Which can predict left ventricular size and systolic function: cardiothoracic ratio or transverse cardiac diameter

The aim of this study is to investigate the association between the cardiothoracic ratio (CTR), transverse cardiac diameter (TCD), and left ventricular (LV) size and systolic function in patients with or without preserved LV ejection fraction (LVEF).

A total of 181 subjects suspected with coronary artery disease underwent chest radiography (CR) and dual source computed tomography coronary angiography (DSCT-CA). TCD and CTR were derived from CR. The LV size and systolic function parameters, such as LV end-diastolic volume (LVEDV), LV end-systolic volume (LVESV) and LVEF were measured from DSCT-CA. The association between TCD, CTR and LV size and systolic function parameters were analyzed according to LVEF value (< 55%, depressed LVEF group; versus ≥ 55%, preserved LVEF group).

Both TCD and CTR were higher in the depressed LVEF group compared with the preserved LVEF group. Significant correlations were found between TCD, CTR and LVEDV, LVESV, LVEF in depressed LVEF group. However, there was no significant association detected between CTR and LV size and systolic function parameters in preserved LVEF group. Both the LVEDV and LVESV showed a positive correlation with TCD in preserved LVEF group.

Although CTR was not a reliable indicator of LV size and systolic function in patients with preserved LVEF, it was correlated with LV size and LVEF in depressed LVEF patients. Furthermore, TCD showed stronger correlations with LV size and systolic function even in patients with preserved LVEF.