Related Experiment Video
Updated: Apr 14, 2026
Author Spotlight: Advancing Cardiovascular Imaging - Introducing the Spatially Weighted Calcium Score for Early Disease Detection
Published on: September 22, 2023
CT attenuation values of blood and myocardium: rationale for accurate coronary artery calcifications detection with
Salah D Qanadli1, Anne-Marie Jouannic2, Jamshid Dehmeshki3
1Department of Radiology, University Hospital of Lausanne, Rue du Bugnon 46, 1011 Lausanne, Switzerland; Quantitative Medical Imaging International Institute, Digital Imaging Research center, Faculty of Computing, Information Systems and Mathematics, University of Kingston, London, United Kingdom.
Insights
Variations in CT attenuation of aortic blood and myocardium exist, but historical calcium scoring thresholds provide high confidence for detecting calcifications. An adaptive threshold may improve accuracy considering patient characteristics.
Area of Science:
- Radiology
- Medical Imaging
- Cardiovascular Imaging
Background:
- Calcium scoring using multi-detector computed tomography (MDCT) relies on attenuation values of blood and myocardium.
- Variations in these attenuation values can affect the accuracy of calcification detection.
Purpose of the Study:
- To quantify inter-session and intra/inter-individual variations in aortic blood and left ventricular myocardium attenuation using MDCT.
- To assess the influence of patient characteristics on these variations.
- To evaluate the reliability of current fixed thresholds for calcium scoring.
Main Methods:
- Fifty-four volunteers underwent non-enhanced CT for calcium scoring.
- Attenuation and standard deviation (SD) of aortic blood and myocardium were measured.
- Inter-session variability was assessed by repeat scans.
- Correlations were made with fat pad thickness and image noise.
- Fixed thresholds (90 and 130 HU) were tested.
Main Results:
- Mean blood attenuation was 46 HU (SD 23 HU), and mean myocardium attenuation was 39 HU (SD 18 HU).
- Blood attenuation and SD were significantly higher than myocardium (p < 0.01).
- Inter-session variation was not significant.
- No strong correlation was found between attenuation variability and fat thickness or noise.
- Fixed thresholds of 90 HU and 130 HU offer high confidence intervals (>95% and >99%, respectively).
Conclusions:
- Historical fixed thresholds for calcium scoring demonstrate high confidence intervals for excluding aortic blood/myocardium and detecting calcifications.
- Significant variations in CT attenuation values exist, influenced by patient characteristics.
- An adaptive threshold approach may offer improved accuracy for calcium scoring.
Objectives:
To determine inter-session and intra/inter-individual variations of the attenuations of aortic blood/myocardium with MDCT in the context of calcium scoring. To evaluate whether these variations are dependent on patients' characteristics.
Methods:
Fifty-four volunteers were evaluated with calcium scoring non-enhanced CT. We measured attenuations (inter-individual variation) and standard deviations (SD, intra-individual variation) of the blood in the ascending aorta and of the myocardium of left ventricle. Every volunteer was examined twice to study the inter-session variation. The fat pad thickness at the sternum and noise (SD of air) were measured too. These values were correlated with the measured aortic/ventricular attenuations and their SDs (Pearson). Historically fixed thresholds (90 and 130 HU) were tested against different models based on attenuations of blood/ventricle.
Results:
The mean attenuation was 46 HU (range, 17-84 HU) with mean SD 23 HU for the blood, and 39 HU (10-82 HU) with mean SD 18 HU for the myocardium. The attenuation/SD of the blood were significantly higher than those of the myocardium (p < 0.01). The inter-session variation was not significant. There was a poor correlation between SD of aortic blood/ventricle with fat thickness/noise. Based on existing models, 90 HU threshold offers a confidence interval of approximately 95% and 130 HU more than 99%.
Conclusions:
Historical thresholds offer high confidence intervals for exclusion of aortic blood/myocardium and by the way for detecting calcifications. Nevertheless, considering the large variations of blood/myocardium CT values and the influence of patient's characteristics, a better approach might be an adaptive threshold.
More Related Videos
04:40Identifying Coronary Artery Calcification on Non-gated Computed Tomography Scans
Published on: August 28, 2018
08:02Author Spotlight: Enhanced Quantification of Cardiovascular Calcification Progression for Longitudinal Micro PET/CT Studies in Small Research Animals
Published on: November 15, 2024
Related Concept Videos
01:25Imaging Studies for Cardiovascular System VI: Calcium -Scoring CT
01:28Imaging Studies for Cardiovascular System V: CT
01:20Imaging Studies for Cardiovascular System III: X-Ray
Definition and Purpose
An X-ray, or radiograph, is a non-invasive method that uses ionizing radiation to take images of internal structures. It is mainly used in cardiac imaging to examine the heart, lungs, and major blood vessels, aiming to identify abnormalities in the heart's size, shape, and position, such as heart failure, congenital defects, and vascular...