Feasibility of aortic valve assessment with low dose prospectively triggered adaptive systolic (PTAS) cardiac computed tomography angiography

Ashley M Lee,Jonathan Beaudoin,Udo Hoffmann,Manavjot S Sidhu,Suhny Abbara,Brian B Ghoshhajra,Leif-Christopher Engel,Bryan Wai,Wai-Ee Thai,Gladwin C Hui

doi:10.1186/1756-0500-6-158

Ashley M Lee, Jonathan Beaudoin + Show 8 more

Open Access

https://doi.org/10.1186/1756-0500-6-158

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Abstract

BackgroundCardiac computed tomography angiography (CTA) is feasible for aortic valve evaluation, but retrospective gated protocols required high radiation doses for aortic valve assessment. A prospectively triggered adaptive systolic (PTAS) cardiac CT protocol was recently described in arrhythmia using second-generation dual-source CT. In this study, we sought to evaluate the feasibility of PTAS CTA to assess the aortic valve at a low radiation dose.FindingsA retrospective cohort of 29 consecutive patients whom underwent PTAS protocols for clinical indications other than aortic valve assessment and whom also received echocardiography within 2 months of CT, was identified. Images were reviewed for aortic valve morphology (tricuspid/bicuspid/prosthetic) and stenosis (AS) by experienced blinded readers. Accuracy versus echocardiography and radiation doses were assessed.All PTAS coronary CTAs were clinically diagnostic with 0 un-evaluable coronary segments. The accuracy of PTAS for aortic valve morphology was 92.6%, and for exclusion of severe AS was 93.1%. Two exams were un-evaluable for the aortic valve due to inadequate number of phases archived for interpretation. Total radiation dose was a median of 2.8 mSv (interquartile range 1.4–4.4 mSv).ConclusionsPTAS CTA protocols using second-generation dual-source CT for aortic valve evaluation are feasible at low doses. This protocol should be investigated further in larger cohorts.

Highlights

The feasibility of cardiac computed tomography angiography (CTA) for aortic valvular evaluation has been established for aortic stenosis (AS) evaluation in small referral cohorts [1,2,3,4,5,6,7,8,9], and has performed well versus transthoracic echocardiography
prospectively triggered adaptive systolic (PTAS) CTA protocols using second-generation dual-source CT for aortic valve evaluation are feasible at low doses
Prospectively ECG-triggered cardiac CT angiography targeted to end-systole for the evaluation of aortic pathology was feasible at a low radiation dose (2.8 mSv) with 128 dual-source CT

Summary

Introduction

The feasibility of cardiac computed tomography angiography (CTA) for aortic valvular evaluation has been established for aortic stenosis (AS) evaluation (via direct planimetry) in small referral cohorts [1,2,3,4,5,6,7,8,9], and has performed well versus transthoracic echocardiography. All initially published studies were performed using retrospective ECG gating to allow systolic phase evaluation of aortic valve opening [10,11]. CT scanners, which allowed a “systolic absolute delay” to specify an acquisition in systole after the R-peak, and a fixed range of data acquisition to enable various reconstruction intervals to achieve motion-free images. This method limits imaging to mid and late systole, phases shown to be ideal for aortic valve area opening measurements [19]. Cardiac computed tomography angiography (CTA) is feasible for aortic valve evaluation, but retrospective gated protocols required high radiation doses for aortic valve assessment. We sought to evaluate the feasibility of PTAS CTA to assess the aortic valve at a low radiation dose

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