# Impact of high-iodine concentration contrast material for dual-energy CT angiography on arterial visualization: A single-blind, randomized controlled trial

## TL;DR

This study compares high-iodine and medium-iodine contrast materials in CT angiography and finds that high-iodine improves visualization of small arteries.

## Contribution

Demonstrates that high-iodine contrast material improves small artery visualization in dual-energy CT angiography.

## Key findings

- High-iodine contrast material (370 mgI/mL) showed better visualization of small arteries compared to medium-iodine (300 mgI/mL).
- Significant differences were observed in bronchial, intercostal, left gastric, and inferior phrenic arteries with high-iodine contrast.
- No significant difference was found for the iliolumbar artery, but high-iodine still showed a higher median score.

## Abstract

To investigate the effect of high-iodine concentration contrast material for dual-energy CT angiography (DECTA) on arterial visualizations by comparing it with medium-iodine concentration.

This prospective, single-blind, randomized controlled trial included 100 consecutive participants undergoing DECTA from November 2023 to February 2025. The participants were randomly assigned into two protocols: receiving high-iodine concentration contrast material of 370 mgI/mL (Group A, n = 51) and receiving medium-iodine concentration of 300 mgI/mL (Group B, n = 49). The axial, coronal, and volume-rendered (VR) images were reconstructed at 40 keV in both groups. Two radiologists reviewed three image types and assessed the arterial visualizations using a five-point scale. The primary outcome was the score for the iliolumbar artery on the VR images, whereas secondary outcomes were the scores for all others. The Wilcoxon rank sum test was conducted to compare the outcomes between the two groups.

No statistical significance in terms of the score for the iliolumbar artery on the VR images was found between the two groups; however, the median score was higher in Group A than in Group B (3.5 vs. 3.0; P = .05). The scores for secondary outcomes in Group A were equal to or greater than that in Group B, and significant differences were observed, especially in the small arteries, including the bronchial, internal thoracic, intercostal, left gastric, and inferior phrenic arteries (P < .05).

In small arteries, the protocol with high-iodine concentration contrast material exhibited better arterial visualizations compared with medium-iodine concentration in DECTA at 40 keV.

•Although low-energy dual-energy CT angiography enables iodine reduction, benefit of high-iodine contrast remains debatable.•Small arteries (bronchial, intercostal, left gastric, and inferior phrenic) were better visualized with 370 mgI/mL than in300 mgI/mL.•At 40 keV dual-energy CT angiography, 370 mgI/mL provides better small-arterial visualization than 300 mgI/mL.

Although low-energy dual-energy CT angiography enables iodine reduction, benefit of high-iodine contrast remains debatable.

Small arteries (bronchial, intercostal, left gastric, and inferior phrenic) were better visualized with 370 mgI/mL than in300 mgI/mL.

At 40 keV dual-energy CT angiography, 370 mgI/mL provides better small-arterial visualization than 300 mgI/mL.