Fifty-sixth annual meeting of the American association of physicists in medicine
TU-C-12A-11: Comparisons Between Cu-ATSM PET and DCE-CT Kinetic Parameters in Canine Sinonasal Tumors
Regions of poor perfusion within tumors may be associated with higher hypoxic levels. This study aimed to test this hypothesis by comparing measurements of hypoxia from Cu-ATSM PET to vasculature kinetic parameters from DCE-CT kinetic analysis.
Ten canine patients with sinonasal tumors received one Cu-ATSM PET/CT scan and three DCE-CT scans prior to treatment. Cu-ATSM PET/CT and DCE-CT scans were registered and resampled to matching voxel dimensions. Kinetic analysis was performed on DCE-CT scans and for each patient, the resulting kinetic parameter values from the three DCE-CT scans were averaged together. Cu-ATSM SUVs were spatially correlated (rspatial) on a voxel-to-voxel basis against the following DCE-CT kinetic parameters: transit time (t1), blood flow (F), vasculature fraction (v1), and permeability (PS). In addition, whole-tumor comparisons were performed by correlating (rROI) the mean Cu-ATSM SUV (SUVmean) with median kinetic parameter values.
The spatial correlations (rspatial) were poor and ranged from -0.04 to 0.21 for all kinetic parameters. These low spatial correlations may be due to high variability in the DCE-CT kinetic parameter voxel values between scans. In our hypothesis, t1 was expected to have a positive correlation, while F was expected to have a negative correlation to hypoxia. However, in wholetumor analysis the opposite was found for both t1 (rROI = -0.25) and F (rROI = 0.56). PS and v1 may depict angiogenic responses to hypoxia and found positive correlations to Cu-ATSM SUV for PS (rROI = 0.41), and v1 (rROI = 0.57).
Low spatial correlations were found between Cu-ATSM uptake and DCE-CT vasculature parameters, implying that poor perfusion is not associated with higher hypoxic regions. Across patients, the most hypoxic tumors tended to have higher blood flow values, which is contrary to our initial hypothesis.
Funding: R01 CA136927