A new method for measurement of left atrial volumes using 64-slice spiral computed tomography: comparison with two-dimensional echocardiographic techniques.

BACKGROUND

Left atrial (LA) volume, is related to cardiovascular morbidity. LA enlargement is usually assessed using trans-thoracic echocardiography (TTE). The association of modern multislice computed tomography (MSCT) imaging and new 3D reconstruction software, allows direct cardiac chamber volume measurement without geometrical assumptions. This study was designed to evaluate the maximal (LAmax) and minimal (LAmin) LA volumes during the cardiac cycle using MSCT and TTE approaches.

METHODS

We screened 26 consecutive patients referred for coronary imaging using a 64-MSCT scanner and a TTE within 12 h. Contiguous multiphase images were generated from axial MSCT data and semi-automated 3D segmentation technique was applied to generate LA volumes. Using TTE, LA volumes and LA ejection fraction (LAEF) were obtained using five assumptions methods: cubing equation, diameter-length formula, area-length formula, ellipsoidal formula and biplane Simpson rule.

RESULTS

Five patients were excluded for inadequate TTE visualization and one for ectopic beats during MSCT. The sample consisted in 20 patients (11 men, age: 56+/-14 years). Using MSCT, LA volumes indexed to body surface area were: LAmax=74+/-27 ml/m(2), LAmin=49+/-26 ml/m(2), with close correlations with TTE measurements and a significant underestimation by all TTE approaches. A close correlation was observed between LAEF using MSCT and TTE Simpson's method: 36+/-14% vs. 37+/-14%, r=0.99, p<0.0001.

CONCLUSION

Theses results suggest that the assessment of LA volumes and ejection fraction was reliable using 64-MSCT in patients referred for coronary computed tomography imaging.