PhD Scientific Days 2026

Surgical Medicine

Comparison of Triple-bolus and Multi-phase Photon Counting Detector CT protocols in preoperative evaluation of Living Kidney Donor Candidates

Name of the presenter

Csákai-Szőke, Péter

Institute/workplace of the presenter

Medical Imaging Centre

Authors

Dr. Csákai-Szőke Péter¹, Dr. Budai Bettina², Dr. Dakhlaoui Hana², Oshriyeh Sina², Hamada Takashi², Dr. Lénárd Zsuzsanna²
1: Semmelweis University Medical Imaging Centre, Heidelberg University Diagnostic and Intervetional Radiology Clinic
2: Medical Imaging Centre

Text of the abstract

Introduction
Accurate preoperative assessment of renal vascularity in living kidney donor candidates
requires high-quality morphological imaging. As donors are typically healthy and relatively
young, minimizing radiation exposure while maintaining diagnostic accuracy is essential.
Photon-counting detector CT (PCD-CT) offers higher spatial resolution, improved image
quality, and reduced radiation and contrast agent doses compared with conventional
Energy-integrating detector CT (EID-CT) systems. However, data on its use in living kidney
donor evaluation are lacking.

Aims
In this study, we aimed to compare two widely accepted CT protocols for donor assessment
– the multiphase protocol and the triple-bolus protocol – using PCD-CT.

Methods
A total of 40 consecutive living kidney donor candidates from Semmelweis University were
included in this study. 20 donor candidates underwent triple-bolus PCD-CT (non-contrast
and combined angiographic-venous-delayed), while 20 donor candidates underwent
conventional four-phase PCD-CT (non-contrast, angiographic, venous and delayed) scans.
Both CTA and triple-bolus scan had a reconstruction slice thickness of 0.4 mm. Ionizing
radiation effective dose (ED) and iodine-based contrast agent dose were recorded for both
protocols. Image quality was assessed using contrast-to-noise ratio (CNR) and signal-tonoise ratio (SNR).

Result
Age, weight, and BMI were comparable between the two PCD-CT groups. In PCD-CT triple
bolus study the average ED was 55% lower, in comparison to that of PCD-CT four-phase
protocol (6.34±1.57 mSv vs 14.1±4.4 mSv, respectively, p < 0.001), while iodine-based
contrast agent dose was significantly higher (0.57±0.09 vs. 0.31±0.03 g iodine/kg, p<0.001).Image quality was similar, with no significant differences in CNR (p=0.436) or SNR (p=0.327)
across the PCD-CT protocols.

Conclusion
A triple-bolus PCD-CT technique optimized for renal assessment enables high-quality
preoperative imaging with substantially reduced radiation exposure in living kidney donor
candidates. Despite its triple-bolus injection protocol, the iodine dose substantially remains
lower than that of standard single-bolus multiphase EID-CT protocols (~0.8–1.2 g/kg).

Funding
No funding was received.