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The aim of this study was to compare left ventricular (LV) volumes and regional wall motion determined by PET with those determined by the reference technique, cardiovascular MRI. Methods: LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV), and LV ejection fraction (LVEF) were measured and regional wall motion was scored in 38 patients with chronic coronary artery disease by both gated F-18-FDG PET and MRI. A 9-segment model was used for PET and MRI to assess regional wall motion. Results: Good correlations were observed between MRI and gated PET for all parameters (r values ranging from 0.91 to 0.96). With PET, there was a significant but small underestimation of LVEDV and LVEF. Mean+/-SD LVEDV, LVESV, and LVEF for MRI were 131+/-57 mL, 91+/-12 mL, and 33%+/-12%, respectively, and those for gated PET were 117+/-56 mL, 85+/-51 mL, and 30%+/-11%, respectively. For regional wall motion, an agreement of 85% was found, with a kappa-statistic of 0.79 (95% confidence interval, 0.70-0.89; SE, 0.049). Conclusion: LV volumes, LVEF, and regional wall motion can be assessed with gated F-18-FDG PET and correlate well with these parameters assessed by MRI.

After acute cerebral stroke, the (peri-) infarct tissue is characterized by calcium (Ca)-mediated neuronal damage and inflammatory processes. Monitoring Ca-mediated damage using the isotope cobalt-55 (Go) as a Ga-tracer may enable PET-imaging of this tissue. Since the fate of (peri-) infarct tissue determines clinical outcome, Go-PET may have prognostic value in stroke. Six stroke patients were examined with Go-PET, MRI and a middle cerebral artery (mca) stroke scale (Orgogozo). In every patient? specific Go-accumulation in the appropriate brain region was seen, irrespective of the integrity of the blood-brain barrier. This pilot study suggests Go-PET as a diagnostic tool in stroke, which may provide additional information on the clinical outcome. Validation of method in larger patient series is necessary. (C) 1997 Elsevier Science B.V.

The posterolateral defect is a common artifact seen when static N-13-ammonia imaging with PET is used to assess myocardial perfusion. The aim of this study was to compare dynamic and static N-13-ammonia PET and to obtain more insight into the cause of the posterolateral defect. Methods: Dynamic N-13-ammonia PET was performed in 19 healthy nonsmoking volunteers at rest. Perfusion was assessed in the early phase of the study using a curve fit method over the first 90 sec. Nitrogen-13 accumulation (static PET) was assessed 4 to 8 min after injection. Each study was normalized to a mean of 100. The average distribution of normalized perfusion and activity was calculated in 24 segments. Heterogeneity of both activity and perfusion distribution were assessed and the activity distribution was compared with perfusion distribution. Results: Perfusion distribution was homogeneous, with the exception of the inferior and apical regions. Activity distribution was inhomogeneous, with a lower activity in the posterolateral and apical regions. In the whole left ventricle, significant differences in distribution were found between static and dynamic imaging. Conclusion: Perfusion distribution was significantly different on dynamic images compared to static images. The posterolateral defect was not found on dynamic images. The posterolateral defect and other inhomogeneities in activity distribution are caused by tracer-dependent features, probably a redistribution of metabolites of N-13-ammonia.