Contrast-enhanced CT for attenuation correction in ultra-high sensitivity long-axial field-of-view lymphoma PET:...

Area of Science:

• Nuclear Medicine
• Radiology
• Medical Imaging

Background:

• Attenuation correction (AC) is crucial for accurate PET quantification.
• Contrast-enhanced CT (CE-CT) is increasingly used for AC, but its impact on high-sensitivity, large axial field-of-view (LAFOV) systems is not fully understood.

Purpose of the Study:

• To assess the clinical feasibility and impact of using CE-CT for AC in LAFOV-[18F]FDG PET/CT scans for lymphoma patients.
• To evaluate potential quantification inaccuracies introduced by CE-CT AC in high-sensitivity LAFOV systems.

Main Methods:

• Retrospective analysis of lymphoma patients undergoing LAFOV-[18F]FDG-PET/CT.
• PET images reconstructed with both low-dose CT for AC and diagnostic CE-CT for AC.
• Comparison of Standardized Uptake Values (SUV) in lesions and reference regions (blood pool, liver) between the two AC methods.

Main Results:

• CE-CT AC resulted in significantly higher SUVmax and SUVmean in reference regions (blood pool, liver) compared to AC-CT.
• Lesion SUVmax also showed a significant increase with CE-CT AC.
• The SUV ratio of lesions to reference organs decreased with CE-CT AC, indicating altered lesion detectability.

Conclusions:

• CE-CT for AC in high-sensitivity LAFOV-[18F]FDG PET/CT leads to elevated SUV measurements in lymphoma patients.
• The observed increase in lesion uptake and potential for higher errors compared to standard PET/CT warrants careful interpretation of borderline cases.
• Clinical feasibility is demonstrated, but quantification accuracy requires attention.