| [Objective]To evaluate diagnostic accuracy of dual source computed tomography (DSCT) for evaluation of Left ventricular (LV) function quantification in Aortic valve replacement,with magnetic resonance imaging (MRI) as the reference standard.[Materials and Methods]We evaluated a total of 21 patients (9 men,12 women;mean age 56.7 years) who underwent both DSCT and MRI.Patients with aortic valve disease who were scheduled to undergo Aortic valve replacement (AVR)All cardiac CT angiographies were performed on DSCT (Somatom Definition, Siemens Medical Solutions, Germany).Retrospective ECG-triggered images were obtained,from the carina to the apex,during one breath-hold.The following scan protocol was used:0.6mm collimation(cardiac mode); tube voltage 120kV; effective mA320-400. The gantry rotation time was 0.33s and the pitch ranged from 0.2 to 0.46,adapted automatically to the heart rate.Coronary enhancement was achieved by intravenous injection of 80ml of nonionic contrast agent (Omnipaque 350mgI/ml, rate of 4.0-5.0mL/sec)followed by a saline bolus flush.Bolus timing was performed automatically with a region of interest set in the descending aorta with a threshold of 100 Hounsfield units. Data sets were transferred to an off-line workstation(Leonardo,Siemens Medical Solution,Gennany).From DSCT data-sets,10 axial image series were reconstructed every 10% of the R-R interval using a slice thickness of 8 mm Multiplanar images were reformatted in the short axis orientation from axial images.All MR studies were performed on a 3.0 Tesla whole-body MR scanner(Intera;Philips Medical Systems)using a 6 channel body-coil. After single-shot localizer images,a retrospective gated cine, breath-hold Turbo field echo (TFE)two-dimensional cine short axis images were obtained with the following parameters:FOV284X350mm, TR3.8ms,TE 1.9ms,flip angle 60,matrix 256X200.Slice thickness was 8mm.TFE cine was implemented to acquire short-axis cine-loops, covering the entire left ventricular cavity from base to apex.No contrast agents were administered.Left ventricular ejection fraction, end-diastolic volume, endsystolic volume, stroke volume were manually assessed for each patient by two blinded readers. Linear correlation and paired-samples t-test was used to analyze the data and was considered significant when p<0.05.Their agreement was measured using the intraclass correlation coefficient(ICC).[Results]There was no significant difference among the measurements for DSCT and MRI of the ventricular function parameters.A strong correlation between DSCT and MRI(r=0.85～0.94)was found for all parameters. However,EDV, ESV,SVand EF were overestimated with DSCT.ICC in MRI (EDV,ESV,SV,EF) was 0.8-1, in DSCT (EDV,ESV,SV,EF) was 0.6-0.75, respectively.[Conclusions]A strong correlation between DSCT and MRI is found for all parameters ECG-gated DSCT angiography can evaluate the coronary tree,whereas the analysis of left ventricular parameters provides additional information of cardiac function without further radiation exposure or scan time. |
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