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Trial Lecture – time and place
See Trial Lecture.
Adjudication committee
- First opponent: Assistant professor Alexandra Platon, Hôpitaux Universitaires de Genève, Switzerland
- Second opponent: Senior Consultant Anna Bågenholm, Universitetssykehuset Nord-Norge,
- Third member and chair of the evaluation committee: Associate Professor Peter Piotr Majak, University of Oslo
Chair of the Defence
Professor II Pål Aksel Næss, University of Oslo
Principal Supervisor
Senior Consultant Johann Baptist Dormagen, Oslo University Hospital
Summary
Trauma is a leading health problem in the younger population. Computed tomography (CT) represents an important imaging tool in trauma radiology, but is based on the use of ionizing radiation. Trauma CT should therefore be optimized with respect to radiation dose and image quality, in order to minimize the radiation-induced cancer risk. The aim of this thesis was to evaluate three approaches for radiation dose reduction in thoracoabdominal trauma CT.
Split-bolus CT is a contrast injection method to reduce radiation dose by combining several contrast phases in one CT scan. We evaluated and compared image quality and injury findings of triple-split bolus CT of the abdomen with portal venous phase CT in the same patient group.
We also assessed the value of additional arterial phase CT compared to portal venous phase CT only to identify pelvic trauma patients in need of angiographic intervention.
The third study was a human cadaver study performed to evaluate image quality of thoracoabdominal CT reconstructed with SAFIRE (Sinogram Affirmed Iterative Reconstruction) iterative reconstruction at two different low dose levels compared to standard FBP (Filtered back projection).
We showed that triple-split bolus CT performed equally compared to portal venous phase CT in both image quality and organ injury diagnosis. Additional arterial phase CT in pelvic trauma did not improve patient selection for angiography in our study population. Readers preferred SAFIRE reconstructed images over FBP also at lower doses, and quantitative image quality parameters showed significant improvement in SAFIRE reconstructed images.
To summarize, the utilization of split-bolus technique in abdominal trauma or exclusive reliance on the portal venous phase for imaging in pelvic trauma are valuable approaches to reduce radiation exposure. Image post-processing techniques such as SAFIRE iterative reconstruction present further opportunities to minimize radiation dosage in trauma CT scans.
Additional information
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