Data-driven gated PET/CT: implications for lesion segmentation and quantitation

Area of Science:

• Medical Imaging
• Radiology
• Nuclear Medicine

Background:

• Data-driven gating (DDG) enhances PET quantitation and mitigates patient motion artifacts.
• Misregistration between DDG-PET and CT, due to differing temporal resolutions, can impact accuracy.
• A novel DDG-PET/CT method was developed to assess these effects.

Purpose of the Study:

• To evaluate the impact of misregistration and respiratory motion on PET quantitation and lesion segmentation.
• To compare different attenuation correction methods, including average CT (ACT) and DDG-CT.
• To assess the efficacy of a new DDG-PET/CT technique.

Main Methods:

• A low-dose cine-CT was acquired for both ACT and DDG-CT generation.
• Four methods were compared: baseline PET/CT, PET/ACT, DDG-PET (helical CT AC), and DDG-PET/CT (DDG-CT AC).
• End-expiration (EE) PET and CT data were extracted; 91 lesions were analyzed for SUVmax, LG, volume, CCD, and DICE coefficients.

Main Results:

• DDG-PET/CT showed significant changes in SUVmax (66±66%) and lesion volume (-26±40%) compared to baseline.
• Lesion glycolysis (LG) was not significantly different with DDG-PET/CT, unlike PET/ACT and DDG-PET.
• Motion correction impact was reduced by misregistration; DDG-PET/CT improved registration but motion correction was more affected.

Conclusions:

• The benefits of DDG-PET for accurate quantitation and segmentation are maximized only when combined with DDG-CT.
• Diminished impact of DDG-PET motion correction occurs with increasing misregistration.
• Simultaneous correction for misregistration and motion is crucial for optimizing clinical PET/CT utility.