redistribution viability protocols. Unfortunately, the value of resting 201 Tl LHR and stress 99m Tc LHR for detecting increased left ventricular end-diastolic pressure (LVEDP) is limited (8)(9)(10). Hence, there is a need for new methods for assessing diastolic dysfunction during MPI.…”