Simultaneous dual-isotope solid-state detector SPECT for improved tracking of white blood cells in suspected endocarditis

Aims High-energy resolution and sensitivity of novel cadmium-zinc-telluride (CZT) detector equipped SPECT systems facilitate simultaneous imaging of multiple isotopes and may enhance the detection of molecular/cellular signals. This may refine the detection of endocarditis. This study was designed to determine the feasibility and diagnostic accuracy of simultaneous imaging of inflammation with In-111-labeled white blood cells (WBCs) and myocardial perfusion with Tc-99m-sestamibi, for localization of WBCs relative to the valve plane in suspected endocarditis. Methods and results A dedicated cardiac CZT camera (Discovery 530c, GE Healthcare) was employed. Anthropomorphic thorax phantom studies were followed by clinical studies in 34 patients with suspected infection of native valves (n = 12) or implants (n = 22). Simultaneous In-111-WBC/(99)mTc perfusion imaging was performed, and compared with standard In-111-WBC planar scintigraphy and SPECT-CT. Phantom studies ruled out significant radioisotope crosstalk. Downscatter on Tc-99m images was not observed for In-111 activity as high as 2.5*Tc-99m activity. In patients, image quality was superior for CZT imaging vs. conventional SPECT-CT and planar scintigraphy (P < 0.01). Cadmium-zinc-telluride dual isotope imaging improved reader confidence for detection of inflammatory foci. Diagnostic accuracy based on surgery or Duke Criteria during follow-up was highest for CZT imaging (P < 0.001). Conclusion Novel CZT SPECT technology improves the accuracy of molecular/cellular cardiac imaging. Simultaneous multi-isotope imaging with In-111 and Tc-99m is feasible and aids in the workup of suspected endocarditis.