Differences in left ventricular measurements: Attenuation versus contour based methods

Coronary computed tomography angiography (CCTA) left ventricle (LV) volumes have prognostic value. LV measurements however can differ depending on post-processing software. Two common methods are the contour (CON) or attenuation (ATT) based methods. This study aims to determine differences in LV volume measurements using the 2 methods.LV mid-diastolic volumes (LVMDV) were measured using both ATT and CON from 2 vendors in 750 consecutive patients undergoing CCTA. 500 were measured in a derivation cohort to establish a linear regression equation that would correct for any detected differences between the two methods. The equation was then assessed in 250 cases in the validation cohort. Comparisons were made between intra-vendor LVMDVCON and LVMDVATT as well as inter-vendor LVMDVATT.In the derivation cohort, the correlation between the two methods and vendors were very good (0.98 and 0.97 respectively). LVMDVCON was 20.4 ± 7.4% greater than LVMDVATT. LVMDVATT was 9.2 ± 6.6% greater with one vendor compared to the other. Validation cohort corrected LVMDVATT was not statistically different to measured LVMDVATT (p = 0.45).A systematic difference was found between ATT and CON measuring methods. Using a derived linear regression equation, we were able to correct for differences in measurement techniques. The method of LVMDV measurement requires careful consideration when establishing reference values and extrapolating published study results.