Results showed strong linear relationship between measured nodule volume and reference standard for both UHR and macro mode.

Receiver operating characteristic (ROC) analysis was performed and area under the ROC curve (AUC) was used as a figure of merit for the differentiation task. Surface curvature was calculated for each nodule and the full width half maximum (FWHM) of the curvature histogram was used as a shape index to differentiate sphere and star shape nodules. Linear regression analysis was performed to compare measured nodule volumes from CT images to reference volumes. A set of synthetic lung nodules (two shapes, five sizes, and two radio-densities) was scanned using both the UHR and macro modes and reconstructed with 2 reconstruction kernels (4 sets of images in total).

The UHR mode has a pixel size of 0.25 mm by 0.25 mm at the iso-center, while the conventional (macro) mode is limited to 0.5 mm by 0.5 mm. A new ultra high-resolution (UHR) mode has been implemented on a whole body photon counting-detector (PCD) CT system.

High resolution siemens star