Increased separability of K-edge nanoparticles by photon-counting detectors for spectral micro-CT

Abstract

BACKGROUND:

X-ray CT/micro-CT methods with photon-counting detectors (PCDs) and high Z materials are a hot research topic. One method using PCDs allows for spectral imaging in 5 energy windows while conventional X-ray detectors only collect energy-integrating data.

OBJECTIVE:

To demonstrate the enhanced separation of contrast materials by using PCDs, multivariate analysis, and linear discriminant methods.

METHODS:

Phantoms containing iodine and aqueous nanomaterials were scanned on a MARS spectral micro-CT. Image volumes were segmented into separate material-specific populations. Contrast comparisons were made by calculating T² test statistics in the univariate, pseudo-conventional and multivariate, spectral CT data sets. Separability after Fisher discriminant analysis (FDA) was also assessed.

RESULTS:

The T² values calculated for material comparisons increased as a result of the spectral expansion. The majority of the tested contrast agents showed increased T² values by a factor of ∼2 -3. The total significant T² statistics in the pure and mixed lanthanide image sets increased in the spectral data set.

CONCLUSION:

This work consolidates the groundwork for photon-counting-based material decomposition with micro-CT, facilitating future development of novel nanomaterials and their preclinical applications.