Breath-hold CT attenuation correction for quantitative cardiac SPECT.

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Cardiology

Background:

• Hybrid SPECT/CT imaging enables attenuation correction using CT-based maps.
• Breath-hold CT acquisition can lead to misalignment with SPECT, causing artifacts.
• Respiratory motion during CT acquisition affects attenuation correction accuracy in cardiac SPECT.

Purpose of the Study:

• To evaluate the impact of respiratory phase during breath-hold CT acquisition on attenuation correction in cardiac SPECT/CT.
• To determine the optimal respiratory phase for CT-based attenuation correction in hybrid imaging.

Main Methods:

• 11 healthy volunteers underwent SPECT/CT with 201Tl and 99mTc.
• CT scans were acquired at end-inspiration (INS), end-expiration (EXP), and midpoint (MID) respiratory phases.
• Quantitative SPECT images were reconstructed with attenuation and scatter corrections, comparing CT- and TCT-based methods.

Main Results:

• SPECT images using EXP phase CT maps showed significant regional differences and positive bias compared to TCT-based images.
• No significant differences were found between MID and INS phases compared to TCT-based images.
• Tendencies for bias were observed in anterior (positive) and inferior (negative) segments for MID and INS phases.

Conclusions:

• Breath-hold CT attenuation maps acquired at INS and MID phases provide accurate quantitative SPECT/CT images.
• These findings are beneficial for improving the reliability of cardiac SPECT/CT studies.
• Optimizing respiratory phase during CT acquisition is key for accurate attenuation correction.