Aims and objectives
Coronary computed tomography angiography (CCTA) allows noninvasive characterization of coronary atherosclerotic plaque,
however reliable plaque visualization with CT is dependent on image quality (IQ),
noise and contrast attenuation.Most CT imaging studies have been reconstructedby using the standard filtered back projection reconstruction(FBR) technique.Hybrid iterative resonstruction (HIR) algorithms have been shown to improve IQ over standard FBP.Recently model based iterative reconstruction (IMR) have been introduced for clinical usage.
We sought to assess the image quality of IMR for visualization of the coronary arteries as compared to FBR...
Methods and materials
52 consecutive patients (mean age 64.7±9.3 years,
BMI 28.2±5.6 kg/m2) underwent CCTA at our institution with 256-slice CT (Philips iCT,
128mmx0.625 mm collimation,
prospective ECG-gating,
120 kV tube voltage,
300 mAs tube current).
All CT images were reconstructed with FBR,
HIR and IMR techniques.
To ensure excellent image quality we have included patients only with heart rate ≤60 bpm during scan.
Qualitative and quantitative IQ parameters were evaluated in the ascending aorta,
proximal and distal coronary segments on axial slices.
Example images are shown in...
Results
The qualitative analysis showed that IMR improves image quality and image sharpness as compared toFBR and HIR (p<0.0001 all).
Image noise was significantly lower with HIR as compared to FBR and was furtherreduced with IMR as compared to HIR (p<0.0001 all).
By quantitative analysis mean attenuation in the aorta did not differ among all three reconstruction techniques (507.9±87.5 vs.
508.1±87.6 vs.
507.1±87.6 HU with FBR,
HIR and IMR techniques,
respectively; p=1.0).Image noise (SD) was highest using FBR and lowest using IMR (42.1±10.7 vs.
28.7±7.3 vs...
Conclusion
IMR leads to significantly improved image quality accompanied with a substantial increase in CNRand decrease in image noise at CCTA.
References
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