Digital Public Defence: L. Kathrine Rydén Suther

MD L. Kathrine Rydén Suther at Institute of Clinical Medicine will be defending the thesis "Imaging assessment with 3.0T MRI after arterial switch operation for transposition of the great arteries" for the degree of PhD (Philosophiae Doctor).

The public defence will be held as a video conference over Zoom.

The defence will follow regular procedure as far as possible, hence it will be open to the public and the audience can ask ex auditorio questions when invited to do so.

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Due to copyright reasons, an electronic copy of the thesis must be ordered from the faculty. In order for the faculty to have time to process the order, it must be received by the faculty no later than 2 days prior to the public defence. Orders received later than 2 days before the defence will not be processed. Inquiries regarding the thesis after the public defence must be addressed to the candidate.

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Adjudication committee

  • First opponent: Associate Professor Åse Allansdotter Johnsson, University of Gothenburg, Sweden
  • Second opponent: Consultant Øystein Olsen, Great Ormond Street Hospital, London, United Kingdom
  • Third member and chair of the evaluation committee: Professor II Tom Stiris, Institute of Clinical Medicine, University of Oslo

Chair of defence

Professor II Henrik Holmstrøm, Institute of Clinical Medicine, University of Oslo

Principal Supervisor

Charlotte de Lange, Oslo University Hospital


Arterial switch operation (ASO) is the procedure of choice for surgical correction of transposition of the great arteries (TGA). The positions of the great arteries are switched and the coronary arteries are re-implanted in the neo-aorta. Postoperative patency of the coronary arteries is of concern, and a non-invasive, non-irradiating method for follow-up of cardiac function and coronary arteries is desirable in this patient group.

The aim of this thesis was to assess coronary artery patency in children/adolescents with TGA corrected with ASO directly and indirectly by using 3.0T cardiac MRI.
Patency of the coronary artery origins was assessed using a non-contrast enhanced coronary MR angiography (CMRA), and the image quality was evaluated with three different methods: fixed point scale (FPS), visual analogue scale (VAS) and figurative VAS (fVAS), finding the latter to have improved intra- and interobserver agreement.
fVAS was then used for comparison of image quality in non-contrast and contrast enhanced CMRA at the coronary artery origins finding contrast enhanced CMRA to provide sufficient-to-good image quality in the coronary artery ostia.

Ventricular function, myocardial viability and T1 mapping were used for indirect evaluation of coronary artery patency, and the findings were related to the coronary artery patency assessed with contrast enhanced CMRA. ASO TGA patients were found to have normal ventricular function, no signs of focal myocardial scarring nor gross pathology in the coronary artery origins. Still, we found increased myocardial extracellular volume fraction in the expected coronary arteries’ distribution territories in the left ventricle in ASO TGA patients compared to young, healthy adults, and this might indicate the presence of diffuse myocardial fibrosis. 

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Published Aug. 13, 2021 12:12 PM - Last modified Aug. 26, 2021 1:54 PM