Traditional, forgotten and new left ventricular systolic function parameters on a 64-row multidetector cardiac computed tomography: a reproducibility study.

BACKGROUND

Multidetector computed tomography angiography (MDCT) can provide data regarding cardiac function if a retrospective scanning is applied. We aimed at examination of the reproducibility of traditional and more sensitive parameters of the left ventricular (LV) contractility by means of a 64-row CT in order to establish errors of measurement and to determine limits that allow for a reliable detection of their changes.

METHODS AND RESULTS

A random sample of 25 individuals, including 15 females (aged 64 ± 13 years) and 10 males (54 ± 13 years), who had MDCT examination were retrospectively included in this study. Data reconstructions were performed on a dedicated workstation. In each case, axial image series were created with a 10% step from 0% to 90% of the RR interval using a 2 mm slice thickness. LV volume was determined in each phase. Detailed LV volume changes within phases were analyzed to determine the largest difference between the neighbor phases (peak ejection volume, PEV, mL) during systole and to calculate the peak ejection rate (PER i.e. PEV/phase duration [1/10th of RR interval], mL/s). The derived parameters were calculated as the PER normalized for LVEDV (PER-V, 1/s), the PER normalized for LVM (PER-M, mL/g × s) and the PER normalized for LVEDV times the PER normalized for LVM product (PER-VM, ml/g × s2). Considering the errors percentages, the respective values for intra- and inter-observer errors were around 5% and 8% for standard LV systolic measures. The percentage intra-observer errors' ranged between -7.8% and -10.8%, and the inter-observer errors' ranged between -11.8% and -15.7% for both PEV and PER. For the same reader, the percentage errors ranged between -8.7% and +11.9% for PER-V, -10% and +12.7% for PER-M and -18.2% and +24% for PER-VM. For the independent reader the corresponding values were -15.2% and +15.5%, -12.3% and +16.3%, and -26.6% and +30.9%. The intra- -class coeffi cients for repeated measurements for both the same reader (intra-observer) or independent reader (inter-observer) did reach values above 0.9 and around 0.8, respectively.

CONCLUSIONS

We concluded that traditional LV systolic parameters, as well as more sensitive measures of cardiac contractility could be determined reliably by means of a 64-row MDCT. The errors for global LV systolic function measures amount to about 5%, for PEV and PER about 15% and for the PER-derived parameters about 25%. The measurement errors established might help to assess the signifi cance of changes in repeated MDCT examinations.