Cine CT for attenuation correction in cardiac PET/CT

Area of Science:

• Medical Imaging
• Nuclear Medicine
• Radiology

Background:

• Positron emission tomography/computed tomography (PET/CT) systems use CT for PET attenuation correction.
• Respiratory motion during PET scans can cause misalignment between CT-derived attenuation maps and PET emission data.
• This misalignment leads to errors in attenuation correction factors and artifacts in the final PET images.

Purpose of the Study:

• To evaluate the efficacy of cine CT in improving attenuation correction for cardiac PET studies.
• To compare cine CT methods (average and intensity-maximum images) against conventional helical CT for mitigating respiratory motion artifacts.

Main Methods:

• Acquired cine CT and cardiac PET data from a cardiac phantom and patient studies.
• Evaluated conventional helical CT, average cine CT, and intensity-maximum cine CT for attenuation correction.
• Assessed image alignment and quality through visual evaluation by three readers in 74 patient studies.

Main Results:

• Helical CT-based attenuation correction introduced significant artifacts in phantom studies.
• Cine CT methods reduced these artifacts, with intensity-maximum cine CT showing a 60% reduction.
• Patient studies demonstrated acceptable alignment for 77% of average cine CT and 88% of intensity-maximum cine CT cases.

Conclusions:

• Cine CT is a viable alternative to helical CT for compensating respiratory motion in cardiac PET attenuation correction.
• Both average and intensity-maximum cine CT images reduce respiration-induced misalignment errors.
• Intensity-maximum cine CT appears to be a more reliable method than the average cine CT for improved attenuation correction.