The influence of photon counting computed tomography of the paranasal sinuses on navigation accuracy and radiation dose

Introduction  Computed tomography (CT)-based navigation is of great importance in functional endoscopic sinus surgery (FESS). However, this often requires additional CT scans using navigation-specific protocols which cause additional, yet avoidable radiation exposure. This could be significantly reduced using photon counting CT (PCCT). Therefore, the aim of the present study was to investigate the navigation accuracy of Dual Energy Dual Source CT (DEDS) and PCCT with respect to radiation dose.

Material & Methods A formalin-fixed cadaver skull was examined using SOMATOM FORCE (DEDS) and NAEOTOM Alpha PCCT (both Siemens Healthcare GmbH) at 100 kV tube voltage with descending tube current (mAs). Image quality was assessed by signal-to-noise ratio (SNR). The setup of electromagnetic navigation (NAV1​ electromagnetic, Karl Storz SE & Co KG) was evaluated by visual analog scale (VAS) and accuracy was analyzed endoscopically using defined anatomical landmarks.

Results Image quality was clearly superior for PCCT compared to DEDS (SNR 10.3 vs. 4.4 at 100 mAs). At maximum tube current (100 mAs), the data sets of both CTs could be easily registered (VAS 8/10) and accurately navigated (navigation error 1.75/1.0 mm). While the PCCT datasets could be navigated accurately as low as 10 mAs, the DEDS showed significant inaccuracies above 40 mAs. This results in a relative reduction of the radiation dose by 45.1%.

Conclusions  PCCT potentially enables a reduction in radiation dose from CTs for FESS navigation without compromising accuracy or image quality.

Publication History

Article published online:
12 May 2023