Atrial volume

The atrial volumes refer to the blood volumes of the left or right atrium and the atrial volume index is the respective atrial volume corrected for the body surface area (BSA).

Usage

Atrial volumes are measured for the assessment of many congenital and acquired cardiac conditions causing left atrial or right atrial enlargement.

Measurement

Echocardiography

Methods include the disk summation technique (Simpson’s method), 3D data sets or a biplane area-length method from apical four-chamber and two-chamber views. The left atrial appendage is excluded from measurement ¹.

MRI

Widely-used postprocessing software solutions for cardiac MRI employ a combination of semi-automated feature recognition and manual contour correction based on the modified Simpson’s method using a stack of SFFP cine images in the short axis, horizontal long axis or transverse plane.

Similar to the end-diastolic and end-systolic ventricular volumes the atrial volumes might be determined by the sum of the computed left/right atrial cross-sectional areas determined by the endocardial contours at atrial end-diastole just before mitral or tricuspid valve opening (chosen as the images with the largest blood volume) accounting for slice thickness and gap ^2,3.

Alternative methods include the employment of 3D modelling software or the biplane area-length method in the horizontal and vertical long axis that can be employed for measurement of the left atrial volume on standard SSFP cine images ^2,4.

The atrial volume index is calculated as atrial volume/BSA [mL/m²]

Interpretation

Normal values differ for the left and right atria depending on gender and age, imaging modality and slightly with the calculation method ^1-3.

Echocardiography

Left atrial volumes values on 2D echocardiography are typically smaller than on cardiac MRI or cardiac CT ¹.

The recommended upper normal left atrial volume indexed for body surface area (BSA) is 34 ml/m² for both women and men ¹.

MRI

Normal values are derived for SSFP cine sequences from the updated publication by Kawel-Boehm ². Values above the normal indicate atrial dilatation.

Left atrium

Simpson’s method (left atrial appendage included) ^2,3:

Women (adult):

• maximum left atrial volume [mL]: 37-94 mL
• maximum left atrial volume/BSA [mL/m²]: 25-53 mL/m²

Men (adult):

• maximum left atrial volume [mL]: 42-115 mL
• maximum left atrial volume/BSA [mL/m²]: 25-56 mL/m²

Biplane area-length method (left atrial appendage excluded) ^2,4:

Women (adult):

• maximum left atrial volume [mL]: 28-100 mL
• maximum left atrial volume/BSA [mL/m²]: 17-61 mL/m²

Men (adult):

• maximum left atrial volume [mL]: 31-112 mL 
• maximum left atrial volume/BSA [mL/m²]: 17-59 mL/m²

Right atrium

Simpson’s method (right atrial appendage included) ^2,3:

Women (adult):

• maximum right atrial volume [mL]: 49-122 mL
• maximum right atrial volume/BSA [mL/m²]: 31-69 mL/m²

Men (adult):

• maximum right atrial volume [mL]: 59-158 mL 
• maximum right atrial volume/BSA [mL/m²]: 32-79 mL/m²

Biplane area-length method (right atrial appendage excluded) ^2,5:

Women (adult):

• maximum right atrial volume [mL]: 24-81 mL
• maximum right atrial volume/BSA [mL/m²]: 16-54 mL/m²

Men (adult):

• maximum right atrial volume [mL]: 24-105 mL 
• maximum right atrial volume/BSA [mL/m²]: 15-61 mL/m²