Assessment of left ventricular function using two different models of semiconductor cadmium zinc telluride (CZT) cameras: A dynamic cardiac phantom study

Objectives Available cadmium-zinc-telluride (CZT) cameras (DNM 530c, GE Healthcare and D-SPECT, Spectrum Dynamics) are not equivalent in terms of sensitivity and spatial resolution. This phantom study compared DNM 530c and D-SPECT for LV function assessment.

Methods The Amsterdam gated (AGATE) dynamic cardiac phantom (Vanderwilt techniques, Boxtel, The Netherlands) was used with the two models of CZT cameras. Thirty-six acquisitions were processed on each camera using both 8- and 16-interval ECG gating. Stop conditions varied from 0.25 Kcts, 0.5 Kcts, 0.75 Kcts, 1 Mcts, 1.25 Mcts and 1.5 Mcts within a myocardial VOI. Heart rate was 70 or 85 per min and left ventricular ejection fraction (EF) was set to 33%, 45% or 60%. EDV, ESV, EF and regional wall thickening (17-segment model) were assessed using QGS.

Results Myocardial volumes were significantly higher with the DNM 530c compared to D-SPECT: EDV (ml): 87 ± 40 vs. 76 ± 32 (P<0.001), ESV (ml): 41 ± 2 vs. 32 ± 5 (all P<0.001), resulting in a decreased LVEF: EF (%): 51±22 vs. 55±23 (P<0.05). One-way ANOVA found no effect of ECG-gating (P=NS) or count statistics (P=NS). Bland Altman plots and Lin's concordance coefficient (CCC) showed an excellent concordance for EDV, ESV and EF between 8- and 16-int gating within each camera (all CCC=0.99). In contrast, the concordance was moderate when comparing between cameras (CCC=0.79 for EDV and ESV, CCC=0.91 for EF). Wall thickening (%) was increased with the DNM 530c: 51±78 vs. 46±63 (P=0.003). Using MANOVA, parameters that significantly impact on myocardial wall thickening assessment were EF (F value=691, P<0.0001), CZT-camera model (F value=14, P=0.0002) and gating interval (F value=12, P=0.0005).

Conclusions DNM 530c and D-SPECT yielded different results for global and segmental LV function assessment. These results should be taken into account in clinical practice.