# Contrast dose determination using effective diameter in patients of unknown weight for dynamic computed tomography of the upper abdomen: a feasibility study

## TL;DR

This study shows that effective diameter can accurately estimate body weight for determining contrast dose in CT scans when actual weight is unknown.

## Contribution

A new method for estimating body weight using effective diameter in CT scans for contrast dose calculation is proposed.

## Key findings

- Deff_axial and BW showed the highest correlation at specific anatomical levels in men and women.
- Estimated BW from Deff strongly correlates with actual BW and can be used when BW is unknown.

## Abstract

The purpose of this study was to validate the accuracy of a method for determining the iodine contrast dose using effective diameter (Deff) when performing dynamic computed tomography (CT) scans of the upper abdomen in patients with unknown body weight (BW).

Deff was measured at the heart, at the right diaphragm upper edge, and at the right pulmonary rib diaphragm levels in the localizer radiograph and axial images. Correlation coefficients between Deff and BW were determined for each cross section.

Deff_axial and BW showed the highest correlation at the right diaphragm upper edge level in men (rS = 0.862) and at the right pulmonary rib diaphragm level in women (rS = 0.890).

The BW estimated from Deff showed a strong correlation with measured BW and may serve as a practical alternative in cases where BW is unknown.