Differences in attenuation pattern in myocardial SPECT between CZT and conventional gamma cameras

Area of Science:

• Medical Imaging
• Nuclear Cardiology
• Diagnostic Radiology

Background:

• Myocardial perfusion imaging (MPI) using single-photon emission tomography (SPECT) can be affected by soft-tissue attenuation artifacts.
• These artifacts, caused by the abdomen, breasts, and chest wall, can mimic true perfusion defects, leading to misdiagnosis.

Purpose of the Study:

• To compare the localization, extent, and depth of attenuation artifacts in MPI SPECT between a multi-pinhole cadmium zinc telluride (CZT) camera and a conventional gamma camera.

Main Methods:

• Phantom and patient studies were conducted using both a CZT camera (GE NM 530c) and a conventional gamma camera (GE Ventri).
• Attenuation correction was performed using externally acquired low-dose computed tomography.
• Artifacts were quantified by comparing attenuation-corrected and non-attenuation-corrected images to determine localization, extent, and depth.

Main Results:

• The CZT camera shifted attenuation artifacts from the inferolateral to the lateral wall compared to the conventional camera.
• Artifact extent was significantly larger with the CZT camera (23% ± 5% vs. 15% ± 5%, P < .001) in patients.
• Artifact depth was less pronounced with the CZT camera (72% ± 3% vs. 68% ± 4%, P < .001) in patients.

Conclusions:

• Attenuation artifacts differ in location, extent, and depth between CZT and conventional gamma cameras in MPI SPECT.
• These differences necessitate careful consideration during the evaluation of MPI SPECT studies.
• Understanding these variations is crucial to avoid misinterpreting myocardial perfusion distribution.