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ECR 2013 / C-0677
Aortic valve evaluation by 128-DSCT prior to TAVI: Optimal time interval for AVA sizing in comparison with echocardiography
Congress: ECR 2013
Poster No.: C-0677
Type: Scientific Exhibit
Keywords: Echocardiography, CT-Angiography, CT, Interventional vascular, Cardiovascular system, Cardiac, Comparative studies, Haemodynamics / Flow dynamics
Authors: M. Kummann1, F. Plank2, G. J. Friedrich2, T. Bartel2, S. Mueller2, L. Kofler2, N. Bonaros3, W. Jaschke2, G. Feuchtner2; 1Innsbruck, [p/AT, 2Innsbruck/AT, 3Innsbuck/AT
DOI:10.1594/ecr2013/C-0677

Methods and Materials

Study population

44 patients (age 82.5 range: 69-92; 50% females) with severe aortic valve stenosis were examined with contrast enhanced ECG-gated 128-slice dual source CT (gantry rot. 0.28s) prior to transcatheter aortic valve implantation (TAVI) for procedure planning.

 

CT examination 

Image acquisition was performed using 128-slice dual source CT (SomatomDefinitionTM Flash, Siemens Healthcare, Forchheim, Germany) 

For contrast enhancement 70 to 110ml of iopromide (Ultravist 370™, Bayer Schering Pharma, Berlin, Germany) were injected via a cubital vein using an automatic injector at a flow rate between 4,5ml/sec and 5,5ml/sec followed by a saline chaser (40 ml).

The CT scan was triggered into the ascending aorta using a ‘bolus tracking technique’, after a CT-attenuation of 100 Hounsfield Units [HU]. Scan delay was 10 seconds after the threshold was reached.

The ECG was recorded simultaneously during scan and retrospective ECG-gating was performed. Images were reconstructed in 5% intervals over the cardiac cycle (5-45%) at 0.75mm width, increment 0.5 and a medium smooth convolution kernel [B 26 f].

 

Echographic examinations

TTE measurements were performed by experienced Cardiologists (Department of Internal medicine III: Cardiology; University hospital Innsbruck) using a standard ultrasound system (Acuson Sequoia 256, Acuson-Siemens Medical Systems, Malvern, Pennsylvania) equipped with a 3.5/1.75-MHz transducer. Especially Doppler flow rates from the left ventricular outflow tract (LVOT), peak transvalvular velocity and AV-gradients were measured. AVA was calculated using continuity equation approach.

 

CT image analysis

CT-Datasets were analyzed retrospectively using a syngo.via workstation (Siemens healthcare, Forchheim, Germany). Image quality was scored in a 4-point scale (1= excellent, no artifacts; 2=good, minor artifacts such as motion blurring, double contouring, stair-steps; 3= moderate, moderate artifacts still being diagnostic 4= poor/non-diagnostic) for each phase.  AVA was measured during all phases from a multiplanar reformation (MPR) in the cross-sectional aortic valve plane.

 

Statistical analysis

The maximal AVA (AVAmax) and minimal AVA (AVAmin) of all systolic phases were selected.

The mean (AVAmean) was calculated from all phases over 10-35%.

AVA by CT was compared to values from transthoracic echocardiography (TTE) calculated by Doppler continuity equation (VTI- integral).

The AVAbestcorrel was defined.


Statistical data analysis was performed using PASW statistics V 18 [SPSS Inc, Chicago, USA]. The correlations between AVA measured by CT and TTE were determined using linear regression analysis and the Pearson’s correlation coefficient. A two-tailed probability value of less than 0.05 was considered statistically significant.

 

 

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