[Quantitative assessment of the infarct size with the unfolded map method of 201Tl myocardial SPECT in patient with acute myocardial infarction].
The unfolded map method of 201Tl single photon emission computed tomography (SPECT) was evaluated as to the ability to quantify and the clinical reliability in estimation of infarct size. At first, the following results were obtained in basic experiments using thoracic phantom: 1) the defect area estimated by the unfolded map method was well correlated with the real defect area in spite of overestimation of the defect area, when the defect area was determined by an isocount method (below 80% of maximum count) (y = 1.941 + 2.29x, r = 0.971, p less than 0.001); 2) the defect volume estimated by short-axis images of 201Tl SPECT was closely correlated with real defect volume in spite of overestimation of defect volume (y = 0.762 + 2.156x, r = 0.982, p less than 0.001); 3) when the defect area was estimated by division of the defect volume by the mean myocardial compartment thickness, it was closely correlated with real defect area (y = 0.946 + 1.232x, r = 0.990, p less than 0.001); 4) when the volume was calculated from the summation of voxels in the regions districted by isocount threshold level at each section of the 99mTc SPECT, the optimal isocount threshold level (percentage to maximum count) was 55%. In addition, the clinical reliability of the unfolded map method as infarct sizing was evaluated in 26 patients with acute myocardial infarction by comparing it with enzymatic method, Bull's eye method, and 99mTc pyrophosphate (PYP) SPECT method. In 14 first attack cases of patient without right ventricular infarction, infarct area (IA) of the unfolded map method correlated most closely with the accumulated creatine kinase MB isoenzyme release (CK-MBr) (r = 0.897), compared with the extent score (ES) (r = 0.853) and the severity score (SS) (r = 0.871) of Bull's eye method and the infarct volume (IV) (r = 0.595) of 99mTc PYP SPECT. In conclusion, although the unfolded map method of 201Tl SPECT has the tendency which overestimate infarct size, it is accurate and clinically reliable method in estimating infarct size.
Kubota
M
M
Department of Radiology, Sapporo Medical College.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000473:pathology; D011237:Predictive Value of Tests; D016698:Technetium Tc 99m Pyrophosphate; D013794:Thallium Radioisotopes; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D013794:Thallium Radioisotopes; D016698:Technetium Tc 99m Pyrophosphate