Akihisa Kataoka MD, Presenter: Nothing to Disclose

Nobusada Funabashi MD, PhD, Abstract Co-Author: Nothing to Disclose

Rei Yajima MD, Abstract Co-Author: Nothing to Disclose

Maiko Takahashi MD, Abstract Co-Author: Nothing to Disclose

Akiyo Takahashi PhD, Abstract Co-Author: Nothing to Disclose

Issei Komuro MD, Abstract Co-Author: Nothing to Disclose

Masae Uehara MD, Abstract Co-Author: Nothing to Disclose

Hiroyuki Takaoka MD, Abstract Co-Author: Nothing to Disclose

00030490-DMT et al, Abstract Co-Author: Nothing to Disclose

Accurate measurement of left atrial (LA) volume and LA emptying fraction (LAEF) are clinically important because they may be related to atrial fibrillation. To evaluate efficacy and reproducibility of 320 slice computed tomography (CT) for measuring LA maximum volume (LAVmax) and minimum volume (LAVmin) during the cardiac cycle, we compared CT with thee dimensional (3D) transthoracic echocardiogram (TTE).

LAVmax and LAVmin (ml), and LAEF (%) were assessed in 26 consecutive patients (18 male, 59.3±14.9 yrs, with 23 normal sinus rhythm and three chronic atrial fibrillation) using enhanced retrospective ECG-gated 320 slice CT (Aquilion One) and 3D TTE (IE-33) with a 3D analysis. CT images was reconstructed every 5% from 0-95% of the R-R interval and a semi automated 3D segmentation technique (ADW 4.5) was applied. LAVmax and LAVmin were selected from the time volume curve. LAEF was calculated as LAVmax/LAVmin x100. Each measurement was performed by two experienced observers.

Mean±SD of LAVmax was 96.1±43.5ml by CT and 51.0±19.6ml by TTE. The correlation coefficient (CC) between CT and TTE in LAVmax was 0.640. Mean difference±1.96SD of LAVmax by the Bland and Altman analysis calculated from CT minus TTE was 45.1±67.4ml. Mean±SD of LAVmin was 75.7±42.3ml by CT and 35.6±16.9ml by TTE. The CC between CT and TTE in LAVmin was 0.693. Mean difference±1.96SD of LAVmin calculated from CT minus TTE was 40.1±64.5ml. Mean±SD of LAEF was 24.6±11.8% by CT and 31.9±8.6% by TTE. The CC between CT and TTE in LAEF was 0.470. Mean difference±1.96SD of LAEF calculated from CT minus TTE was -7.4±21.2ml. CCs of interobserver variation between analyzer 1 and 2 were 0.91 in CT and 0.94 in TTE (LAVmax), 0.97 in CT and 0.96 in TTE (LAVmin), and 0.62 in CT and 0.77 in TTE (LAEF).

Interobserver reproducibility of 3D CT was equal to or slightly less than with 3D TTE. In a Bland and Analysis (Figure), the larger the LA size, the larger the difference between CT and TTE. This may be complex LA morphological enlargement, and 3D TTE may not allow visualization of the whole LA.

Assessment of LA volumes by 3D CT was as reproducible as by 3D TTE, but absolute values by 3D CT were larger than by 3D TTE, especially in larger LA size.

Kataoka, A, Funabashi, N, Yajima, R, Takahashi, M, Takahashi, A, Komuro, I, Uehara, M, Takaoka, H, et al, 0, Quantitative Evaluation of Left Atrial Volume and Its Emptying Fraction by 320 Slice Computed Tomography Compared with Three-dimensional Echocardiogram.  Radiological Society of North America 2009 Scientific Assembly and Annual Meeting, November 29 - December 4, 2009 ,Chicago IL. http://archive.rsna.org/2009/8010805.html