CT Viable Alternative to Cardiac MRI for When Assessing Heart Chamber Size

November 26, 2018

Axial chest CT identifies enlargement with high specificity and reasonable sensitivity.

Computed tomography is a viable alternative to cardiac MRI for assessing heart chamber enlargement, according to a study published in the American Journal of Roentgenology.

Researchers from Canada performed a retrospective study to establish sex-specific chest CT measurement thresholds for detection of cardiac chamber enlargement with cardiac MRI as the reference standard.

Related article: Cardiac Findings Should Be Noted on Chest CT When Observed

Study subjects included 115 men and 102 women (mean age 52.8 years) who underwent contrast-enhanced chest CT (64- or 320-MDCT) and cardiac MRI within a 7-day interval between August 2006 and August 2016. Measurements were performed on axial CT images to evaluate right atrial (RA), right ventricular (RV), left atrial (LA), and left ventricular (LV) chamber size. The presence of chamber enlargement (RAE, RVE, LAE, and LVE) was established with cardiac MRI as the reference standard. ROC analysis was performed. Optimal sex-specific CT measurement thresholds were identified that ensured specificity of 90% or greater and maximized sensitivity.

Prevalence of chamber enlargement:

RAE26%16%
RVE11%15%
LAE40%27%
LVE24%12%

The following CT measurement thresholds were optimal:

  • For RAE, RA transverse diameter ≥67 mm for men (AUC, 0.825) and ≥64 mm for women (AUC, 0.926)
  • For RVE, RV transverse diameter ≥60 mm for men (AUC, 0.846) and ≥57 mm for women (AUC, 0.858)
  • For LAE, LA anteroposterior diameter ≥50 mm for men (AUC, 0.795) and ≥45 mm for women (AUC, 0.841)
  • For LVE, LV transverse diameter ≥58 mm for men (AUC, 0.917) and ≥53 mm for women (AUC, 0.840)

The researchers concluded that cardiac chamber enlargement can be identified with high specificity and reasonable sensitivity on axial chest CT images by use of sex-specific measurement thresholds.