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M O N D A Y P M A P R I L
Abstracts Monday afternoon, April 7, 1997
Journal of Nuclear Cardiology January/February 1997, Part 2
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ASSESSMENT OF MYOCARDIAL VIABILITY: THE ROLE OF TC99M SESTAMIBI GATED SPECT A. Maes, J. Nuyts, W. Flameng, LPh. Cambier, M. Borgers, L. Mortelmans, U.Z.K.U. Leuven, Belgium
SESTAMIBI TOMOGRAPHY AND LOW-DOSE DOBUTAMINE ECHOCARDIOGRAPHY IN THE PREDICTION OF DELAYED RECOVERY OF PERFUSION AND CONTRACTION AFTER MYOCARDIAL INFARCTION.
In 18 patients with CAD and anterior walt motion abnormalities, a gated Tc99m-Sestamibi resting study and a nuclear angiography were performed preoperatively. During revascularisation, a biopsy specimen was obtained from the LV anterior wall. Three months after surgery, radionuclide angiography was repeated. Optimal thresholds were calculated for Tc-99m-Sestamibi summed and enddiastolie perfusion maps and for wall thickening using improvement of regional ejection fraction as gold standard by maximising [100 - (% false positives) - (% false negatives)]. The optimal threshold was 60% for both summed and enddiastolic perfusion maps. Sensitivity and specificity values were 69% and 80% respectively for the summed perfusion maps and 71% and 100% for the enddiastolic perfusion maps. Concerning the wall thickening data, an optimal threshold of 20 degrees for thickening phase resulted in a sensitivity of 69% and a specificity of 80%. Sensitivity and specificity values for thickening amplitude (threshold = 0.4) were 73% and 71%. Analysis of the histological data revealed 23+12% fibrosis in the patients with preserved MIBI uptake, while 60-219% fibrosis was found in the group with MIBI uptake values <60% (p<0.01). 24+12% fibrosis was found in the patients with preserved wall thickening while 53+24% fibrosis was found in those with decreased wall thickening (p<0.0l). From these data it can be concluded that both perfusion and thickening data can be used for identification of myocardial viability using Tc-99m Sestamibi. Analysis of wall thickening supported perfusion data and provided additional confirmation of the presence of viable myocardium.
A. Cuocolo, E. Nicolai, M.R. Grivet-Fojaja, A. Nappi, F. Squame, P. Sullo, A. Discepolo, L. Spinelli, M. Salvatore. Universit& Federico I1, Napoli, Italy. The aim of this study was to compare the results of low-dose dobutamine (5 gg/kg/min i.v.) 2D-echocardiography (echo) and those of Tc-99m sestamibi tomography in the identification of viable myocardium after myocardial infarction (MI). Thirty-one patients with recent MI were studied 14 days of MI (study 1) and after 9+3 months (study 2). At study 1, all patients underwent Tc-99m sestamibi tomography and dobutamine echo. Regional Tc-99m sestamibi activity and systolic function were assessed in 16 segments/patient. Of the 136 infarct-related segments with severe dysfunction at rest at study 1, 43 (32%) showed contractile reserve and 93 (68%) did not show contractile reserve at dobutamine echo. The majority (98%) of the 43 asynergic segments with contractile reserve had preserved Tc-99m sestamibi uptake (>_50% of peak). However, a substantial number (56%) of asynergic infarct-related segments without contractile reserve had preserved Tc-99m sestamibi uptake. Of these latter segments, 48% showed delayed recovery of perfusion and contraction at study 2. These results suggest that in patients with recent MI the evaluation of contractile reserve alone may underestimate the identification of dysfunctional but still viable myocardium compared to Tc-99m sestamibi tomography.
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COMPARATIVE SENSITIVITIES OF WALL THICKENING, THALLIUM UPTAKE, AND F-18 FDG SPECT IN DETECTING MYOCARDIAL VIABILITY.
PROGNOSTIC VALUE' OF NORMAL REST TETROFOSMIN SPECT IN PATIENTS WITH A C U T E CHEST PAIN AND NONDIAGNOSTIC ECG IN E M E R G E N C Y DEPARTMENT. Frans J. Th. Wackers, Gary V, Heller, Stephen Stowers, Robert C. Hendel, Steve Herman, Jack Baron, Edouard Daher. Acute Chest Pain Trial, Yale U., New Haven, CT.
O. DePuey, M. Ghesani,M. Schwartz M. Friedman, K. Nichols. St. Luke's-RooseveltHospital and Columbia University, New York, NY To evaluate the comparative sensitivities in detecting myocardial viability of gated SPECT wall thickening (WT), delayed TI-201 SPECT (TL), and F-18 FDG SPECT (FDG), 15 patients (pts) with prior myocardial infarction and clinically suspected viability were studied. Each patient demonstrated at least one extensive ~ 30% of LV) and severe (<40% maximal myocardial tracer uptake) fixed perfusinn defect on rest/stress Te-99m sestamibi SPECT. A total of 26 major vascular territories had fixed defcets. Mean (&l SD) LVEF determined from gated perfusion SPECT was 27+13%. WT was assessed semiquantitativelyby the regional increase in myocardial intensity during systole, and was oonsidered normal when a >20% increase was observed. T1-201 SPECT was acquired 4 hours after resting tracer injection. Viability was considered present when regional defect T1-201 count density was at least 20% greater than on the resting sestamibi scan. FDG SPECT was performed independently using 10 mCi and a camera equipped with ultrahigh energy collimation. Criteria of viability were the same as for TI-201. In the 15 pts viabilitywithin the fixed sestamibi defects was manifest by preserved WT in 2 pts, delayed TL uptake in 4 pts, and FDG uptake in 7 pts. Two major vaseular territories with fixed defects were judged viable by WT, 5 by TL, and 11 by FDG (p=.01). In each territory with delsyed TL uptake, FDG uptake was relatively greater. We conclude that FDO SPECT is mol-esensitive than either gated sestamibi WT or delayed TL in detecting viability.
Rest Tc-99m Tetrofosmin (Tetro) SPECT imaging in the emergency department (ED) in patients (pts) with acute chest pain and nondiagnostic ECG has a high negative predictive value for detecting acute infarction(MI). The prognostic value of ED rest Tetro SPECT imaging was evaluated in 357 pts with chest pain and nondiagnostic ECG. All Pts were admitted to hospital and had follow-up (FU) in-hospital (IH) and for 30 days (30d). Managing physicians were blinded to SPECT imaging results. Endpoints were ischemic death, recurrent MI and revascularization (Revasc). Events IH(#pts) 30d(#pts) Total(#pts) Death 0 0 0 MI 20 0 20 Revasc 34 2 36 At 30d FU, 62 pts with abnormal ED Tetro SPECT had significantly more acute MI (21% vs. 2%, p<0.001) and more Revasc (23% vs. 7%, p<0.001) than 295 pts with normal rest ED Tetro SPECT. Thus, abnormal rest ED Tetro SPECT in pts with chest pain and nondiagnostic ECG identifies pts with higher clinical need for Revasc during subsequent 30d follow-up.