Reverse redistribution of Tc-99m-tetrofosmin in patients with acute myocardial infarction

Abstract

We examined reverse redistribution (RR) of Tc-99m-tetrofosmin after a single injection in patients with acute myocardial infarction (AMI). Tc-99m-tetrofosmin myocardial SPECT was performed in 28 patients with AMI 10-14 days after the onset. Myocardial images were obtained 30 min and 180 min after the injection of 740 MBq of Tc-99m-tetrofosmin. The left ventricular wall was divided into 9 segments. Regional myocardial uptakes of Tc-99m-tetrofosmin were scored by 4-point scoring (0 = normal, 1 = mildly reduced, 2 = moderately reduced, and 3 = defect). RR was defined as an increase of more than 1 in the regional score in images at 180 min. RR of Tc-99m-tetrofosmin was observed in 17 of 20 patients with direct PTCA and 3 of 8 patients without reperfused therapy. RR was observed in 61 of all 252 segments. Coronary angiography performed 1 month later revealed that the infarct-related artery was patent in 19 of 20 patients (95%) with RR and in 3 of 8 patients (37.5%) with persistent defects (PD) (p < 0.05). In segment-by-segment analysis, the incidence of regional wall motion abnormality I month later was reduced in regions with RR compared to those with PD (p < 0.0001). In conclusion, RR of Tc-99m-tetrofosmin was frequently observed in patients with successful direct PTCA. As the segments with RR showed signs of preserved function 1 month later, this phenomenon may reflect a salvaged myocardium in AMI.

Reverse Redistribution Phenomenon on Rest 99mTc-Tetrofosmin Myocardial Single Photon Emission Computed Tomography Involves Impaired Left Ventricular Contraction in Patients With Acute Myocardial Infarction

“…Although the present study did not provide such a pathophysiological interpretation, the finding that the mean %CI in regions with RR after exercise was as low as that observed in scarred areas adds to the findings of Sugihara et al, 7 elucidating the clinical significance of RR on 99m Tc-tetrofosmin SPECT imaging.…”

“…[19][20][21] In patients with AMI who underwent reperfusion therapy, the RR phenomenon has been demonstrated on 99m Tc-labeled flow tracers myocardial scintigraphy and the myocardium that shows the RR phenomenon of 99m Tc-labeled flow tracers is thought to be damaged, though contractile function is preserved to a certain extent. [7][8][9] Sugihara et al 7 reported that the impairment of the LV wall motion in the regions showing the 99m Tc-tetrofosmin RR phenomenon, evaluated using contrast left ventriculography, ranged from akinesis/dyskinesis to normal, but was significantly better than that in the regions with a fixed defect. Takeishi et al 9 had a comparable result for LV wall motion evaluated by contrast left ventriculography in the regions with the 99m Tc-sestamibi RR phenomenon, and both those studies had findings that were similar to those observed in regions with RR on 201 Tl scintigraphy.…”

The relationship between reverse redistribution of 99mTc-tetrofosmin in sub-acute phase and left ventricular functional recovery in chronic phase in patients with acute myocardial infarction

“…Reverse redistribution (RRD) was observed between the initial and delayed images of AMI on myocardial perfusion images using a 99m Tc-labeled agent with almost no clearance in normal myocardium, which is reported to reflect mitochondrial damage in myocardium [14][15][16][17]. It has also been reported that RRD can predict functional recovery in the chronic phase.…”

“…However, these studies assessing myocardial uptake of 99m Tc-labeled agents were conducted using visual semi-quantitative analysis. Moreover, left ventricular function was assessed using left ventriculography (LVG) or echocardiography [14][15][16][17][18][19][20][21]. The findings of these studies on RRD were, therefore, not necessarily valid.…”

Interpretation of reverse redistribution of 99m Tc-tetrofosmin in patients with acute myocardial infarction

“…Arii et al [12] reported that reverse redistribution of 99m Tc-tetrofosmin is more prominent in the infarct area. Sugihara et al [13] reported that reverse redistribution of 99m Tc-tetrofosmin indicates salvaged myocardium. The present study was performed to investigate the time evolution of the 99m Tc-tetrofosmin reverse redistribution pattern and its relation to regional wall motion in patients with acute myocardial infarction; in addition, we aimed to assess the clinical implications of this phenomenon.…”