RT Journal Article SR Electronic T1 Electrocardiogram-Gated 18F-FDG PET/CT Hybrid Imaging in Patients with Unsatisfactory Response to Cardiac Resynchronization Therapy: Initial Clinical Results JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 67 OP 71 DO 10.2967/jnumed.110.078709 VO 52 IS 1 A1 Uebleis, Christopher A1 Ulbrich, Michael A1 Tegtmeyer, Roland A1 Schuessler, Franziska A1 Haserueck, Nadine A1 Siebermair, Johannes A1 Becker, Christoph A1 Nekolla, Stephan A1 Cumming, Paul A1 Bartenstein, Peter A1 Kääb, Stefan A1 Hacker, Marcus YR 2011 UL http://jnm.snmjournals.org/content/52/1/67.abstract AB The present study aimed to distinguish responders to cardiac resynchronization therapy (CRT) from nonresponders, using electrocardiogram-gated 18F-FDG PET/CT. Methods: Seven consecutive CRT nonresponders were included in the study, along with 7 age- and sex-matched CRT responders, serving as reference material. Therapy response was defined as clinical improvement (≥1 New York Heart Association class) and evidence of reverse remodeling. Besides PET/CT, we measured brain natriuretic peptide levels and assessed dyssynchrony using transthoracic echocardiography. Results: Compared with nonresponders, CRT responders showed significant differences in the declines of left-ventricular end-systolic volume and brain natriuretic peptide and in left-ventricular dyssynchrony (global left-ventricular entropy), extent of the myocardial scar burden, and biventricular pacemaker leads positioned within viable myocardial regions. Among the nonresponders, further therapy management was guided by the PET/CT results in 4 of 7 patients. Conclusion: Cardiac hybrid imaging using gated 18F-FDG PET/CT enabled the identification of potential reasons for nonresponse to CRT therapy, which can guide subsequent therapy.