title: Combining FDG-PET and 99mTc-SPECT to predict functional outcome after coronary artery bypass surgery.
abstract: OBJECTIVE
  Single-photon emission computed tomography (SPECT) and positron emission tomography (PET) are suggested to improve clinical decision-making in ischaemic cardiomyopathy. Here, we present a unique cohort of patients who underwent nuclear medicine studies and cardiac magnetic resonance imaging (MRI) both before and 1 year after coronary artery bypass (CABG) surgery to assess benefit from surgery.
  
  
  RESULTS
  Before CABG, we applied three quantitative techniques using (18)F-fluorodeoxyglucose-PET and (99m)technetium-tetrofosmin-SPECT with a software tool to measure defects with hypoperfused but viable and non-viable myocardium in 15 patients. One method used solely PET, two others combined PET and SPECT at different thresholds. As a reference, we used change in left-ventricular (LV) function and volume by MRI. Preoperatively, ischaemic but viable areas detected by the method with a 10% threshold combining PET-SPECT and the PET-only method correlated significantly with preoperative regional wall thickening (WT; P = 0.03 and P = 0.005, respectively). When compared with global functional outcome (change in LV ejection fraction) and LV remodelling (change in end-diastolic volume) 1 year postoperatively, no correlation appeared with preoperative PET- or PET-SPECT-derived viable or non-viable tissue. Neither was any correlation observable between local change in WT and local preoperative defect size evaluated by any of these three methods.
  
  
  CONCLUSIONS
  Preoperatively, PET and PET-SPECT with 10% threshold detected dysfunctional myocardium, but all analysis methods failed to predict 1-year functional outcome assessed by MRI. In patients with three-vessel disease and heart failure, SPECT perfusion and PET viability study results show substantial heterogeneity; this should be considered when selecting patients for revascularization.
authors.affiliation: Department of Cardiothoracic Surgery, Heart and Lung Center, Helsinki University Central Hospital, Haartmaninkatu 4, Helsinki 00029 HUS, Finland miia.l.lehtinen@helsinki.fi.
authors.forename: Miia
authors.initials: M
authors.lastname: Lehtinen
authors.affiliation: Division of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Schildt
authors.affiliation: Division of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Aapo
authors.initials: A
authors.lastname: Ahonen
authors.affiliation: Division of Nuclear Medicine, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Päivi
authors.initials: P
authors.lastname: Nikkinen
authors.affiliation: Division of Roentgenology, HUS Medical Imaging Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Kirsi
authors.initials: K
authors.lastname: Lauerma
authors.affiliation: Division of Cardiology, Heart and Lung Center, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Juha
authors.initials: J
authors.lastname: Sinisalo
authors.affiliation: Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland.
authors.forename: Esko
authors.initials: E
authors.lastname: Kankuri
authors.affiliation: Department of Cardiothoracic Surgery, Heart and Lung Center, Helsinki University Central Hospital, Haartmaninkatu 4, Helsinki 00029 HUS, Finland.
authors.forename: Antti
authors.initials: A
authors.lastname: Vento
authors.affiliation: Department of Cardiothoracic Surgery, Heart and Lung Center, Helsinki University Central Hospital, Haartmaninkatu 4, Helsinki 00029 HUS, Finland.
authors.forename: Tommi
authors.initials: T
authors.lastname: Pätilä
authors.affiliation: Department of Cardiothoracic Surgery, Heart and Lung Center, Helsinki University Central Hospital, Haartmaninkatu 4, Helsinki 00029 HUS, Finland Institute of Biomedicine, Pharmacology, University of Helsinki, Helsinki, Finland.
authors.forename: Ari
authors.initials: A
authors.lastname: Harjula
mesh_terms: D000368:Aged; D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects / Q000379:methods*; D023921:Coronary Stenosis / Q000000981:diagnostic imaging* / Q000401:mortality / Q000601:surgery*; D005260:Female; D005500:Follow-Up Studies; D006084:Graft Rejection; D006085:Graft Survival; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D011182:Postoperative Care; D011237:Predictive Value of Tests; D011300:Preoperative Care; D018570:Risk Assessment; D015996:Survival Rate; D013667:Technetium; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome
chemical_list: D013667:Technetium
keywords: coronary bypass surgery; heart; magnetic resonance imaging; positron emission tomography; single-photon emission computed tomography