Seung Choul Lee, Presenter: Nothing to Disclose

Sung Min Ko, Abstract Co-Author: Nothing to Disclose

To determine the feasibility of evaluating planimetered regurgitant orifice area (ROA) of aortic regurgitation (AR) using ECG-gated dual-source CT (DSCT) and to compare ROA by DSCT with the grade of AR by cardiac magnetic resonance (CMR) and transthoracic echocardiography (TTE).

We retrospectively enrolled 183 patients (101 men, 54.2 ± 14.7 years old) with AR who underwent TTE, DSCT, and CMR within 2 weeks. AR is graded as mild, moderate, or severe based on qualitative assessment from Doppler flow mapping on TTE and quantitative assessment of regurgitant fraction (mild< 20%, moderate 20-40%, severe >40%) by CMR. Two blinded observers manually planimetered the ROA by using a computer workstation on mid-diastolic short-axis CT images and measurements were compared with the grade of AR by CMR and TTE. Receiver operating characteristic (ROC) curves were calculated for differentiation between grades of AR with ROA measurements.

The mean patient radiation dose was 7.7 ± 2.5 mSv on DSCT. The interobserver agreement for the planimetered ROA by DSCT was excellent (r = 0.98, p <.0001). There were 112 patients with mild AR, 40 with moderate AR, and 31 with severe AR by TTE. There were 65 patients with mild AR, 68 with moderate AR, and 50 with severe AR by CMR. There was good agreement (κ = 0.62) between CMR and TTE in assessing the grade of AR. Quantification of the ROA by DSCT (mean, 0.25 ± 0.2 cm2) was significantly correlated with the severity of AR by CMR and TTE (r = 0.866 and 0.807 p < .0001, respectively). With ROC analysis, discrimination between degrees of AR with DSCT was highly accurate when cutoff ROAs (0.16 cm2 and 0.30 mm2 in comparison with CMR and 0.19 cm2 and 0.40 mm2 in comparison with TTE) were used.

Measurement of the ROA by DSCT allows quantitative assessment of AR.

DSCT has the potential to provide accurate quantitative assessment of AR by measuring ROA.

Lee, S, Ko, S, Assessment of the Regurgitant Orifice Area in Aortic Valve Regurgitation Using Dual-Source Computed Tomography: Comparison with Cardiac Magnetic Resonance and Transthoracic Echocardiography.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11014136.html