M ultidetector computed tomography (MDCT) is a versatileimaging technique, which, in a single scan, permits the evaluation of coronary anatomy, as well as ventricular function (1) as an accessory finding. A thorough evaluation, however, is rather timeconsuming, because each study involves a huge number of images at different cardiac phases, and processing the images just to calculate left ventricular (LV) ejection fraction (EF) can require up to 20 min by a dedicated technician or physician (2). A simpler method, the long-axis area-length (AL) method, which is regularly used to calculate LV volumes and EF by echocardiography, invasive LV angiography and magnetic resonance imaging (3) has, to the best of our knowledge, yet to be validated for MDCT. We aimed to compare the accuracy of LV volumes and EF calculated by the AL method with the more exact and previously validated Simpson's method (2,4) in a group of patients with a high prevalence of regional LV dysfunction. We also compared these results with right anterior oblique LV angiography, which is a routine clinical standard used for the estimation of EF. In addition, we aimed to compare single-plane with biplane results and assess interuser variability when the method is performed by users of varying experience. We hypothesized that the biplane long-axis AL method gives clinically valid results relative to the gold standard, the Simpson's method.
CLINICAL STUDIES©2008 Pulsus Group Inc. All rights reserved J Lessick, E Ghersin , S Abadi, S Yalonetsky. Accuracy of the longaxis area-length method for the measurement of left ventricular volumes and ejection fraction using multidetector computed tomography. Can J Cardiol 2008;24(9):685-689.BACKGROUND: Multidetector computed tomography (MDCT) is useful for assessing left ventricular (LV) volumes and function. Validation has mainly been carried out using Simpson's method of summing up consecutive short-axis areas. Because the latter method is time-consuming, many users prefer using a quicker method, based on a single view or a pair of views. OBJECTIVES: To evaluate the accuracy of the long-axis area-length method (AL), which has not been validated for MDCT, using Simpson's method as the gold standard, as well as right anterior oblique LV angiography as a clinical standard. METHODS: Twenty-three patients admitted with acute chest pain were clinically evaluated with electrocardiogram-gated MDCT and invasive LV angiography. MDCT-based end-diastolic, end-systolic and stroke volumes, and ejection fraction (EF) were calculated using Simpson's method, biplane AL and single-plane AL. For LV angiography, EF was calculated using single-plane AL. RESULTS: A Bland-Altman analysis showed a close agreement between biplane AL and Simpson's method for EF, with 1% underestimation, 95% CI of ±11% and a correlation of 0.89. For end-diastolic, end-systolic and stroke volumes, overestimations of 7 mL, 4 mL and 2 mL, and 95% CI of ±27 mL, ±15 mL and ±26 mL, respectively were found. Correlation coefficients were 0.95, 0.97 and 0.82, respe...