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

Abstract

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.