Abstract
PurposeMyocardial computed tomography perfusion (CTP) allows the assessment of the functional relevance of coronary artery stenosis. This study investigates to what extent the contour sharpness of sequences acquired by dynamic myocardial CTP is influenced by the following noise reduction methods: temporal averaging and adaptive iterative dose reduction 3D (AIDR 3D).Materials and methodsDynamic myocardial CT perfusion was conducted in 29 patients at a dose level of 9.5±2.0 mSv and was reconstructed with both filtered back projection (FBP) and strong levels of AIDR 3D. Temporal averaging to reduce noise was performed as a post-processing step by combining two, three, four, six and eight original consecutive 3D datasets. We evaluated the contour sharpness at four distinct edges of the left-ventricular myocardium based on two different approaches: the distance between 25% and 75% of the maximal grey value (d) and the slope in the contour (m).ResultsIterative reconstruction reduced contour sharpness: both measures of contour sharpness performed better for FBP than for AIDR 3D (d = 1.7±0.4 mm versus 2.0±0.5 mm, p>0.059 at all edges; m = 255.9±123.9 HU/mm versus 160.6±123.5 HU/mm; p<0.023 for all edges). Increasing levels of temporal averaging degraded contour sharpness. When FBP reconstruction was applied, contour sharpness was best without temporal averaging (d = 1.7±0.4 mm, m = 255.9±123.9 HU/mm) and poorest for the strongest levels of temporal averaging (d = 2.1±0.3 mm, m = 142.2±104.9 HU/mm; comparison between lowest and highest temporal averaging level: for d p>0.052 at all edges and for m p<0.001 at all edges).ConclusionThe use of both temporal averaging and iterative reconstruction degrades objective contour sharpness parameters of dynamic myocardial CTP. Thus, further advances in image processing are needed to optimise contour sharpness of 4D myocardial CTP.
Highlights
When filtered back projection (FBP) reconstruction was applied, contour sharpness was best without temporal averaging (d = 1.7±0.4 mm, m = 255.9±123.9 Hounsfield units (HU)/mm) and poorest for the strongest levels of temporal averaging (d = 2.1±0.3 mm, m = 142.2±104.9 HU/mm; comparison between lowest and highest temporal averaging level: for d p>0.052 at all edges and for m p
While non-invasive computed tomography coronary angiography (CTA) is highly accurate in diagnosing coronary artery stenosis [1, 2] compared with conventional coronary angiography (CCA), it is limited in the assessment of the haemodynamic relevance of coronary stenosis [3]
Myocardial CT perfusion (CTP) is a promising approach to detect myocardial ischaemia as a predictor of the functional relevance of a coronary stenosis diagnosed during computed tomography angiography (CTA) [5, 6]
Summary
While non-invasive computed tomography coronary angiography (CTA) is highly accurate in diagnosing coronary artery stenosis [1, 2] compared with conventional coronary angiography (CCA), it is limited in the assessment of the haemodynamic relevance of coronary stenosis [3]. This is especially relevant in patients with intermediate coronary diameter stenosis of 30–70% [3] or heavily calcified plaques and in patients with coronary stents [4], which might reduce the evaluability of the corresponding coronary segment due to artefacts resulting from the stent strut. Only 4D CTP allows estimation of the absolute myocardial blood flow from the respective input and output function [16]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
