H.Kitamura

Comparison of determinations of left atrial volume by the biplane area-length and Simpson's methods using 64-slice computed tomography

OBJECTIVES There is increasing evidence that left atrial (LA) size is an important predictor of adverse cardiovascular outcomes such as atrial fibrillation, stroke, and congestive heart failure. The aim of this study was to determine whether there is a difference in results of quantification of LA volume by the area-length and Simpsons methods using multislice computed tomography (MSCT). METHODS AND RESULTS The study population consisted of 51 patients with sinus rhythm (sinus group) and 20 patients with atrial fibrillation (af group) clinically indicated for MSCT angiography for evaluation of coronary arteries. Maximum LA volume, obtained at end-systole from the phase immediately preceding mitral valve opening, was measured using the area-length and Simpsons methods. In the sinus group, the mean LA volumes, indexed to body surface area, were 48.4+/-17.9 ml/m(2) with the area-length method and 48.3+/-17.0 ml/m(2) with the Simpsons method. In the af group, the mean indexed LA volumes with the area-length method and the Simposons method were 91.5+/-47.5 ml/m(2) and 90.3+/-45.9 ml/m(2), respectively. LA volumes calculated by the area-length method exhibited a strong linear relationship and agreement with those calculated using Simpsons method in both the groups (sinus group: r=0.99, P<0.0001, af group: r=0.99, P<0.0001). CONCLUSIONS The area-length method is a simple and reproducible means of assessment of LA volume. Standardization of LA volume assessment using MSCT is important for serial follow-up and meaningful communication of results of testing among institutions and physicians.

Usefulness of three-dimensional automated quantification of left ventricular mass, volume, and function by 64-slice computed tomography.

OBJECTIVES Quantification of left ventricular (LV) mass has important prognostic implications. However, accurate measurement of LV mass has been difficult, in part because of the oblique angle at which the heart lies within the chest and the continuous movement of the heart itself. Multislice computed tomography (MSCT) allows assessment not only of coronary stenosis but LV volume, function, and mass. A novel three-dimensional (3D) region-growing-based semi-automated segmentation algorithm for measurements of LV mass, volume, and function was recently developed. This study evaluated this new 3D automated method for measurement of LV mass, by comparison with a well-established 2D manual contour-drawing algorithm. METHODS AND RESULTS The study population consisted of 50 consecutive patients who underwent ECG-gated MSCT for evaluation of coronary arteries. The 3D algorithm for reliable segmentation was unsuccessful in two patients. In the remaining 48 patients, however, LV segmentation using this algorithm was performed and delivered visually reliable segmentation results. The 3D algorithm for analysis of LV function and mass is feasible based on volumetric data, and exhibits good correlation and agreement with the results obtained with the conventional 2D algorithm. The time required for the new automated algorithm was significantly shorter than that for the manual contour-drawing algorithm (P<0.0001) (automated algorithm: 468.0±205.1 s, manual algorithm: 1362.4±410.5 s, mean ±S.D.). CONCLUSIONS The 3D semi-automated region-growing segmentation algorithm for analysis of LV function and mass is feasible based on volumetric data, and exhibits good correlations and agreement with the results of the conventional 2D manual contour-drawing algorithm.