# Quantification of Chest Wall Asymmetry in Healthy Females Using Standardized Computed Tomography–Derived Curve Modeling: A Proof of Concept

## TL;DR

This study introduces a new method to measure chest wall asymmetry in healthy women using CT scans, revealing a common leftward asymmetry.

## Contribution

A reproducible, curve-based CT method for quantifying anterior thoracic skeletal asymmetry in healthy populations.

## Key findings

- Left chest wall showed significantly greater outward projection than the right in both horizontal and vertical planes.
- Over 65% of patients exhibited leftward prominence in both planes.
- Mean volume discrepancy between left and right chest walls was 19.3 cc.

## Abstract

Anterior chest asymmetry is common, with potential implications for aesthetic and reconstructive breast surgery. However, current assessments rely on visual inspection or linear measurements, and few studies offer a reproducible, quantitative framework for analyzing skeletal asymmetry in healthy populations.

The aim of the study is to develop and evaluate a proof-of-concept methodology for quantifying anterior thoracic skeletal asymmetry using standardized, computed tomography (CT)-derived curve segmentation and polynomial modeling.

Chest CT scans from 50 female patients aged 18 to 45 with a BMI of 20 to 25 were evaluated using semi-automated segmentation. The right and left chest wall curvatures were extracted in both a horizontal and vertical plane at the level of the fourth rib insertion and one-fourth of the maximum thorax width, respectively.

The left chest wall displayed significantly greater outward projection than the right chest in both planes (P < .001). The most pronounced differences were observed from 2 to 5 cm from the sternum in the horizontal plane and 0 to 1 cm from the manubrium in the vertical plane. Individual assessments showed that >65% of patients exhibited leftward prominence in the horizontal and vertical planes. The estimated mean volume discrepancy between the left and right chest walls was 19.3 cc.

This study introduces a reproducible, curve-based methodology for quantifying skeletal chest wall asymmetry using CT images. In this healthy female cohort, a statistically significant leftward asymmetry was common. Although the volumetric difference may be small and not clinically significant in isolation, these findings support individualized skeletal assessment as a basis for surgical planning, warranting future studies with 3D modeling and more diverse populations.