Clinical usefulness of ECG-gated 18F-FDG PET combined with 99mTC-MIBI gated SPECT for evaluating myocardial viability and function.
OBJECTIVE
This study sought to evaluate an imaging approach using gated 99mTc-MIBI (MIBI) SPECT and gated 18F-FDG (FDG) PET for assessment of myocardial viability and cardiac function.


METHODS
Forty-eight patients (38 men, mean age 68.1 +/- 9.6 years) underwent ECG-gated FDG PET and MIBI SPECT within a week. The baseline diagnoses were coronary artery disease (31), mitral regurgitation (1), paroxysmal arrhythmia (10), and dilated cardiomyopathy (6). The gated FDG PET data were analyzed using pFAST software, and the gated MIBI SPECT data were analyzed using QGS software. Fifteen patients were diagnosed with myocardial infarction, and follow-up study was performed to assess the functional outcome four months later. An improvement in LVEF of >5% was defined as significant. The LV myocardium was divided into 17 segments, and regional defect scores were visually assessed using a 4-point scale for each segment (0 = normal, 1 = mildly reduced, 2 = moderately reduced, 3 = absent). A segment with a greater defect score on MIBI SPECT than on FDG PET was defined as a mismatch. The patients were divided into two groups: those with at least two mismatched segments (MM-group), and those with none or one (M-group).


RESULTS
LVEF, EDV and ESV measured by gated FDG PET were highly correlated with those obtained by gated MIBI SPECT (r = 0.848, 0.855 and 0.911, p < 0.0001, respectively). The mean values of LVEF did not differ significantly, but EDV and ESV obtained by gated FDG PET were significantly grater than those obtained by gated MIBI SPECT (p < 0.0001). In 15 patients diagnosed with myocardial infarction, a significant association (p < 0.05) was found between the relative uptake of FDG PET and MIBI SPECT and the functional outcome 4 months later. Global LV function improved in 6 of the 8 patients showing mismatch but in only 1 of the 7 patients with matched defects, resulting in a sensitivity of 86% and specificity of 75%. The overall accuracy to predict global functional outcome was high (80%).


CONCLUSIONS
This imaging approach allows accurate evaluation of myocardial viability. Furthermore, the high correlations of gated FDG PET and gated MIBI SPECT measurements hold promise for the assessment of left ventricular function using gated FDG PET.
Second Department of Internal Medicine, Yokohama City University School of Medicine, 3-9 Fukuura, Yokohama 236-0004, JAPAN. yama9433@tokai.or.jp
Yohei
Y
Yamakawa
Nobukazu
N
Takahashi
Toshiyuki
T
Ishikawa
Kazuaki
K
Uchino
Yasuyuki
Y
Mochida
Toshiaki
T
Ebina
Tsukasa
T
Kobayashi
Kohei
K
Matsushita
Katsumi
K
Matsumoto
Noriko
N
Kawasaki
Mie
M
Shimura
Yasuo
Y
Ohkusu
Shinichi
S
Sumita
Kazuo
K
Kimura
Tomio
T
Inoue
Satoshi
S
Umemura
D000368:Aged; D002648:Child; D004562:Electrocardiography; D005260:Female; D019788:Fluorodeoxyglucose F18; D015637:Gated Blood-Pool Imaging / Q000379:methods; D006321:Heart / Q000000981:diagnostic imaging* / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging*; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D012044:Regression Analysis; D015203:Reproducibility of Results; D017256:Technetium Tc 99m Sestamibi
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18; D017256:Technetium Tc 99m Sestamibi