Objective: The aim of this study is to evaluate the agreement between myocardial 18F-FDG PET imaging and cardiac magnetic resonance imaging (cMRI) in assessing cardiac function and relationship of cMRI late gadolinium enhancement (cMRI-LGE) and myocardial perfusion/metabolism pattern in patients with idiopathic dilated cardiomyopathy (IDCM).
Methods: Forty-two consecutive patients diagnosed with IDCM were enrolled. All patients underwent 99mTc-MIBI SPECT, gated 18F-FDG PET imaging, and cMRI within 3–7 days. Cardiac function parameters were calculated using PET and cMRI. The segments analysis was performed using a 17-segment model. Patterns of perfusion/metabolism were classified as normal, mismatch, mild-to-moderate match, and severe match, and cMRI-LGE was classified into 3 categories (non-LGE, mid-wall LGE, and transmural LGE).
Results: The correlation between gated PET and cMRI was excellent for end-diastolic volume (EDV; r = 0.948, P < 0.001), end-systolic volume (ESV; r = 0.939, P < 0.001), and left ventricular ejection fraction (LVEF; r = 0.685, P < 0.001). EDV and ESV were underestimated, whereas LVEF was slightly overestimated by gated PET in comparison to cMRI. Perfusion/metabolism patterns varied in 3 different categories of non-LGE, mid-wall LGE, and transmural LGE (χ2 = 14.276, P < 0.001). Also, 71.0% (44/62) segments with mid-wall LGE had normal perfusion/metabolism patterns, and 75.9% (63/83) perfusion/metabolism mismatch segments were shown as non-LGE. The incidence of LGE was significantly higher in segments with severe match than the other 3 segment groups (χ2 = 112.53, P < 0.001).
Conclusion: There is an excellent agreement between gated PET and cMRI in assessment of cardiac function. LGE-cMRI is much more sensitive in detecting moderate fibrosis, while PET could detect more impaired but viable myocardium. Combining the 2 imaging modalities is useful for providing more comprehensive evaluations of myocardial injury in patients with IDCM.
From the *Department of Nuclear Medicine, and †Department of Radiology, Cardiovascular Institute and Fu Wai Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100037, China.
Received for publication May 26, 2012; and revision accepted August 22, 2012.
Conflicts of interest and sources of funding: none declared.
Reprints: Wei Fang, MD, or Chaowu Yan, MD, Department of Nuclear Medicine, Cardiovascular Institute and Fu Wai Hospital, Peking Union Medical College and Chinese Academy of Medical Sciences, 167 Beilishi Road, Beijing 100037, China. E-mail: firstname.lastname@example.org.