Global and regional functional measurements with gated FDG PET in comparison with left ventriculography

The purpose of this study was to validate the measurement of global and reg ional left ventricular cardiac function with EGG-gated fluorine-18 fluorode oxyglucose (FDG) positron emission tomography (PET) by comparison with the corresponding indices from X-ray left ventriculography (LVG), Twenty-six pa tients (23 men, 3 women, mean age 60.4 years) underwent LVG and EGG-gated ( eight frames/cycle) FDG-PET within an interval of 10.2+/-6.8 days. A volume tric sampling approach was used to obtain both global (EF: ejection fractio n) and regional [%WT: relative regional count increase from end-diastolic ( ED) to end-systolic (ES) phase] functional parameters, The gated PET parame ters were compared with the corresponding findings of LVG in seven myocardi al segments. EF(gated PET) and EF(LVG) did not differ significantly (30%+/- 10% vs 32%+/-10%, P=NS). The two EF values correlated significantly, showin g no significant systematic measurement bias [EF(gated PET) = 2.61+0.86 x E F(LVG), R=0.84, P<0.0001]. Inter- and intra-observer reproducibility for EF were R=0.95, P<0.0001 and R=0.92, P<0.0001, respectively. Regional functio n was evaluated with LVG in 144 myocardial segments comprising 35 normokine tic, 70 hypokinetic and 39 a/dyskinetic segments. Visual analysis of LVG an d gated PET correlated significantly (P<0.001), with an overall concordance ratio of 58% (83/144, kappa=0.35). Gated PET overestimated the regional fu nction in 27% (39/144) and underestimated it in 15% (22/144). %WT showed si gnificant differences between each pair of groups (a/dyskinesis, 13.2%+/-9. 3%; hypokinesis, 17.1%+/-8.8%; normokinesis, 21.8%+/-10.9%). Inter- and int ra-observer reproducibility was significant for %WT (R=0.77, P<0.0001 and R =0.79, P<0.0001, respectively). In conclusion, gated FDG PET permits assess ment of global left ventricular cardiac function. In addition, assessment o f regional function is feasible using the visual or the quantitative parame ters.