Left Ventricular Function Assessment Using 2 Different Cadmium-Zinc-Telluride Cameras Compared with a γ-Camera with Cardiofocal Collimators: Dynamic Cardiac Phantom Study and Clinical Validation

Abstract

This study compared two SPECT cameras with cadmium-zinc-telluride (CZT) detectors to a conventional Anger camera with cardiofocal collimators for the assessment of left ventricular (LV) function in a phantom and patients. Methods: A gated dynamic cardiac phantom was used. Eighteen acquisitions were processed on each CZT camera and the conventional camera. The total number of counts within a myocardial volume of interest varied from 0.25 kcts to 1.5 Mcts. Ejection fraction was set to 33%, 45%, or 60%. Volume, LV ejection fraction (LVEF), regional wall thickening, and motion (17-segment model) were assessed. One hundred twenty patients with a low pretest likelihood of coronary artery disease and normal findings on stress perfusion SPECT were retrospectively analyzed to provide the reference limits for end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction, and regional function for each camera model. Results: In the phantom study, for each ejection fraction value, volume was higher for the CZT cameras than for the conventional camera, resulting in a decreased but more accurate LVEF (all P , 0.001). In clinical data, body-surface-indexed EDV and ESV (mL/m 2 ) were higher for one of the CZT cameras (Discovery NM 530c) than for the other (D-SPECT) or the conventional camera (respectively, 40.5 ± 9.2, 37 ± 7.9, and 35.8 ± 6.8 for EDV [P , 0.001] and 12.5 ± 5.3, 9.4 ± 4.2, and 8.3 ± 4.4 for ESV [P , 0.001]), resulting in a significantly decreased LVEF: 70.3% ± 9.1% vs. 75.2% ± 8.1% vs. 77.8% ± 9.3%, respectively (P , 0.001). Conclusion: The new CZT cameras yielded global LV function results different from those yielded by the conventional camera. LV volume was higher for the Discovery NM 530c than for the D-SPECT or the conventional camera, leading to decreased LVEF in healthy subjects. These differences should be considered in clinical practice and warrant the collection of a specific reference database.

Left ventricular function assessment using 123I/99mTc dual-isotope acquisition with two semi-conductor cadmium–zinc–telluride (CZT) cameras: a gated cardiac phantom study

“…Imbert et al [21] reported the following classification of measured central spatial resolution: DNM 530c (6.7 mm) and DSPECT (8.6 mm). These results are concordant with previous findings by Bailliez et al [22] showing in both phantom and patients that LV volumes were higher using the DNM 530c model compared to DSPECT and to Anger camera equipped with cardiofocal collimators.…”

“…The phantom was filled under static equilibrium conditions at atmospheric pressure to provide a reproducible ejection fraction. Based on this equilibrium, ejection fraction was imposed by injecting a stroke volume into the ventricular cavity [15, 22]. As a consequence, true EDV and ESV were not known and thus could not be compared with measured volumes.…”

Multiplexed imaging for diagnosis and therapy

“…Simultaneous imaging of SPECT tracers labelled with different isotopes is feasible on the basis of the distinct gamma energies. However, because of crosstalk between energy spectra and scatter, non-trivial correction methods must be applied, and the energy resolution of scanners is continuously sought to improve this outcome 166,167 . Despite this limitation, dual-tracer SPECT imaging is feasible using 201 Tl or 111 In in healthy volunteers and in diverse disease settings, and including brain imaging, cardiac imaging and cancer imaging 166,[168][169][170][171] .…”

One Year of Nuclear Cardiology in France

“…Bailliez et al studied the impact of new CZT cameras on global and regional LV function assessment using phantom and patient data (10,11). In (10), LV volumes and EF measurements were compared using two CZT cameras (DNM 530c and D-SPECT) and a multipurpose camera equipped with multifocal collimators (IQ-SPECT, Siemens Healthcare).…”