Myocardial imaging with 99mTc-Tetrofosmin: Influence of post-stress acquisition time, regional radiotracer uptake, and wall motion abnormalities on the clinical result.

BACKGROUND: We previously demonstrated that early (15', T1) post-stress myocardial imaging with Tetrofosmin could be more accurate than standard acquisitions (45', T2) in identifying coronary artery disease. METHODS AND RESULTS: To clarify this phenomenon, 120 subjects (age 61 +/- 10 years) with both T1 and T2 scans were divided into Group 1 (53/120 pts) with more ischemia at T1 vs T2 imaging (T1-T2SDS > or = 3); Group 2 (67/120 pts) with similar results (T1-T2SDS < or = 2). Myocardial areas were categorized as control nonischemic, ischemic, and scarred on the basis of perfusion/contraction properties and coronary anatomy. In each area, regional myocardial count statistic and semiquantitative wall motion/thickening values were obtained. Analysis of T1 and T2 post-stress myocardial counts demonstrated a significant Tetrofosmin wash-out rate that was higher in Group 1 control nonischemic regions (15 +/- 8% vs 13.6 +/- 9.6%, P < .02), significantly lower in Group 1 ischemic regions (7 +/- 10% vs 12.2 +/- 9.5%, P < .0001), and comparable between scarred areas of the two groups (P = NS). Delta post-stress wall thickening (T1-T2) was lower in Group 1 ischemic regions (-4.5 +/- 9.15% vs -1.90 +/- 7.0%, P < .001) and comparable in both control nonischemic and scarred areas of the two groups (P = NS). CONCLUSION: The clinical result of Tetrofosmin gated-SPECT can be influenced by the post-stress acquisition time because of ischemic-induced regional wall thickening abnormalities and the existence of a differential radiotracer myocardial wash-out.

Single-shot cardiorenal scintigraphy with 99mTc-tetrofosmin: a dynamic characterization at rest and during adenosine infusion.

UNLABELLED: Renal function is known to be a strong predictor of cardiovascular prognosis, and cardiorenal disease is increasingly investigated in medical research. In this study, we tested the hypothesis that a single combined cardiorenal scintigraphy examination with the perfusion tracer (99m)Tc-tetrofosmin is feasible and may allow the simultaneous investigation of cardiac and renal pathology in cardiovascular patients. METHODS: Thirty patients scheduled for dual-day gated SPECT also gave their informed consent for a renal acquisition after a single injection of 370 MBq of (99m)Tc-tetrofosmin, at rest (30 patients) or with adenosine (21 patients), and to undergo an additional standard renal study with the glomerular tracer (99m)Tc-diethylenetriaminepentaacetic acid (DTPA) (74 MBq) after 1 wk (24 patients). Kidney images and renograms were obtained. Renal uptake index, expressed as the percentage ratio of kidney counts cumulated over the second minute after injection to the administered dose, was calculated as a functional renal parameter. Time to peak activity and separate kidney percentage uptake (as the percentage contribution of each kidney to total renal uptake) were also calculated. RESULTS: Compared with (99m)Tc-DTPA, (99m)Tc-tetrofosmin provided better-quality kidney images, with a higher uptake index (13.17% +/- 4.76% vs. 8.33% +/- 2.45%, P < 0.001) and with comparable separate kidney percentage uptake and times to peak activity. (99m)Tc-tetrofosmin uptake index was significantly lower in the patients who were more compromised according to renal and cardiovascular functional parameters, and correlated with (99m)Tc-DTPA uptake index (r = 0.77, P < 0.001), serum creatinine (r = 0.59, P < 0.005), log brain natriuretic peptide N-terminal levels (r = -0.65, P < 0.005), myocardial and carotid intima-media wall thickness (for both, r = -0.61, P < 0.005), and the Doppler index of renal vascular resistance (r = -0.60, P < 0.005). In the 21 patients who underwent the provocative test, adenosine induced a significant decrease in renal (99m)Tc-tetrofosmin uptake index (from 14.12% +/- 4.50% to 11.81% +/- 3.33%, P < 0.005) suggesting a decrement in renal perfusion or function. CONCLUSION: (99m)Tc-tetrofosmin cardiorenal scintigraphy is feasible at low cost as a single-shot study and may allow both the evaluation of renal morphology and renograms during a cardiac study and the calculation of renal functional parameters.