Image-derived arterial input function in dynamic positron emission tomography-computed tomography: a method using...

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Dynamic positron emission tomography (PET) studies require accurate measurement of the arterial input function (AIF) for quantitative analysis.
• Traditional AIF measurement often involves invasive arterial blood sampling.
• Integrating computed tomographic (CT) data with PET may offer a non-invasive alternative for AIF determination.

Purpose of the Study:

• To assess the feasibility of measuring the arterial input function (AIF) using combined PET and CT imaging in dynamic PET studies.
• To compare AIF measurements derived from PET-CT versus PET-only data.
• To evaluate the impact of different AIFs on the quantitative assessment of glucose metabolism (Ki) in head and neck cancer.

Main Methods:

• Dynamic PET-CT scans were performed on 18 head and neck cancer patients and a phantom.
• Arterial input function (AIF) was measured from both PET-CT images (corrected for partial volume effect - PVE) and PET-only images.
• Net flux of [18F]fluoro-2-deoxy-D-glucose (Ki) was calculated using both AIFs, and their correlation was analyzed.

Main Results:

• PET-CT derived AIF was significantly larger than PET-only AIF.
• The net glucose flux (Ki) calculated using PET-CT AIF was lower than that calculated using PET-only AIF.
• Despite quantitative differences, the two sets of Ki values showed a high correlation (r = 0.969, P < 0.001).

Conclusions:

• Measuring AIF in dynamic PET-CT studies is feasible without blood sampling.
• PET-CT AIF differs substantially from PET-only AIF, particularly when PVE is not corrected.
• PET-CT AIF may be preferable for quantifying glucose metabolism (Ki) to prevent potential overestimation with PET-only methods.