Abstract
Background and purpose
Parathyroid 4-dimensional CT (4DCT) involves repeated noncontrast and multiphase contrast-enhanced acquisitions, leading to increased radiation exposure. Because the examination targets the anatomically complex structures of the neck, maintaining high image quality is particularly important. Photon-counting CT (PCCT) is a novel technology reported to improve dose efficiency and image quality compared with conventional energy-integrating detector CT (EIDCT). This study provides a systematic, quantitative comparison of CT scanner radiation output (volume CT dose index [CTDIvol] and dose-length product [DLP]) and image quality, assessed by SNR and contrast-to-noise ratio (CNR), between PCCT and EIDCT for multiphase parathyroid 4DCT examinations.Materials and methods
In this institutional review board-approved retrospective study, 96 patients who underwent a 4DCT for the work-up of hyperparathyroidism (PCCT, n=32; EIDCT, n=64) were reviewed. ROIs were placed on the noncontrast, arterial, and venous phase images in the sternocleidomastoid muscles at the upper thyroid level, the anterior scalene muscles at the lower thyroid level, and in the extracorporeal air. Mean attenuation, SNR, and CNR were measured. Statistical analyses included unpaired t tests and 2-way ANOVA.Results
PCCT had significantly lower radiation output across all 4DCT phases (total CTDIvol 30.6 ± 3.3 vs 60.8 ± 15.7 mGy; DLP 859 ± 178 vs 1523 ± 519 mGy·cm; P P Conclusions
PCCT substantially reduces CT scanner radiation output while improving quantitative image quality in multiphase parathyroid 4DCT, including technically challenging arterial-phase acquisitions at the lower thyroid level, supporting its technical advantage over conventional EIDCT.