Unit:
Κατεύθυνση Ιατρική Φυσική-ΑκτινοφυσικήLibrary of the School of Health Sciences
Author:
Androulakis Ioannis
Supervisors info:
Περισυνάκης Κωνσταντίνος, Αναπληρωτής Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Κρήτης
Δαμηλάκης Ιωάννης, Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Κρήτης
Μαζωνάκης Μιχάλης, Επίκουρος Καθηγητής, Τμήμα Ιατρικής, Πανεπιστήμιο Κρήτης
Original Title:
The effect of heart rate on CAC Scoring
Translated title:
The effect of heart rate on CAC Scoring
Summary:
Objective: The purpose of this study was to investigate the effect of heart rate on the coronary artery calcium (CAC) score estimate provided by a modern 64-slice multi-slice CT system.
Methods and Materials: Cylindrical calcified lesion phantoms of varying size and calcium concentration were constructed to mimic atheromatic plaques occurring in atheromatous patients. These artificial athermomatic lesions were introduced into a dynamic anthropomorphic cardiac phantom which has the ability to produce three dimensional recurrent movement with heart rate defined by the user. The motion of coronary arteries, and consequently the atheromatic plaque(s) developed in the arteries, was thus simulated. The cardiac phantom loaded with the atheromatic lesions was subjected to the standard 120 kVp cardiac CT examination protocol and image series were acquired for different heart rates in the range 40-100 bpm. The Agatston score (AS), the calcium mass score (CMS), the calcium volume (CVS) and calcium density score (CDS) were estimated for each image dataset using a dedicated processing software package.
Results: The AS and the CMS were found to considerably decline with increasing heart rate. The coefficient of the linear function of CAC score against heart rate was found to be -0.2±0.1% and -0.4± 0.0% per 1 bpm for AS and CMS, respectively. CVS and CDS were found to irregularly be affected by heart rate. The size of lesions was found to be associated with the level of decline in calcium scores with increasing heart rate. The decline of CMS with increasing heart rate was found to be steeper for smaller size lesions and for lower calcium concentrations.
Conclusion: The AS, CMS, CVS and CDS are dependent on heart rate. Scores tend to decline for higher heart rates. The size as well as the calcium concentration of atheromatic lesion affect the decline of calcium scores with increasing heart rate.
Main subject category:
Health Sciences
Keywords:
Computed Tomography, Heart Rate, Medical Physics, Coronary Arteries, Heart, Phantom
