Myocardial viability index in chronic coronary artery disease: technetium-99m-methoxy isobutyl isonitrile redistribution.
The purpose of this study was to evaluate whether an additional redistribution image after a rest 99mTc-MIBI injection enhances detection of viable myocardium and predicts functional recovery after coronary revascularization in patients with chronic coronary artery disease (CAD).


METHODS
Thirty-one patients (29 men, mean age 55 +/- 10 yr) with proven CAD and left ventricular (LV) dysfunction (ejection fraction 39% +/- 9%) underwent resting 99mTc-MIBI tomography with initial (1 hr) and delayed (5 hr) images. Within 1 wk of MIBI imaging, all patients underwent rest-distribution 201Tl imaging. Eight patients also underwent two-dimensional echocardiography before and 5 +/- 3 mo after coronary revascularization.


RESULTS
On the initial 99mTc-MIBI images, 302 myocardial segments were normal, 183 showed moderate and 197 severe reduction of tracer uptake. Of these 197 segments, 47 (24%) demonstrated increased tracer uptake (> or = 10% versus initial) on delayed images (from 43% +/- 8% to 60% +/- 8%, p < 0.001) and were considered as showing 99mTc-MIBI redistribution. These 47 segments were observed in 20 (65%) patients in whom 201Tl images detected viable myocardium in the same segments. In the eight patients studied before and after revascularization, 83% of segments with 99mTc-MIBI redistribution and abnormal LV function showed functional recovery after revascularization, while 96% of segments without 99mTc-MIBI redistribution did not show functional recovery.


CONCLUSIONS
Resting 99mTc-MIBI redistribution frequently occurs in patients with chronic CAD. Acquisition of 99mTc-MIBI redistribution images enhances detection of viable myocardium and predicts functional recovery after revascularization.
D003327:Coronary Disease / Q000000981:diagnostic imaging* / Q000628:therapy; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009204:Myocardial Revascularization; D011446:Prospective Studies; D017256:Technetium Tc 99m Sestamibi; D013794:Thallium Radioisotopes; D013997:Time Factors; D015899:Tomography, Emission-Computed, Single-Photon; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging
D013794:Thallium Radioisotopes; D017256:Technetium Tc 99m Sestamibi