On the assessment of right ventricular function
using cardiac magnetic resonance imaging andechocardiography av
Stina Jorstig
Akademisk avhandling
Avhandling för medicine doktorsexamen i medicinsk vetenskap med inriktning mot kirurgi,
som kommer att försvaras offentligt fredagen den 18 november 2016 kl. 09.00, Hörsal C3, Campus, Universitetssjukhuset Örebro
Opponent: Docent Einar Heiberg Lunds universitet
Lund
Örebro universitet
Institutionen för medicinska vetenskaper 701 82 ÖREBRO
Abstract
Stina Jorstig (2016): On the assessment of right ventricular function using cardiac magnetic resonance imaging and echocardiography. Örebro Studies in Medicine 152.
Transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging are two commonly used imaging modalities for evaluat-ing the size and function of the heart. There are advantages and disad-vantages associated with both modalities when examining the right ven-tricle (RV).
The RV is positioned partly behind the sternum and lung, sometimes causing shadows in the TTE images. This along with the complex shape of the RV makes volume calculations challenging by 2D TTE. CMR is considered to be the reference method for volume calculations of the ventricles. The valve separating the RV from the right atrium is however often oblique compared to the valve separating the left ventricle from the left atrium. This complicates RV volume calculations using conventional CMR short-axis stack images. The aim of this thesis was to find ways to improve the RV stroke volume and ejection fraction calculations using TTE and CMR.
A method, transferring the position of the tricuspid plane from RV long-axis images to short-axis images, was developed to improve the separation of the right atrium from the RV when calculating RV stroke volumes by CMR. The method provided calculations of RV stroke vol-umes with good agreement to reference volvol-umes. Further, the movements contributing to the RV stroke volume was studied aiming to find new ways of calculating RV stroke volumes and ejection fraction by TTE. A model for RV stroke volume and ejection fraction calculations was eval-uated showing underestimation of stroke volumes by TTE compared to CMR, which probably depend on differences in distance measurements using the two modalities. The model provided, however, promising re-sults for ejection fraction calculations which was validated in a study of 37 participants that covered a wide range of EF.
Keywords: right ventricle, stroke volume, ejection fraction, cardiac
magnetic resonance, ehocardiography. Stina Jorstig, School of Medical Sciences
