The aim of this study was to investigate the potential of liver-specific gadolinium-based contrast agents (GBCAs) for photon-counting detector computed tomography (PCD-CT), focusing on gadolinium ethoxybenzyl-diethylenetriaminepentaacetic acid (Gd-EOB-DTPA). Current CT imaging relies on iodine-based contrast agents, which offer rapid enhancement but are limited by short retention times and potential adverse effects, including allergic reactions and nephrotoxicity^1,2. Liver-specific agents that remain within hepatocytes for prolonged periods could provide improved lesion characterization and functional liver assessments, addressing the limitations of iodine agents in delayed-phase imaging ³.

PCD-CT systems provide superior spectral resolution by directly counting photons at different energy levels, enhancing material differentiation and attenuation characterization, especially at low energy levels where GBCAs show greater attenuation⁴. This study aimed to determine whether low-energy monoenergetic reconstructions in PCD-CT could achieve sufficient hepatic enhancement with Gd-EOB-DTPA to make it viable for liver-specific imaging, particularly in patients for whom MRI is contraindicated.

The purpose was to evaluate the stepwise attenuation of Gd-EOB-DTPA across a range of concentrations in a controlled phantom setup and to estimate potential in vivo hepatic enhancement based on published pharmacokinetic data^5–7. By exploring the dose-response relationship and contrast-to-noise ratios at different energy levels, the study sought to assess whether PCD-CT can overcome the dose limitations observed in conventional CT systems and provide meaningful diagnostic contrast with Gd-EOB-DTPA.